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1 1 - - Spore-Forming Gram-Positive Bacilli: Spore-Forming Gram-Positive Bacilli: A- Strict aerobic – Genus A- Strict aerobic – Genus Bacillus Bacillus . . B- Strict anaerobic – Genus B- Strict anaerobic – Genus Clostridium Clostridium . . Spore- forming gram positive strict aerobic capsulated bacilli, 1x3-4 u size, arranged in long chains; spores may central, subterminal or terminal, depending on the species. Most members are saprophytic prevelent in soil, water, air and vegetation such B. cereus, and B. subtilius. Some are insect pathogens . Cause the disease Anthrax in animals in which the organism is transmitted through eating vegetations containing the spores. Human is infected through contact with animals or their products . A- Cutaneous Anthrax(malignant pustule): Generally occurs on exposed surfaces of the arms, face and neck through wound contamination by the spores of the organism. About 95% of the cases with amortality rate 20% . B- Inhalation Anthrax(wool sorter disease): About 5% of the cases with 85-90% mortality .

1- Spore-Forming Gram-Positive Bacilli: A- Strict aerobic – Genus Bacillus. B- Strict anaerobic – Genus Clostridium. Spore- forming gram positive strict

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11 - -Spore-Forming Gram-Positive Bacilli:Spore-Forming Gram-Positive Bacilli: A- Strict aerobic – Genus A- Strict aerobic – Genus BacillusBacillus..B- Strict anaerobic – Genus B- Strict anaerobic – Genus ClostridiumClostridium..

Spore- forming gram positive strict aerobic capsulated bacilli, 1x3-4 u size, arranged in long chains; spores may central, subterminal or terminal, depending on the species. Most members are saprophytic prevelent in soil, water, air and vegetation such B. cereus, and B. subtilius. Some are insect pathogens.

Cause the disease Anthrax in animals in which the organism is transmitted through eating vegetations containing the spores. Human is infected through contact with animals or their products.

A- Cutaneous Anthrax(malignant pustule): Generally occurs on exposed surfaces of the arms, face and neck through wound contamination by the spores of the organism. About 95%

of the cases with amortality rate 20% .

B- Inhalation Anthrax(wool sorter disease): About 5% of the cases with 85-90% mortality.

The anthrax bacillus, Bacillus anthracis, was the first bacterium shown to be the cause of a disease. In 1877, Robert Koch grew the organism in pure culture, demonstrated its ability to form endospores, and produced experimental anthrax by injecting it into animals.

Robert Koch's original micrographs of the anthrax bacillus Robert Koch's original micrographs of the anthrax bacillus

Robert Koch's original Robert Koch's original micrographs of the anthrax micrographs of the anthrax

bacillusbacillus

Bacillus anthracis. Bacillus anthracis. Gram stain. The cells have Gram stain. The cells have characteristiccharacteristic

squared ends. The endospores are ellipsoidal shaped and squared ends. The endospores are ellipsoidal shaped and locatedlocated

centrally in the sporangium. The spores are highly centrally in the sporangium. The spores are highly refractile torefractile to

light and resistant to staininglight and resistant to staining..

Bacillus cereus

C- Gastrointestinal Anthrax: Is very rare.C- Gastrointestinal Anthrax: Is very rare.Laboratory DiagnosesLaboratory DiagnosesSpecimen: Specimen: Fluid, pus, blood, sputum.Fluid, pus, blood, sputum.Gram stain.Gram stain.Culture on blood agar.Culture on blood agar.Treatment: PenicillinTreatment: Penicillin..

Cause food poisoning: Two types

1 -Emitic type associated with fried rice.

2 -Diarrheal type associated with meat dishes and sauces

Large anaerobic gram positive spore forming motile rods. Many decompose protein or form toxins and some do both. Their natural habitat is the soil or the intestinal tract of

human and animals, where they live as saprophytes. Among the pathogens are the organisms causing botulism, tetanus, gas gangrene, and

pseudomembranous colitis.

Spores of clostridia are usually wider than the diameter of the rods in which they are formed.

In most species, the spores are located centrally, subterminally or terminally. Most species of

Clostridia are motile with peritrichous flagella.

Culture: Clostridia are anaerobes and grow under anaerobic conditions. Few are aerotolerant. Anaerobic conditions can be established by:

1 -Agar plates or culture tubes incubated in anaerobic jar(Gaspack jar).

