Bacteria - cvm.ncsu.edu · Yes, R-factor is an old but sometimes still used term that implies a plasmid that contains an antibiotic resistance determinan\൴ \⠀最攀渀攀尩

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Bacteria

Bacteria of Ophthalmic ImportanceDiane Hendrix, DVM, DACVOProfessor of Ophthalmology

BacteriaProkaryotic organisms

– cell membrane

– cytoplasm

– RNA

– DNA

– often a cell wall

– +/- specialized surface structures such as capsules or pili.

– lack a nuclear membrane or mitotic apparatus, but the DNA is organized into a single circular chromosome

www.norcalblogs.com/.../GeneralBacteria.jpg

Bacteria+/- smaller molecules of DNA termed plasmids that carry information for drug resistance or code for toxins that can affect host cellular functions

www.fairscience.org

Presenter

Presentation Notes

Yes, R-factor is an old but sometimes still used term that implies a plasmid that contains an antibiotic resistance determinant (gene).

Variable physical characteristics Mycoplasma lacks a rigid cell wall Borrelia and Leptospira have flexible thin walls. Pili are short, hair-like extensions at the cell

membrane that mediate adhesion to specific surfaces.

http://www.stopcattlepinkeye.com/about-cattle-pinkeye.asp

Presenter

Presentation Notes

Fimbriae or pili aid in initial colonization �of the host, but they may also increase susceptibility of bacteria to phagocytosis.

Bacteria reproductionAsexual binary fissionThe bacterial growth cycle includes: the lag phase the logarithmic growth phase the stationery growth phase the decline phase

Iron is essential for bacteria

Presenter

Presentation Notes

in a rate limiting closed environment or culture The availability of iron affects bacterial growth and can influence the nature of a bacterial infection. The fact that the eye is iron-deficient may aid in its resistance to bacteria.

Opportunistic bacteria Staphylococcus epidermidisBacillus sp. Corynebacterium sp. Escherichia coliKlebsiella sp. Enterobacter sp. Serratia sp. Pseudomonas sp.

(other than P aeruginosa).

Bacteria

Presenter

Presentation Notes

Bacteria that are considered to be nonpathogenic or weakly pathogenic can cause infection in compromised hosts or present as co-infections.

Infectivity Adhesins are protein determinates of

adherence. Some are expressed in bacterial pili. Virulent factors increase the capacity of an

organism to cause tissue inflammation and destruction. (Proteses, elastases, hemolysins, cytoxins)

Secretomes and lipopolysaccharide core biosynthetic genes inhibit corneal epithelial cell migration

Pseudomonas aeruginosa and Moraxella bovis

Presenter

Presentation Notes

The infectivity of microorganisms is influenced by their ability to initiate the infectious process. Bacterial adhesion to epithelial cells is a critical initial step. Adhesins, which are protein determinates of adherence, have been identified for most bacterial pathogens.

Presenter

Presentation Notes

Primary bacterial conjunctivitis is more common in cats than other species, whereas in dogs bacterial conjunctivitis is most often secondary to keratoconjunctivitis sicca. Systemic diseases such as pyometra, prostatic abscesses and periodontal disease may result in chorioretinitis, which is probably often unnoticed. Other systemic diseases such as rickettsial diseases frequently cause ophthalmic signs in dogs.

Normal bacterial and fungal floraBacteria can be cultured from 50 to 90% of normal dogs.

Gram + aerobes are most common. Gram - bacteria have been recovered from

8% of normal dogs. Anaerobes are rarely isolated.

Normal flora varies with the season and the breed of dog. Fungi have been isolated from 22% of dogs in one study.

Bacteria

Presenter

Presentation Notes

Staphylococcus spp.,Bacillus spp.,Corynebacterium spp. and Streptococcus spp. Predominating.. While fungi are rare, the most commonly cultured are Cladosporium oxysporum and Curvularia lunata. One must keep in mind that one can only find what is looked for. Anaerobes will only be isolated under the correct conditions, for example. As well, organisms isolated by culture may represent transient environmental contaminants rather than true resident flora.

Conjunctival flora in dogs with ulcerative keratitis. Bacteria are more commonly isolated. Malassezia pachydermatitis is present in 23% of

eyes with corneal ulceration

Bacteria

Presenter

Presentation Notes

. Malassezia pachydermatitis, a lipophilic yeast that is most commonly associated with otitis and dermatitis, was found to be present in 23% of eyes with corneal ulceration and only 3% of healthy eyes. The increased number of bacteria and yeast could be due to decreased ocular defenses, increased phospholipids secondary to inflammation, or due to decreased concentration of tear lysozyme from increased tear production secondary to ulceration.

Equine flora

Normal bacterial floraCorynebacterium spp., beta-hemolytic Streptococcus, Staphylococcus spp., Klebsiellaspp., Bacillus cereus and Moraxella spp.

Fungal floraUnidentifiable molds, dematiaceous molds, Chrysosporuim spp., Cladosporium spp., Aspergillus spp. and Penicillium spp.

Presenter

Presentation Notes

Donkeys are similar

Bovine flora

Cladosporiumspp. and Penicillium spp.

No seasonal or housing difference.

May represent transient seeding from the environment, including the hay, as suspected in other species.

Normal flora Bats Alpacas Chelonians

Staphylococcus spp.

Ubiquitous and are part of the microflora of the skin and mucous membranes.

Gram + organisms that appear cytologically as individuals, pairs, small groups or grapelike clusters.

Facultative anaerobes and fermentative.

Isolates commonly recovered from ocular sources are coagulase-positive species.

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Staphylococcus spp.

Infectious Keratitis S aureus is isolated from about 5% of horses S intermedius is isolated from 2% of horses and

29% of dogs Coagulase-negative species include

S epidermidis (isolated from 6% of affected horses).

Canine isolates are sensitive to cefazolin, ciprofloxacin, and chloramphenicol.

Of 4 equine isolates all were sensitive to bacitracin, chloramphenicol, neomycin, and enrofloxacin.

Resistance

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ia.orgStaphylococcus spp.

http://upload.wikimedia.org/wikipedia/commons/6/68/Staphylococcus_aureus,_50,000x,_USDA,_ARS,_EMU.jpg

http://upload.wikimedia.org/wikipedia/commons/6/68/Staphylococcus_aureus,_50,000x,_USDA,_ARS,_EMU.jpg

Ubiquitous, suppurative bacteria

Enterococci are opportunists Streptococcal keratitis is

relatively common

Most pathogenic Streptococci produce varying hemolysins.

Streptococcus spp.and related cocci

Presenter

Presentation Notes

that may be found among normal mucosal flora. Enterococci are opportunists and may be found in the intestinal tract �of most mammals. Streptococcal keratitis is relatively common in domestic animals, especially the horse, in which streptococcal endophthalmitis may also occur. Most pathogenic Streptococci produce hemolysins with the �type of hemolysis produced varying with the species. Generally, β-hemolytic S. equi subspeces zooepidemicus in horses or β-hemolytic Streptococcus sp.in dogs are the most pathogenic strep.

β-hemolytic Strep spp -17% of dogs

S. equi subsp zoo - 12% and 22% of the isolates from horses.

Streptococcus spp.

Presenter

Presentation Notes

Both of these have the ability to digest a conjunctival graft.

UT – Equine and canine all isolates were susceptible to ciprofloxacin, cephalothin

and chloramphenicol

> 80% resistance to neomycin, polymixin B and tobramycin

UF - Equine All susceptible to chloramphenicol, bacitracin

An increase in resistance of S.equi subsp zooepidemicus to gentamicin was found over time

Australia>80% of isolates were resistant to ciprofloxacin but

remained susceptible to chloramphenicol and cephalexin

Streptococcus spp.

