Chapter 21 Miscellaneous Bacterial Agents of Disease

Chapter 21Chapter 21

Miscellaneous Bacterial Miscellaneous Bacterial Agents of DiseaseAgents of Disease

Spirochetes Spirochetes

Genus - Genus - TreponemaTreponema T. pallidumT. pallidum ssp. pallidum (syphilis) ssp. pallidum (syphilis) T. pallidumT. pallidum ssp. pertenue (yaws) ssp. pertenue (yaws) T. pallidumT. pallidum ssp. endemium (non-endemic ssp. endemium (non-endemic

syphilis)syphilis) T. carateumT. carateum (pinta) (pinta)

Genus - Genus - BorreliaBorrelia B. recurrentisB. recurrentis - relapsing fever - relapsing fever B. burgdorferiB. burgdorferi - Lyme disease - Lyme disease

Genus - Genus - Leptospira interrogansLeptospira interrogans

General characteristics of General characteristics of Spirochetes Spirochetes

Flexible, helically-Flexible, helically-shaped cylindrical body shaped cylindrical body composed of composed of peptidoglycan & peptidoglycan & cytoplasmic membrane cytoplasmic membrane enclosing cytoplasmenclosing cytoplasm TreponemaTreponema - loosely - loosely

coiledcoiled BorreliaBorrelia - loosely coiled - loosely coiled LeptospiraLeptospira - thin, tightly - thin, tightly

coiled with hooked endscoiled with hooked ends

General characteristics of General characteristics of SpirochetesSpirochetes

Multi-layered outer envelope Multi-layered outer envelope surrounding cellsurrounding cell

Flagella attached between outer Flagella attached between outer membrane & cylindrical body at each membrane & cylindrical body at each end (internal)end (internal)

Have a flexous form of motilityHave a flexous form of motility

Clinical Manifestations of Clinical Manifestations of Treponema Treponema

T. pallidumT. pallidum ssp. pallidum (syphilis) ssp. pallidum (syphilis) Goes through several stages over a period of years Goes through several stages over a period of years Primary syphilis - characterized by lesion at portal of entry Primary syphilis - characterized by lesion at portal of entry

into body = hard chancre; occurs about 3 weeks after into body = hard chancre; occurs about 3 weeks after infection; large numbers of organisms present in lesion; infection; large numbers of organisms present in lesion; lesion heals spontaneouslylesion heals spontaneously

T. pallidumT. pallidum ssp. pallidum ssp. pallidum (syphilis)(syphilis)

Secondary syphilis - may occur either before or after chancre has Secondary syphilis - may occur either before or after chancre has healed; lesions are widespread (organisms spread by lymphatics healed; lesions are widespread (organisms spread by lymphatics and blood) and contain many organisms; lesions most often and blood) and contain many organisms; lesions most often found on mucous membranes and skin (including palms of hands found on mucous membranes and skin (including palms of hands & soles of feet); lesions disappear in 2-4 weeks; disease is either & soles of feet); lesions disappear in 2-4 weeks; disease is either cured spontaneously after secondary stage or becomes latentcured spontaneously after secondary stage or becomes latent

T. pallidumT. pallidum ssp. pallidum ssp. pallidum (syphilis)(syphilis)

Tertiary syphilis - may occur Tertiary syphilis - may occur 3-20 years after initial 3-20 years after initial infection; characterized by infection; characterized by granulomatous lesions granulomatous lesions called gummas which may called gummas which may involved skin, mucous involved skin, mucous membranes, soft tissue, membranes, soft tissue, bone, eyes, CNS (may lead bone, eyes, CNS (may lead to paralysis and dementia) to paralysis and dementia) & cardiovascular system & cardiovascular system (may cause aortic (may cause aortic aneurysm) aneurysm)

T. pallidumT. pallidum ssp. pertenue ssp. pertenue (yaws) (yaws)

Largely restricted Largely restricted to rural areas of to rural areas of tropical countriestropical countries

Characterized by Characterized by destruction of destruction of lesions of skin & lesions of skin & bonebone

T. pallidumT. pallidum ssp. endemium ssp. endemium (nonvenereal endemic syphilis)(nonvenereal endemic syphilis)

Found solely in less-developed Found solely in less-developed tropical & subtropical areastropical & subtropical areas

Milder form of syphilis occurring in Milder form of syphilis occurring in childhoodchildhood

T. carateumT. carateum (pinta) (pinta)

Occurs in South & Central AmericaOccurs in South & Central America Characterized by dyschromic skin Characterized by dyschromic skin

lesions that eventually become lesions that eventually become depigmenteddepigmented

Epidemiology of Epidemiology of TreponemaTreponema

Habitat Habitat Oral cavity, intestinal tract & genitals of Oral cavity, intestinal tract & genitals of

humans & animalshumans & animals Routes of transmissionRoutes of transmission

Venereal (Venereal (T. pallidumT. pallidum ssp. pallidum) and non- ssp. pallidum) and non-venereal (other treponemes) venereal (other treponemes)