2 -Fluid media in deep tubes containing either fresh animal tissue(chopped cooked medium) or

o.1% agar and a reducing agent(fluid thioglycolate).

Colony Forms

Growth Characteristics.

Causes botulism, found in soil and occasionally in animal feces.

Toxins: Seven varieties(A-G). Types A & B and occasionally F cause human illness.

PathogenesisPathogenesisClinical Finding:Clinical Finding: Symptoms begin 18-24 hours after ingestion of the toxic food. GI Symptoms begin 18-24 hours after ingestion of the toxic food. GI symptoms are not regularly prominent. No fever, with visual disturbances, inability to swallow symptoms are not regularly prominent. No fever, with visual disturbances, inability to swallow and speech difficulty, paralysis and death due toand speech difficulty, paralysis and death due torespiratory paralysis or cardiac arrest.respiratory paralysis or cardiac arrest.Diagnostic Laboratory TestsDiagnostic Laboratory TestsTreatmentTreatment

Causes Tetanus, worldwide in distribution in the soil,and in the feces of horses and other animals.

Toxins: Tetanospasmin

Pathogenesis: Wound contamination, not an invasive organism. The toxins released from vegetative cells reaches the CNS and rapidly becomes fixed to receptors in the spinal cord and brain stem and exerts their action.

Clinical Findings: Incubation period: 4-5 days to many weeks. The disease is chacterized by tonic contraction of voluntary muscles.

Diagnosis

Prevention and Treatment

Many different- toxin producing clostridia can produce invasive infections(including myonecrosis and gas gangrene) if introduced into damaged tissue. About 30 species of clostridia may produce such an infection, but the most common in invasive disease is C. perfringens(90%). An enterotoxin of C. perfringens is a common cause of food poisoning.

Toxins: produce different types of toxins and enzymes that result in spreading infection. They have lethal, necrotizing, and hemolytic properties .

Pathogenesis: Wound contamination.

Clinical Findings: Infection spreads in 1-3 days. Crepitation in subcutaneous tissue and muscle, fever, tissue necrosis, hemolytic anemia, severe toxemia and death.

Laboratory Diagnosis

Treatment

Prevention and Control

Pseudomembranous colitis(Antibiotic – Associated Diarrhea).

The Genus The Genus ClostridiumClostridiumLeft. Stained pus from aLeft. Stained pus from a mixed anaerobic infection. mixed anaerobic infection.

At least three different clostridia are apparent. At least three different clostridia are apparent. Right. Electron micrograph of Right. Electron micrograph of Clostridium tetaniClostridium tetani

C. botulinum

C.perfringens

C. tetaniC. difficile

These are a diverse group of bacteria, many members of which are normal flora of the skin and mucous membranes.

Morphology and Identification

Corynebacteria are 0.5-1u in diameter and several micrometers long.. Metachromatic granules(metaphosphate) are irregularly distributed within the rods giving them beaded appearance. The rods tend to be parallel or at acute angles to one another. Colonies on blood agar are small, granular and gray and may have small zone of haemolysis. Four biotypes: Gravis, mitis,intermedius and belfanti.

Pathogenesis

The disease Diphtheria is caused by lysogenic C. diphtheriae(toxin producer). It is a droplet infection in which the organism pass through the nasopharynx.

Stained Corynebacterium cells. The "barred" appearance is due to the presence of polyphosphate inclusions called metachromatic granules. Note also the characteristic "Chinese-letter" arrangement of cells.

C. diphtheriaeC. diphtheriae

PathologyPathologyPseudomembrane over the tonsils, pharynx, larynxPseudomembrane over the tonsils, pharynx, larynxDamage by toxins to heart muscle, liver, kidneys, and adrenals. Also nerve damage Damage by toxins to heart muscle, liver, kidneys, and adrenals. Also nerve damage resulting in paralysis of the soft palate, eye muscles or extermities.resulting in paralysis of the soft palate, eye muscles or extermities.

Clinical FindingsClinical FindingsFever, sore throat, dyspnea because of the obstruction caused by the membrane. Later onFever, sore throat, dyspnea because of the obstruction caused by the membrane. Later ondifficulties with vision, soeech, swallowing, or movement of the arms or legs. Var gravis is difficulties with vision, soeech, swallowing, or movement of the arms or legs. Var gravis is more severe. Symptoms ten to subside spontaneously.more severe. Symptoms ten to subside spontaneously.