Presenter

Presentation Notes

This correlates with the first line antibiotics used at these universities

Streptococcus equi subsp. equi

Transmission via direct contact and fomites

Colonizes within the pharyngeal and nasal mucosa

Signs Lymphadenopathy

Pyrexia

Malaise

Purulent discharge

Pharyngitis

Abscessed lymph nodes

Strangles

Streptococcus spp.

Cases involving any area other than the pharyngeal area.

Ocular abnormalities

Serous then mucopurulent discharge

Panophthalmitis

Chorioretinitis

Central blindness

Dx via culture or PCR

Bastard strangles

Streptococcus spp.

Corynebacterium spp. Gram + rods

Appear singly or in pairs

+/- clubbed ends

Flora of normal skin and mucous membranes

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Presentation Notes

Found in intestine and may propagate in soil following fecal dissemination. Usually part of mixed infections specific etiologic role???? Following periocular trauma, corynebacterium may cause blepharitis, orbital cellulitis, or orbital abscesses, especially in large animal species.

Bacillus spp. Gram + rods found singly, in pairs or chains. May have a single endospore More pathogenic organisms usually present

as co-infections.

http://content.answers.com/main/content/wp/en-commons/thumb/4/42/260px-Bacillus_subtilis_Spore.jpg

Most common organism isolated from endophthalmitis in humans.

Listeriosis Rod-shaped, Gram + bacterium

L monocytogenes most common in animals

Spoiled or incompletely fermented corn or hay silage is the main source of infection in outbreaks.

VCNA Food AnimPract. 2010 Nov;26(3):487-503

CNS disease is most likely to be associated with ocular signs in food animal species. vestibular ataxia

cranial nerve deficits

brain stem involvement facial nerve paralysis

Kcs

Keratitis Anterior uveitis w/hypopyon Purulent endophthalmitis

VCNA Food AnimPract. 2010 Nov;26(3):487-503

Presenter

Presentation Notes

Photo Lesions of listerial encephalitis (microabscessation) in the midbrain of a cow.

Other species Dog

Conjunctivitis, neurologic signs, and pancytopenia with generalized infection.

Sheep & goats Scleral hyperemia

Unilateral keratitis +/- ulceration

CNS signs

en.wikipedia.org/wiki/Listeriosis_in_animals

Presenter

Presentation Notes

Lateral deviation of head and neck

http://upload.wikimedia.org/wikipedia/commons/7/78/Sheep_encephalitic_listeriosis_neck_lateral_deviation.jpg

http://upload.wikimedia.org/wikipedia/commons/7/78/Sheep_encephalitic_listeriosis_neck_lateral_deviation.jpg

http://en.wikipedia.org/wiki/Listeriosis_in_animals

Swine listeriosis Septicemia

Encephalitis

Diagnosis clinical signs

culture and identification of the organism from body fluids

Pseudomonas spp. Gram - rods Widely distributed. Found in the skin and

mucous membranes. Cytologically

indistinguishable from other rods

Antibiotic susceptibility testing is especially important

Presenter

Presentation Notes

Widely distributed in soil and water, as saprophytic bacteria as multiple drug resistance associated with plasmids is not uncommon.

Pseudomonas aeruginosa Isolated from about 15% of horses with bacterial

keratitis Isolated from 21% of dogs

Innate resistance

Evans 2013

Presenter

Presentation Notes

The normal cornea is exquisitely resistant to microbial attack; the inoculation of extremely large inocula (a thick bacterial suspension) of either invasive or cytotoxic P. aeruginosa onto intact mouse or rat corneas in vivo results in rapid bacterial clearance from the ocular surface without pathology (Evans 2013). 1 tear fluid and blinking can physically cleanse the ocular surface and wash away potential pathogens 2 tear fluid also contains molecules with direct antimicrobial activity against many microbes, for example, lysozyme and lactoferrin. 3Although many P. aeruginosa strains grow readily in undiluted human tear fluid, tear fluid can still protect corneal epithelial cells against them. In this case, it may be that tear fluid acts directly upon corneal epithelial cells to make them more resistant to P. aeruginosa virulence strategies. 4 Corneal epithelial-associated barriers to P. aeruginosa consist of defenses against adhesion and against microbial penetration (traversal). The players involved likely include junctional complexes, secreted and internal antimicrobial peptides, mucins, and the basal lamina foundation that provides a physical barrier while also supporting epithelial homeostasis. 5 During and after P. aeruginosa challenge, corneal epithelial defenses are enhanced and regulated by epithelial-derived cytokines and chemokines that can facilitate communication with cells of the immune system to boost corneal defenses.

Pathogenic mechanisms

www.cdc.gov www.asylumresearch.co.uk/.../Bacteria/Cell!.jpgsciencephoto.com

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Presentation Notes

is a pigment produced by many strains of P. aeruginosa and may contribute to tissue damage by inhibiting cellular oxygen uptake. Adherance contributes to invasiveness and tissue destruction and is the first step of pathogenesis. Pseudomonas organisms adhere poorly to intact epithelium or bare stroma, but they adhere readily to injured epithelium at the edge of an epithelial defect. Therefore, trauma is a necessary prerequisite for bacterial adherence and subsequent corneal infection. Studies have shown that after only 30 minutes Pseudomonas organisms had been engulfed by epithelial cells and had reached the corneal stroma through transcellular migration.

Major matrix metalloproteinasesAlkaline protease

attacks the helical structure of native type I, III, IV collagen

interferes with host defense systems by degrading complement components, IG, IFN, IL 1 and 2, and tumor necrosis factor.

Pathogenic mechanisms of Pseudomonas aeruginosa

Elastase As above Activates proMMPs

MucD

Presenter

Presentation Notes

Recently, it has been shown that the elastase strongly activates proMMPs via limited proteolysis to generate active forms of MMPs. During active ulceration concentrations of latent and active forms of MMP-2 and MMP-9 are higher than in contralateral unaffected eyes and control dogs. Concentrations of latent and active forms of MMP-2 and MMP-9 in the healed eyes were significantly lower than concentrations in the ulcerated eyes on the day of admission. (Wang, AJVR 2008) Need more info

Cytotoxic and invasive strains Cytotoxic strains remain mostly extracellular Invasive strains enter cells and replicate within

them. Tobramycin vs ofloxacin Steroids? Both antibiotics hastened disease resolution infections caused by either strain.

Pathogenic mechanisms of Pseudomonas aeruginosa

Presenter

Presentation Notes

Studies have shown that both cytotoxic and invasive strains of P. aeruginosa exist. A study was done evaluating the hypothesis that ofloxacin, which easily penetrates host cell membranes, would be more effective than the less cell-permeable antibiotic tobramycin, for treatment of corneal infection by an invasive P. aeruginosa strain. Both antibiotics hastened disease resolution over the next 7 days for infections caused by either strain. Corticosteroid use during the 12 hour treatment period was of little added benefit and decreased eradication of bacteria. The results suggested that successful management might be improved by addressing factors contributing to disease progression during sterilization of the cornea by antibiotics, but steroids don’t appear to be the answer.

IOVS 2011 March; 52(3): 1368–1377

Presenter

Presentation Notes

Surfactant protein D (SP-D) is an important innate immune defense molecule that mediates clearance of pathogens and modulates the inflammatory response B. But no sustained patholdogy

Resistance No resistance to gentamicin, tobramycin,

ciprofloxacin, neomycin and polymixin B in horses at UT

At UF a statistically significant increase in resistance to gentamicin and tobramycin was found in horses between the isolates from 1992 to 1998 and those from 1999 to 2000.