Prevention & Control Prevention & Control As with other venereal disease As with other venereal disease

Treatment Treatment Penicillin or tetracycline Penicillin or tetracycline

LeptospiraLeptospira - leptospirosis - leptospirosis

Zoonosis of worldwide distribution in rodents, bats Zoonosis of worldwide distribution in rodents, bats fox, opossum and raccoon (usually asymptomatic)fox, opossum and raccoon (usually asymptomatic)

May be transmitted to domesticated animals May be transmitted to domesticated animals including cattle, sheep, goats, pigs, horses & dogsincluding cattle, sheep, goats, pigs, horses & dogs

Infection in humans not diagnostic - can manifest Infection in humans not diagnostic - can manifest as meningitis, hepatic disease & kidney disease as meningitis, hepatic disease & kidney disease with symptoms such as headache, muscle with symptoms such as headache, muscle tenderness, anorexia, nausea & vomiting; usually tenderness, anorexia, nausea & vomiting; usually self-limitingself-limiting

Severe human infections characterized by icterus; Severe human infections characterized by icterus; often referred to as Weil’s disease; kidney failure often referred to as Weil’s disease; kidney failure may also occurmay also occur

Epidemiology of Epidemiology of LeptospiraLeptospira

Habitat Habitat Maintained in wild animals Maintained in wild animals

Routes of transmission Routes of transmission Direct or indirect contact with infected urine Direct or indirect contact with infected urine

Prevention & Control Prevention & Control Drink only potable water; vaccines available for Drink only potable water; vaccines available for

domestic animals, especially dogsdomestic animals, especially dogs Treatment Treatment

Penicillin; appears to be effective only if given Penicillin; appears to be effective only if given during early (2-4 days) of illness; supportive during early (2-4 days) of illness; supportive therapy may also be necessarytherapy may also be necessary

Borrelia: Borrelia: Arthropod-Borne Arthropod-Borne SpirochetesSpirochetes

B. recurrentisB. recurrentis - relapsing fever - relapsing fever Louseborne (epidemic) or tickborne (endemic)Louseborne (epidemic) or tickborne (endemic) Fever occurs 2-15 days after infection Fever occurs 2-15 days after infection

accompanied by headache & myalgia which accompanied by headache & myalgia which lasts 4-10 days (spirochetemia) followed by lasts 4-10 days (spirochetemia) followed by afebrile period lasting a few days to several afebrile period lasting a few days to several weeks during which new antigenic types developweeks during which new antigenic types develop

Cycle repeats (usually once in louseborne & up Cycle repeats (usually once in louseborne & up to 10 times in tickborne)to 10 times in tickborne)

Myocarditis most common cause of deathMyocarditis most common cause of death

The Pattern in Relapsing Fever, The Pattern in Relapsing Fever, based on symptoms (fever) over based on symptoms (fever) over

timetime

Borrelia: Borrelia: Arthropod-Borne Arthropod-Borne SpirochetesSpirochetes

B. burgdorferiB. burgdorferi - Lyme - Lyme DiseaseDisease

Zoonoses associated with Zoonoses associated with rabbits transmitted to man rabbits transmitted to man via ticks that are via ticks that are maintained in environment maintained in environment in deerin deer

Begins as lesion at site of Begins as lesion at site of tick bite characterized by tick bite characterized by erythema that expands erythema that expands with time appearing as a with time appearing as a bullseye; may be bullseye; may be accompanied by malaise, accompanied by malaise, fatigue, headache, fever, fatigue, headache, fever, chills, stiff neck, arthralgias chills, stiff neck, arthralgias & myalgias & myalgias

May develop aseptic May develop aseptic meningitis, encephalitis & meningitis, encephalitis & carditiscarditis

Untreated cases often Untreated cases often develop arthritisdevelop arthritis

Disease rarely fatalDisease rarely fatal

The Cycle of Lyme Disease in The Cycle of Lyme Disease in the northeastern USthe northeastern US

Epidemiology of Epidemiology of BorreliaBorrelia

Habitat Habitat Humans only reservoir of louseborne Humans only reservoir of louseborne B. recurrentisB. recurrentis; ;

tickborne tickborne B. recurrentisB. recurrentis primarily zoonoses in rodents primarily zoonoses in rodents with rabbits major sourcewith rabbits major source

B. burgdorferiB. burgdorferi maintained in nature in rabbits & deer & maintained in nature in rabbits & deer & transmitted to man via tickstransmitted to man via ticks

Routes of transmission Routes of transmission Insect borne Insect borne

Prevention & Control Prevention & Control Avoid contact with lice & ticks Avoid contact with lice & ticks

