Lecture |Bacilli Flashcards
(190 cards)
1
Q
Spore formers
A
- Bacillus anthracis
- Bacillus cereus
2
Q
Non-spore formers
A
- Corynebacterium
- Listeria
- Erysipelothrix
- Gardnerella
3
Q
Branching, non-spore- formers
A
- Nocardia
- Aerobic actenomycetes
4
Q
is Bacillus spp. aerobic, anaerobic, or facultative anaerobic?
A
aerobic & facultative anaerobic
5
Q
Is Clostridium aerobic, anaerobic, or facultative anaerobic?
A
anaerobic
6
Q
- Gram positive
- Aerobic or facultative anaerobic bacilli
- Endospores
- Catalase positive
A
Bacillus spp.
7
Q
Clostridium spp. form endospores–
A
anaerobically
8
Q
Bacillus spp. form endospores—
A
aerobically and anaerobically
9
Q
causative agent of antrax.
A
Bacillus antracis
10
Q
a disease of wild and domestic animals including sheep, goats, horses, and cattle.
A
Anthrax
11
Q
Types of Anthrax
A
- Cutaneous Anthrax
- Gastrointestinal/Ingestion Anthrax
- Inhalation Anthrax (wool sorter’s disease)
- Injectional Anthrax
12
Q
Causes a typical presentation of the ulceration is a black, necrotic lesion known as an
A
eschar
13
Q
accounts for most human infections and is associated with contact with infected animal products.
A
Cutaneous Anthrax
14
Q
results from ingestion of endospores
A
Gastrointestinal/Ingestion Anthrax
15
Q
Gastrointestinal/Ingestion Anthrax presents in two forms:
A
oral or oro pharyngeal
16
Q
Usually attributed to toxemia and sepsis.
A
Gastrointestinal/Ingestion Anthrax
17
Q
Most fatal; previously referred to pulmonary anthrax, Woolsorters’ disease and ragpickers’ disease
A
Inhalation Anthrax (wool sorter’s disease)
18
Q
Bacillus antracis virulence factor
A
- Lethal toxin (LT)
- Edema toxin (ET)
19
Q
Each of virelence toxins consists of proteins such as
A
protective antigen (PA), lethal factor (LF) and edema factor
20
Q
associated with food borne illness.
A
B. cereus group
21
Q
organisms are often associated with infections in immunocompromised patients who have debilitating disease such as cancer or diabetes.
A
B. cereus
22
Q
most common type of non gastrointestinal infection caused by B. cereus
A
endophthalmitis
23
Q
also referred to as hemolysin IV
A
cytotoxin K
24
Q
B. cereus group Virulence factors
A
- hemolysin BL (HBL)
- Nonhemolytic enterotoxin (Nhe)
- cytotoxin K (Cytk) (hemolysin IV)
- Cereulide
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believed to act synergistically
hemolysin BL, nonhemolytic enterotoxin, and cytotoxin (hemolysin IV)
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heat-stable, proteolysis, and acid-resistant toxin
cereulide
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Specimen procession for Bacillus spp.
heat or alcohol shock
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heat specimen 70°C for
30 minutes
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heat heat specimen 80°C for
10 minutes
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heat specimen 62°C to 65°C for
15-20 minutes (B. anthracis only)
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only clinically relevant aerobic organisms capable of producing endospores in the presence of oxygen.
Bacillus spp.
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inhibited by high concentrations of CO2
Sporulation
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production of spores may be induced by
growth in triple sugar iron (TSI), urea, or nutrient agar containing 5 mg/L manganese sulfate.
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a stain required to visualize endospores.
malachite green
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appear pink from the secondary stain, safranin
vegetative cells
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stains green
endospore
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attributed by the fact that the endospores may appear as intra cellular or extracellular clear oval structures upon Gram staining.
Box car or bamboo rod appearance
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selective agar for gram-positive organisms that isuseful for the removal of contaminating organisms and the isolation of Bacillus spp.