Isolates of P. aeruginosa from dogs were susceptible to tobramycin and gentamicin and had limited resistance to ciprofloxacin (0.07%).

Pseudomonas aeruginosa

Resistance 27 P aeruginosa isolates from dogs

7 fluoroquinolones

24/ 27 isolates were susceptible to all fluoroquinolones evaluated

Susceptibility ranged from 88.9% to 100%

No significant differences among isolate susceptibilities to the individual antimicrobials or among generations of fluoroquinolones


Presenter

Presentation Notes

7 fluoroquinolones Second generation- �(ciprofloxacin, ofloxacin, norfloxacin, and lomefloxacin) third- (levofloxacin) fourth-generation (gatifloxacin and moxifloxacin)

Multi-drug resistant, extensively drug resistant, and pan-drug resistant strains of P aeruginosa

Risk factors: bandage contact lens, topical steroids, previous therapeutic graft, preservative-free lubricant ointment and ocular surface disorders.

Of 15 isolates, 6 were sensitive only to imipenem, 3 to colistin, 2 to neomycin, 1 each to imipenem and colistin, imipenem and ceftazidime, and azithromycin. One isolate was resistant to all antibiotics.

Success with medical therapy alone was not common. These cases are more likely to require the use of tissue adhesives and keratoplasty and are likely to have treatment failure.

Another study compared the efficacy of topical 1.5% and 0.5% levofloxacin.

Bacteriophages/Predatory Prokaryotes

AJVR 2011 Aug;72(8):1079-86


Presenter

Presentation Notes

Transmission electron micrographic images of P aeruginosa PA5 in coculture with phage P5U5 obtained after 30 minutes of incubation at 37°C. A—Bacterial debris is evident (solid arrows), and a single bacterium is starting to rupture (its inner membrane is spilling through a hole caused by the phage [dotted arrow]). B—At higher magnification, the bacterial rupture can be seen in more detail. Notice the externalized cytoplasmic content. Bar in panels A and B = 2 and 0.5 μm, respectively.�

Moraxella spp. A large, plump, Gram - coccobacillus

Primary cause of infectious bovine keratoconjunctivitis (IBK) “pinkeye”

Highly contagious ocular infection of cattle

Monetary losses caused by: decreased weight gain

decreased milk production

devaluation because of eye disfigurement

cost of treatment

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Presentation Notes

A 1993 study estimated that these losses totaled over $150 million per year. Weaning weight losses of IBK-affected calves can range between 8 to 40 pounds and up to 80% of the herd can have disease during an epizootic outbreak.

Transmission Opportunistic pathogen Environmental factors

Exposure to UV light

Irritants- face fly

Host factors Genetic

Nutritional

Immune status

Current infections

Moraxella bovis

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Presentation Notes

Opportunistic pathogen whose virulence is influenced by both host and environmental factors. Environmental factors include ultraviolet light exposure, face fly populations, climate and pasture conditions. Host factors include genetics, breed, age, nutrition, immune status and current infections.

Nonpiliated, nonpathogenic forms can exist in a carrier state in the host.

Carrier animals are asymptomatic, but shed the organism.

Harbored in nasal, ocular, and vaginal secretions

Transmitted by direct contact, aerosol, or fomites. Cattle are the primary natural reservoir for M bovisand have a high nasal carrier rate.

Transmission of Moraxella bovis

The face fly Musca autumnalis is a primary mechanical vector and serves as an irritant.

www.forestryimages.org bugguide.net popgen.unimaas.nl


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Presentation Notes

3 days

http://bugguide.net/node/view/123765

http://bugguide.net/node/view/123765

http://www.forestryimages.org/

UV light causes direct conversion of nonhemolytic, nonpiliated organisms to pathogenic forms in carrier animals.

Then a rapid logarithmic growth phase of the organism begins.


Bos taurus is more susceptible to IBK than is Bos indicus (such as Zebu and Brahman)

Calves are more prone to disease than adults.

IBK is more common in summer and fall


Presenter

Presentation Notes

this is attributed to high-level exposure to ultraviolet light, which predisposes the eye for infection.

Pathogenesis of Moraxella bovis - PiliM. bovis attaches to undamaged older, hypermature corneal epithelial cells with smaller, more densely packed microvili.

Two kinds of pili

Q-pili are specific for colonization of the bovine corneal epithelium

I-pili enable maintenance of an established infection.

Pili alone cannot cause disease www.hgsc.bcm.tmc.edu/projects/microbial/Mbovis

Presenter

Presentation Notes

M. bovis has several pathogenic mechanisms; however, only 2, fimbriae or pili and the secretion of a β-hemolytic cytotoxin have been determined to cause clinical disease.The pili allow the bacteria to attach to the dark cells of the corneal epithelium. These cells are seen on EM and have few microplicae and may represent cells in their final stages. The pili demonstrate interstrain and intrastrain antigenic heterogeneity and a single strain can produce both pili types. The orientation of an invertible DNA determines which pili gene will be transcribed. The presence of pili alone is insufficient to cause disease following infection with M. bovis. (Rogers, Vet Path 1987) Where bacteria are seen to be attached to the epithelial cells, a small depression is present. This pit may be associated with the β-hemolysin of M. bovis that is also required for disease. 2 hours post – on dark cell

http://www.hgsc.bcm.tmc.edu/projects/microbial/Mbovis/

http://www.hgsc.bcm.tmc.edu/projects/microbial/Mbovis/

http://www.hgsc.bcm.tmc.edu/projects/microbial/Mbovis

β-hemolysin of M bovis is also required to cause disease.

RTX family of toxins

causes clinical signs directly as a result of damaged ocular cells or indirectly through lysis of the WBCs attracted to the site.

Pathogenesis of Moraxella bovis

Presenter

Presentation Notes

The hemolysin is a pore forming toxin that lyses corneal epithelial cells leading to ulceration and causes lysis of bovine leukocytes. With the lysis of leukocytes, enzymes are released which cause fragmentation and aggregation of collagen fibrils which delays healing. It belongs to the RTX family of toxins which also includes the Mannheimia (Pasteurella) haemolytica leukotoxin. Hemolysin is important for the pathogenesis of M. bovis because it causes clinical signs either directly as a result of damaged ocular cells or indirectly through lysis of the leukocytes attracted to the affected site. This latter effect results in delayed corneal healing and may contribute to corneal damage due to the release of endogenous enzymes. (Postma, Comp Immunol Microbiol Infect Dis 2008) causes clinical signs directly as a result of damaged ocular cells or indirectly through lysis of the WBCs attracted to the site. This latter effect results in delayed corneal healing and may contribute to corneal damage to the release of endogenous enzymes.

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Fig 1 bacteria with swollen epith cells in superficial and polyhedral layers 2 hrs. post Fig 2 bacteria with swollen epith cells surround vesicle 4 hrs. post bacteria are superficial to bowmans membrane Fig 3 24 hours post stromal edema, bacterial subjacent to bowmans PMNS Fig 4 peripheral to ulcer 45 hours post bacteria distrib diffusely in stroma no pmn seen

Pink eye – Infectious Bovine Keratitis

Summer and fall

Younger cattle

Incubation period 2-3 days.

Moraxella bovis

Presenter

Presentation Notes

older animals have most likely developed acquired surface immunity as a result of previous exposure.

