Intermediate Microorganisms

INTERMEDIATE MICROORGANISMS Dr. Rose Elaine D. Tan

Disease : Rickettsiosis • zoonotic disease which infects primarily wild animals • human are accidental host • arthropod-borne • acquired through bite of infected arthropods: lice, tick, flea, & mite o except Q fever (C. burnetti) which is acquired by inhalation • 4 groups of diseases: o Spotted fever group o Typhus group o Scrub typhus group o Others:  Q fever  Trench fever  Sennetsu Rickettsiosis • Characterized by fever, headache and generalized skin rashes • except Q fever - no rashes

RICKETTSIA CLASSIFICATION OF THE RICKETTSIA Order: Rickettsiales Family: Rickettsiaceae Tribe: Rickettsieae Genus Rickettsia Species: R. rickettsii R. akari R. conori R. prowazekii R. typhi R. tsutsugamuchi R. australis R. siberica Genus Rochalimaea Specie: R. Quintana Genus Coxiella Specie: C. burnetti GENERAL CHARACTERISTIC OF RICKETTSIA:  Small gram negative pleomorphic rods or coccobacilli  filterable, size 0.3 – 0.6µm W X 0.8 – 2µm L  obligate intracellular  cannot synthesize their own AMP  cell wall structure same with gram ( - ) bacteria  contains both RNA and DNA  replicate freely in the cytoplasm  has tropism for endothelial cell that lines the blood vessel causing vasculitis  Genus Rickettsia are unstable extracellularly under ordinary environmental conditions  C. burnetti – resistant to heat and drying

TREATMENT : DOXYCYCLINE, TETRACYCLINE, CHLORAMPHENICOL LABORATORY DIAGNOSIS : 1. Direct demonstration of organism from clinical material • • •

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multiply & reproduce by binary fission difficult to stain stain used for demonstration/visualization 1. Gimenez – pink – red 2. Machiavello – red 3. Giemsa – blue 4. Castañeda – blue growth is inhibited by antimicrobials susceptible to Chloramphenicol & Tetracycline require living cells for growth can be cultured using living cell medium: 1. Yolk sac developing chick embryo 2. Live animal ( mice / male guinea pig ) 3. Tissue culture except for R. quintana which can grow in artificial media containing blood with specific nutritional requirement

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Isolation of organism from animal model • Infected whole blood inoculated intra-peritoneally to male guinea pig • R. rickettsii – testicular swelling • R. prowazekii – no testicular swelling Serological

Serologic Diagnosis  specific antibodies develop in response to rickettsial infection  demonstration of an immune response during convalescence  is the most widely used method of confirming clinical diagnosis  Complement-fixing antibodies are useful in identifying infection due to Rickettsiae in different genera and groups  serologic procedures: o microagglutination o indirect hemeagglutination o Microimmunoflourescent antibody test  more sensitive and specific  detect specific antibodies  used for confirmation of disease

Treatment  Drug of choice – Chloramphenicol

 Weil-Felix Reaction

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Based on the cross reaction between antigens in the rickettsial organism and Proteus polysaccharide O antigen antibodies to the rickettsial organism will agglutinate certain non-motile strains of Proteus (0X-19, 0X-2 & OX-K) presumptive low sensitivity and specificity only 17% had been confirmed by this test Proteus agglutinins usually do not appear until after a week of illness, thus limits their usefulness in early diagnosis False positive: Proteus bacterial infections ( UTI, bacteremia, wounds) most widely used test in US

Prevention o Use preventive clothing, boots and leggings o Use forceps for removal of ticks o Care should be taken during removal to prevent crushing the ticks and contaminating the fingers because both tick tissues and tick flees are highly infectious o NO vaccine available B. Rickettsial Pox • agent: R. akari 

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mite vector: Liponyssoides sanguineus (formerly Allodermanyssus sanguineus) incubation period: 9-14 days Clin. Mx:

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I. SPOTTED FEVER GROUP

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basic pathologic process is a widespread vasculitis involving the skin, with production of a rash more severe disease can lead to dessiminated intravascular coagulopathy with petechial and purpuric skin manifestation a. Rocky Mountain Spotted fever b. Rickettsial Pox c. Other Tick-borne Diseases • resemble RMSF • Boutonneuse fever – R. Conorii • North Asian tick Typhus – R. sibirica • Queensland tick typhus – R. australis • Japanese spotted fever – R. japonica