Laboratory DiagnosesLaboratory DiagnosesSpecimen: Specimen: Throat swabThroat swabGram stainGram stainMedia for Culture:Media for Culture: Blood agar, potassium tellurite, Loefler slant. Blood agar, potassium tellurite, Loefler slant.

Toxigenicity test: Toxigenicity test: Invitro and Invivo test.Invitro and Invivo test.

Treatment: Treatment: Antitoxin and antibiotics(penicillin).Antitoxin and antibiotics(penicillin).

Epidemiology, Epidemiology, Prevention and controlPrevention and control

DPT VaccineDPT Vaccine..

Listeria monocytogenes are facultative anaerobic non-sporing Gram-positive motile rods that are catalase positive. They are widespread throughout nature, having been isolated from the environment and from many animals. L. monocytogenes grows under refrigeration temperatures from 1°C up to 44°C. It grows at pH values of between 4.6 and 9.6 and their minimum water activity value for growth is 0.90. L. monocytogenes is easily destroyed by heat and food poisoning outbreaks are relatively rare. There are several species in the genus listeria, L. monocytogenes is important as a cause of a wide spectrum of disease in animals and humans.Pathology and Mode of TransmissionInfection is through eating contaminated foods such cheese, meat, or vegetables.Clinical Findings The symptoms of listeriosis are variable and are dependant on the susceptibility of the person affected. Some people experience flu-like symptoms such as fever, convulsions, chills, backache, headache, diarrhoea and vomiting. Susceptible people may experience pyrexia, meningitis, septicaemia and spontaneous abortion just to name a few.Perinatal human listeriosis(granulomatosis infantiseptica may be intrauterine infection which may result inintrauterine sepsis and death before or after delivery. Meningitis between birth and 3rd week of life.Laboraytory DiagnosesTreatment

Morphology and IdentificationMorphology and Identification

Causes erysipelas in animals specially swine. Human is infected directly by contact. The disease is called erysipeloid usually occurs on the fingers.

Large diverse group of gram positive bacilli with a tendency to form chains and filaments. Most are saprophytes that live in the soil. Members are responsible for three humen infections

1 -Actinomcosis: Chronic suppurative granuolomatous infection.

Caused by Actinomyces israeli. Cervicofacial, thoracic, and abdominal

2 -Nocardiosis

Caused by Nocardia asteroides , gram positive, weakly acid fast. Present as subacute and chronic pulmonary infection that may disseminate to other organs, usually the brain or skin.

,3 -Actinomycetoma

Mycetoma(Madura foot) is a localized slowly progressive , chronic infection that begins in subcutaneous tissue and spread to adjacent tissues. It is destructive and often painless

Gram positive cocci1 um in diameter arranged in irregular clusters, single,pairs, chains, tetrads, nonmotile, uncapsulated, non-spore formers, facultative anaerobes, grow most rapidly at 37c. They grow readily on many types of media and active metabolically, fermenting carbohydrates and produce pigment that range from white to deep yellow. All staphylococci are catalase positive.

The genus Staphylococcus has at least 30 species. The three main species of clinical importance are: Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus saprophyticus.

Can produce disease both through their ability to multiply and spread widely in tissues and through their production of many intracellular substances. Some are enzymes, others are toxins.

Catalase, Coagulase, hyaluronidase, staphylokinase, exotoxins, leukocidin, exfoliative toxin, toxic shock syndrome toxin, entertoxins.

Pathogenesis and pathology

Clinical findings

Laboratory diagnosis

Treatment

Usually present as normal flora on the skin, nonpathogenic.

Urinary tract infection specially in sexually active young womenUrinary tract infection specially in sexually active young women

Gram stain of Gram stain of Staphylococcus aureusStaphylococcus aureus

    Negative tube coagulase test

    Positive tube coagulase test

Mannitol negative Mannitol positive

                                        

StreptococciStreptococci

Dividing Streptococci M protein

Impetigo Tonsillitis

Morphology and IdentificationMorphology and IdentificationIndividual cocci are spherical or ovoid arranged in chains and diploes, non-motile, some are capsulated, Individual cocci are spherical or ovoid arranged in chains and diploes, non-motile, some are capsulated,

anaerobes, facultative anaerobes, non-spore formers. Some require 5-10% CO2 for growth. Streptoccci anaerobes, facultative anaerobes, non-spore formers. Some require 5-10% CO2 for growth. Streptoccci are alpha hemolytic, Bata hemolytic or nonhemolyticare alpha hemolytic, Bata hemolytic or nonhemolytic..

