RICKETTSIA
ORIENTIA
EHRLICHIA
ANAPLASMA
COXIELLA
BARTONELLAJialin Jin
Fudan university huashan hospital
Department of infectious diseases
2014 Nov
General introduction
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
Culture:in animate media
Anthropods:
ticks, mites, lice, and fleas
Tick 扁虱Mite 螨虫
Louse 虱子
Live louse
Flea 跳蚤
Category of rickettsia
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)
Biological features
Variable shape, coccobacilli
Gram negative
Microcapsule and slime layer
Culture : in york sacs of embryonated eggs
Antigenic structure
LPS
Rickettsia tsutsugamushi
Coxiella burnetii (Q fever)
LPSⅠ smooth
LPSⅡ rough
Weil-Felix reaction
Surface protein(SPA)
Transmission
Typhus, spotted fever and trench fever are
transmitted via arthropod vectors;
Q fever is acquired via inhalation or
ingestion of contaminated milk or food.
Pathogenesis:vasculitis
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).
Replication cycle of Rickettsia and
Orientia
rickettsial family of diseases
Four groups
The spotted fever group
The typhus group
The Ehrlichia group
Q fever
spotted fever group typhus group Ehrlichia group Q fever
R. rickettsii
(Rocky Mountain
spotted fever)
R. prowazekii
(louseborne
or epidemic
typhus and
Brill–Zinsser
disease)
E. chaffeensis
[human monocytotropic
ehrlichiosis (HME)]
Q fever
(Coxiella
Burnetii)
R. Conorii
(Boutonneuse fever)
R. Typhi
(murine typhus)
Anaplasma
phagocytophilum
[human
granulocytotropic
anaplasma (HGA)]
R. australis
(Queensland tick
typhus)
Orienta
tsutsugamushi
(scrub typhus)
pathogens E. ewingii
R. Sibirica
(North Asian tick typhus)
E. muris
R. akari
(rickettsial pox)
Neorickettsia
sennetsu
Rocky Mountain spotted fever
Most severe disease in the spotted fever
group
Motality 22% in untreated
Motality 6% with treatment.
occurs throughout the United States,
Mexico,and Central and South America
late spring and summer
Dog tick or wood tick
Pathogenesis
Injected into the skin by ticks
Proliferates in the skin, disseminates via the
bloodstream.
Survives in the host cell cytoplasm
spreads cell-to–cell
producing necrotic cells
hemorrhage in heart, lung, CNS, skin, intestine,
pancreas,liver, skeletal muscle, and kidneys.
Clinical presentation : RMSF
Incubation period is 2 to 14 days.
Acute onset of nonspecific symptoms:
fever,headache, malaise, myalgias, and
nausea.
Abdominal pain may mimic cholecystitis or
appendicitis.
Clinical presentation: RMSF
Macular, petechial rash begins on ankles
and wrists and spreads to trunk 5 days after
symptoms begin
“Spotless” infection occurs in 10%—usually
elderly and dark skinned individuals.
Urticaria or pruritic rash makes the diagnosis
unlikely.
Macular rash in
the early stage
of RMSF
Necrosis in
the toes in
the late stage
of RMSF
Clinical presentation : RMSF
Other symptoms include aseptic
meningitis, conjunctivitis, fundoscopic
hemorrhages, and ARDS in severe
disease.
Death within 8 to 15 days if treatment is
not initiated within 5 days.
Diagnosis
epidemiology and clinical manifestations.
Culture not recommended.
Skin biopsy with immunofluorescence staining
has high specificity. Not recommended if
antibiotics has been given
Serology provides a retrospective diagnosis
Can be mistaken for viral syndrome, drug
allergy, and meningococcemia.