Clinical Signs Initially

Decreased appetite Moderate pyrexia. Epiphora Blepharospasm Chemosis and hyperemia of the conjunctiva

Day 2 A small opaque area appears axially

Day 6 Entire cornea is gray-white to yellow with axial

corneal ulceration +/- corneal vascularization

Moraxella bovis

OutcomeTypically Complete recovery in 3-5 weeks Some with persistent scar

Moraxella bovis

Infrequent outcomes Severe ulceration

Corneal rupture with iris prolapse

Conical bulging of the eye

Blindness

Treatment - Parenteral

Oxytetracycline (LA200 2 injections, 20 mg/kg IM at 72 hour intervals)

Oxytetracycline (Tetradur, 300 mg/ml, 1-2 ml IM, lasts 7-10 days.)

Florfenicol (2 IM dosages of 20 mg/kg 48 hours apart or a single 40 mg/kg SC dosage)

Moraxella bovis

Presenter

Presentation Notes

Elimination of M bovis in calves with IBK has been demonstrated following parenteral treatment with oxytetracycline or florfenicol. The most common treatments are intramuscular oxytetracycline (LA200 2 injections, 20 mg/kg at 72 hour intervals) or (Tetradur, 300 mg/ml, 1-2 ml IM, lasts 7-10 days.) Oxytetracycline is an amphoteric molecule that should theoretically diffuse into tears; however, parenteral administration of long-acting oxytetracycline leads to a tear concentration less than1g/ml although conjunctival levels are >2g/ml for 72 hours. Substantial conjunctival concentrations of oxytetracycline are present for as long as 20 hours after a single 20 mg/kg IM injection. The drug localizes within the lacrimal gland, conjunctiva, and cornea but not within tear film or aqueous humor. The efficacy of parenterally administered oxytetracycline likely linked to these higher tissue levels. Treatment with two doses of long-acting oxytetracycline (20 mg/kg, 72 hours apart) has been shown cause a reduction in M bovis organisms and decrease in corneal ulcer healing time and recurrence. Some antimicrobial resistance to tetracycline has been reported in M bovis isolates in the United States. Florfenicol is dosed at 2 IM dosages of 20 mg/kg 48 hours apart or a single 40 mg/kg SC dosage can be administered. Florfenicol provides a treatment option in Anaplasma endemic regions where oxytetracycline use is restricted. Simultaneous administration of these drugs to all animals reduces the incidence of IBK in the herd. (McConnel, AVJ 2007 review)

Treatment - Subconjunctival Procaine penicillin (1-2 ml) +/- subconjunctival

dexamethasone (1-2 ml)

Oxytetracycline (100 mg/ml subconjunctival 1-2 ml)

Moraxella bovis

Presenter

Presentation Notes

Subconjunctival treatment is also effective. Subconjunctival procaine penicillin (1-2 ml) +/- subconjunctival dexamethasone (1-2 ml) or 100 mg/ml subconjunctival oxytetracycline (1-2 ml) can be given. In calves given a bulbar subconjunctival injection of a conventional (100 mg/ml) oxytetracycline formulation, the antibiotic concentration in tears is above MIC for 24 hours. Although a single subconjunctival dose of a long-acting oxytetracycline formulation achieved tear concentrations above MIC for longer than 72 hours, severe tissue necrosis at the injection site precludes such therapy.

Treatment - other

Ceftiofur crystalline-free acid (CCFA)(6.6 mg of ceftiofur equivalents/kg, SC)****

Tulathromycin 1 dose SC Tilmicosin SC (5 or 10 mg/kg)

Moraxella bovis

Presenter

Presentation Notes

A newer drug, ceftiofur crystalline-free acid (CCFA), is administered in the posterior aspect of the ear to the reduce the risk for tissue residue and lower potential for injection-site trimming at slaughter. Concentrations of ceftiofur metabolites in plasma remain above published M bovis modal MIC values for more than 7days when administered via this particular route. A single dose of CCFA (6.6 mg of ceftiofur equivalents/kg, SC) is effective in beef calves decreasing clinical signs and leading to a 50% increase in the percentage of healed calves in 14 days. Tulathromycin at 1 dose SC and tilmicosin administered SC (5 or 10 mg/kg) are also both effective. (McConnel, AVJ 2007 review)

Treatment Nictitating membrane flaps or temporary

tarsorrhaphies

Decreasing the fly population

Decreasing UV radiation

Autogenous vaccines

Cytokines with inactivated bacteria

Intranasal vaccines

Moraxella bovis

Presenter

Presentation Notes

Some work is now being done to try to preserve cellular piliation level of M. bovis during the growth of bacteria in stirred bioreactors. (Prieto, Vaccine 2009)

Moraxella bovoculi Isolated from IBK cases Blepharitis and conjunctivitis Respond to IBK treatments Association with M bovis?

Other diseases by Moraxella spp. Moraxella spp. cause other ocular infections of

small ruminants and horses. Moraxella ovis

Gram - diplococcus

cultured from normal small ruminants

Cultured from sheep and goats with keratoconjunctivitis.

May occur as a co-infection with chlamydial or mycoplasmal conjunctivitis

May complicate other ocular diseases

Pasteurellosis Pasteurella multocida

Very small, non-motile, Gram - ovoid, coccoid or short rod

Bipolar staining

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Opportunistic bacteria

Virulent factorsendotoxin adhesins filamentous appendages help P. multocida

colonize mucous membranes

Pasteurellosis

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Presentation Notes

Disease occurs when predisposing factors give the bacteria the opportunity to multiply and overwhelm the physiological and immunologic defenses of the respiratory tract. During these episodes clones of virulent bacteria increase, which are usually transmitted to neighboring animals.

Rhinitis (or snuffles) Pneumonia Genital infections Wound infections Abscesses Otitis media

Clinical signs in rabbits

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Pasteurellosis

Ocular signs Conjunctivitis Dacryocystitis

mucopurulent discharge pressure below the medial canthus expresses

purulent material lacrimal sac may be distended secondary conjunctivitis and keratitis

http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/171317.htm

Pasteurellosis

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Presentation Notes

which can be profuse and malodorous and is most marked at the medial canthus of the eye through the lacrimal puncta into the conjunctival sac. While Pasteurella is often incriminated in dacryocystitis, a recent publication of 28 cases of dacryocystitis in rabbits did not grow pasteurella on any of the 6 positive of 8 cultures.(Florin VO 2009)

Brucellosis Brucella canis Zoonotic aerobic Gram-coccobacillus Survives in mononuclear cells. Penetrates mucous membranes. Ingestion and venereal transmission are

common. Can be transmitted via fomites, such as cages or

equipment.

Ocular signs Occur in ~ 14 % of dogs with brucellosis.

Endophthalmitis

Chronic uveitis

Hyphema

Chorioretinitis

Brucellosis

Systemic signs Diskospondylitis Glomerulopathy Meningoencephalitis Abortion and infertility are common in breeding

dogs Dogs not used for breeding may have

undetected disease for long periods of time due to the prolonged bacteremia and secondary localization

Brucellosis

Diagnosis Isolation and identification Serologic screening involves the rapid slide

agglutination test with and without 2-mercaptoethanol.

Tube agglutination, ELISA or IFA tests or the cytoplasmic protein agar gel immunodiffusion test have greater specificity

Zoonotic potential

Brucellosis

Presenter

Presentation Notes

Diagnosis is difficult, but due to the zoonotic potential it is especially important Tube agglutination, ELISA or IFA tests that employ multiple dilutions or the cytoplasmic protein agar gel immunodiffusion test have greater specificity and are used as confirmatory serologic tests.

Case Report 3 neutered dogs Chronic recurrent uveitis Blood culture or PCR Responded to therapy

Brucellosis

Vet Ophthalmol. 2009 May-Jun;12(3):183-91.