Treatment Treatment TetracyclineTetracycline

Curviform Gram-Negative Curviform Gram-Negative Bacteria and Enteric DiseasesBacteria and Enteric Diseases

VibrionaceaeVibrionaceae VibrioVibrio Comma-shaped rods, with a single polar Comma-shaped rods, with a single polar

flagellumflagellum CampylobacteriaceaeCampylobacteriaceae

CamylobacterCamylobacter Short spirals or curved rods with one flagellumShort spirals or curved rods with one flagellum

HelicobacteriaceaeHelicobacteriaceae HelicobacterHelicobacter Tight spirals and curved rods with several polar Tight spirals and curved rods with several polar

flagellaflagella

V. cholerae O:1 and non-O:1 - V. cholerae O:1 and non-O:1 - choleracholera

Severity varies greatly - most severe Severity varies greatly - most severe characterized by massive loss of fluid (10-15 characterized by massive loss of fluid (10-15 liters/day) and electrolytes through intestine; liters/day) and electrolytes through intestine; produce condition sometimes called “rice-produce condition sometimes called “rice-water stools”; organisms do not spread water stools”; organisms do not spread beyond intestine; may be fatal in a few hoursbeyond intestine; may be fatal in a few hours

Acquired via contaminated food (esp. meat, Acquired via contaminated food (esp. meat, fish and other seafood, milk & ice cream) & fish and other seafood, milk & ice cream) & water - person to person transmission rarewater - person to person transmission rare

Fluid loss due to enterotoxin (choleragen) Fluid loss due to enterotoxin (choleragen) that acts similar to LT enterotoxin produced that acts similar to LT enterotoxin produced byby E. coli E. coli

V. parahemolyticusV. parahemolyticus

Causes acute illness characterized by Causes acute illness characterized by severe cramping, abdominal pain severe cramping, abdominal pain and explosive watery diarrheaand explosive watery diarrhea

Organisms present in coastal waters Organisms present in coastal waters throughout world including Louisiana; throughout world including Louisiana; most cases in US traced to ingestion most cases in US traced to ingestion of incompletely cooked shellfishof incompletely cooked shellfish

V. vulnificusV. vulnificus

Causes both wound infections & Causes both wound infections & gastroenteritisgastroenteritis

Can also produce a life-threatening Can also produce a life-threatening bacteremia which is most severe in bacteremia which is most severe in persons with liver disease - acquired persons with liver disease - acquired by ingestion of contaminated by ingestion of contaminated seafood or contamination of cuts seafood or contamination of cuts with seawaterwith seawater

Epidemiology of Epidemiology of VibrioVibrio

Habitat Habitat Primarily of aquatic habitat; infections often acquired Primarily of aquatic habitat; infections often acquired

from water sourcefrom water source Routes of transmission Routes of transmission

Ingestion - contaminated food (fish = vibrios) and water Ingestion - contaminated food (fish = vibrios) and water Prevention & Control Prevention & Control

Proper cooking of fish Proper cooking of fish Vaccines - cholera vaccines give only limited protection; Vaccines - cholera vaccines give only limited protection;

do not confer life-long immunity do not confer life-long immunity Treatment Treatment

Antimicrobial therapy based on antibiogramAntimicrobial therapy based on antibiogram Supportive therapy - fluid replacement Supportive therapy - fluid replacement

CampylobacterCampylobacter

C. fetusC. fetus ssp. fetus - septicemia of ssp. fetus - septicemia of debilitated, immunosuppressed or debilitated, immunosuppressed or elderly personselderly persons

C. jejuniC. jejuni - one of leading causes of - one of leading causes of bacterial diarrhea world-wide; usually bacterial diarrhea world-wide; usually self-limiting with symptoms resolving self-limiting with symptoms resolving in 3-6 daysin 3-6 days

HelicobacterHelicobacter

H. pyloriH. pylori - - associated with associated with chronic active chronic active gastritis (peptic gastritis (peptic ulcer disease); may ulcer disease); may be associated with be associated with carcinoma of carcinoma of stomachstomach

Epidemiology of Epidemiology of CampylobacterCampylobacter and and

HelicobacterHelicobacter Habitat Habitat

Part of normal flora (intestinal tract) of humans or animalsPart of normal flora (intestinal tract) of humans or animals Routes of transmissionRoutes of transmission

Ingestion - contaminated food (chicken = campylobacters) Ingestion - contaminated food (chicken = campylobacters) and water (campylobacters) and water (campylobacters)

Prevention & ControlPrevention & Control Proper treatment & disposal of human wasteProper treatment & disposal of human waste Proper cooking of meat Proper cooking of meat

Treatment Treatment Antimicrobial therapy based on antibiogramAntimicrobial therapy based on antibiogram Supportive therapy - fluid replacement, analgesics to Supportive therapy - fluid replacement, analgesics to

lower fever lower fever

FamilyFamily Rickettsiaceae Rickettsiaceae

Rickettsia of clinical importance in the USRickettsia of clinical importance in the US Genus -Genus - Rickettsia Rickettsia

