practicum Flashcards
collection and transport of specimens
name, date, intials
midstream clean catch
transport in sterile cup ASAP
what test differentiates staph aureus from nonpathogenic staph?
coagulase
principle of the catalase test
differentiate staph from strep
what test is used to distinguish the coliform bacteria from the enteric pathogens?
TSI to determine nonlactose fermentors
6.5% NaCl (Enterococcoc, Strep D and Strep V)
what type of collection is not appropriate for anaerobic culture?
swab
how could you differentiate Listeria monocyteges from Corynebacterium diptheroids?
Listeria motility +
Listeria camp test +
how could you differentiate Alpha Strep from strep pneumo?
p disk (strep pnuemo +)
what agar is used for kirby-bauer sensisitivity testing?
mueller hinton
which enteric pathogen would be least likely to survive if the stool is left at room temp for an extended period of time or refrigerated?
shigella
organisms that cause food poisoning?
campy E. coli shigella salmonella staph aureus
what organism is gram = rod, motile, oxidase +, with a grape like odor?
psuedomonas aeriginosa
which genus contains chromogenic, gram = motile rods which have been implicated in septicemia, pulmonary and urinary tract infections?
serratia
what is the most common organism in the human intestine?
bacteroides
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 (pyogenes)
how do you differentiate the genus enterobacter from the genus klebsiella?
Entero motility +
Klebsiella motility =
Interpret K/K, alkaline/alkaline
nonfermentor
interpret K/A, alkaline/acid
glucose fermentor only
interpret A/A, acid/acid
lactose and/or sucrose
interpert H2S
hydrogen sulfide production
gas
the satellite phenomenon indicates that staphylococci produce which factor?
V factor
what is beta-lactamase?
enzyme produced by bacteria to inhibit penicillins….resistant to penicillins
what sugar is fermented by all enterobacteriaceae?
glucose
meningitis due to Hemophilius influenza is most common in which age group?
infants to young children
which genera of Enterobactericiae are non-motile?
klebsiella and shigella
which genera of Enterobacteriaceae are resistant to many antibiotics and are frequently found in nosocomial infections?
serretia, proteus
which organism is most frequently isolated from a cat or dog bite?
pasteurella, multocida
from what type of specimen are members of the genus lactobacillus isolated?
GI track, vaginal and urine (from females)
what steps must be taken to identify campylobacter in laboratory?
use campy plate
incubate at 42 degrees in CO2
oxidase +
gmst (bent rods) “seagulls”
what antibiotics are added to Thayer-Martin media?
Vancomycin ( inhibits gram +)
Colistin (inhibits gram =)
Nystatin (inhibits fungi)
what are faculative organisms?
grows aerobic or anaerobic
in the performance of a gram stain what effect would omitting iodine step have on the final color of the gram positive and gram neg organism?
crystal violet would not adhere to the 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 than the amount of NF to be significant
which sterilization method utilizing heat is the most effective and useful method for the clinical lab?
steam autoclave
which organism could staphyloccocus growing on
SBA be confused with?
Group A strep
appearance of Neisseria gonorrhoeae in a urethral smear
intracellular gram negative coffee bean shaped diplococci
if organisms are seen on a direct gram-stained smear but are not recovered on routine culture, what type of organism is implicated?
anaerobic organism
which body fluid is often cultured in an effort to trace Salmonella typhi carriers
bile
what is the appearance of an encapsulated organism on blood agar and what effect does the capsule have on the organisms virulence?
mucoid
increased virulence
principle of the decarboxylase test
reactions:
purple—yellow =
purple +
deifinition of MIC
minimum inhibitory concentration of antimicrobial that inhibits bacterial growth
incubation conditions for anaerobes
no oxygen (bio-bag) and placed in a gas pak providing CO2 at 36 degrees. Use anaerobic media
what terms are used to describe the morphology of the members of the genus corynebacterium?