Presenter

Presentation Notes

topical ophthalmic anti-inflammatories and a novel antimicrobial protocol that included doxycycline, enrofloxacin, rifampin, and streptomycin. Ocular inflammation resolved in all dogs during treatment, with preservation of vision in two dogs. Following treatment, B. canis could not be cultured from blood, and serological values declined, with seronegativity achieved in all dogs after a median of 96 weeks of therapy

http://www.ncbi.nlm.nih.gov/pubmed?term=ledbetter%20brucellosis

Haemophilus spp. Haemophilus spp. requires factors from blood for

growth.

Normal flora of the oral cavity and nasopharynx

Also primary etiology for acute mucopurulent conjunctivitis in humans.

Little affinity for the avascular cornea, and corneal involvement is a rare complication of conjunctivitis.

ThromboembolicMeningoencephalitisHaemophilus somnusAcute septic TEME most commonly occurs in

feedlot cattle

Can Vet J. 1971 September; 12(9): 180–182.

Zoonotic Disease Acid-fast bacterium,

Mycobacterium bovis Ocular tuberculosis is

rare in cattle and swine subretinal exudation

retinal hemorrhage

anterior uveitis

endophthalmitis with a granulomatous response

Bovine tuberculosis

Basic Science Guides Design of New TB Vaccine Candidates M. J. Friedrich JAMA. 2005;293:2703-2705.http://jama.ama-assn.org/cgi/content/extract/293/22/2703

Affected small animals are in farm settings and are drinking unpasteurized milk.

Presenter

Presentation Notes

NOT IN NOTES

Mycoplasma Smallest prokaryotic cells capable of self-

replication

Ubiquitous free-living saprophytes (eg. members of the Genus Acholeplasma)

Animal pathogens include the genera Mycoplasma and Ureaplasma

Lack a true cell wall, but have a plasma membrane. accounts for their plasticity and pleomorphism,

including cocci, spiral filament, and ring-like structures

http://www.malp-research.de/malp_history.html, webmedia.unmc.edu/.../2SL31-mycoplasma.jpg

Mycoplasma

http://www.malp-research.de/bilder_highres/pleomorph_mycoplasmas_high.jpg

http://www.malp-research.de/bilder_highres/pleomorph_mycoplasmas_high.jpg

stain poorly with Gram stain Giemsa and other Romanowsky stains are better fragility, pleomorphism and weak staining

characteristics make direct examination of stained smears of limited value in making a diagnosis

Mycoplasma

Vet Clin Pathol 41/2 (2012) 283–290

Presenter

Presentation Notes

Epithelial cells with small basophilic coccoid structures consistent with Mycoplasma organisms in a PCR-positive cat. Mycoplasma organisms were paler than chlamydial inclusions and were often near the edge of the epithelial cells. Hemacolor, ×100 objective.

Pathogenesis Adhere to host mucous membranes where they

remain extracellular Produce

hemolysins proteases nucleases other toxic factors

Latency can occur Host specific Eye infections are characterized by serous

discharge and conjunctival hyperemia

Mycoplasma

Presenter

Presentation Notes

Latency can occur and stresses can predispose animals to low grade, chronic mycoplasma infections.

M. felis, M. gateae, M. arginini and Acholeplasma laidlawiiCats Recovered from the eyes of

cats with ocular disease Also recovered from the

normal conjunctiva

Mycoplasma

Koch’s postulates have not been fulfilled with these organisms with the exception of M felis. Inoculating kittens with M. felis causes clinical signs It is more commonly cultured from ill cats versus normal cats

Presenter

Presentation Notes

Clinical signs associated with M. felis are conjunctivitis, lymphoid follicle formation and development of pseudomembranes.

M conjunctivae and M agalactiaeSheep

keratoconjunctivitis (with corneal vascularization but not corneal ulcers)

Goats (and maybe sheep)

M. agalactiae causes systemic disease including arthritis, mastitis or abortion

M. mycoides subsp. mycoides (large-colony type) causes septicemia, mastitis, and arthritis

Ophthalmic signs in sheep and goatsMycoplasma keratoconjunctivitis anterior uveitis choroiditis hyalitis

M. mycoides in goats keratoconjuctivitis with perilimbal corneal

opacities eye lesions may occur without systemic signs

M. bovoculi, Ureaplasma spp.,M. laidlawii and M. bovirhinisCattle bovine conjunctivitis association with M bovis has not been

confirmed. tends to occur in the summer mild and self-limiting

Mycoplasma bovisCattle

Pneumonia

Arthritis

Mastitis

Meningitis

Infertility

Subcutaneous abscesses in cattle

Keratoconjunctivitis

Mycoplasma

Chlamydophila sp.

Obligate intracellular organisms

Cell walls similar to those of other Gram-bacteria

Lack the machinery that allow autonomous survival and replication http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/201700.htm

(Chlamydiae)

The cell replication cycle involves:

Extracellular (elementary body)

0.2-0.6 µm in size with rigid cell walls

Intracellular (initial body, reticulate body)

0.5 – 1.5 µm lack cell walls

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Presenter

Presentation Notes

The cell replication cycle involves extracellular �(elementary body) 0.2-0.6 µm in size with rigid cell walls resistant, metabolically inactive and infectious. They undergo extracellular migration and transform within vacuolar inclusions into larger vegetative replicating forms. Intracellular (initial body, reticulate body) 0.5 – 1.5 µm lack cell walls Noninfectious proliferate by budding and fission within the cytoplasmic vesicle of the host cell. After rapid division the initial bodies transform again and become a large membrane-bound population of elementary bodies. After this 2 day cycle the elementary bodies are released from the cell after lysis and infect new host cells.

http://en.wikipedia.org/wiki/Image:Chlamydophila_pneumoniae.jpg

http://en.wikipedia.org/wiki/Image:Chlamydophila_pneumoniae.jpg

Previously all members of the family Chlamydiaceae were known as one species Chlamydia psittaci

Currently there are 2 genera, Chlamydia and Chlamydophila, and multiple species within each

Chlamydophila felis Transmission

direct contact or aerosols.

Only survives a few days in the environment. Cellular and hormonal mechanisms play a role in

immunity. Cats under < 8 weeks and > 5 years are unlikely

to become infected. In general chlamydiae are considered to have a

restricted host range.

Presenter

Presentation Notes

In general chlamydiae are considered to have a restricted host range. transmission of C. felis from cats to humans. transmission of chlamydia from a macaw to a cat Psittacosis (caused by Chlamydophila psittaci) transmitted from birds to humans is a well recognized zoonosis.

Pathogensis Highly contagious Spreads rapidly by direct contact A low dose incites unilateral disease and a high

dose incites bilateral disease. Spread internally to colonize many tissues

including the tonsil, lung, liver, spleen and kidney.

Shed in the tears and nasal secretions May persist in the ocular tissues for months

following remission of ocular signs.

Chlamydophila felis

Clinical signs initial chemosis

suppurative conjunctivitis

petechial hemorrhages

conjunctival lymphoid follicles

+/- respiratory signs

Chlamydophila felis

Presenter

Presentation Notes

The initial chemosis followed by suppurative conjunctivitis is typical and petechial hemorrhages may occur along with conjunctival lymphoid follicles. Only occasionally are respiratory signs seen.

Clinical signs

Serous ocular discharge becomes mucoid or mucopurulent within 3-5 days

Cats that become bilaterally affected have clinical signs persist for 22-25 days.

Recovery can result in persistent infections with conjunctival shedding for up to 8 months.

Chronic shedding of organisms from the urogenital and GI tract has been documented.