Phenylethyl alcohol agar (PEA),
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used for selection and isolation from fecal contamination
Polymyxin-lysozyme-EDTA-thallous acetate (PLET)
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used to induce B. anthracis capsule formation
Bicarbonate agar
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an agar that should be incubated in increase carbon dioxide environment
Bicarbonate agar
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in this agar, colonies of B. anthracis are nonhemolytic, large (2 to 5 mm), gray, and flat with an irregular margin because of outgrowths of long, filamentous projections.
SBA
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has been used to describe the colony morphology of B. anthracis.
Medusa head
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colonies of B. anthracis have what type of consistency
tenacious consistency
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bacteria having the appearance or characteristic of beaten egg whites.
B. anthracis
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ferments glucose
B. anthracis
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produces lecithinase
B. anthracis
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grows in 7% NaCl and pH<6
B. anthracis
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susceptible to penicillin (10 U/mL)
B. anthracis
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B. anthracis does not ferment ?
mannitol, arabinose or xylose
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Grow on Egg Yolk Agar
B. anthracis
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opaque zone around colonies
Lecithinase
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oily sheen
Lipase
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The hydrolyzed tube remain liquid even after freezing at 4°C
Gelatin Hydrolysis test
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clearing of the x ray film
Gelatin Hydrolysis test
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nonmotile bacterias
B.anthracis & B. mycoides
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motility can be tested by either
1. wet mount preparation
2. inoculation into motility test medium.
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Capsule production by B. anthracis can be detected by
1. India ink staining on blood or CSF specimens
2. on cells isolated in media supplemented with sodium bicarbonate
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penicillin susceptibility of B. anthracis
susceptible
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penicillin susceptibility of B. cereus
resistant
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Lecithinase +
B. anthracis
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Lecithinase -
B. cereus
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motile -
B. anthracis
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motile +
B. cereus
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B. anthracis Hemolysis on BAP
none
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B. cereus Hemolysis on BAP
Beta-hemolysis
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B. anthracis gelatin hydrolysis
negative
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B. cereus gelatin hydrolysis
postive
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negative growth on PEA
B. anthracis
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positive growth on PEA
B. cereus
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Serodiagnosis of B. anthracis is typically available for the detection of the
PA antigen or toxin protein, LF, and EF
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immunochromatographic test that presumptively identifies B. anthracis from blood agar within 15 minutes
Red Line Alert Test
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most rapid detection method and differentiation of B. anthracis
PCR
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recommended vaccine after aerosol exposure to B. anthracis, such as in a bioterrorist event.
Chemoprophylaxis with ciprofloxacin or doxycycline
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gram positive "club-shape"
corynebacteria
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- nonlipophilic/lipophilic
- catalase +
- Nonmotile
corynebacteria
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type of corynebacteria often considered fastidious and grow slowly on standard culture media
Lipophilic corynebacteria
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Disease caused by C. diphtheriae is referred to as
diphtheria.
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2 Forms of Diptheria
1. Respiratory
2. Cutaneous
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Humans are the only natural hosts of this bacteria
C. diphtheriae.
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Respiratory Diptheria are carried in the upper respiratory tract and spread by
droplet or hand-to-mouth contact.
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C. diphtheriae most common site of infection
tonsils or the pharynx
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C. diphtheriae produce toxin that requires infection with
bacteriophage
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causes tissue necrosis and exudate formation triggering an inflammatory reaction.
C. diptheria
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combination of cell necrosis and exudate forms this which attaches to the tissues
a tough gray-to white pseudomembrane
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consists of nonhealing ulcers with a dirty gray membrane
Cutaneous diphtheria
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major virulence factor associated with C. diphtheriae.
Diphtheria toxin
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Diphtheria toxin s produced by strains of C. diphtheriae infected with a
lysogenic β-phage
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1. one of the Corynebacterium species most frequently recovered from human specimens.
