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RICKETTSIAE
Types

Props

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Rickettsia
Orientia
Coxiella
Erlichia
Obligate intracellular
Smaller than usual bact
Cell wall=bact (G-ve)
Divide=bact
Enzyme (metabolism)
RNA:DNA ratio=bact
Tetracycline,
Chloramphenicol

MYCOPLASMA
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Morph

- Can’t stain by Gram stain!!
-pleomorphic
-stain: Giemsa stain

M
...
Hominis
Ureaplasma
urealyticum
Smallest bact
Pass tru bact
filters (no
vaccine!)
No cell wall
(only 3layer
memb, sterols)
No need tissue
culture, only
agar rich in
sterols, center
of colony
depressed
...

-pleomorphic
-examined by:
 Dark ground
microscopy

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IF (specific
fluorescent Ab)
Giemsa stain

Culture

1) yolk sac of embryonated
eggs
2) cell culture
3) animal inoculation

-aerobic + 10% CO2 +
30% serum
-slow growers
Small , rounded
colonies, fried-egg
appearance
-urogenital
mycoplasma: + 10%
urea

Resistanc
e

-all killed by heat, bactericidal,
drying except Cox
...

Most imp
...

cells of small bv->
vasculitis-> thrombosis,
rupture, necrosis
...


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Colonize
mucosa of RT &
GUT
Attach to spc
...
injured cells->
swell, impaired ciliary
f(x)

C/P

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Fever
Headache
Myalgia
Malaise
Prostration
Skin rash (except Q
fever)
Hepatosplenomegaly

A) TYPHUS
 Endemic typhus
-severe, centrifugal rash
 Endemic (murine)
typhus
-milder
 Scrub typhus
-black eschar, generalized
lymphadenopathy,
lymphocytosis

B) SPOTTED FEVER
-centripetal rash
 Rocky mountain
spotted fever
 Mediterranian spotted
fever
 Rickettsial pox (mild)
-papulovesicular rash= varicella
-black eschar

C) Q FEVER (Coxiella Burnetii)
-like influenza, atypical
pneumonia, hepatitis,
encephalopathy
-NO rash/ local lesion
-↑ titer of Cox
...
PNEUMONIAE

M
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UREALYTICU
M

Ab (microIF)
-infective endocarditis: blood
culture is –ve Ag but +ve Ab (↑
titer)
-MOT:
humans-> inhalation dust cont
org
animals (sheep, goats, cattle)->
ticks

D) BRILL’S DISEASE
(R
...
dt ↓immune syst of
d ptnts
-Human as reservoir: org persist
many years in LN without any
symptoms
-Atypical pneumonia (x
respond to penicillin)
-MOT: resp secretions
-affects all age gps
-asymptomatic>severe
-10% of all pneumonia
-tracheobronchitis,
pharyngitis

FEMALE
pyelonephriti
s
-cystitis
-salpingitis
-Tuboovarian
abscess
-postabortal/ postpartum fever
-abortion

MALE -X

Lab diag

1) specimen: blood, skin
biopsies

2) direct demo: direct IF (frm
skin biopsies of RMSF)

3)serology:
 Latex agg
 ELISA

1) specimen: sputum,
nasopharyngeal swabs,
aspirates, blood

2) N
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Test

Stuart’s
transport
medium

5) cold haemagg tech
 X specific
 Cold Ab=
IgM+surface Ag
gp O RBC @ 4°C
 60% +ve
 Titre 64++

2)isolation:
-specimen
from swabs->
spread on
medium
-moist
atmosphere,
5-10% CO2,
37°C-> friedegg app
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urealyticum
+10% urea ->
urease
activity
-liquid med
cont urea n
phenol red
-produce
NH3 -> alters
pH -> change
colour
-colonies
tiny, friedegg app

3)
serodiagnosis
-x rely on it!!

Tx

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Tetracyclin (T)

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Tetracyclin

Only

 Chloramphenicol (C)
-only suppress d growth, x free
frm this bact, recover depend
on our immunity

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