R. prowazekiiR. prowazekii - epidemic typhus & Brill-Zinsser disease - epidemic typhus & Brill-Zinsser disease R. typhiR. typhi - endemic typhus - endemic typhus R. rickettsiR. rickettsi - Rocky Mountain Spotted Fever - Rocky Mountain Spotted Fever R. akariR. akari - Rickettsial pox - Rickettsial pox

Genus - Genus - Coxiella Coxiella ( ( C. burnetiC. burneti); insect vector not ); insect vector not requiredrequired

Genus - Genus - Rochalimaea Rochalimaea ((R. quintanaR. quintana) - grow in cell-) - grow in cell-free mediafree media

General characteristics of General characteristics of RickettsiaRickettsia

All are obligate, intracellular parasites All are obligate, intracellular parasites except except Rochalimaea quintanaRochalimaea quintana Grow only in cytoplasm of eucaryotic cells Grow only in cytoplasm of eucaryotic cells

(require living cells for growth)(require living cells for growth) Obligate parasiticism stems from a leaky Obligate parasiticism stems from a leaky

cell membrane - causes loss of essential cell membrane - causes loss of essential metabolites; in particular ATP (possess both metabolites; in particular ATP (possess both synthetic and energy-yielding enzymes)synthetic and energy-yielding enzymes)


Require insect vectors for transmission Require insect vectors for transmission exceptexcept Coxiella Coxiella

Multiply by binary fissionMultiply by binary fission Contain both DNA and RNAContain both DNA and RNA Pleomorphic, but typically rod-like in formPleomorphic, but typically rod-like in form Cell wall composition similar to Gram Cell wall composition similar to Gram

negativesnegatives Stain poorly or not at all with usual bacterial Stain poorly or not at all with usual bacterial

stainsstains


Diseases of humans classified into 4 Diseases of humans classified into 4 major groupsmajor groups Typhus feversTyphus fevers Spotted fevers Spotted fevers Q feverQ fever Trench feverTrench fever


Pathogenesis of infectionsPathogenesis of infections Infect vascular endothelium, usually after bite Infect vascular endothelium, usually after bite

of an infected arthropod vectorof an infected arthropod vector Organisms multiply in endothelial cells and Organisms multiply in endothelial cells and

become disseminated throughout vascular become disseminated throughout vascular systemsystem

Manifested as fever, headache and rashManifested as fever, headache and rash Virulence factors Virulence factors

Endotoxin-like shock has been demonstrated in Endotoxin-like shock has been demonstrated in animals but role in human disease unknownanimals but role in human disease unknown

Clinical manifestations of Clinical manifestations of RickettsiaRickettsia

Typhus fever group Typhus fever group Epidemic (louse-borne) typhusEpidemic (louse-borne) typhus

Acute infection caused byAcute infection caused by R. prowazekii R. prowazekii Transmitted to man via body louseTransmitted to man via body louse Appears during times when conditions are Appears during times when conditions are

favorable for human body louse (war, famines, favorable for human body louse (war, famines, and social upheaval)and social upheaval)

Infected louse defecates while feeding; organism Infected louse defecates while feeding; organism is rubbed into wound when host scratchesis rubbed into wound when host scratches

Fatality increases with age of host from 10 to 60%Fatality increases with age of host from 10 to 60%


Typhus fever groupTyphus fever group Brill’s disease (Brill-Zinsser disease)Brill’s disease (Brill-Zinsser disease)

Relapse or recrudescence of louse-borne Relapse or recrudescence of louse-borne typhus; occurs years after a primary attacktyphus; occurs years after a primary attack

Factors triggering relapse unknown - may Factors triggering relapse unknown - may involve fading immunity to organisms that involve fading immunity to organisms that have remained dormant in RE cellshave remained dormant in RE cells

Milder, shorter and less debilitating than Milder, shorter and less debilitating than primary (partial immunity)primary (partial immunity)


Typhus fever groupTyphus fever group Endemic (murine) typhusEndemic (murine) typhus

Caused by Caused by R. typhiR. typhi Natural reservoir is urban rodent - Natural reservoir is urban rodent -

transmitted to humans by rat fleatransmitted to humans by rat flea 40-60 cases reported annually in US; 40-60 cases reported annually in US;

predominantly in SE & Gulf states, predominantly in SE & Gulf states, especially Texasespecially Texas

Clinical manifestations of Clinical manifestations of Rickettsia:Rickettsia:Spotted feversSpotted fevers

Rocky Mountain Spotted Fever Rocky Mountain Spotted Fever (RMSF)(RMSF)

Caused by Caused by R. rickettsiR. rickettsi - primarily a - primarily a parasite of ticksparasite of ticks