chinese letters
picket fence
palisade
characteristics of bacterial spores
hard and thick walled capsule, dormant, non-reproductive
interpretations of reactions on XLD
highly selective also differential
- salmonella (red colonies with black centers)
- shigella (red colonies, lac pos (yellow)
biochemical characteristics of E. coli
lactose fermentor
indole and methyl red pos
urea and H2S neg
appearance and pathogenicity of klebsiella pneumoniae
large, pink, mucoid on mac
what screening test is used in the laboratory to differentiate E. Coli 0157:H from normal strains of E. Coli?
mac w/sorbital
latex agglutination serotyping
what test can be used to differentiate the two species of proteus?
p. vulgarius indole +
p. mirabilit indole =
which species might be considered as contaminants if they were isolated from a blood culture?
staph epi
diptheroids
bacillus
If two organisms are to be used as quality controls, for a particular test or procedure, should the reactions be the same or different?
They have to be different, one demonstrating a positive reaction one demonstrating a neg reaction
what are the designations for the cell wall, flagellar and capsular antigens in bacteria?
cell wall = O
flagella = H
which antigens can mask the cell wall antigen in serological typing?
K or Vi
the safety hood should be used for which procedures in micro?
respiratory, AFB, fungal, stool cultures
what characteristics of a specimen might cause you to suspect an anaerobe and on what type of laboratory media should such a culture be inoculated?
strong odor from a deep wound or abcess
BAP, MAC, CHOC, PEA, ANA, ET tube
what is the gram stain morphology of bacteroides and fusobacterium?
Bacteroides: GNR with round ends (pleomorphic)
Fusobacterium: GNR pointed ends
what types of specimens are suitable for anaerobic culture?
deep wounds, abscesses, tissue, blood, transtracheal aspirate, sterile body fluid, suprapubic urine
what types of specimens are unsuitable for anaerobic culture?
anything thing that comes in contact with O2
what gram stain morphology of Neisseria meningitidis and what sugars are utilized?
gram neg diplococci, coffee bean shaped
glucose and maltose
what stains are used for staining memebers of the genus mycobacterium?
ziehl-neelsen
why is n-acetyl-l-cystine the most common agent used for sputum concentration for AFB cultures?
it is a mucolytic agent that breaks up the specimen and enhances the recovery of mycobacteria; destroys NF; good recovery of AFB
what is the colonial morphology of mycobacterium tuberculosis on Lownestein-Jensen medium?
rough tough (appearance) and buff (colored), fuzzy, heaped up
what can be used as a clearing agent to remove protein material from a mycology specimen?
KOH
what is the procedure of choice for the demonstration of cyrptococcus in CSF?
indian INk
what is the best single medium for the primary isolation of fungi?
Sabourauds (SABS) SDA
what stage in the development of a parasite is best demonstrated by permanent stained smear?
troph
which method of concentrating stool specimen is best for which parasites?
flotation-nematodes, cestode eggs, and coccidia oocysts
sedementation- trematode eggs operulated dont show on flotation, they will sink
what is the appearance of the cyst of entamoeba histolytica?
mature has 4 nuclei, immature has fewer than 4 nuclei, even staining, cigar shaped chromatid
how can differentiate the various species of plasmodium
p. falciparum 8-36 merizoites
p. malariae 6-12 merozoites
which genera are oxidase positive?
psuedomonas, neisseria, and campy
which fungi are dimorphic?
coccidiodes imitis blastomyces dermatisis hitoplasma capsulatum paracoccidioides brazilliensis sporothrix shenckii
hemophilus aegypticus
pink eye
bordetella pertussis
whooping cough
brucella abortus
brucellosis/malto fever/ undulant fever
hemophilus influenza
meningitis
hemophilus ducrey
chancroid
bacillus anthracis
anthrax
clostridium perfringens
gangrene
clostridium tetanus
lock jaw
listeria monocytogenes
still birth
clostridium difficile
psuedomoembranous diptheria
borrelia recurrentis
relapsing fever
letospira
hemorrhagic jaundice
treponema pallidum
syphilis
enteric fever
salmonella typhi
treponema carateum
pinta
treponema pertenue
yaws
corynebacterium diptheria
klebs-lobeffler bacillus
klebsiella pneumoniae
freedlanders bacillus
haemophilus aegyptius
kock-weeks bacillus
streptococcus pneumoniae
lobar pneumonia, sepsis