A. Rocky Mountain Spotted fever  aka: Tick-borne typhus  transmission: bite of a tick infected w/ R. rickettsii  accounts for >95% of reported cases in the US  common among children and adults  incubation period: 3-12 days  Clinical manifestation: 1. cardinal features: headache, fever, diffuse myalgia, rash 2. rash appears 2-4 days after onset maculopapular petechial hemorrhagic stiff neck,

3. Gastrointestinal complaints, arthalgia, conjunctivitis, periorbital edema 4. splenomegaly 5. hyponatremia, thrombocytopenia 6. severe disease leads to DIC with petechial & purpuric

rashes produce

7. vasculitis involving viscera (brain, heart, kidneys) can significant complications

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Fatality Rate if Untreated 20-25% Pathogenesis o R. ricketsii produces widespread endothelial damage that results in occlusion of small vessels, microthrombi, microhemorrhages, secondary fluid and electrolyte changes, and in severe cases, necrosis, shock and death o Kinins play a role in pathophysiology of the vasculitis and DIC

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Lab Diagnosis: 1. Initial diagnosis and treatment should be based on clinical grounds 2. Isolation – rarely done 3. Weil-Felix 4. Microimmunoflourescent Antibody test 5. ELISA 6. PCR

reddish macular rash develops at the site of the mite bite and subsequently develops an eschar which roughly coincides with the appearance of fever, headache, chills, rigors, profuse sweating, myalgias, rhinorrhea, cough, sore throat, nausea, vomiting, and abdominal pain regional lymphadenopathy a papulovesicular rash (blister) that bursts and crusts over develops 1-10 days after the eschar appears and lasts for several wks

Rickettsialpox

Chickenpox

• Common in adult • associated with primary eschar – A red papule with a vesicle in the center dries and forms a black eschar with surrounding induration • The cutaneous vesicles are surrounded by papular rings (papulovesicular rash) is usually on the trunk and extremities; the palms, soles, and oral mucosa may also be involved.

• Common in children • Lacks a primary lesion • The papule turns into a vesicle on an erythematous base and resembles a "dew drop on a rose petal“ • The rash begins on the head and progresses to the trunk, arms, and then legs

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Pathogenesis: o Microscopically, the maculopapular rash shows a mononuclear perivascular infiltrate and necrosis of epithelial cells that result in intraepidermal vesicles

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Lab dx: o isolation of organism ( blood & vesicular fluid) o Weil-Felix antibodies does not appear after infection with R. akari

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TREATMENT: CHLORAMPHENICOL AND TETRACYCLINE

C. Other Tick-borne Diseases • Found in several continents • Cause sporadic cases of mild clinical pattern • resemble RMSF • North Asian tick Typhus – R. sibirica (central Asia, Mongolia, Siberia) • Queensland tick typhus – R. australis (Australia) • Japanese spotted fever – R. japonica (Japan) • Boutonneuse fever – R. conorii (Mediterranean, Africa, India) (aka: African tick fever, Kenya tick typhus, Indian tick typhus) • Humans are accidental hosts • Arthropod vectors: Ixodid ticks • MOT: tick bite • •

incubation period varies from 6-10 days triad of symptoms are most characteristic: o fever, headache, and malaise o erythematous papules appears on days 3-5 of the illness w/c spreads from the extremities to the trunk, neck, face, palms, and soles o Disease is characterized local eschars or skin lesions at the site of the tick bite

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BOUTONNEUSE FEVER

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is transmitted by the dog tick Rhipicephalus sanguineus

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has a characteristic rash and a distinct mark:

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tache noire (eschar or cutaneous necrosis ) at the site of the tick bite caused by rickettsial vasculitis ("black spot") is pathognomonic heals slowly over 10-20 days without leaving a scar

c. Murine typhus • aka: endemic typhus, flea-borne typhus, rat typhus • etiologic agent: R. typhi