Antigenic structureAntigenic structure11 - -Group – specific cell wall antigen: Carbohydrate present in the cell-wall of many streptococci and Group – specific cell wall antigen: Carbohydrate present in the cell-wall of many streptococci and

forms the basis of serological groupings( Lancefield groups A-H, K-U )forms the basis of serological groupings( Lancefield groups A-H, K-U )..22 - -M protein: Major virulence factor of group A Streptococcus pyogenesM protein: Major virulence factor of group A Streptococcus pyogenes..

33 - -T substance: Has no relation to virulenceT substance: Has no relation to virulence..44 - -Nucleoprotein: Called P substances which probably make up most of the streptococcal cell bodyNucleoprotein: Called P substances which probably make up most of the streptococcal cell body..

Toxins and EnzymesToxins and EnzymesA- Streptokinase(Fibrinolysin)A- Streptokinase(Fibrinolysin)..

B- StreptodornaseB- Streptodornase..C- HyaluronidaseC- Hyaluronidase..

D- Erythrogenic ToxinsD- Erythrogenic Toxins..E - Diphosphopyridine nucleotidaseE - Diphosphopyridine nucleotidase..

F- HemolysinsF- HemolysinsS. pyogenesS. pyogenes elaborates two hemolysins(streptolysins): Streptolysin O (ASOT) and Streptolysin S(B elaborates two hemolysins(streptolysins): Streptolysin O (ASOT) and Streptolysin S(B

hemolysis)hemolysis)

A- A- Streptococcus pyogenesStreptococcus pyogenes( Group A B Hemolytic Streptococci)( Group A B Hemolytic Streptococci)..B- B- Streptococcus agalactiaeStreptococcus agalactiae: These are group streptococci: These are group streptococci..

C- Groups C and GC- Groups C and G..D- D- Enterococcus fecalis(E. faecum, E duransEnterococcus fecalis(E. faecum, E durans): Group D): Group D..

E- E- Streptococcus bovisStreptococcus bovis: Nonenterococcal group D streptococci: Nonenterococcal group D streptococci..F- F- Streptococcus anginosisStreptococcus anginosis..

G- Group N StreptococciG- Group N Streptococci..H- Groups E,F,G, H and K-U StreptococciH- Groups E,F,G, H and K-U Streptococci..

I- I- Streptococcus pneumoniaeStreptococcus pneumoniae..J- Viridans Strepococci: J- Viridans Strepococci: (S. mitis, S. mutans, S. salivaris, S. sanguis(S. mitis, S. mutans, S. salivaris, S. sanguis))..

K- Nutritionally Variant StreptococciK- Nutritionally Variant Streptococci..L- L- Peptostreptococcus Peptostreptococcus (Many Species) (Many Species)..

Pathogenesis and Clinical FindingsPathogenesis and Clinical FindingsInfections can be divided into several categoriesInfections can be divided into several categories::

A- Diseases caused by A- Diseases caused by S. pyogenesS. pyogenes::11 - -ErysipelasErysipelas

22 - -CellulitisCellulitis33 - -Necrotizing fasciitis(streptococcal gangrene)Necrotizing fasciitis(streptococcal gangrene)..

44 - -Puerperal feverPuerperal fever..55 - -SepsisSepsis..

66 - -Streptococcal sore throatStreptococcal sore throat

Alpha haemolytic streptococciBeta hemolytic

77 - -Streptococcal pyodermaStreptococcal pyoderma8- Infective endocarditis: acute and subacute.8- Infective endocarditis: acute and subacute.9- Streptococcal toxic shock syndrome9- Streptococcal toxic shock syndrome10- Scarlet fever.10- Scarlet fever.

Poststreptococcal DiseasesPoststreptococcal Diseases1- Rheumatic Fever1- Rheumatic Fever2- Acute Glomerulonephritis2- Acute Glomerulonephritis

Laboratory Diagnosis

-!Specimen

2 -Smear

3 -Culture

4 -Antigen Detection Test

5 -Serology

Streptococcal pneumoniae

Pathology and Clinical Findings

Laboratory Diagnosis

Treatment

Gram negative cocci usually in pairs, nonmotile, nonspore forming o.8u in diameter, facultative anaerobes, or aerobes. All neisseriae are oxidase positive.