Chlamydophila felis

Experimental infection unilateral conjunctivitis within 5-

10 days of exposure

Presenter

Presentation Notes

Histologically, a neutrophilic infiltrate is seen with macrophages, lymphocytes, and plasma cells becoming more numerous between days 10 and 21.

Diagnosis C. felis, in contrast to Chlamydial infections in

other species, is not associated with keratitis. Isolation from conjunctival cotton swabs (without

wooden sticks) ELISA PCR FA

Chlamydophila felis

Intracytoplasmic elementary bodies

Vet Clin Pathol 41/2 (2012) 283–290

Presenter

Presentation Notes

Isolation is best. The swabbing must be vigorous to acquire enough cells. One study evaluated conjunctival smears from 88 cats with conjunctivitis and 10 healthy control cats. The smears were stained with a Romanowsky stain and cytologic results were compared with PCR analysis for FHV-1, C felis, and M felis. Inclusions interpreted as chlamydial inclusions were found in all 8 cytologic smears from cats positive for C felis by PCR analysis and in 3 PCR-negative cats. Inclusions interpreted as Mycoplasma organisms were found in 3 of 6 cats that were PCR-positive for M felis and in 1 PCR-negative cat. FHV-1 inclusion bodies were not detected on the 9 cats that were positive for herpes.(Hillstrom 2012)

Treatment Topical oxytetracycline QID for 2 weeks past

resolution of clinical signs

Erythromycin and chloramphenicol are also effective

Pradofloxacin vs doxycycline

Chlamydophila felis

Presenter

Presentation Notes

Pradofloxacin vs against Chlamydophila felis and Mycoplasma spp. in comparison to doxycycline has been studied. The groups received 5 mg/kg pradofloxacin q24h or 5 mg/kg doxycycline q12h for 42 consecutive days. Cats of both groups responded rapidly with a marked improvement in clinical signs within the 1st week. Complete elimination of Mycoplasma spp. was achieved in both groups. All cats that received doxycycline eliminated C. felis, but some cats treated with pradofloxacin remained PCR-positive.

Disease in Farm Animals Chlamydophila pecorum

Chlamydophila abortus

Chlamydia suis

C. pecorum Cattle, sheep and swine Encephalomyelitis Enteritis Polyarthritis Metritis Pneumonia Conjunctivitis Typically young animals are affected in sporadic

outbreaks.

C. abortus Sheep

Conjunctivitis

Keratitis

Polyarthritis

Pneumonia

Orchitis

Epididymitis

Abortion

Chlamyodophilosis among lambs and kids may produce both ocular signs and polyarthritis.

C. abortus

Ocular signs Bilateral in 80% Conjunctiva lesions

Conjunctivitis

Petechial hemorrhages

Epiphora and purulent exudation

Lymphoid follicle proliferation (which may become confluent, producing folds)

Cornea Peripheral edema and neovascularization

Ulceration is rare

C. abortus

Treatment Topical oxytetracycline

is used to treat lambs

and kids

LA200 is effective

Usually self limiting in 2-3

weeks.

C. abortus

Diagnosis Conjunctival cytology

Culture

ELISA

PCR

C. abortus

Persistent infection with intermittent shedding is common among ovine chlamydial diseases.

The elementary bodies are relatively resistant and may remain viable for several days.

C suisSwine Conjunctivitis Keratoconjunctivitis Enteritis Pneumonia Lymphofollicular hyperplasia of the palpebral

conjunctiva Isolated from the conjunctiva of healthy pigs.

Journal of Zoo and Wildlife Medicine 44(1): 159–162, 2013

Chlamydophila psittaci

Avian chlamydiosis

Subclinical, acute, subacute, or chronic infection

Worldwide at least 150 avian species

Respiratory, digestive, or systemic infection.

10-30% of surveyed avian populations may be found positive.

Serotypes All share an identical genus-specific antigen in

their lipopolysaccharide Currently, 8 serotypes are recognized The same strain may cause mild disease or

asymptomatic infection in one species, but severe or fatal disease in another species.

Avian serotypes are capable of infecting people and other mammals.


Presenter

Presentation Notes

Currently, 8 serotypes are recognized; 6 (A-F) infect avian species and are distinct from mammalian chlamydia serotypes.

Transmission Airborne elementary bodies are resistant to

drying. Also spread by fecal oral transmission. Stress can initiate shedding and cause

recurrence. Carriers can shed the organism for extended

periods. The incubation period typically is 3-10 days.


Clinical signs Nasal and ocular discharge Conjunctivitis Sinusitis Green to yellow-green

droppings Fever Inactivity Ruffled feathers Weakness Inappetence, and weight loss Asymptomatic infections are common


Diagnostics clinical findings

hematology

clinical chemistries

radiology

organism can be seen in impression smears of affected tissues stained by Giemsa, Gimenez, or Macchiavello’s method.

IFA, ELISA, PCR

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Disease in koalas

Veterinary Microbiology 165 (2013) 214–223

Chlamydophila pecorum

keratoconjunctivitis urinary tract disease reproductive tract disease rhinitis/pneumonia

Treatment

Chlamydophila pecorum

Response to treatment is variable Decreased palpebral fissure, entropion

and corneal scarring may result. Enrofloxacin, chloramphenicol Not tetracyclines and macrolides

Bartonella Gram-negative

Facultative intracellular rod or coccobacillus

Bartonellaceae family

Transmitted by arthropods Infection is suspected to be primarily in RBCs, but

infection of vascular endothelium also occurs.

In Cats Bartonella henselae is the most frequently

reported species to infect cats Naturally occurring infection is mild and transient Clinical findings: pyrexia, lymphadenopathy,

lethargy, anorexia, CNS disorders, urologic diseases and endocarditis

Ocular disease: uveitis, keratitis and chorioretinitis

Bartonella

Presenter

Presentation Notes

Existing data indicate that few cats naturally infected with Bartonella have notable clinical signs. Some small epidemiologic studies have evaluated the association between Bartonella exposure and clinical conditions such as some neurologic conditions, stomatitis, uveitis, and fever, but a statistically significant association of documented active Bartonella infection with the those conditions in naturally infected cats has not been found.

In DogsB henselae, B vinsonii, B clarridgeiae, &

B elizbethaeAnterior uveitisHyphemaChorioretinitisRetinal detachment due to systemic

hypertensionMultiple systemic signsDiagnosis is based on serology

Bartonella

Presenter

Presentation Notes

Including - Lethargy, weight loss, muscle and joint pain, hind-limb paresis, fever, endocarditis, cutaneous vasculitis, granulomatous lymphadenitis, myocarditis, neurologic and dermatologic signs can be seen. In one case identifying the bacterium from aqueous humor using PCR was unsuccessful, but the dog did respond to therapy with azithromycin.

Diagnosis in cats Serology Blood culture PCR In the United States, 12-67% of the cats are

seropositive for Bartonella. A higher prevalence of affected cats occurs in

warm, humid areas which have more fleas.

