rotation test Flashcards
what test differentiates staph aureus from non pathogenic staph
coagulase
principle of the catalase
differentiates between staph species and strep species
1ml of 3% hydrogen peroxide if bubbles appear, then it is +
what test is used to distinguish the coliform bacteria from the enteric pathogens?
TSI- pathogens are usually nonlactose fermenters
collection and transportation of anearobic specimens, what type of collection system is not suitable for anearobic cultures?
routine swabs
how could you differentiate listeria monocytogenes from cornebaterium dipetheroids?
motility - L is positive C is negative
CAMP test- L is positive C is negative
how could you differentiate alpha streptococci from S. pneumonia?
S. pneumoniae is P disc positive (suscpetible) all others are negative
what agar is used fro kirby bauer sensitivity testing?
mueller-hinton
which enteric pathogen would be last likely to survive if the stool is left at room temperature fro an extended period of time or refrigerated?
shigella
organisms that cause food poisioning?
campylobacter, E. Coli, shigella, salmonella, s. aureus
what organism is a gram neg, motile, oxidase pos, rod wth a grape-like odor?
pseudomonas aeruginosa
which genus contains, chormogenic, gram =, motile rods, which have been implicated in septicemia, pulmonary, and urinary tract infections?
serratia
what ist he most common oragnism in the human intestine?
bacteroides spp.
which genus and species is best cultured in an alkaline peptone medium and causes a severe type of diarrhea producing rice water stools?
vibrio cholera
to which lancefield group do most of the human pathogens which are beta hemolytic streptococci belong?
group A
how do you differentiate the genus Enterobacter from Klebsiella?
motility E is pos
K is neg
interpretation of TSI rxc?
K/K- alkaline/ alkaline- non fermenter
K/A - alkaline/acid- glucose fermetner
A/A- acid/acid- sucrose or lactose and glucose fermenter
h2s is black
how does a gram pos, and gram neg, bacteria differ?
gn are red and have more lipid in the cell membrane, preventing them from drying out during the decolorizer and acid alcohol allowing them to lose the primary dye and take up the counter dye
where as gp are purple and have less lipid so decolorizer and acid alcohol have littler affect
the “satellite phenomenon” indicates that staph has what factor?
V factor
what is beta-lactamase?
enzymes that a bacteria posses that makes them resistant to penicillin drugs
what sugar is fermented by all enterobaceriaceae?
glucose
meningitis due to Haemophilus influenzae is most common in which age group?
infants to young children
which genera of enterobactericeae are nonmotile?
klebsiella and shigella
which genera of enterobacteriaceae are resistant to many antibiotics and are frequently found in noscomial infections
serratia and proteus
which organism is most frequently isolated from a cat or dog bite?
pasteurella multocida
from what type of specimens are members of the genus lactobacillus isolated?
GI trac, vaginal and urines (female)
what steps must be taken to identify campylobacter in laboratory?
use campy plate in 42 degree microaeophillic environment, seagull gram stain, tumbling motility, ox and cat pos
what antibiotics are added to thayer-martin media? why are they added?
vancomysin - inhibits gram pos
colistin- inhibits gram neg
nystatin- inhibits fungal
to inhibit normal commensal organisms
what are facultative organism
microorganisms that can metabolize aerobically or anaerobically
in the performance of a gram stain, what effect would omitting the iodine step have on the final color of gram positive and gram neg organisms?
crystal violet would not adhere tot he cells and the stain will be pink
which organism can be normal in the upper respiratory tract?
small amounts of pathogens are normal, must be more tan the amount of NF to be significant
which sterilization method utilizing heat is the most effective and useful fro the clinical lab?
steam autoclave
which organism could young staph growing on SBA be confused with?
group A
appearance of Neisseria gonorrhoeae in a urethral smear
intracellular gram negative, coffee bean shaped diplococci
if oragism are seen on a direct gram-stained smear but are not recovered on routine culture, what type of organism is implicated?
anaerobe
which body fluid is often cultured in an effort to trace salmonella typhi carriers?
bile
what ist he appearance of an encapsulated organism on blood agar and what effect does the capsule have on the organisms virulence?
mucoid and increased virulence
principle of the decarboxylase test
reactions: puple- yellow (=)-purple (+)
definition of MIC
minimum inhibitory concentration: lowest concentration of antimicrobial that inhibits bacterial growth
incubation conditions for anaerobes
no oxygen (bio bag) and place din gas pak providing CO2 at 36 degrees. use anaerobic media K&V (laked blood agar)
what terms are used to describe the morphology of the members of the genus corynebacterium
chinese letters
palisade
picket fence
characteristics of bacterial spores
hard and thick walled capsule, dormant, non reproductive
interpretation of reactions on the XLD
highly selective also differential
salmonella (red colonies with black centers)
shigella (red colonies)
lactose positive, yellow
biochemical characteristics of E.coli
lactose fermenter; indole and methyl red pos
urea and h2s neg
appearance (colonial morphology) and pathogenicity of klebsiella pneumoniae
large, pink, mucoid, stringy colonies on MAC
what screening test is used in the lab to differentiate E.coli 0157:H from normal strains of E.coli
mac with sorbital; latex agg serotyping
what test can be used to differentiate the two species of proteus?