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man is infected when, by scratching, he introduces the feces or contents of a crushed rat-flea, Xenopsylla cheopis, which has fed on infected rat similar to louse-borne typhus but tends to have a milder and shorter course

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Clin. Mx: mild; Fatality Rate if Untreated 1-2 percent o Incubation period: 1-2 weeks o fever is less pronounced and remittent, headache is less severe o rash is less extensive, o headache, malaise, myalgia,

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Lab. Diagnosis: Serology o Weil-Felix Reaction

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Treatment: Tetracycline, Chloramphenicol

II. TYPHUS FEVER • •

Is a louse-bourne disease Typhus-group organisms are characterized by intracytoplasmic growth and a common, soluble, group-specific, complementfixing antigen a. Epidemic Typhus

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Brill-Zinsser Disease Murine Typhus

a. Epidemic typhus • Aka: Louse-bourne Typhus • etiologic agent: R. prowazekii • transmitted by infected feces of the louse usually through scratching the skin, or sometimes by bite

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Pediculus humanus corporis - body louse Pediculus humanus capitis – head louse

During each blood meal, the feeding process is irritating and scratching by the host produces minor excoriations that function as portals of entry for the rickettsia in the louse feces Clin Mx: o o o o

incubation period: 10-14 days severe frontal headache, fever, malaise skin rash (hallmark) 4-7 days after onset, noted at the trunk spreading to the extremities (centrifugal spread) Rash usually spares the palms, soles and face

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patchy cutaneous erythema  maculpopapular

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 hemorrhagic 2nd week of illness the CNS becomes involved and apathy and dullness, delirium and coma

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Fatality Rate if Untreated 30%

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lab dx: o o o o

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isolation of organism serologic test Weil-Felix reaction PCR

Treatment: o Tetracycline, Chloramphenicol o Patients who develop circulatory and renal complications before receiving antibiotics may die despite therapy

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Clin. Mx: o o o o

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Clin. Mx: o incubation period 1-3 weeks after bite of a chigger

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sudden onset of chills, HA, fever, cough, nausea, vomiting, myalgia

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the site of the mite bite develops a necrotic black scab (eschar), becomes indurated and covered by a scale Lymphadenopathy proximal to the eschar gen. maculopapular rash appears 5-8days after

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deterioration of mental status, pneumonia, circulatory failure

Diagnosis: Serology o Weil-Felix Reaction

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b. Brill – Zinsser disease • aka: relapsing louse-borne typhus • secondary to recrudescent R. prowazaki • the organisms appear to lie dormant, most likely in the cells of the reticuloendothelial system, until they are reactivated by an unknown stressor, multiply and cause another acute but milder infection •

III. SCRUB TYPHUS • aka: Chigger-borne typhus; Tsutsugamushi disease • etiologic agent : R. tsutsugamushi • endemic in Australia, Japan, Korea, India and Vietnam • vector: trombiculid mites • Larval stage of mite (chigger) – stage that feeds on vertebrae • 3 major antigenic type (Karp, Gilliam, Kato)

milder than epidemic typhus Shorter duration of the disease (less than 2 weeks) skin rash rarely seen headache, malaise, myalgia

Lab. Diagnosis: o microimmunofluorescent test using IgM and IgG antibody o Weil-Felix agglutinins usually do not develop

Agglutinins to Proteus OX-K antigen appear in the convalescent sera of many but not all patients with scrub typhus

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Treatment: Tetracycline, Chloramphenicol

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Prevention:

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Prevent chigger bites  Wear protective clothing  Insect repellents Control of mite population  Insecticides  Clearing of vegetation  Chemical treatment of the soil

IV. Q FEVER • etiologic agent: Coxiella burnetti • Q from the word “querry” • Arthropod vector: ticks • worldwide distribution • resistant to desiccation and exposure to light or temperature extremes

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Human outbreaks 2° to: o Consumption of infected milk o handling of contaminated wool or hides o soil contaminated by infected animal feces o infected straw o dusty clothing

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Modes of transmission: o through the skin – contaminated minor abrasions o through the lungs – inhalation of infectious aerosols