Most likely encountered rickettsial Most likely encountered rickettsial disease in US; >1000 cases/yeardisease in US; >1000 cases/year

Mortality approximately 7%; most Mortality approximately 7%; most individuals recover spontaneouslyindividuals recover spontaneously

Highest attack rates occur in mid-Highest attack rates occur in mid-Atlantic states, the Carolinas and Atlantic states, the Carolinas and Virginias between April & Virginias between April & September when exposure to ticks September when exposure to ticks most likelymost likely

Symptoms include fever, headache, Symptoms include fever, headache, rash and mental confusionrash and mental confusion

Rash begins on extremities & Rash begins on extremities & spreads to trunk - diagnostic if rash spreads to trunk - diagnostic if rash appears on palms of hands and appears on palms of hands and soles of feetsoles of feet

Complications occasionally Complications occasionally encountered = DIC, encountered = DIC, thrombocytopenia, encephalitis, thrombocytopenia, encephalitis, vascular collapse and renal and/or vascular collapse and renal and/or heart failureheart failure

Trends in infection for Rocky Trends in infection for Rocky Mountain spotted feverMountain spotted fever

The transmission cycle in Rocky The transmission cycle in Rocky Mountain spotted fever. Dog ticks and Mountain spotted fever. Dog ticks and

wood ticks are the principal vectorswood ticks are the principal vectors


Spotted feversSpotted fevers Rickettsial poxRickettsial pox

Caused by Caused by R. akariR. akari Transmitted by rodent mite - primary Transmitted by rodent mite - primary

reservoir is house mousereservoir is house mouse Distinguishing features is eschar at site of Distinguishing features is eschar at site of

bite, vesicular rash and absence of Weil-bite, vesicular rash and absence of Weil-Felix agglutination reactionFelix agglutination reaction

Self limiting after 1 week - no deaths Self limiting after 1 week - no deaths reportedreported

Clinical manifestations of Clinical manifestations of Rickettsia:Rickettsia:

Q feverQ fever Only rickettsial disease transmitted from animals Only rickettsial disease transmitted from animals

to humans by inhalation - does not require insect to humans by inhalation - does not require insect vectorvector

Caused by Caused by Coxiella burnetiCoxiella burneti Primarily disease of cattle, sheep, goats, rodents Primarily disease of cattle, sheep, goats, rodents

and marsupialsand marsupials Occurs sporadically among people who work with Occurs sporadically among people who work with

infected animals or their productsinfected animals or their products Manifested as systemic infection with or without Manifested as systemic infection with or without

pneumonia - fever, chills, mild dry, hacking pneumonia - fever, chills, mild dry, hacking cough, no rash*cough, no rash*

Clinical manifestations of Clinical manifestations of Rickettsia:Rickettsia:

Trench fever Trench fever Caused by Caused by Bartonella quintanaBartonella quintana Transmitted from human to human via body Transmitted from human to human via body

louselouse Only rickettsia to grow on cell-free mediaOnly rickettsia to grow on cell-free media Disease characterized by abrupt onset with Disease characterized by abrupt onset with

chills & fever which tend to subside and then chills & fever which tend to subside and then recur in repeated cycles of 3-5 days durationrecur in repeated cycles of 3-5 days duration

Rash commonly present during febrile periodsRash commonly present during febrile periods

Epidemiology of Epidemiology of RickettsiaRickettsia

Treatment - tetracycline and Treatment - tetracycline and chloramphenicolchloramphenicol

Control - insect vector (insecticides); Control - insect vector (insecticides); personal hygienepersonal hygiene

Other Obligate Parasitic Other Obligate Parasitic Bacteria:Bacteria:

The ChlamydiaceaeThe Chlamydiaceae Chlamydia of clinical significanceChlamydia of clinical significance

Chlamydia psittaciChlamydia psittaci (birds) (birds) Chlamydia trachomatisChlamydia trachomatis (humans) (humans) TWAR strains (TWAR strains (Chlamydophila Chlamydophila

pneumoniaepneumoniae))

General characteristics ofGeneral characteristics ofChlamydiaChlamydia

Obligate intracellular parasitesObligate intracellular parasites Once believed to be large virusesOnce believed to be large viruses Are metabolically deficient - cannot synthesize Are metabolically deficient - cannot synthesize

ATP or reoxidize reduced NADPATP or reoxidize reduced NADP Possess both DNA and RNAPossess both DNA and RNA Multiply in host cells by binary fissionMultiply in host cells by binary fission Are susceptible to several antibacterial agentsAre susceptible to several antibacterial agents Are small, generally rounded but show Are small, generally rounded but show

variation during replicative cyclevariation during replicative cycle Cell wall composition similar to Gram Cell wall composition similar to Gram

negativesnegatives

Unusual replication cycle Unusual replication cycle having morphologically distinct having morphologically distinct

forms forms Elementary body - small, extracellular, Elementary body - small, extracellular,

infectious stageinfectious stage Enters host by endocytosis using specific Enters host by endocytosis using specific

cell receptorscell receptors Remain within phagosomesRemain within phagosomes Are metabolically active, reorganize within Are metabolically active, reorganize within

one hour into larger form called an initial or one hour into larger form called an initial or reticulate bodyreticulate body