2. It is part of the normal skin microbiota
3. Often been misidentified by clinical laboratories as C. striatum, C. xerosis, and C. minutissimum.
4. Opportunist
C. amycolatum
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named after Johnson and Kaye
C. jeikeium
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most common cause of Corynebacterium-
associated prosthetic valve endocarditis in adults
C. jeikeium
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also causes septicemia, meningitis, prosthetic joint infections, and skin complications, such as rash and subcutaneous nodules.
C. jeikeium
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veterinary pathogens .
C. pseudotuberculosis & C. ulcerans
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Human infections typically have been associated with contact with sheep and are rare.
C. pseudotuberculosis
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1. Causes a granulomatous lymphadenitis in humans.
2. The organism produces a dermonecrotic toxin that causes death of various cell types, and it can produce diphtheria toxin.
C. pseudotuberculosis
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1. most commonly associated with UTIs
2. Up and incoming cause of cystitis
C. urealyticum
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1. Cause skin ulcers and oxidative pharyngitis
2. isolated from humans with diphtheria-like illness, and a significant number of isolates produce the diphtheria toxin
C. urealyticum
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a veterinary pathogen That causes mastitis in cattle and other domestic and wild animals
C.ulcerans
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1. gram positive bacillus
2. appears in palisades
3. "V" and "L" formations
4. club-shaped swellings
5. Babès-Ernst granules.
C. diphtheriae
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C. diphtheriae often stain irregularly, also giving a beaded appearance with the stain?
methylene blue
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In C. diphtheriae, The metachromatic areas of the cell, which stain more intensely than other parts
Ernst granules or Volutin granules
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The presence of this in C. diphtheriae indicates the accumulation of nutrient reserves and differs with the type of medium and the metabolic state of the individual cells.
Babès-Ernst granules
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Corynebacterium spp. usually grow on what type of agars
5% sheep blood and chocolate agars
104
produce much larger colonies when cultured on 5% sheep blood agar supplemented with 1% Tween 80
1. C. jeikeium
2. C. urealyticum
3. C. afermentans subsp. lipophi lum
4. C. accolens
5. C. macginleyi
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lipophilic coryneform bacteria demonstrate better growth in broths supplemented with
rabbit serum
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is corynebacterium facultatively anarobe?
YES
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medias to be used if diphtheria is suspected.
Selective and differential media for C. diphtheriae
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medium that can promote production of metachromatic granules because it contains egg yolk
Loeffler medium
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medium C. diptheria shows brown-black colonies with a gray-brown halo
Tinsdale medium
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a modification of Tinsdale medium, contains sheep red blood cells, bovine serum, cystine, and potassium tellurite.
Cystine-tellurite blood agar (CTBA)
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inhibits many noncoryneform bacteria
potassium tellurite
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When grown on CTBA, corynebacteria form -- ? --(color) colonies from the reduction of tellurite
black or brownish
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On Sheep Blood Agar, corynebacteria can display what type of hemolysis
very small zone of beta-hemolysise
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useful for differentiating corynebacteria because only C. diphtheriae, C. ulcerans, and C. pseudotuberculosis form a brown halo as a result of cystinase activity.
Cystine-tellurite blood agar (CTBA)
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1. urease negative
2. ferments glucose and maltose (w/o gas
production
3. reduces nitrate to nitrite
C. diptheriae
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produces urease and on SBA forms small, yellowish-white colonies.
C.pseudotuberculosis
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colonies of this are flat and dry, have a matte or waxy appearance, and are nonlipophilic. It does not produce any halo in Tinsdale medium; negative for urease; is only able to produce acid from glucose
C. amycolatum
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produce acid from starch and is gelatin hydrolysis positive, does not reduce nitrate, urease positive
C.ulcerans
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1. pinpoint, nonhemolytic, white colonies 2. lipophilic
3. coryneform morphology
4. nitrate -
5. catalase +
6. urease +
C. urealyticum
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urease positive within minutes after inoculation on a Christensen urea slant.
C. urealyticum
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test whether diphtheria antitoxin neutralizes the lethal effect of a cell-free suspension of the suspect organism
Guinea pig lethality test
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test utilizes the principle of immunodiffusion.