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Clin Mx: o o o o o o o

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Lab. Dx: o o o o

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through the mucus membrane – conjunctival contact with infectious materials through the GIT – ingestion of contaminated raw milk incubation period ranges from 2-6 weeks can manifest various signs no one classic presentation exists inapparent infection, influenza-like illness, Pneumonia, endocarditis, hepatitis Usually begins with sudden onset of chills, HA, fever, myalgia Characteristically, rash is absent Fatality Rate if Untreated 2.4 %for the acute form; 60 % if chronic endocarditis develops

obligate intracellular Although capable of synthesizing macromolecules, they have no system for generating energy NO ATP (no energy - yielding enzyme) the host cell's energy system fuels the chlamydial metabolic processes contain both RNA & DNA rigid cell wall that resemble gram (-) bacteria o due to disulfide bond cross-linking among the major outer membrane proteins (MOMP) lack peptidoglycan layer and muramic acid, not susceptible to lysozyme has tropism for columnar epithelial cells lining the mucous membrane sensitive to antibiotics reproduce and multiply binary fission o

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Most definitive – isolation of C. burnetii from clinical specimens Can be accomplished by intraperitoneal inoculation of guinea pigs, mice or embryonated hens’ egg Serology – Complement-fixation test Weil-Felix antibodies are not elicited in response to infection with C. burnetii

Treatment: o Tetracycline - preferred drug of choice o Chloramphenicol o Pts do not uniformly respond and as quickly compared to other rickettsial disease Prevention: o Identify and decontaminate affected areas o Milkbourne transmission – prevented by pasteurization

2 distinct morphologic forms: 1. ELEMENTARY BODY ( EB ) • small, dense spherical body measuring 0.2 -0.4 µ • found extracellularly (outside of cell) • infectious form • capable of extracellular survival • has rigid outer membrane 2. RETICULATE BODY (RB) • reproductive form of organism • size 0.7 - 1.0 µ (larger than EB) • Found intracellularly • non-infectious • grow only within host cell • incapable of survival outside cell • metabolically active form

V. TRENCH FEVER • aka: Shinbone fever

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etiologic agent: Rochalimaea quintana (Bartonella quintana) Arthropod vector: Body louse (Pediculus humanus corporis) transmitted by inoculation of the organism in louse feces through a skin break or a louse bite R. quintana – the only rickettsia that can be grown on cell-free media Reservoir: Human only

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Clin. Mx: o diverse clinical presentations o Ranges from asymptomatic to a persistent fever lasting months o incubation period is 5-20 days o Fever, HA, malaise, chills, myalgia, maculopapular rash o Bone pain - tends to occur in the shin (tibia), neck, and back; worsens during subsequent attacks

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Lab. Diagnosis: o Xenodiagnosis  Feeding of uninfected lice on an infected patient and the later demonstration of rickettsia in the louse tissue o Primary isolation on enriched-blood agar media o Like other Rickettsia, can also be grown in yolk sacs of embryonated hens’ eggs o Serology  CFT  Indirect immunoflourescent antibody test

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TREATMENT: TETRACYCLINE, CHLORAMPHENICOL

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Prevention: control human louse infestation

CHLAMYDIA

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small round → oval/ovoid-shaped cell

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non-motile

Life Cycle: 5 MAJOR PHASES: 1. Attachment and penetration of EB 2. Transition of metabolically inert EB into metabolically active RB 3. Division of RB and production of many progeny 4. Maturation of the non-infectious RB into EB 5. Release of EB from the host cell (after 48 hours)

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Trachoma – leading cause of preventable blindness in the world leading cause of neonatal ocular disease USA leading cause STD in USA and Europe

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men: begins as urethritis and spread to epididymis women: begins in the cervix, uterus, fallopian tubes and can result in PID and infertility

the presence of basophilic intra-cytoplasmic, iodine-staining inclusion bodies (Halberstadter-Prowazek bodies) is specific for C. trachomatis inclusion bodies of the other species of chlamydia do not contain glycogen and do not stain with iodine

