2 Flashcards
Default shape of bacteria
Coccus
Default shape of bacteria is coccus because it doesn’t have
Mreb cytoskeleton
Elongation of your cell is dependent on your
Mreb cytoskeleton
Curving of bacterial cell is dependent on the
cresentin cytoskeleton
Spore forming genera in gram positive bacilli
Genus bacillus
Genus clostridum
Branching genus appears like a fungi in microscope
Genus nocardia
Genus actinomyces
NON-SPORE-FORMING, NON-BRANCHING, CATALASE POSITIVE:
Corynebacterium
Rothia
Listeria
SPORE-FORMING, NON-BRANCHING, CATALASE POSITIVE:
Bacillus
NON-SPORE-FORMING, NON-BRANCHING, CATALASE NEGATIVE:
Erysiphelotrix
Gardnerella
NON-SPORE-FORMING, BRANCHING:
Nocardia and other actinomyces
Clubbed or irregularly shaped, non-motile, non-capsulated, non-spore- forming, highly pleomorphic
Genus corynebacterium
Why is Corynebacterium highly pleomorphic?
Because it has an incomplete binary fission
Lipophilic (fastidious, slow growers):
C. jeikeium
C. urealyticum
Non-Lipophilic (fermentative/oxidative):
C. ulcerans
C. pseudotuberculosis
C. amycolatum
C. striatum
C. xerosis
C. minutissimum
Non-fermentative:
C.pseudodiphtheriticum
C.auris
C.glucuronolyticum
Inhabits the nasopharynx causes multi organ failure
Corynebacterium diphtheriae
Heat-labile polypeptide; alkaline & iron loving, Carried by TOX gene from β-phage
Corynebacterium diphtheriae
Respiratory Diphtheria (toxigenic)
* Pharyngitis characterized by the development of an ______ that covers tonsils, uvula, palate & pharyngeal wall.
exudative membrane (pseudomembrane)
Color of pseudomembrane
Greyish black-leathery
-edema in the neck area (cervical &
submandibular lymphadenopathy)
-common in children, due to lymphadenopathy
(swelling of lymph nodes)
Bull’s Neck Appearance
Difficulty swallowing
Respiratory Diphtheria
Veldt sore or Barcoo root
Cutaneous diphtheria
It is characterized by slow healing ulcers with dirty gray membrane may or may not develop immunity
Cutaneous diphtheria
is disease of the children (6-8 yrs old)
Diphtheria
Most effective treatment from diphtheria
Diphtheria antitoxin (DAT)
inhibits bacterial growth (also
eliminates streptococcal infection)
Penicillin and erythromycin
- Frequently isolated and most clinical significant
- Urinary pathogen
o Marked by rapid urease production
C. urealyticum
- Indigenous microbiota of inguinal, axillary and rectal areas
- Multi-drug resistant (β-Lactams)
- Common cause to infect:
o prosthetic valve o catheters
o CSF shunts - Common nosocomial pathogen
C. jeikeium
- Zoonotic source of infection
o Unpasteurized milk - Diphtheria-like symptoms
- Diphtheroid group
C. ulcerans
- Zoonotic source of infection mostly seen in cows
- It produces dermonecrotic toxin
- Diphtheroid group
C. pseudotubercolosis
C. pseudotubercolosis
* Common manifestation in man
Suppurative granulomatous lymphadenitis
- Multiple antibiotic resistance pattern
- Prosthetic joint infection; neonatal sepsis
- Nosocomial infection
C. amycolatum
- Erythasma:
o Superficial
o Pruritic infection
C. minutissimum
- Can be confused with C. amycolatum; * Infection immunocompromised patients
C. xerosis
- Hospital-acquired pneumonia and lung abscess
(immunocompromised patients)
C. striatum
- Associated with otitis media in children
C. auris
- Indigenous microbiota of human pharynx
- Can cause respiratory infection, UTI and cutaneous
infection in HIV patients
C. pseudodiphtheriticum
- Prostatitis and non-gonococcal urethritis
- Pathogen of male genitourinary tract
C. glucoronolyticum
urine present as pure culture as predominant organism at greater than
10,000 CFU/L
sole isolate at colony count of greater than
100,000 CFU/mL
What are the culture medium used for isolation in Corynebacterium
5% SBA, 1% TWEEN 80, Rabbit Serum
Cysteine Tellurite Blood Agar (CTBA)
Tinsdale Medium
Lamb Loeffler’s/ PAI coagulated egg/ LSS
non-hemolytic; large, flat, dark-grayish colonies, “daisy-head” (corrugations sa side)
Biotype Gravis
5% SBA
(1% TWEEN 80) (Rabbit Serum)
non-hemolytic; pinpoint, flat, grayish-black, “frog’s egg”
Biotype Intermedius
5% SBA
(1% TWEEN 80) (Rabbit Serum)
hemolytic; small, convex, black colonies, “fried-egg”
Biotype Mitis
5% SBA
(1% TWEEN 80) (Rabbit Serum)
CTBA
1. (+) result:
2. Intermedius:
3. Mitis:
4. (+) brown halo for:
- Black to brown colonies after 48 hours
- Black colonies with gray borders
- Mitis: bleach-like odor
- (+) brown halo for: Diphtheroid group
Tinsdale Medium (+) result
Brown to black with gray to brown halos (C. diphtheriae group)
Enhances pleomorphism and metachromatic granule formation
Loeffler’s Medium/ Pai coagulated egg/ LSS
Gray-white translucent colonies after 12-18 hrs (poached –egg appearance)
Loeffler’s Medium/ Pai coagulated egg/ LSS
preferred medium for isolation of Corynebacterium diphtheria
CTBA
- club-shaped, highly pleomorphic cells arranged in X, V, Y, L, picket fence, Chinese letters, palisade, parallel rows
C. diphtheriae
Why does C. diphtheriae has swollen tip?