Unusual replication cycle Unusual replication cycle having morphologically distinct having morphologically distinct

formsforms Initial or reticulate body - larger, Initial or reticulate body - larger,

intracellular, noninfectious stageintracellular, noninfectious stage Does not survive outside cellDoes not survive outside cell Uses ATP generating capacity of host cell to Uses ATP generating capacity of host cell to

divide by binary fission elementary bodydivide by binary fission elementary body Replicate within the cytoplasm of host cells Replicate within the cytoplasm of host cells

forming characteristic intracellular inclusions forming characteristic intracellular inclusions which can be seen by light microscopywhich can be seen by light microscopy

Between 48-72 hours, cell ruptures and Between 48-72 hours, cell ruptures and infective elementary bodies are releasedinfective elementary bodies are released

Clinical manifestation: Clinical manifestation: C. C. psittacipsittaci

Primarily disease of birdsPrimarily disease of birds Human psittacosis = ornithosisHuman psittacosis = ornithosis

Contracted through inhalation of respiratory secretions, or Contracted through inhalation of respiratory secretions, or dust from droppings of infected birdsdust from droppings of infected birds

Seen primarily in poultry workers and owners of psittacine Seen primarily in poultry workers and owners of psittacine birdsbirds

Decreased incidence in US may be associated with use of Decreased incidence in US may be associated with use of antimicrobics in poultry feeds & quarantine of imported birdsantimicrobics in poultry feeds & quarantine of imported birds

Symptoms in humans include those of lower respiratory Symptoms in humans include those of lower respiratory infection with acute onset of fever, headache, malaise, dry infection with acute onset of fever, headache, malaise, dry (non-productive) cough and Xray evidence of bilateral (non-productive) cough and Xray evidence of bilateral pneumoniapneumonia

CNS involvement common - encephalitis, convulsions, coma, CNS involvement common - encephalitis, convulsions, coma, headacheheadache

Clinical manifestation: Clinical manifestation: C. trachomatisC. trachomatis

Eye infections - two distinct forms Eye infections - two distinct forms Trachoma - caused by serotypes A, B, Trachoma - caused by serotypes A, B,

Ba and C Ba and C Inclusion conjunctivitis Inclusion conjunctivitis

Genital infections - single most Genital infections - single most frequent cause of sexually frequent cause of sexually transmitted disease in US (4 million transmitted disease in US (4 million cases/year in US)cases/year in US)

Trachoma Trachoma Chronic keratoconjunctivitisChronic keratoconjunctivitis Seen most often in underdeveloped Seen most often in underdeveloped

countries (esp. Africa) - in US = countries (esp. Africa) - in US = American IndiansAmerican Indians

Usually contracted in infancy or early Usually contracted in infancy or early childhood by close contact with childhood by close contact with another infected individualanother infected individual

Transmitted by droplet, hands, Transmitted by droplet, hands, contaminated clothing and eye-contaminated clothing and eye-seeking fliesseeking flies

Begins as acute conjunctivitis Begins as acute conjunctivitis followed by severe corneal scarring - followed by severe corneal scarring - blindness often occurs in 15-20 years blindness often occurs in 15-20 years if not treatedif not treated

Persistence and reinfections and Persistence and reinfections and associated inflammatory responses associated inflammatory responses provide stimulus for major provide stimulus for major pathological effectspathological effects

Leading cause of preventable Leading cause of preventable blindness in developing countriesblindness in developing countries

Inclusion conjunctivitis Inclusion conjunctivitis

Acute inflammation of conjunctiva seen in adults and Acute inflammation of conjunctiva seen in adults and infants in population where chlamydial genital infections infants in population where chlamydial genital infections are commonare common

Neonatal form results from direct contact with infected Neonatal form results from direct contact with infected cervical secretions of mother at delivery (use of cervical secretions of mother at delivery (use of tetracycline, erythromycin, or chloramphenicol eye drops at tetracycline, erythromycin, or chloramphenicol eye drops at birth decreases incidence) - occurs 2-3 days after birthbirth decreases incidence) - occurs 2-3 days after birth

Presents as acute, copious, mucopurulent eye dischargePresents as acute, copious, mucopurulent eye discharge Symptoms may resolve without medical treatmentSymptoms may resolve without medical treatment Adult form usually associated with concomitant (occurring Adult form usually associated with concomitant (occurring

at the same time) genital disease - autoinoculation believed at the same time) genital disease - autoinoculation believed to be route of transmissionto be route of transmission

