MICROBIOLOGY PPT LECTURE NOTES | Karya Tulis Ilmiah

RICKETTSIA
ORIENTIA
EHRLICHIA
ANAPLASMA
COXIELLA
BARTONELLA

General introduction
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Gram-negative, obligate intracellular
coccobacilli bacteria that infect
mammaols and arthropods
Rickettsiae are transmitted in the
arthropods,which serves as both
vector and reservior

Both DNA and RNA
Is sensitive to antibiotic.

Category of rickettsia
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Genus
Rickettsia, Coxiella ,Orientia,Ehrlichia Bartonella
Species
Rickettsia prowazekii (epidemic typhus),
Rickettsia typhi (endemic typhus), Rickettsia
rickettsii (spotted fever), Rochalimaea quintana
(trench fever), Coxiella burnetii (Q fever)

Bilogical features

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Variable shape, coccobacilli
Gram negative
Microcapsule and slim layer
Culture : in york sacs of
embryonated eggs

Antigenic structure
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LPS
Rickettsia tsutsugamushi
Coxiella burnetii (Q fever)
LPSⅠ smooth
LPSⅡ rough
Weil-Felix reacrion

Surface protein(SPA)

Transmission
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Typhus, spotted fever and trench fever are
transmitted via arthropod vectors;

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Q fever is acquired via inhalation or
ingestion of contaminated milk or food.

Pathogenesis
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Virulence factors: endotoxin,
phospholipase A, and slime layer
Sites: vascular system producing
vasculitis 血管炎
Characteristic triad of symptoms: fever,
headache and rash (no rash with Q fever).

Rickettsia prowazekii
普氏立克次体
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epidemic typhus
average incubation periods (days):8
the louse
Respiratory tract and conjunctiva

Latent period: 2 weeks
Abrupt onset,fever,chills,headache,
myalgia,arthralgia

Replication cycle of Rickettsia and Orientia

Rickettsia typhi
地方性斑疹伤寒立克次体
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endemic typhus
7-14 days
Mice
the louse&flea
Mouth,nose and conjunctiva

Gradual onset,fever,headache,myalgia,
cough

Rickettsia tsutsugamushi
恙虫病立克次体
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Tsutsugamushi disease(scrub typhus)
Mice
tsutsugamushi
Black eachar 焦痂

Coxiella burnetti 贝纳柯斯体
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Q fever
Cow and sheep
tick
High resistance

abrupt onset
,fever,headache,chills,myalgia
,granulomatous hepatitis

chronic diaease with
subacute onset
,endocarditis,hepatic
dysfunction

Replication of C. burnetii

Generalized Life Cycle of Dermacentor variabilis and
Dermacentor andersoni Ticks

Bartonella henselae 汉赛巴通体
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CSD (cat scratch disease)
Cat and dog
Conjunctiva inflammation and lymph node
swell

Ehrlichia 埃里希体属
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Ehrlichia chaffeensis: human
monocytotropic ehrlichiosis
Ehrlichia sennetsu : human granulocyto
tropic ehrlichiosis

Replication of Ehrlichia 埃里希体

Proposed life cycle for the agent of Human
Granulocytic Ehrlichiosis 埃里希体病

Diagnosis
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The use of immunofluorescent antibodies to
examine a biopsy can be diagnostic.
The organism can be inoculated into tissue
culture and grown over 4-7 days but this is very
hazardous to personnel.
The Weil-Felix test looks for the production of
serum antibody that is reactive against Proteus
OX19, OX2 or OXK antigens but it is not always

reliable.

Control
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Sanitary: Arthropod and rodent control
Immunological: No vaccines are
currently available.
Chemotherapeutic: Tetracycline or
chloramphenicol are drugs of choice.