Chlamydia trachomatis Serovar

Lab diagnosis 1. direct microscopic examination of clinical specimen for chlamydial inclusion bodies • very hard to stain • for visualization: Machiavello and Giemsa stain 2. isolation of the organism • can be cultures only using living cell media : 1. yolk sac of 6-8 day chick embryo (observed characteristic inclusion body can be found) 2. live laboratory animal inoculation ( mice ) 3. tissue culture (Hela cells, McCoy cells) 3. detection of specific antibodies against these bacteria serologic test: • CF • micro-immunoflourescence technique • ELISA Antigenic Composition: 3 MAJOR GROUPS OF ANTIGEN HAVE BEEN IDENTIFIES: 1. Genus-specific Ag • heat stable

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LPS with an acidic polysaccharide as the antigen determinant

2. Species-specific Ag • found on or near the envelope surface • protein antigen are shared by all members of the specie

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trachomatis (18); C. psittaci (15)

3. Serotype-specific Ag • common only to certain isolate within the specie • C. trachomatis subdiv. into 2 biovars : o Trachoma – 12 serovars

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Disease

A B Ba C

Trachoma

Asia and Africa

D- K

Disease of eye and genitals: Conjunctivitis Urethritis Cervicitis Respirtaory System: Infant pneumonia

World wide

LGV1 LGV2 LGV3

Lymphogranuloma venerium (LGV)

Worldwide

1. Trachoma • most common cause of chronic infection of the conjunctiva that is currently the leading cause of preventable blindness throughout the world • MOT 1. Transplacental transmission mother → infant 2. Contaminated eye-to-hand-to-eye 3. Fomites (infected towel rub to eye) • Pathogenesis: o C. trachomatis replicates preferentially on mucosal surfaces within squamocolumnar epithelial cells o They stimulate a brisk infiltration of polymorphonuclear cells; esp. early in infection o Submucosal lymphocytic infiltration leads to lymphoid follicle formation and fibrotic changes •

Clinical Manifestations: o MacCallan Classification of Trachoma  Stage 1 – (Incipient Trachoma)

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LGV – 3 serovars 

CHLAMYDIA TRACHOMATIS • human only known host • primarily involves the eyes and genital tract

Distribution

maybe asymptomatic, with little if any conjunctival exudates minimal keratitis is usually present

Stage 2 established trachoma with follicular and papillary hypertrophy Trachomatous pannus accompanies corneal infiltration Stage 3 includes cicatricial complications with scarring of the conjunctiva; trichiasis, entropion and further pannus develop Stage 4 healed trachoma without evidence of active inflammation maybe asymptomatic if with no complications develop

Stage 2 - Follicular trachomatous inflammation is the presence of 5 or more follicles (each at least 0.5 mm in diameter) on the central part of the upper tarsal conjunctiva Stage 2 - Intense trachomatous inflammation is pronounced inflammatory thickening of the upper tarsal conjunctiva that obscures more than one half the normal deep tarsal vessels Stage 3 -Trachomatous conjunctival scarring (TS) is the presence of easily visible scars in the tarsal conjunctiva

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CF

3. Lymphogranuloma venereum ( LGV ) • aka: Lymphogranuloma inguinale, climatic bubo, tropical bubo, • • • • • •

Stage 3 - Trachomatous trichiasis (TT) is defined as the presence of at least 1 eyelash rubbing on the eyeball or evidence of recent removal of in-turned lashes

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Caused by C. trachomatis biovar LGV; serovar LGV 1, 2, 3 sexually acquired common among sexually active young adults 15-40 years More recognized among males than in females All patients with LGV should be thoroughly examined for evidence of other STDs LGV replicates preferentially on the regional lymph nodes o Autopsies of patients with chronic LGV infection reveal lesions of the lymph node composed of aggregates of large mononuclear cells forming abscesses surrounded by epithelial cells heal with scarring

Stage 3 - Easily visible corneal opacity over the pupil; it is so dense that at least part of the pupil margin is blurred when viewed through the opacity

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lab dx: PCR – method of choice direct fluorescein-labeled monoclonal antibody enzyme immunoassay (EIA) Direct microscopic examination

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the presence of glycogen-containing, iodine-staining intracellular microcolonies or inclusion bodies (HalberstadterProwazek bodies) is specific for C. trachomatis