Because of excessive production of polyphosphate/ metachromatic granules can also be called as babes-ernst, volutin
is used for metachromatic
granule/Babe’s – Ernst granule observation
Albert & Neisser Staining Method
- used to observe urease production of C. urealyticum
Christensen’s Urea Slant
Reverse CAMP:
C. pseudodipthericum
C. ulcerans
Positive for halo production is only for those who belong in
diphtheroid group
Esculin hydrolysis all are
Negative
Gelatinase is unique to your
ulcerans
is nitrate producer while the rest are negative
or variable
Diphtheriae
are urease producer
while the rest are negative
Ulcerans and pseudotubercolosis
is a rapid producer of urease in your
Christensen’s urea agar
Urealyticum
are positive for black type hemolysis or reverse cap hemolysis.
Pseudodiphthericum and ulcerans
Positive result for ELEK test (immunodiffusion test)
4-mm to 5-mm fine precipitin lines at a 45 degree angle to the streaks; arch of identity
Positive for Shick test
Reddening
used to detect and ascertain the neutralization
effect of diphtheria antitoxin on a cell-free suspension of suspected organism
Guinea Pig Lethality Assay
Detection of 300 fatty acids and related
compounds such as aldehydes and dimethyl-acetals via Gas-Liquid Chromatography (GLC).
Whole Cell Fatty Acid Analysis
Detection of meso-diaminopimelic acid (meso-DAP), L-Lysine, DD or LL-DAP, β- OHDAP,DorLornithineandDorL Diamino butyric (DAB) via High Performance Liquid Chromatography (HPLC).
Cell Wall Diamino Acid Analysis
Used to reliably identify toxigenic strains of Corynebacterium
Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectroscopy (Malditof- Ms)
Detection of Diphteria toxin gene (tox gene) via
16 s rRNA
MOE: Ingestion of contaminated food (primary), vertical transmission, cross-infection
Listeria monocytogenes
is uncommon but is able to cause serious infections primarily in neonates, pregnant women, elderly & immunocompromised patients
Listeriosis
PATHOGENESIS/VIRULENCE FACTOR ( Listeria monocytogenes)
Adhesins
Surface protein p60 / Internalin A and B
Act A
Listeriolysin O
Catalase: Superoxide dismutase; Phospholipase A, B, C
Sidephores
Facilitates bacterial binding to the host cell
Adhesins
targets your non-specific host
receptors
Autolysin Amidase (Ami)
binds to intestinal
epithelium
FbpA (Fibronectin-binding Protein A)
adhesion to mammalian cells
CtaP (Cystiene transport associated Protein)
promotes binding in intestinal origin
LapB (Listeria adhesion protein B)
Increases adhesion and penetration into mammalian cells
Surface Protein (p60)/Internalin A & B
Actin polymerization within the host cells enabling a cell-to- cell spreading
Act A
- Destroys the phagosome membrane by pore-formation that reduces T-cell responsiveness
- Plasmid-borne virulence
Listeriolysin O (hemolysin)
Enables the bacteria escape the bacterial killing
Catalase; Superoxide Dismutase; Phospholipase A, B &C
Competes with transferrin for iron
Siderophores
Which among the following gram positive bacilli has the ability to cause spontaneous abortion? within 3-7 days
Listeria monocytogenes
Intra-uterine origin of neonatal systemic septic infection with lesions and granuloma in fetus’s organs; high mortality rate (50%)
Early Onset Infection (granulomatosis infantiseptica)
occurs 6-48 hrs after ingestion of contaminated food (Listeria)
Meningoencephalitis and Bacteremia
causes foodborne outbreak
Febrile Gastroenteritis
Are used as medication combination; is the drug of choice in Listeria
Ampicillin and Gentamicin
Is the drug of choice for CNS infection on patients allergic to penicillin
Trimethoprim-sulfamethoxazole
Are not effective against listeria infection
Cephalosporins and Flouroquinolones
Medium for Listeria
McBride Medium
Wet Motility examination
Tumbling Motility
Listeria growth in SIM
Inverted Christmas tree or umbrella growth
CAMP reaction in Listeria
Block type hemolysis
Biochemical Test is positive for
Catalase, Hippurate Hydrolysis, Bile Esculin Test, Vogues-Proskauer, Methyl Red & growth in 6.5% NaCl, acid fermentation from glucose
Biochemical Test is negative for
H2S, nitrate reduction and urease
an enzyme that is produced only by L. monocytogenes and L.