Genital infections Genital infections

Cause a spectrum of sexually transmitted infections Cause a spectrum of sexually transmitted infections similar to similar to N. gonorrhoeaeN. gonorrhoeae including urethritis and including urethritis and epididymitis in men and cervicitis, salpingitis and epididymitis in men and cervicitis, salpingitis and urethral syndrome in womenurethral syndrome in women

Shown to cause approximately 40% of non-Shown to cause approximately 40% of non-gonococcal urethritis in men which may be gonococcal urethritis in men which may be indistinguishable from one the caused by indistinguishable from one the caused by N. N. gonorrhoeaegonorrhoeae (chlamydia will not be seen in Gram (chlamydia will not be seen in Gram stained smears)stained smears)

Approximately one-half of all infants born to mothers Approximately one-half of all infants born to mothers excreting excreting C. trachomatisC. trachomatis during labor develop during labor develop chlamydial diseases during the first year of lifechlamydial diseases during the first year of life

Lymphogranuloma venereum (LGV) is a Lymphogranuloma venereum (LGV) is a distinctdistinct

venereal disease caused by venereal disease caused by C. trachomatisC. trachomatis

One of five classic sexually transmitted diseases One of five classic sexually transmitted diseases (gonorrhoeae, syphilis, herpes, chancroid and LGV)(gonorrhoeae, syphilis, herpes, chancroid and LGV)

Occurs principally in S. America and Africa- uncommon in Occurs principally in S. America and Africa- uncommon in US - reservoir in US is mostly homosexual malesUS - reservoir in US is mostly homosexual males

Two stages with systemic manifestations occur; stage 1 = Two stages with systemic manifestations occur; stage 1 = genital lesion - begins as a small genital ulcer which is genital lesion - begins as a small genital ulcer which is usually painless and inconspicuous; stage 2 = lymph usually painless and inconspicuous; stage 2 = lymph adenitis (marked swelling of inguinal lymph nodes; may adenitis (marked swelling of inguinal lymph nodes; may suppurate) fever, headache and myalgia may accompanysuppurate) fever, headache and myalgia may accompany

Systemic manifestations include hepatitis, pneumonitis & Systemic manifestations include hepatitis, pneumonitis & meningoencephalitis meningoencephalitis

Diagnosis usually based on characteristic clinical Diagnosis usually based on characteristic clinical appearanceappearance

TWAR strains - proposed name TWAR strains - proposed name = = Chlamydophila pneumoniaeChlamydophila pneumoniae

An acronym -TW (first isolated in Taiwan) An acronym -TW (first isolated in Taiwan) and AR (acute respiratory)and AR (acute respiratory)

WW in distributionWW in distribution Most infections seen in persons between Most infections seen in persons between

7-30 years of age7-30 years of age Associated with pneumonia, bronchitis, Associated with pneumonia, bronchitis,

pharyngitis, sinusitis and flu-like illnesspharyngitis, sinusitis and flu-like illness Infections may be severe in elderly - Infections may be severe in elderly -

otherwise are mild to moderate in severityotherwise are mild to moderate in severity

Epidemiology of Epidemiology of ChlamydiaChlamydia

Treatment - antimicrobics; most Treatment - antimicrobics; most commonly use tetracycline, commonly use tetracycline, erythromycin, sulfonamides and erythromycin, sulfonamides and rifampinrifampin

Control - treatment of known cases Control - treatment of known cases and prevention of exposure and prevention of exposure

MycoplasmataceaeMycoplasmataceae

MycoplasmaMycoplasma - require cholesterol for growth - require cholesterol for growth Genital organismsGenital organisms

M. hominisM. hominis M. fermentansM. fermentans M. gentaliumM. gentalium

Respiratory organismsRespiratory organisms M. pneumoniaeM. pneumoniae M. salivariumM. salivarium M. oraleM. orale

UreaplasmaUreaplasma - require urea for growth; - require urea for growth; hydrolyzes urea -hydrolyzes urea -

U. urealyticumU. urealyticum

General characteristics of General characteristics of MycoplasmaMycoplasma

Smallest free living Smallest free living organism; organism; pleomorphic (coccoid, pleomorphic (coccoid, filamentous and large filamentous and large multinucleoid form multinucleoid form found)found)

Lack cell wallsLack cell walls Bounded only by a cell Bounded only by a cell

membrane with no membrane with no evidence of a cell wallevidence of a cell wall

Do not Gram stain but Do not Gram stain but can be stained with can be stained with GiemsaGiemsa

General characteristics of General characteristics of MycoplasmaMycoplasma

Cell membrane unlike those of bacteria - contain sterols – Cell membrane unlike those of bacteria - contain sterols – sterols are not synthesized by the organism but are sterols are not synthesized by the organism but are acquired as essential components from media or tissue in acquired as essential components from media or tissue in which it is growingwhich it is growing