CLINICAL MANIFESTATIONS: • First stage (primary LGV) o occurs 3-30 days after inoculation o The primary lesion begins as a small, unnoticed painless papule or pustule that may erode to form a small, asymptomatic open sore (ulcer) that usually heals rapidly without scarring within a week o men: coronal sulcus, prepuce, glans, and scrotum o women: posterior vaginal wall, posterior cervix, fourchette, and vulva •

Second stage (secondary LGV)

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WHO recommends 2 antibiotics: o oral azithromycin or Doxycycline or Tetracycline

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Good standards of hygiene

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tetracycline eye ointment

2. Inclusion Conjunctivitis • Caused by C. trachomatis serotypes D through K • acute infection of conjunctiva among neonates o acquired from genital tract during passage thru an infected birth canal of mother with genital chlamydia o Characterized by inflammation of the conjunctiva accompanied w/ purulent yellowish discharge which usually occurs 5 - 12 days after birth o Vulvovaginitis, ear infection, and mucopurulent rhinitis may accompany ocular disease

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Third stage (tertiary LGV) o termed genitoanorectal syndrome

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Adult inclusion conjunctivitis o Is a sexually transmitted disease o but also contamination from unchlorinated swimming pools o presents as a unilateral (or less commonly bilateral) red eye with mucopurulent discharge, marked hyperemia, papillary hypertrophy, and a predominant follicular conjunctivitis Lab. Diag. :

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Microbiological - conjunctival scrapping ↓ (specimen) Yolk sac / Hela cell  demonstrate basophilic intra-cytoplasmic inclusion body (Halberstadter Prowazek inclusion body) Serological  Direct Fluorescent antigen staining - 90% sensitive  ELISA

begins 2-6wks after the primary lesion Early symptoms of fever, headache and myalgia consists of painful regional lymphadenopathy (usually in the inguinal and/or femoral lymph nodes) About 1/3 of infected people develop a "groove sign" caused by pressure from the tight ligament separating the groin lymph nodes These nodes join together to form "buboes,“(abscesses) which may split open and drain and form sinus tracts, or they may become hard and then slowly heal on their own Women may not have any visible lymph node and have only mild back or belly pain

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rectal involvement is more common in men who have sex with men and in women who practice analreceptive intercourse Patients initially develop proctocolitis and later may present with pain on defecation, deep boils (abscesses), perirectal fistulas, strictures, rectal stenosis and scarring hyperplasia of intestinal and perirectal lymphatics forming lymphorrhoids women: this stage may be the first time symptoms are seen as enlargement, thickening, and fibrosis of the labia (lymphatic obstruction can lead to elephantiasis of the vulva – “esthiomene”) men: chronic lymphatic obstruction leading to elephantiasis  Penile and scrotal edema and distortion have been termed “saxophone penis”

LAB DX: • compatible clinical Manifestations • recovery of the organism from site of infection and identification of C. trachomatis, biovar LGV • Demonstration of risinf antibody titer of LGV by microimmunoflourescent antibody titer • • • •

Frei test intradermal skin test previously used to diagnose LGV indicative of delayed hypersensitivity to chlamydial antigens not specific

Antibiotic regimens: • Doxycycline 100 mg PO bid for 21 d

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Erythromycin Tetracycline Sulfadiazine

Pneumonia in young adults (most char. presentation)

CLIN MX: • Fever in the first few days

4. Chlamydial urogenital infections • Caused by C. trachomatis serotype D through K • occurs in men with history of other venereal disease and promiscuity and frequently in the consorts of women with cervical chlamydia infection • Males: o most common manifestation is nongonococcal urethritis o develop a white, cloudy or watery discharge from the tip of the penis • Females: o chronic cervicitis and urethritis o characterized by mucopurulent cervical discharge, erythema, and inflammation

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Pharyngeal erythema without exudate occurs in various atypical pneumonias Rhonchi and rales are present even in mild dse

LAB. DIAG: • PCR/ Isolation/ CFT/ MIFT Treatment: Erythromycin and Tetracycline

Reiter’s Syndrome • now referred to as reactive arthritis • triad of recurring symptoms including: o conjunctivitis/iridocyclitis o Polyarthritis o Genital inflammation  Males: non-gonococcal urethritis associated with reactive arthritis may be postdysenteric or postvenereal, with frequency, dysuria, urgency, and urethral discharge  Females: Cervicitis within 1 month of the arthritis • 50-65% of pts have C. trachomatis genital infection 5. Neonatal Pneumonia • Prevalent cause of pneumonitis in infants • Characteristically becomes ill 4-16wks of age with prominent respiratory symptoms of wheeze and cough and lack systemic findings of fever and toxicity • Chlamydial neonatal conjunctivitis often precedes the onset of pneumonia