Nonpathogens:

N. flavescens, N. flava, N. subflave, N. sicca, N. lactamica.

Two important pathogens

N. gonorrhoeae(gonococcia)

N. meningitidis(meningococcia)

N. Gonorrhoeae

Antigenic structure

Pathogenesis and clinical findings

Gonococci attack mucous membranes of the genitourinary tract, eye, rectum, and throat, producing acute suppuration that may lead to tissue invasion, this is followed by chronic inflammation and fibrosis.

Ophthalmia neonatorum

Diagnostic Laboratory test1 -Specimen

2 -Smear

3 -Culture

Immunity

Treatment

Epidemiology

Antigenic Structure

Pathogenesis and Clinical Findings

Diagnostic Laboratory Tests

1 -Specimens

2 -Smears

3 -Culture

4 -Serology

Immunity

Treatment

Epidemiology

Neisseria

Neisseria

Large heterogeneous group of gram negative rods whose natural habitat is the intestinal tract of humans and animals. Facultative anaerobes, oxidase negative, ferment glucose with the production of acid or acid and gas, reduce nitrate to nitrite. Most are motile with

peritrichous flagella, some have a polysaccharide capsule .

According to lactose fermentation, enterobacteriaceae are classified into:

1 -Rapid lactose fermenters: ferment lactose in 24 hours.

Escherichia coli

Klebsiella pneumoniae

Enterobacter aerogenes

2 -Late lactose fermenters: ferment lactose in 48 hours or do not ferment lactose.

Edwardsella, Serratia, Citrobacter, Arizona, Providencia, Erwinia.

3 -Non-lactose fermenters

Shigella, Salmonella , Proteus

Some enteric organisms are present as normal flora in the intestinal tract of human and animals causing infections in other tissues and organs.

Others are pathogens:

1 -E. coli associated with diarrheal disease.

2 -Shigella.

3 -Salmonella.

Antigenic Structure

Enterobacteriaceae have a complex antigenic structure.

>150 different heat stable somatic O Ag.

>100 heat labile K (capsular ) Ag.

>50 H (flagellar ) Ag.

Bacteriocines

Protein antibiotics like substance produced by many gram negative bacteria in which their production is controlled by a plasmid. They are active against strains of the same species and closely related species but not the producer strain.

Colicins by E. coli.

Marcescins by Serratia marcescins.

Pyocins by Pseudomonas aeruginosa.

Salmonella Shigella Listeria

Norwalk virus E. coli 0157:H7 Campylobacter

HAV

Salmonella

Salmonella

Diseases Caused by Enterobacteriaceae Other Than Salmonella and Shigella

A- E. coli

1 -Urinary tract infection.

2 -E. coli associated diarrheal diseases

a- EPEC

b- ETEC

C- EHEC

d- EIEC

e- EAEC

3 -Sepsis.

4 -Meningitis.

5 -Otitis media

6 -Wound infection

B- Klebsiella-Enterobacter-Serratia; Proteus-Morganella-Providencia; and Citrobacter: Respoiratory tract, urinary tract, sepsis, otitis media

S. dysenteriae, S. sonnei, S. flaxonari, S. boydii.: Bacillary dysentery

Morphology and Growth Characteristics

Pathogenesis and Pathology

Toxins

Clinical Findings

Diagnostic Laboratory Tests

Immunity

Treatment

Epidemiology, prevention and control.

S. typhi, S. paratyphi A and B , S. cholerasuis, S. typhimurium, S. entertidis.

Morphology and Identification.

Classification.

Pathogenesis and Clinical Findings

S. typhi, S. paratyphi A and B , S. cholerasuis, S. typhimurium, S. entertidis are of human origin. The vast majority are animal pathogens that constitute the reservoir for human infection.

Three main types of disease in human:

A- The Enteric Fevers

B- Bacteremia with Focal Lesions

C- Enterocolitis

Diagnostic Laboratory Tests

1 -Specimens.

2 -Culture.

3 -Identification by biochemical tests and serology.

4 -Agglutination test( Widal test).

Immunity

Treatment

Epidemiology