Bartonella

Presenter

Presentation Notes

Epidemiologic studies show that there are high numbers of cats that are seropositive for Bartonella species in many countries. Because of the high percentage of chronically bacteremic yet healthy cats, drawing conclusions between presence of the bacteria and disease states is problematic. Specific intraocular IgG antibody production was documented in 8 of 50 cats with naturally occurring uveitis, in 4 of 9 experimentally infected cats, and in 0 of 49 healthy shelter cats. The C value considered significant in these papers, however, was >1. Typically C values >8 are considered more likely to be associated with local antibody production. B. henselae DNA was identified by PCR from the aqueous humor of 3 of 24 cats with uveitis, 1 healthy shelter control cat and 4 of 9 experimentally infected cats. Although these data are interesting, it must be kept in mind that an organism that naturally infects RBCs may easily be included in an aqueocentesis sample, confounding PCR results. Another study looked at the relationship between bartonellosis and feline anterior uveitis. The hypothesis was that Bartonella spp can cause uveitis in cats. identified 116 cats with uveitis and 156 controls. A significant negative association between a positive antibody titer to bartonella and clinical uveitis was found. Because of the limitations of this study, it does not support or deny the premise that cats affected with bartonella are likely to have uveitis

Neonatal septicemia/bacteremia

Commonly isolated bacteria in foals E coli Klebsiella spp Actinobacillus spp Enterobacter spp Pseudomonas spp Rhodococcus equi

Presenter

Presentation Notes

The most commonly isolated bacteria is Escherichia coli. In a recent study only Gram negative bacteria were detected in the uveitic bacteremic foals. The pathogenicity of E. coli in the eye has not been clearly established. Ocular disease could be associated with direct bacterial spreading to the uveal tissue or with local vascular alterations induced by secondary endotoxemia, causing inflammation and exudation of proteins and cells into the aqueous humor.

In foalsRoutes of entry for bacteria

Placenta, umbilicus, lungs & GI tract. The major risk factor for septicemia is failure of passive transfer of colostral antibodies.Other factors include

unsanitary environmental conditions gestational age of the foal (prematurity) health and condition of the mare difficulty of parturition new pathogens in the environment


Frequently affected organ systems Umbilical remnants

CNS

Respiratory

Cardiovascular

Musculoskeletal

Renal

Hepatobiliary

GI organs

Foals in the early stages of sepsis are depressed and lethargic. The foals do not nurse with normal frequency.


Ophthalmic findings Fibrin in the anterior chamber Hypopyon Severe miosis Entropion (if the foal is dehydrated)


Neonatal septicemia/bacteremiaCommonly isolated bacteria in farm animals E coli Klebsiella spp Actinobacillus spp Streptococcus spp Arcanobacterium

pyogenes Salmonella spp Pasteurella spp

Presenter

Presentation Notes

The most commonly isolated bacteria is Escherichia coli. In a recent study only Gram negative bacteria were detected in the uveitic bacteremic foals. The pathogenicity of E. coli in the eye has not been clearly established. Ocular disease could be associated with direct bacterial spreading to the uveal tissue or with local vascular alterations induced by secondary endotoxemia, causing inflammation and exudation of proteins and cells into the aqueous humor.

Disease in farm animals Calves, piglets, kids and

lambs

Umbilical infections or ingesting bacteria.

Clinical signs include polyarthritis, meningitis and/or diarrhea.

Ocular lesions: fibrin clots in the AC, hypopyon or hyphema, miosis, and chorioretinal embolic lesions


Anaerobic Pathogens Anaerobic bacteria possess complex species-

dependent virulent mechanisms. Direct corneal damage

Elaboration of toxins, metabolites, enzymes, and degradation products

Indirect corneal damage Stimulation of corneal immune responses.

Anaerobic Bacteria Isolated from dogs, cats, horses and alpacas

with ulcerative keratitis.

Isolated from 13% of corneal samples.

Genera Clostridium, Peptostreptococcus, Actinomyces, Fusobacterium, and Bacteroides.

Positive correlation between isolation and ocular trauma, preexisting corneal disease and chronic dermatologic disease.

Anaerobic Pathogens

Concurrent or prior facultative aerobic bacterial multiplication

Aerobic bacteria may also produce essential nutrients, growth factors, energy substrates and protective enzymes.

Mixed infections provide mutual protection from phagocytosis and intracellular killing.

Anaerobic Pathogens

Most antimicrobials have limited to no microbial action against anaerobic pathogens.

Antimicrobial susceptibility patterns are relatively predictable (except Bacteriodes spp.)

Elimination of synergistic aerobic bacteria and disruption of low oxygen corneal microenvironment may be mechanism.

Anaerobic Pathogens

Stromal abscess in a dog.

Implicated in necrotic and suppurative deep tissue infections

Often mixed infections with facultatively anaerobic bacteria

Anaerobic Pathogens

Other Bacterial Infections

Rickettsia

Ehrlichia

Borrelia

Leptospira

Rickettsial species minute, obligate intracellular bacteria transmitted by ticks rod-shaped or coccobacilli 0.3 to 0.6 µm in length

•users.wfu.edu/derkls4/images/attachment%20of%...

contain both RNA and DNA replicate primarily within the

cytosol of target cells. nonmotile aerobic

Rocky Mountain Spotted Fever R rickettsii An acute febrile illness in dogs and humans. USA, Western Canada and Central and South

America.

Tick vectors are D variabilis and D andersoni. Methods for tick infection Transmission does not occur for 5-20 hours post

attachment

stri.discoverlife.org/IM/I_GA/0000/640/Dermac...

Rocky MountainSpotted Fever

Presenter

Presentation Notes

The ticks become infected horizontally during feeding on infected mammals or following transtatal replication within the tick midgut and transovarial transmission between generations of ticks.

Pathogenesis Vasculitis is the primary lesion Pathogenesis relates directly to the vascular lesions

which initiate platelet activation and activation of the coagulation system.


Presenter

Presentation Notes

The vasculitis occurs from direct infection of the vascular endothelium and perithelial smooth muscle from spread through the circulatory system later it occurs secondary to immunologic phenomena

Clinical signs in dogs FeverNeurologic dysfunction Polyarthritis Petechial and ecchymotic hemorrhages ThrombocytopeniaNonregenerative anemia

Signs begin within 3 days of tick attachment.

Hemorrhages most commonly occur on mucous membranes, but epistaxis, melenaand hematuria may be present in severely affected animals.


Ocular signs Altered vascular permeability in the conjunctiva,

uvea, and retina results in ocular signs.


Conjunctivitis conjunctivitis chemosis petechial hemorrhages mucopurulent to purulent

ocular discharge Anterior segment iris stromal petechiations anterior uveitis hyphema


Presenter

Presentation Notes

Evidence of conjunctivitis usually begins with onset of fever and includes conjunctival hyperemia, chemosis, petechial hemorrhages, and a mucopurulent to purulent ocular discharge.

Posterior segment retinitis characterized by perivasculitis,

focal areas of edema, and petechiation.

Unilateral or bilateral optic neuritis

Ocular disease may be confined to the retina

Ophthalmic lesions are usually mild



Experimental infectionFluorescein angiography ↑permeability in retinal

vessels beginning 6 days post infection and 2 days after onset of pyrexia.

Venules are more permeable than arterioles


Histopathology Necrotizing vasculitis with perivascular

accumulations of PMNs and lymphoreticular cells.

Organs with endarterial circulation such as skin, brain, heart, kidney and retina are affected.


Presenter

Presentation Notes

different from ehrlichiosis in that the most prominent lesion is one of necrotizing vasculitis with perivascular accumulations of polymorphonuclear and lymphoreticular cells.

Diagnosis

rising serum titers on micro IFA test

isolation

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http://www.answers.com/main/Record2?a=NR&url=http://commons.wikimedia.org/wiki/Image:Rickettsia%20rickettsii.jpg

http://www.answers.com/main/Record2?a=NR&url=http://commons.wikimedia.org/wiki/Image:Rickettsia%20rickettsii.jpg

http://www.answers.com/.../rocky-mountain-spotted-fever

Treatment Doxycycline Tetracycline Chloramphenicol Enrofloxacin 14-21 days is usually effective +/- inflammatory doses of oral prednisone in

conjunction with antibiotic therapy.


Ehrlichia canis

Causes canine monocytic ehrlichiosis

Acute, subclinical and chronic disease.