ELEK test
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only effective control of diphtheria
immunization with a multidose diphtheria toxoid
124
in ELEK test, the presence of this indicates that the strain produced toxin that reacted with the homologous antitoxin.
fine precipitin lines
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only effective control of diphtheria is through immunization with
multidose diphtheria toxoid
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a preparation of antibodies capable of toxin neu tralization before its entry into the patient’s cells.
Hyperimmune antiserum produced in horses, diphtheria anti toxin (DAT)
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1. facultative anaerobe
2. catalase-positive
3. nonbranching,
4. oxidase-negative
5. gram-positive rod
Listeria monocytogenes
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a common cause of meningitis in neonates and immunocompromised individuals especially those who undergone renal transplantation and cancer patients.
Listeria monocytogenes
129
Contaminated ice cream, hot dogs, and luncheon meats have served as vehicles for this foodborne disease.
L. monocytogenes
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a common cause of meningitis in neonates and immunocompromised individuals especially those who undergone renal transplantation and cancer patients
L. monocytogenes
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the major virulence factor of L. monocytogenes
Listeriolysin O
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a pore- forming toxin that reduces T-cell responsiveness.
Listeriolysin O
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This toxin-induced unresponsiveness, in combination with phospholipases, enables the organism to escape from the phagosome of white blood cells, avoid intracellular killing, and spread to the bloodstream
Listeriolysin O
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forms pseudopod-like projections that are then ingested by neighboring cells. This provides a means of cell-to-cell spread of the organism. The bacterium eventually reaches the central nervous system and the placenta, resulting in disease (listeriosis).
Actin polymerization
135
organism produces a bacterial surface protein that induces host cell actin polymerization
Actin polymerization or Act A
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short, gram-positive rod that may occur singly or in short chains, resembling streptococci
L. monocytogenes
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The colonies are small, round, smooth, and translucent. They are surrounded by a narrow zone of β-hemolysis, which may be visualized only if the colony is removed. The colonies and hemolysis resemble those seen with S. agalactiae
L. monocytogenes
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The optimal growth temperature for L. monocytogenes
30° to 35° C
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L. monocytogenes grows at 4° C and this technique may be used to isolate the organism from polymicrobial clinical specimens.
cold enrichment
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also called a refrigerator bacilli
L. monocytogenes
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1. Motile
2. Ferments salicin
3. Hydrolyzes esculin
L.monocytogenes
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1. Non motile
2. Does not ferment salicin
3. Do not hydrolyzes esculin
Corynebacterium
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1. hippurate hydrolysis positive
2. catalase positive
3. bile esculin hydrolysis positive
4. motile at room temperature
L.monocytogenes
144
exhibits tumbling motility (end-over-end motility)
In wet mount
145
In motility semi-solid medium “umbrella” pattern is seen when the organism is incubated at temperature?
22° to 25° C but not at 35° C
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Block type
CAMP +
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Confirmatory findings of L.monocytogenes include
acid production from glucose and positive Voges-Proskauer and methyl red reactions.
148
Anton’s test--ocular test
Keratoconjuctivitis
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The organism may be transmitted through direct contact or ingestion of contaminated water or meat.
Erysipelothrix rhusiopathiae
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1. gram-positive
2. catalase-negative
3. non–spore-forming, pleomorphic rod that has a tendency to form long filaments
Erysipelothrix rhusiopathiae
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the most common infection caused by E. rhusiopathiae in humans, and a localized skin infection
Erysipeloid
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Erysipelas =
S. pyogenes
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ssociated with individuals employed in occupations such as fish handlers, farmers, slaughterhouse workers, food preparation workers, and veterinarians
Erysipelothrix infections
154
Erysipeloid =
Erysipelothrix
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make use of Tissue biopsy of the skin lesion
E. rhusiopathiae
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1. Gram positive
2. Short rods/long filaments
3. Singly, in short chains, or in “V” shape
E. rhusiopathiae
157
grows on standard culture media, including SBA and chocolate agar. The colonies often appear α-hemolytic after a few days of growth.