Treatment
infection drug doseRelative
efficacycomments
Rocky
Mountain
Spotted
Fever
doxycycline
100mg PO or IV q12h for
3-5 days after afebrile
Children <45 kg:
2.2 mg/kg per dose q12h
for 3 days after afebrile
First line
Short-course
doxycycline
causes
minimal harm
to developing
teeth
Chloramphenicol500mg PO or IV q6h for
3-5 days after afebrile Alternative
For pregnant
women
Typhus
pathogen diseases severity motality vector
R.
prowazekii
louse-borne typhus
epidemic typhusMost serious form 30-70% Body lice
Reactivation
of R.
prowazekii
Brill–Zinsser
disease
Mild, similar to
primary disease<5% Body lice
R. typhi
Flea-borne typhus
murine
or endemic typhus Milder form <5% Flea
R.
tsutsugamu
shi
Scrub typhus More gradual
onset;
Black eschar
mite larvae
(chiggers 恙螨)
Rickettsia prowazekii
普氏立克次体
epidemic typhus
average incubation periods : 1 week
the louse, sometimes fleas from flying squirrels
Respiratory tract and conjunctiva
Latent period: 2 weeks
Abrupt onset, fever, chills, headache,
myalgia, arthralgia
Rickettsia prowazekii
普氏立克次体 small-vessel vasculitis - tissue necrosis -
multiple organs involves
Lungs
Liver
gastrointestinal tract
Central nervous system
Skin: 60%, trunk-spreading outward, macular to
maculopapular to petechiae to peripheral
gangrene(occlusion)
30%-70% motality
Rickettsia typhi
地方性斑疹伤寒立克次体
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
Tsutsugamushi disease (scrub typhus)
Epidemiology:Asia Pacific rim(mite island)
Incubation time: 6 to 21 days
the onset is usually gradual
high fever, chills, and anorexia
Diffuse lymphadenopathy,
splenomegaly, conjunctivitis, and pharyngitis
Black eachar 焦痂 (~50%)
Diagnosis
based on clinical and epidemiologic findings
Acute and convalescent antibody titers
Immunofluorescence staining of the primary
eschar: rapid
Cross reaction to antigen of Bacillus proteus ,
Not recommended now for poor sensitivity and lack of specifity
Treatment
infection drug doseRelative
efficacy
typhus doxycycline
100mg PO or IV q12h for 3-5
days after afebrile
Children: Same as RMSF
First line
Chloramphenicol500mg PO or IV q6h for 3-5
days after afebrile Alternative
Add rifampin in
areas with resistant
strains
600-900mg PO q24h for 3-5
days after afebrile
EHRLICHIA
HME HGA
pathogen Ehrlichia chaffeensis Anaplasma phagocytophilum
disease human monocytic
ehrlichia
human granulocyte anaplasma
anthropods Lone Star tick found on
the whitetail deer
Ixodes, the same tick that
transmits Lyme disease and
babesiosis
Epidemic
region
southeast United States California, Minnesota, Wisconsin,
Massachusetts, Connecticut, New
York, and Florida.
Proposed life cycle for the agent of Human
Granulocytic Ehrlichiosis埃里希体病
Replication of Ehrlichia埃里希体
Clinical manifestation of
ehrichiosisHME HGA
Incubation time 7 days
Targeted cell monocytes granulocytes
motality 5% (mainly elderly and immunocompromised)
symptoms Gradual onset of fever, chills,headache,myalgias,
anorexia, and malaise.
Severe form respiratory insufficiency,
renal insufficiency, and
meningoencephalitis
(with lymphocytosis noted
in the cerebrospinal fluid)
respiratory insufficiency,
rhabdomyolysis, and
neutropenia resulting in
gram-negative sepsis
rash Macular, petechial rash
Rash incidence 30% to 40% 2% to 11%
Diagnosis: presumptive
Thrombocytopenia and leukopenia are
common (neutropenia in granulocytic form).
Moderate transaminase elevations
Morulae are rare in peripheral blood smears
in the monocytic form, common in the
granulocytic form.
Retrospective serology makes the diagnosis.
Morulae
Morulae found in human granulocytotropic
ehrlichiosis caused by Anaplasma phagocytophilum.
Coxiella burnetti贝纳柯斯体
Q fever
Resevoir: Cow and sheep
Vector: tick
High resistance
changes its outer LPS:
Phase II outer antigens in the environment.
Phase I outer antigens when infecting the host.
Replication of C. burnetii
Clinical manifestation of Q fever
Incubation period is 3 weeks
abrupt flu-like illness with cough.
maculopapular rash (<10%)
ARDS
Hepatitis
myocarditis and pericarditis;
Meningitis
chronic endocarditis (negative echo early
in the disease, high mortality).