Gram - bacteria

Lack peptidoglycan and lipopolysaccharide components.

Transmission Obligate intracellular parasite transmitted by the

brown dog tick, Rhipicephalus sanguineus. The tick can transmit the disease more than 5

months after detaching from the canine host.

E. canis

Pathogenesis Replicates in mononuclear inflammatory cells

and circulating leukocytes

As perivascular tissues become infected, severe vasculitis may occur, resulting in bleeding and platelet consumption.

The morulae, which are cytoplasmic clusters of dividing organisms, can be seen microscopically in monocytes.

E. canis

Presenter

Presentation Notes

Circulating leukocytes are also targeted.

Disease in dogs Acute phase occurs 8-20 days post infection and

lasts 2-4 weeks. Common clinical signs include fever and depression +/- neurologic signs petechial and ecchymotic hemorrhages,

epistaxis lymphadenopathy limb edema vomiting

Ticks are found on 40% of dogs.

E. canis

Subclinical phase The subclinical phase lasts for weeks to months.

Clinical signs may regress.

E. canis

Chronic phase May persist for years Signs may include:

depression

weight loss

pale mucous membranes

abdominal tenderness

bleeding episodes

secondary infections

limb edema

E. canis

Associated with:

acute vasculitis

perivasculitis

thrombocytopenia

platelet dysfunction

hyperviscosity

Ocular signs

E. canis

Ocular signs Conjunctival hyperemia

and hemorrhages Corneal edema Deep corneal

vascularization Anterior uveitis Chorioretinitis Panuveitis Optic neuritis

E. canis

Chronic ocular signs

hyperproteinemia and hyperviscosity syndrome lead to retinal vascular engorgement

E. canis

Laboratory abnormalities Presence of morula on stained blood smears Bone marrow cytology with hypoplastic

elements, plasmacytosis, and mastocytosis IFA and PCR

Diagnosis

E. canis

Histopathology of E. canis The most consistent histopathologic finding is a

predominantly monocytic or lymphocytic cell infiltrate of the uveal tract, retina and optic nerve.

E. canis

Anaplasma platys Rickettsial parasite

Causes infectious thrombocytopenia in dogs

Reported to cause uveitis

E. chaffeensis, E. ewingii, and E. equi (in dogs) may also cause anterior uveitis.

Borreliosis or Lyme’s Disease Tick-borne spirochetosis Borrelia burgdorferi Small corkscrew shaped

motile microaerophilic bacteria.

Do not survive free living in the environment.

www.medicalecology.org/diseases/lyme/em.jpg

Highest incidence of disease remains in the northeastern US.

Transmission of B. burgdorferi Ticks of the Ixodes sp. Primary reservoirs are

small rodents and birds. Transmission relates to

contact time of the tick on the host 48 to 72 hours for a

38-92% transmission rate.

www.cdc.gov/.../images/TickMaster4_12_w452.gif

Pathogenesis Once inside the host, the

organisms use their specialized endoflagella to move through the connective tissues.

Organisms can survive for years in skin, connective tissue, joints and nervous system.

Borreliosis

Disease in dogs and cats Systemic signs in dogs and cats include

lameness, joint pain, pyrexia and lymphadenopathy.

Ocular lesions include conjunctivitis, corneal edema, anterior uveitis, retinal petechia, chorioretinitis, and retinal detachment

Definitive proof is lacking…..

Borreliosis

Borreliosis in other species Organisms were found in the anterior chamber

of a pony and 2 horses.

Humans exhibit conjunctivitis, keratitis, panuveitis, chorioretinitis, retinal detachment, optic neuritis and periorbital edema.

Borreliosis

VO (2012) 15, 6, 398–405

Diagnosis There is a high prevalence of serum + antibody

titers (75%) with actual disease in ~ 5-10% of dogs.

www.lersus.de/.../1/res/files/borrelia_0_.jpg

Current lab tests employ the specific c6 lipoprotein antigen in ELISA and western blot

Borreliosis

Presenter

Presentation Notes

Diagnosis was previously problematic because vaccination resulted in positive results using ELISA and IFA tests. Antibodies may persist for months to years following vaccination or natural infection. Current lab tests that employ the specific c6 lipoprotein antigen (EIA, ELISA) or western blot �procedure have overcome this problem.

Leptospirosis Motile spirochetal bacteria The predominant serovars responsible for

causing disease in dogs are canicola, icterohemorrhagica, grippotyphosa, pomona, and bratislava.

Maintained in host adapted species that act as reservoir hosts and is shed in the urine.

Direct transmission through contact with infected urine, bites, ingestion of affected material and contact with contaminated water.

http://www.med.monash.edu.au/microbiology/staff/adler

Presenter

Presentation Notes

. Leptospira are the smallest spirochete bacteria, measuring < 0.3 µm in width and 6 to 30 µm in length. They have a tightly wound spiral shape. The organisms are motile and able to enter hosts by penetrating mucous membranes or abraded skin mechanically. They do not stain with conventional pathology stains and require a special silver impregnation stain for identification. Leptospira are aquatic unicellular organisms found in river and lake waters and in sewage. Principle reservoirs are deer, cattle, swine, and rats. The organisms multiply in the kidneys of adapted hosts and are shed in the urine. Organisms only have a short life in soil; however, they can live in water for up to six weeks. Horses pastured next to unvaccinated cattle or pigs and horses that live on farms frequented by deer or infested with rats are at increased risk for exposure. Direct transmission can occur through contact with infected urine, bites, ingestion of affected material and contact with contaminated water.

Vasculitis and endotheliitis involving the kidneys, liver, spleen, muscles, central nervous system, and eyes occur.

Leptospirosis

Presenter

Presentation Notes

Multifocal hepatic necrosis Interstitial nephritis

Lesions in dogsInfrequent

conjunctivitis with mucopurulent oculonasal discharge

scleritis

anterior uveitis

Systemic signs renal or hepatic failure or dysfunction.

Leptospirosis

Disease in horsesAcute signs Transient depression, fever, icterus, anemia

and anorexia. Serologic surveys of horses have shown that

exposure to Leptospira is common, but variable, according to the geographic location or climate.

Horses positive for leptospirosis are common in the Ohio, Delaware, Tennessee, and Mississippi river valleys.

Leptospirosis

Leptospira interrogansmost likely plays a role in many cases of ERU.

20 serovars L interrogans serovar

pomona is most often associated with ERU.

Usually horses develop ERU 18 to 24 months after the initial infection.

Leptospirosis

Presenter

Presentation Notes

Leptospiral bacteria have been avidly sought in ocular tissues. Evidence of their presence has been intriguing, yet sparse.

Diagnosis

Clinical signs Microscopic agglutination test or ELISA Histology PCR Cultured from the aqueous humor of dogs Can be shed in the urine up to 3 months

www.buddycom.com/bacteria/nongram/leptofa1346.jpg

Sequestered in kidneys, liver, spleen, CNS and eyes.

Presenter

Presentation Notes

only the MAT is serovar specific Leptospira can be shed in the urine for up to 3 months.



Proteases and toxins Increase virulence by damaging tissue and

interfering with host defense systems. Exo-products contribute directly to keratitis

through toxic effects on corneal cells and degradation of corneal proteins and indirectly through activation of corneal proteases.

Presenter

Presentation Notes

P. aeruginosa produces several proteases and toxins that increase virulence by damaging tissue and interfering with host defense systems. Exo-products including exotoxin-A and enzyme-S contribute directly to keratitis through toxic effects on corneal cells and degradation of corneal proteins and indirectly through activation of corneal proteases.

Documents

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