Coxiella burnetii

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Introduction

Coxiella burnetti is the causative agent of

‘Q-fever’

Obligate intracellular, gram negative

bacterium

Distributed globally

Found in many species of animals

Morphology:-

obligate intracellular pathogen . gram negative . Pleomorphic . size : rods:- 0.2 – 0.4 x 0.4 – 1.0 mc spheres :- 0.3 – 0.4 mc filterable . better stained with GIMINEZ and other

rickettsiael stains .

C. burnetii

i

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Culture

Grows well in yolk sac of chick embryos and in various cell cultures .

Ag structure

shows phase variation . phase – I ,II . phase – I :- autoagglutinable

more immunogenic

activity due to periodate sensitive trichloracetic acid-soluble surface carbohydrate .

o Phase – II :- more suitable for CFT .o both phase I ,II elicit good Ab response .

Resistance

Resistant to physical and chemical agents In pasteurization flash method is effective Can survive in dust and aerosols Inactivated by 2% formaldehyde

5% H2O2

1% Lysol .

Contd….

Resistant to heat, drying and disinfectants

Air samples test positive for 2+ weeks

Soil samples test positive for 150+ days

Spore formation

PATHOGENESIS

History

Q stands for Query or Queensland

Origin of disease unknown

First reported cases were in

Queensland, Australia

Differentiating features :

1. Having smaller size

2. Resistance to heat and drying

3. Major route of transmission is-

inhalation/ingestion

Primary ReservoirPrimary Reservoir

Cattle Sheep

Goats

* All eukaryotes can be infected

Bacteria is excreted in:

Feces

Urine

Milk

of infected animalsof infected animals

Release Into Environment:- During birthing the organisms are shed in high

numbers in amniotic fluids and the placenta

109 bacteria per gram of placenta

Do not touch!

Transmission Most common route is inhalation of

aerosols Contaminated dust, manure,

birthing products Tick bites (rare) Human to human also very rare

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Contd…..

Who’s at risk?

Farmers, veterinarians, researchers,

abattoir (slaughterhouse) workers etc.

People who breed animals

Immunocompromised

*Bacteria spread through blood

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Acute or Chronic Q fever

Symptoms

Acute Q fever Self-limiting, flu-like disease Fever, nausea, headaches, vomiting, chest/abdominal

pain Pneumonia & granulomatous hepatitis

Chronic Q fever (> 6 months) Endocarditis & meningoencephalitis Pre-existing disease

Host interaction Entry via inhalation Alveolar macrophages encounter bacteria C. burnetii phagocytosed

Macrophage C. burnetii

R Heinzen, NIAID

Host interaction

Replication within phagolysosme

Low pH needed for metabolism

No cellular damage unless lyses

occurs

Can invade deeper tissue and cause

complications

Phagocytosis

Binding/entry into macrophages via: Integrin Associated Protein (IAP) Leukocyte Response Integrin (LRI)

macrophagebacteria

Lysis of phago-lysosome and macrophage

Phago-lysosome fusion: bacteria survive and multiplies

Phagocytic vesiclePhagocytosis

Binding & Entry

LAB DIAGNOSISHard to diagnose because:

Asymptomatic in most cases

Looks like other disease (Flu or cold)

Serology continues to be best method

PCR, ELISA and other methods

WEIL – FELIX test is negative .

Contd…..

Bio safety level 3 (BSL-3) facility Very infectious (one organism causes infection) Listed by the CDC as a potential bioterrorism

agent. Isolated in cell cultures or embryonated eggs

Treatment Once infected, humans can have life-long immunity Acute Q fever treated with:

doxycycline,

chloramphenicol,

erythromycin or

fluoroquinolones

Chronic Q fever treated with: More than one antibiotic tetracycline and cotrimoxazole for 2 years

Vaccines :- prepared from formalin killed whole

cells

attenuated strains

trichloroacetic acid extracts

Prophylaxis:-

Pasteurization and sterilization of milk and other dairy products

Disinfect utensils, machines used in farm areas for birthing

Regular testing of animals and those who work closely with them

Protective Personal Equipment

BARTONELLA

INTRODUCTION

Family Bartonellaceae contain two genera

Bartonella

Grahamella

Grahamella does not infect humans

Bartonella contain 3 species:

B.bacilliformis

B.quintana

B.henselae

BARTONELLA BACILLEFORMIS

Carrions disease

Causes OROYA fever

MORPHOLOGY:

Gram negative

Pleomorphic

strict aerobe

motile, small bacillu0.3-0.5x0.2-0.5mc

found inside erytrocyte infected persons

Opt. temp 25-28 c

CULTURE;

Grow in semisolid nutrient agar with

10% rabbit serum

0.5%Hb

Growth is slow takes about 10 days

PATHOGENISIS:- Causes OROYA fever

Transmitted by SAND flies

INCUBATION PERIOD;

3 weeks to 3 months

CLINICAL FEATURES:- Fever Headache Chills Severe anemia Several weeks after recovery pt. develop nodular lesions on the body Secondarily infect produce ulcers – VERUGA PERUANA

Lab diagnosis:-

Demonstrated in blood smear by GIEMSA stain

Seen in cytoplasm and adhere to cell surface Grown on NA agar contain rabbit serum,

Hb Guinea pig inoculation leads to

VERUGA PERUANA

TRETMENT:-

Susceptible to penicillin

streptomycin

Tetracycline

Chloramphenicol

PREVENTION

Insecticides such as DDT should be used

to eliminate sand flies

BARTONELLA QUINTANA

MORPHOLOGY:-

small gram negative bacillus

0.3-0.5 mc to1.0-1.7 mc

Does not posses flagella

show twitching movments by fimbriae

CULTURE:- Grows on rabbit /sheep blood agar opt. temp -35 c in 5% CO2 colonies appear after 14 days primary

inoculation

PATHOGENESIS:-

Formerly called Rochalimaea quintana

Causes TRENCH fever

also called FIVE DAY fever

Transmission; by body louse

vertical transmission does not occur in lice

Lice after acquiring infection remain infectious through out life

CLINICAL FEATURES:-

Mild symptoms

leads to chronic rickttesiaemia

Relapse have been observed even after 20 years primary disease

Lab diagnosis:-

Detected in the gut of infected lice

Isolate from pt. blood by cultur sheep blood agar

Weil-felix test negative

PCR- detect organism in tissues

BARTONELLA HENSELAE

MORPHOLOGY:-

Gram negative

Slightly curved

Show twitching movments

CULTURE:-

Grows on chocolate agar

columbia agar with 5%sheep blood

tryptic-soy agar opt.temp-35-37 c in 5% CO2

COLONY MORPHOLOGY:-

white, dry, cauliflower like and

embedded in the agar

PATHOGENESIS:-

Causes CAT-SCRATCH disease

Occur by contact with scratch / bite of

an infected cat

Cat contact(scratch, bite, ? cat flea bite)

1 - 3 weeks

Resolutionin weeks tomonths

Disseminationin immuno-compromisedhosts

CLINICAL FEATURES:-

Regional lymphadenopathy Fever Endocarditis In AIDS pt. leads to;

bacillary angiomatosis

Lab diagnosis:-

lymph node biopsy – stained with

WARTIN-STARRY SILVER IMPREGNATION –clusters of bacillus

Grow on chocolate agar/ columbia agar

TREATMENT:-

Self limiting

No specific treatment required