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Clinical Bacteriology
FINALS
Aerobic Gram Positive Bacilli
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SF, NB, catalase POSITIVE bacilli
Second Year Flashcards > Clinical Bacteriology > FINALS > Aerobic Gram Positive Bacilli
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NSF, Branching, Aerobic Actinomycetes
Second Year Flashcards > Clinical Bacteriology > FINALS > Aerobic Gram Positive Bacilli
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NSF, NB, Catalase NEGATIVE bacilli
Second Year Flashcards > Clinical Bacteriology > FINALS > Aerobic Gram Positive Bacilli
13 cards
Rothia
Second Year Flashcards > Clinical Bacteriology > FINALS > Aerobic Gram Positive Bacilli
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Cards (64)
Corynebacterium also known as
Kleb Loeffler's bacillus
slightly
curved
slightly
wider
ends
club
shaped
diptheroid
lipophilic
and
no lipophilic
Lipophilic Corynebacterium
is
fastidious
that grow
slowly
on standard culture media
When we talk about
lipophilic
organism, the growth is enhanced if
lipids
are included in the culture media
major virulence factor of Corynebacterium diphtheria
heat labile
this toxin is produced by the strains of Corynebacterium diphtheriae infected with a lysogenic B-phage which carries the gene tox
has a protein of 62,000 daltons
Diphtheria Toxin
responsible for the
cytotoxicity
Fragment
A
responsible for
binding
to
receptors
on human cells; mediated the entry of fragment A into the
cytoplasm
Fragment
B
Respiratory
diphtheria: sudden onset with exudative pharyngitis, sore throat, low grade fever and malaise.
MOT:
aerosol
through
nasopharyngeal route
or
nasal oral discharges
Exotoxin can lead to
pseudomembrane
formation
Patients that has respiratory diphtheria are characterized as having
bulls neck
appearance
Cutaneous diphtheria
: a
papule
can develop on the skin, which progresses to a non healing
ulcer
(lesions on skin)
Corynebacterium
diphtheria laboratory diagnosis
highly
pleomorphic
palisades
or as individual cells lying at sharp angles to another in
V
or
L
formations
club
shape swellings or beaded forms are common
stain
irregulary
especially with methylene
blue
metachromatic areas: Babes Ernst granules
Babes Ernst granules
represents the accumulations of
polymerized polyphosphates
Culture characteristics of C. diphtheriae
facultative anaerobic
optimal growth temp:
37C
multiply at:
15
-
40C
Grows on
nutrient
agar
Loefflers
serum or
Pai
agars - morphology of he organism is demonstrated
Cystine Tellurite Blood agar
(CTBA)
selective
and
differential
media
presence of
potassium tellurite
which inhibits many non coryneform bacteria
modification of
tindsdale
medium
black or
brownish
due to the
reduction
of
tellurite
Organisms that produces brown halo on CTBA
C. diphtheriae
C. ulcerans
C. pseudotuberculosis
C. diphtheriae
lacks
urease
production
ferment:
glucose
&
maltose
producing
acid
but no
gas
reduces
nitrate
to
nitrite
The in
vitro diphtheria
toxin detection procedure is an immunodiffusion test described first by Elek
Elek
test : organisms are streaked on medium of
low
iron
content
10mm
apart
Laboratory Diagnosis: Treatment
Diphtheria is treated by prompt administration of
anti toxin
DOC :
penicillin
Erythromycin
: used for penicillin sensitive people
Corynebacterium amycolatum
the most frequently recovered
corynebacterium
species from human
part of normal skin
biota
flat, dry,
matte
,
waxy
appearance and non lipophilic
resistant to wide range of anti microbials including
B lactams
,
fluoroquinolones
, macrolides, and aminoglycosides
Corynebacterium jeikeium
named after
Johnson
and
Kaye
limited to patients who are
IMCP
most common cause of
corynebacterium
associated
prosthetic valve endocarditis
in adults.
lipophilic
non hemolytic
urease
and nitrate reduction negative
TOC :
Vancomycin
Corynebacterium pseudodiphtheriticum
often appear
palisades
grows well on standard
laboratory
media
reduces
nitrate
produces
urease
their
respiratory
tract infection can mimicmimic the
respiratory
diphtheria
does not show characteristic of
pleomorphic
morphology
Corynebacterium
pseudotuberculosis
veterinary
pathogen
causes
granulomatous
lymphadenitis
in human
dermonecrotic toxin
: causes death in various cell types
produces
diphtheria toxin
produces
brown halo
on CTBA
produces
urease
SBA:
small
,
yellowish-white
colonies
Corynebacterium striatum
considered
commensal
or skin contaminant
non
lipophilic
and
pleomorphic
produces
small
,
shiny
,
convex
colonies in about 24 hours
resistant to
penicillin
, other
B lactams
, macrolides, and fluoroquinolones
Susceptible to
vancomycin
Corynebacterium
ulcerans
veterinary pathogen
causing
mastitis
in cattle
humans usually acquire thru
contact
with animals and ingestion of
unpasteurized
dairy
Grows well on
SBA
does not reduce nitrate to nitrite
urease
positive
Corynebacterium urealyticum
most commonly associated with
UTI
lipophilic and strict aerobe
pinpoint
, non hemolytic,
white
colonies
DOC :
Vancomycin
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