Highly fastidious in growth requirementsHighly fastidious in growth requirements Require enriched media containing peptones, yeast extract Require enriched media containing peptones, yeast extract

(contain preformed nucleic acid precursors) and cholesterol (contain preformed nucleic acid precursors) and cholesterol (usually supplied by animal serum - 10 to 20%) to maintain (usually supplied by animal serum - 10 to 20%) to maintain proper osmotic conditionsproper osmotic conditions

Urea needed for Urea needed for UreaplasmaUreaplasma Grow slowly - produce minute colonies on agar after several Grow slowly - produce minute colonies on agar after several

days; center of colony grows into agar; appears denser days; center of colony grows into agar; appears denser (inverted “fried egg” appearance)(inverted “fried egg” appearance)

M. pneumoniaeM. pneumoniae is aerobe but most other species are is aerobe but most other species are facultativefacultative

Clinical manifestations of Clinical manifestations of Mycoplasma pneumoniaeMycoplasma pneumoniae

Atypical pneumonia or walking pneumoniaAtypical pneumonia or walking pneumonia Associated with several syndromes including Associated with several syndromes including

pharyngitis, tracheobronchitis, otitis media pharyngitis, tracheobronchitis, otitis media and pneumonitis; occasionally with arthritis, and pneumonitis; occasionally with arthritis, meningitis, hemolytic anemia and a rashmeningitis, hemolytic anemia and a rash

Accounts for approximately 20% of Accounts for approximately 20% of pneumoniaspneumonias

Usually less severe than common bacterial Usually less severe than common bacterial pneumoniaspneumonias

May be called primary atypical pneumonia May be called primary atypical pneumonia (PAP) or walking pneumonia(PAP) or walking pneumonia

Clinical manifestations of Clinical manifestations of Mycoplasma pneumoniaeMycoplasma pneumoniae

Insidious onset with fever, headache, and Insidious onset with fever, headache, and malaise followed by a nonproductive coughmalaise followed by a nonproductive cough

Organisms interfere with ciliary action; leads Organisms interfere with ciliary action; leads to desquamation of mucosa & subsequent to desquamation of mucosa & subsequent inflammatory reaction and exudateinflammatory reaction and exudate

Organisms shed in URT for 2-8 days before Organisms shed in URT for 2-8 days before onset of symptoms; continues for as long as onset of symptoms; continues for as long as 14 weeks after infection14 weeks after infection

Epidemiology of Epidemiology of Mycoplasma Mycoplasma pneumoniaepneumoniae

Natural habitat - human respiratory tract; more Natural habitat - human respiratory tract; more common in summer; especially prominent in common in summer; especially prominent in temperate climatestemperate climates

Most common age is between 5-15 years Most common age is between 5-15 years (accounts for more than one-third of all cases of (accounts for more than one-third of all cases of pneumonia in teenagers); uncommon in children pneumonia in teenagers); uncommon in children less than 6 monthsless than 6 months

Modes of transmission - dropletModes of transmission - droplet Prevention and control - no method known; Prevention and control - no method known;

vaccines have been disappointingvaccines have been disappointing Treatment - erythromycin and tetracyclineTreatment - erythromycin and tetracycline

Clinical manifestations of Clinical manifestations of Mycoplasma hominisMycoplasma hominis

GenitalGenital Major clinical condition is postabortal or Major clinical condition is postabortal or

post-partum fever - isolated from the post-partum fever - isolated from the blood of about 10% of women with this blood of about 10% of women with this conditioncondition

Disease appears to be self-limiting but Disease appears to be self-limiting but antimicrobial therapy may decrease antimicrobial therapy may decrease duration of fever and hospitalizationduration of fever and hospitalization

PID may be associated with PID may be associated with M. hominisM. hominis infection of fallopian tubesinfection of fallopian tubes

Epidemiology of Epidemiology of Mycoplasma Mycoplasma hominishominis

Natural habitat - genital tract of Natural habitat - genital tract of sexually active men and women; sexually active men and women; rarely found before pubertyrarely found before puberty

Transmission - endogenous; sexualTransmission - endogenous; sexual Prevention and control - none knownPrevention and control - none known Treatment - tetracyclineTreatment - tetracycline

Ureaplasma urealyticumUreaplasma urealyticum

Clinical manifestationsClinical manifestations Approximately one-half of cases of Approximately one-half of cases of

nongonococcal, nonchlamydial urethritis nongonococcal, nonchlamydial urethritis in men caused by in men caused by UreaplasmaUreaplasma

Chorioamnionitis and postpartum fever Chorioamnionitis and postpartum fever in womenin women

Epidemiology - same as Epidemiology - same as M. hominisM. hominis

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Chapter 21 Miscellaneous Bacterial Agents of Disease