Diagnosis (culture negative)
IgG (titer above 1:200) and IgM (titer above 1:50)
anti-phase II antigens indicate acute disease.
IgG (titer above 1:800) and IgA (titer above 1:100)
anti-phase I antigens indicate chronic disease.
PCR is sensitive and specific (available in some
locations).
treatment
not as effective as for rickettsial infections.
Treat with doxycycline for 2 weeks for
acute disease; fluoroquinolones may also
be helpful.
Treat with doxycycline and
hydroxychloroquine for 18 months to 4
years or life for chronic endocarditis.
Treatment
infection drug dose comments
Ehrlichiosis
and
anaplasmaDoxycycline
100 mg PO or IV q12h for
3–5 days after afebrile
Children: Same as Rocky
Mountain Spotted Fever
Also preferred
for children
Q fever Doxycycline, plus
hydroxycholoroquine
100 mg PO or IV q12h
200 mg PO q8h
Add hydroxy-
chloroquine for
endocarditis
Cat scratch disease and bacillary
angiomatosis
Caused by bartonella
Usually localized disease and seldom
cause serious illness
Epidemiology
Found worldwide, more common in warm
humid climates and young people
Cat as the primary vector
Fleas, also responsible for spread from cat to cat
pathogen disease
B. henselae CSD and bacillary angiomatosis
B. quintata Angiomatosis and trench fever
B. bacilliformis Oroya fever and Verruga peruana
Pathogen: Bartonella
Pleomorphic gram-negative bacilli
Take up Gram stain poorly
Binds silver and can be identified by
Warthin-Starry stain
pathogenesis
Enter the host through the break in the skin
Multiply at the site and spread to local lymphatic
system and adjacent lymph nodes
Flagellar and other surface protein mediate
attachment to red blood cells and endothelial cells
Multiply in vacuoles
Forming intracellular clusters similar to the
morulae of Ehrlichia.
Induce the formation of new vessels
Reason why not dissemination
Grow in both intracellular and extracelluar
environments
Induce both
Granulomatous reaction consisting of
macrophages and histiocytes
Acute inflammatory response consisting
primarily of PMNs
Bacteremia and dissemination in HIV
Clinical manifestation
Presents with a warm, tender, swollen lymph
node 2 weeks after the scratch.
Axillary node is most common (depend on the site
of innoculation)
The primary scratch can often be identified.
Low-grade fever is common.
Rarer manifestations
conjunctivitis, encephalopathy, and granulomas in
the liver and spleen,Parinaud’s oculoglanduar
syndrome (conjunctivitis and preauricular
lymphadenopathy )
Bacillary angiomatosis
AIDS with body lice
B. quintana primarily , B. henselae sometimes
Skin lesion: cluster of small reddish papules
that can enlarge to form nodules
Appear vascular and bleed when traumatized
Biopsy: multiple small blood vessels, enlarged
endothelial cells and polymorphonuclear
leukocyte infiltration
Treatment
infection drug dose comments
Bartonella
Lymphatic
disease
Azithromycin, or
clarithromycin, or
doxycycline, or
ciprofloxacin
500 mg PO once,then 250
mg
500mg PO q12h
100mg PO q12h
500mg PO q12h
All equally
effective
Severe
disease
Azithromycin, plus
rifampin
500mg PO q24h
600mg PO or IV q24h
Efficacy not
proven
Epidemiology summary
Organism disease vector reservior Incubation
R. rickettsii HMSF tick tick 2-14
R. prowazekii Epidemic
typus
Louse human 8
R. typhi Endimic
typus
Louse and
Flea
mice 7-14
R. tsutsugamushi Scrub typus Mite larva Wide mice 10-12
E. chaffeensis ehrlichiosis tick tick 12
C. burnetii Q fever tick Wild animal
Cow, sheep
20
B. hanselae CSD Cat, dog 14
Control
Sanitary: Arthropod and rodent control
Immunological: No vaccines are
currently available.
Chemotherapeutic: Tetracycline or
chloramphenicol are drugs of choice.
Thank u
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