CHLAMYDIA PSITTACI • etiologic agent of Psittacosis, an infection of birds & mammals that is transmissible to humans • can cause a pneumonia-like illness • the respiratory tract is the main portal of entry • acquired by inhalation of infectious dropping from: o birds, parrot, parakeets = Psittacosis o turkey, duck, chicken = Ornithosis • other source of material: blood, tissue, excreta, feathers GENERAL CHARACTERISTICS OF C. PSITTACI: • The intracellular microcolonies contain little glycogen and do not stain recognizably with iodine • The inclusion bodies are more diffuse and irregular in shape and do not indent the nucleus of the host cell • These inclusions (( Levinthal - cole - lillie bodies) stain with Giemsa and Macchiavello stain • The development of inclusions is not inhibited by sulfadiazine or cycloserine

MYCOPLASMA • smallest & simplest procaryote capable of self - replication • cell wall-less (absence of cell wall) o lack of a reaction to Gram stain o lack of susceptibility to antimicrobial agents, including beta-lactams • originally called PPLO (Pleuropneumonia like organisms) • frequent causative agent of primary atypical pneumonia • usually associated with mucosal surfaces, residing extracellularly in the respiratory and urogenital tracts •

Species of Medical importance : o Mycoplasma pneumoniae o Mycoplasma hominis o Ureaplasma urealyticum o

CLINICAL MANIFESTATIONS: • Onset of fever, severe frontal headache, myalgia • Followed by pulmonary manifestations: non-productive cough, rales, and consolidation • X-ray suggests bronchopneumonia or atypical pneumonia LAB. DIAG. : 1. Direct microscopic examination 2. Detection of inclusion body (levinthal - cole - lillie 3. Serological  CF test ( non-specific )

body)

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Immunoflourescent AB test (more sensitive & confirmatory)

Treatment: Tetracycline, Erythromycin CHLAMYDIA PNEUMONIAE • 1986 – new strain of C. psittaci (TWAR strain) Gen. Charac: • more homogenous than other chlamydia • EB is pear shaped • human pathogen • MOT

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inhalation of aerosolized droplets person-to-person transmission by resp. secretions

GEN. CHARACTERISTICS: • extremely pleomorphic cells (no definite morphologic form) can appear as spherical, ovoid or pear-shaped to filamentous • size 0.2 - 0.8 µm in diameter x 8 - 10 nm thick • filtrable (can pass thru bacteriological filters of 450nm pore size) • reproduce by binary fission • facultative anaerobe

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motile → gliding motility 2O to specialized tip structure which serves as attachment and movement site of the cell stain poorly with gram stain but are ( gram - ) Dienes stain for visualization of the organism Phase-contrast microscopy & Darkfield microscopy – are recommended for microscopic examination

CULTURAL CHARACTERISTICS: • have a unique requirement for cholesterol and related sterol for membrane synthesis • lack enzymatic pathways for purine and pyrimidine synthesis • can be cultured on non-living cell media • requires complex culture media for growth such as: o beef-heart infusion broth (BHIB) supplemented with horse serum, yeast extract and nucleic acid

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solid media (beef-heart infusion agar BHIA) → domeshaped colony with a dense central core “fried egg appearance”

The organism has a remarkable gliding motility and specialized filamentous tips end that allows it to burrow between cilia within the respiratory epithelium, eventually causing sloughing of the respiratory epithelial cells 2 properties correlated with its pathogenicity in humans: o selective affinity for respiratory epithelial cells  organism attaches to respiratory epithelial with the help of protein P1 (adhesin) o ability to produce hydrogen peroxide, which is thought to be responsible for much of the initial cell disruption in the respiratory tract and for damage to erythrocyte membranes