E. rhusiopathiae
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1. Catalase negative
2. Nonmotile
3. VP negative
4. Hydrogen sulfide production positive
E. rhusiopathiae
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Growth of E. rhusiopathiae in a gelatin stab culture yields a highly characteristic “test tube brush– like” pattern at a temperature of
22° C
160
short, pleomorphic gram-positive rod or coccobacillus that often stains gram variable or gram negative
Gardnella vaginalis
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primarily known for its association with bacterial vaginosis (BV) in humans.
G.vaginalis
162
characterized by a malodorous discharge (fish-like odor) and vaginal pH greater than 4.5 (alkaline)
bacterial vaginosis
163
BV generally results from a reduction in the
Lactobacillus population in the vagina
164
Gram staining of vaginal secretions is generally regarded as the
reference method for diagnosing BV.
165
aids the diagnosis of BV
1. “clue cells,”
2. large squamous epithelial cells with gram positive
3. gram- variable bacilli and coccobacilli clustered on the edges
4. Lactobacillus rods are absent in the wet mount.
166
low lactobacillus in vagina gives this bacteria the chance to grow
Gardnella
167
Culture Media of Gardnella
1. Human blood bilayer Tween (HBT( agar
2. 5% to 7% CO2 at a temperature of 35C to 37C
168
G. vaginalis also produces what type of hemolysis
β-hemolytic
169
G. vaginalis also produces β- hemolytic colonies on media made with
rabbit or human blood
170
AEROBIC ACTINOMYCETES
1. Nocardia
2. Rhodococcus
3. Gordonia
4. Tsukamurella
5. Streptomyces
6. Actinomadura
171
1. aerobic, branched, beaded, gram-positive bacilli
2. Catalase positive
3. partially acid fast, meaning they are able to retain the primary stain only when a weak acid is used as the decolorizer during the acid-fast staining process
Nocardia spp.
172
decolorizer used in Nocardia spp.
0.5-1% H2SO4 Sulfuric acid
173
Generally, infections caused by Nocardia occur in
immunocompromised patients.
174
Nocardia infection begins as a localized subcutaneous abscess that is invasive and quite destructive of the tissues and underlying bone that is termed as
actinomycotic mycetomas
175
Nocardia infection occurs by two routes:
pulmonary and or other disseminated infections
176
In Nocardia infection, the pus may be pigmented and contain
“sulfur granules”
177
“sulfur granules” appear color
yellow or orange
178
These granules contain masses of filamentous organisms with pus materials
“sulfur granules”
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Nocardia spp. grow well on
selective laboratory media
180
Nocardia spp. grow well on most common nonselective laboratory media incubated at temperatures between
22° and 37° C
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days before Nocardia spp. growth is seen
3 to 6 days or more
182
may enhance recovery of Nocardia spp. by inhibiting the growth of contaminating organisms.
modified Thayer-Martin agar
183
Nocardia spp. grow on nonselective BCYE agar. what is BCYE agar
buffered charcoal–yeast extract agar.
184
Colonies have a chalky, matte, velvety, or powdery appearance and may be white, yellow, pink, orange, peach, tan, or gray pigmented.
Nocardia spp.
185
grow at the presence of enhanced 10% CO2 and in 48 hours but colonies typically appear in 5 to 10 days. They can have a dry, crumbly appearance similar to breadcrumbs
Nocardia spp.
186
Unique Characteristic of Nocardia spp.
Lysozyme Resistant
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1. partially acid fast or acid fast
2. On SBA, the colonies resemble Klebsiella and can form a salmon pink pigment
3. diphtheroid gram-positive rods with traces of branching
Rhodococcus equi
188
1. agent of Whipple disease
2. gram-positive actinomycete
3. A facultative intracellular pathogen (culture is useless)
TROPHERYMA WHIPPLEI
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The presence of characteristic periodic acid–Schiff staining is strongly suggestive of
Whipple disease.
190