ivanovii and activity of this enzyme is
measured using chromogenic media. (MANIFESTATION IS BLUE GREEN COLONIES)
Phosphatidylinositol specific phospholipase C (PIPL-C)
L. monocytogenes is known to have ____ serovars based on _____ and ______antigens.
13
O somatic
H flagellar
Serotype ____ causes most foodborne infection
4b
The presence of a target sequence is detected using an oligonucleotide probe of complementary sequence to the target DNA sequence which contains a label for detection
DNA Hybridization
Ano mostly dinedetect sa L. monocytogenes?
Specific virulence factor
A reliable and reproducible technique for identification and differentiation of L. monocytogenes from other Listeria species using primers targeting genes of virulence factors of RNA sub-unit genes
PCR based detection
C. diptheriae, ano dinedetect sa diagnosis?
Immunoserological reactions
gram-positive cocci that can appear rod-like that belongs to the family Micrococcaceae
Rothia spp.
linked to endocarditis, bacteremia & pneumonia
Rothia mucilaginosa
normal human oropharyngeal microbiota found in saliva & supragingival plaque: assosciated with
endocarditis
Rothia dentacariosa
Which bacillus is crystal forming?
B. thuringiensis
Which bacillus is heat tolerant?
B. cytotoxicus
Which bacillus is Probiotic?
B. toyonensis
Which bacillus is cold tolerant?
B. weihenstephanensis
B. anthracis VIRULENCE FACTORS
Produced during environmental stress;
evades phagocytosis
Endospores
B. anthracis VIRULENCE FACTORS
Resistant to hydrolysis of host proteolytic
enzymes
D-glutamic acid capsule
(plasmid-borne virulence)
Exotoxins (Anthrax Toxin)
Binding molecule of EF & LF for them to attach to specific receptors in the host cell
Pinaka carrier ng active toxins
Protective Antigen (PA)
An adenylate cyclase that increases
the concentration of cyclic adenosine monophosphate (cAMP) in host cells
Effect ng CAMP ay fluid release.
Edema Factor (EF)
A protease that kills the host cell by disrupting the transduction of extracellular regulatory signals
Lethal Factor
Common disease of livestock when vaccine is not used
Anthrax bacillus
Develops if spores are introduced in skin abrasions, cuts or insect bites
Cutaneous Anthrax
Also known as:
o Wool-sorter’s disease
o Rag-picker’s disease
o Pulmonary anthrax (previous name)
* Acquired by inhalation of spores in to
pulmonary parenchyma
lnhaltion anthrax
MAC activation causing Colloid Osmotic Lysis
Hemolysis BL
Food poisoning is a common manifestation of infection especially in rice dishes.
B. cereus
Heat-stable, proteolysis and acid-
resistant toxin that causes emetic
symptoms
Cerulide
pore-forming toxins (PFTs) disrupt the
membrane of epithelial cells lining the
gastrointestinal tract
Cytotoxin K/ Hemolysin IV
Cerulide Enterotoxin:
Parasporal crystalline inclusions (Cry and Cyt
proteins):
Vegetative insecticidal proteins (Vips) & Secreted insecticidal protein (Sips)
Bacillus thuringiensis
Common laboratory contaminant
Bacillus subtilis
Active Disinfectants:
Formaldehyde, glutaraldehyde, hydrogen peroxide, peracetic acid
Heat (70C for 30 mins or 80C for 10 mins) and alcohol shock treatment (to kill non-spore formers in a sample)
Enrichment Method
> 1 μm; no swelling of endospore:
B. anthracis, B. cereus, B. mycoides, B. thuringensis, B. megaterium
< 1 μm; no swelling of endospore:
B. subtilis, B. pumulis, B. licheniformis
< 1 μm; swelling of endospore:
B. circulans, B. coagulans, B. sphericus, B. brevis, P. spp.
Non hemolytic “Medusa head or comet tail”
Bacillus anthracis
B-hemolytic “beta hemolysis”
Bacillus cereus
Used for contaminated cultures that appears creamy-white, domed, circular colonies
PLET