Disease: Primary Atypical Pneumonia (Walking Pneumonia) • found worldwide • Common among healthy patients younger than 40 years, with the highest rate in 5- to 20-year olds • MOT: acquired by aerosol droplets • incubation period 2-3 weeks • Pneumonia is generally mild and self-limited

• • Mycoplasma hominis • most frequently isolated mycoplasmas from the urogenital tract • M. hominis – a large colony-forming mycoplasma 200-300µm in diameter with a characteristic fried egg appearance

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M. hominis and Ureaplasma species are common commensal inhabitants of the lower genitourinary tract in adolescents and adult men and women who are sexually active 20% of healthy sexually active women carry M. hominis in their vagina Implicated in post-partum fever, post-abortal fever, PID and pyelonephritis Recent isolate M. genitalium o isolated from urethral specimens of patients with nongonococcal urethritis o Shares extensive serologic cross-reactivity with M. pneumoniae o Has attachment mechanism and surface protein similar with M. pneumoniae

Ureaplasma urealyticum • most frequently isolated mycoplasmas from the urogenital tract

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U. ureatycum were originally referred to as T-strain mycoplasma (T for Tiny) because of the small colonies (15-60µm) produced They also differ from other mycoplasmas because of their unique ability to metabolize urea with the production of ammonia Ureaplasma causes nonchlamydial nongonococcal urethritis Ureaplasma species are common commensal inhabitants of the lower genitourinary tract in adolescents and adult men and women who are sexually active 60% of healthy sexually active women carry U. urealyticum in their vagina Play a role in perinatal mortality

MYCOPLASMA PNEUMONIAE • number one cause of bacterial bronchitis and pneumonia in young adult • responsible for 20% of all cases of community acquired pneumonia • Reimann described the 1st cases of mycoplasmal pneumonia o Reimann coined the term "primary atypical pneumonia" after observing 7 patients in Philadelphia with marked constitutional symptoms, upper and lower respiratory tract symptoms, and a protracted course with gradual resolution • Peterson discovered the phenomenon of cold agglutinin in 1943, where high titers were seen among pts with M. pneumoniae

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in 1944, Eaton was credited with discovering a specific agent, coined Eaton's agent, as the principal cause of primary atypical pneumonia

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First thought to be a virus, Eaton's agent was proved to be a Mycoplasma species in 1961

PATHOPHYSIOLOGY • M. pneumoniae is a surface parasite colonizing the epithelial lining in the mucosa of the respiratory tract • the prolonged paroxysmal cough seen in this disease is thought to be due to the inhibition of ciliary movement

M. pneumoniae is perhaps best known as the cause of walking or atypical pneumonia characterized by gradual onset of fever, malaise, headache, sore throat and persistent dry, hacking non-productive cough for as long as a month the most frequent clinical syndrome caused by this organism is tracheobronchitis or bronchiolitis, often accompanied by upper respiratory tract manifestation

Lab Studies • WBC count generally is not helpful, since results may be normal or elevated

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Sputum Gram stains and cultures usually are not helpful, since M pneumoniae lacks a cell wall and cannot be stained Elevated ESR may be present but are nonspecific

Imaging Studies • Radiographic findings are variable, but abnormalities are usually more striking than the findings on PE o Bronchopneumonia often involves a single lower lobe

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Reticulonodular or interstitial infiltrates, primarily in the lower lobes, may resemble other diseases with granulomatous pathology, such as tuberculosis, mycoses, and sarcoidosis Hilar adenopathy sometimes is mistaken for malignancy

Diagnosis: 1. Early stage of infection → based on clinical manifestations 2. Culture - specimen: sputum / throat swab o difficult to culture and requires 7-21 days to grow → “fried - egg” colonies with a small zone of hemolysis 3. Cold Agglutination test

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a nonspecific test for M pneumoniae, but findings are positive in 50-70% of patients after 7-10 days of infection o measures the titer of cold agglutinins (antibodies) in patient serum during acute and convalescent phase 4. Complement Fixation

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5. Elisa, PCR

Patient serum + glycolipid antigen  fourfold rise in antibody titer (diagnostic)

Treatment: Tetracycline and Erythromycin Prevention: • No vaccine available • Avoid close contact with acutely ill patient bajah-bajah16.08.08