indole
P. vulgaris +
P. mirabilis =
which species might e considered as contaminants if they were isolated from a blood culture
coag neg staph
corynebacterium
bacillus spp.
if two organism are to be used as quality control for a particular test or procedure, should their reactions be the same or different
they have to be different one demonstrating a pos and one demonstrating a neg
what are the designations for the cell wall, flagellar, and capsular antigens in bacteria? which antiges can mask the cell wall antigen in serological typing?
cell wall = O
falgella= H
** capsule = K or Vi
the safety hood should be used for which procedures in the micro lab
respiratory, AFB, funal, stool cultures
what characteristics of a specimen might cause you to suspect an anaerobce and on what type of lab media should such a culture be inoculated
strong odor and from a deep wound, or abscess
BAP MAC CHOC PEA ANA ANA W/KV ET broth
what is the gram stain morphology of bacteroides and fusobacterium
bacteroides: GNR with rounded ends; pleomorphic
fusobacterium: GNR with pointed ends
what types of specimens are suitable for anaerobic culture?
which are unsuitable?
suitable: deep wounds, abscesses, tissue, blood, trans-tracheal aspirate, sterile body fluids, supra pubic aspirate,
unsuitable: stools, urines, vaginals, etc
what is the gram stain morphology of Neisseria meningitids and what sugars are utilized by this organism
gram negative coffee bean shaped diplococci, glucose and maltose
what stains are used for staining members of the genus mycobacterium
ziehl-neelsen
what is the N-acetyl-L-cysteine the most common agent used for sputum concentrations for AFB cultures?
because it is a mucolytic agent that breaks up the specimen and enhances the recovery of mycobacteria, destroys NF,
what is the colonial morphology of mycobacterium tuberculosis on lowenstein-jensen medium
rough tough apperance, buff colored, fuzzy,
what can be used as a clearing agent to remove protein mateiral from a mycology specimen
KOH
what is the procedure of choice for the demonstration of cryptococcus in CSF?
india ink
what is the best single media for the primary isolation of fungus?
sabourauds
what are the growth characteristics and other identifying characteristics of candida albicans?
germ tube pos
budding yeast with pseudohyphae
creamy white colonies
what stage in the development of a parasite is best demonstrated by permanent stained smear?
troph
which method of concentrating stool specimens is best for which parasites?
flotation- nematode, cestode, eggs, and coccidia occysts sedimentation- trematode eggs operculated ont show on flotation they will sink
how can you differentiate the various species of plasmodium
P. falciparum- schiznot has 8-36 merozoites
maleariae has a band and merozoites in the shape of a flower`
biochemical reactions of staph epi
catalase pos and coag neg
which genera are oxidase positive
pseudomonas
neisseria
campylobacter
rapid methods of ID for the enterobacteriaceae
API
enterotube
micro-ID less than 4 hours
minitek
which growth factors are required by the various species of haemophilus
X and V
which fungi are dimorphic
coccidiodes imits blastomyces dermatididis histoplasma capsulatum paracoccidiodes braziliensis sporothrix shenckii
haemophilus aegypticus
pinky eye
bordetella pertusis
whooping cough
brucella abortus
brucellosis/ malto fever/ undulant fever
haemophilus influenzae
meninigitis
haemophilus ducrey
chancroid
bacillus anthracis
anthrax (woolsorters disease_
clostridium perfringes
gangrene
clostridium tetanus
lock jaw
listeria monocytogenes
stillbirths
clostridium difficile
pseudomembranous diptheria
borrelia recurrentis
relapsing fever
leptospira
hemorrhagic jaundice
treponema pallidum
syphilis
enteric fever
salmonella typhi
treponema carateum
pinta
treponema pertenue
yaws
corynbecaterium diptheria
klebs-lobeffler bacillus
klebsiella pneumoniae
friedlanders bacillus
haemopnilus aegypticus
kock-weeks bacillus
strep pneumoniae
lobar pneumonia
sepsis
strep pyogenes (group A)
RHEUMATIC FEVER, SCARLET FEVER
group D enterococci
uti and wound infections
s. aureus
food poisioning
osteo myelitis
strep. agalactiae (group B)
neonatal meninigitis and sepsis
