question

Blood culture collection , clean with

answer

2% iodine and then 70% alcohol

question

When cleansing the skin with alcohol and then iodine for the collection of a blood culture , the iodine must stay on skin for:

answer

60 seconds

question

The purpose of adding 0.025%-0.050% sodium polyanethol sulfonate (SPS) to the nutrient broth is:

answer

It inhibits phagocytosis and complement.

question

A flexable calcium alganite nasophrangeal swab is the collection device of choice for the recovery of which organism?

answer

C diphtheriae

question

Semisolid transport media such as amies , Stuart, or Cary Blair are suitable for the transport of swabs for culture of most pathogens except:

answer

Neisseria gonorrhoeae

question

Select the method of choice for recovery of bacteria from a deep abcess:

answer

Needle aspirate after surface decontamination

question

Primary and differential media of choice for the recovery of most fecal pathogens:

answer

Hektoen. MacConkey and Colistin nalidixic acid (CNA) agars.

question

Media for vibrio from stool:

answer

TCBS

question

CNA agar is used for:

answer

S. aureus

question

BAP plates

answer

5% or 10% sheep blood agar

question

To isolate N gonorrhea:

answer

Charcoal transport, MTM media, New york or Martin Lewis.

question

Chocolate agar and MTM are for

answer

Hemophilus spp. and Neisseria spp.

question

CCFA is used for

answer

Clostridium difficile

question

Deoxycholate agar (DCA) is used for :

answer

Enterobacteriacae

question

Xylose, lisine, Deoxycholateis a highly selective media for the recovery of

answer

Enterobacteriacae from gastrointestinal specimens.

question

A sheep blood agar plate is used for the primary isolation medium when all of the following organisms are to be recovered from a wound EXCEPT:

answer

Hemophilus influenzia and Hemophilus para influenzia

question

Prereduced vitamine K supplimented blood agar plates are recommended media for

answer

Bacteroids, peptostreptococcus, and Clostridium spp. think anaerobic

question

Procedure for recovery of chlamydia:

answer

Inoculate cyclohexide treated Mccoy cells.

question

Virus should be transported in media containing:

answer

Antibiotics and nutrient

question

Cerebrospinal fluid should be cultured immediately , but if delayed , specimen should be:

answer

Incubated at 37 and cultured as soon as possible.

question

How to detect B-lactamase in bacteria Most sensitive.

answer

Chromogenic cephalosporin.

question

The breakpoint of an antimicrobial drug refers to:

answer

The level of drug that is acheivable in serum.

question

Varibles that change the results of the MIC:

answer

Inoculun size, incubation time, Growth rate of bacteria.

question

According to the kirby bauer standard antimicrobial susceptibility testing method, what should be done when interpreting the zone size of a motle swarming organism such as proteus.

answer

The swarming area should be ignored.

question

Which class of antibiotics is used for the treatment of serious gram negative infections as well as infections with Mycoplasm tuberculosis.

answer

Aminoglycosides

question

Biochemically the Enterobacteriaceae are gram negative rods that:

answer

Ferment glugose, Reduce nitrate to nitrite, and are oxidase negative.

question

The ortho-notriphenol-B- galactopyoanoside (ONPG) test is most useful when differentiting :

answer

Shigella from some strains of e-coli. The ONPG detects B-galactosidase activity and is most useful in distinguishing late lactose fermenters from nonfermentesrs.

question

The volkes-proskauer (VP) test which end product of glucose fermentation.

answer

ACETOIN or carbinol ... turns red to pink.

question

At which Ph does the Methyl red test become positive.

answer

4.5
MR and VP detect acid

question

A positive simmons citrate is seen as a

answer

Blue color in the medium. ..............alkaline.................

question

In the test for urease production, ammonia reacts to form which product?

answer

Ammonium carbonate. This turns the indicator pink at Ph 8.0

question

Which reagent is added to detect the production of indole.

answer

p-Dimethylaminobenzaldehyde

question

Decarboxylation of the amino acids lusine, ornathene and arginine results in the formation of

answer

Amines... decarboxylases split dibasic amino acids, forming alkaline amines.

question

Lysine iron agar (LIA) showing a purple slant and a blackned butt indicates:

answer

Salmonella spp. Salmonella =black butt LIA=salmonella.

question

Putrisine is an alkaline amine product of which bacterial enzyme?

answer

Oranithine decarboxylase.

question

Which genera are positive for phenlalanine deaminase? PAD

answer

Morganella providencia and proteus.

question

Kligler iron agar (KIA) differs from triple sugar iron agar (TSI) in the

answer

use of sucrose in the medium.

question

The malonate test is useful in differentiating which members of enterobacteriaceae?

answer

Salmonella subgroups 2,2
(the former arizona)

question

Which genera of the enterobacteriaceae are known to cause diarrhea and are considered enteric pathogens?

answer

Eschericia, salmonella, shigella and yersinia

question

An isolate of e-coli recovered from the stool of a patient with severe bloody diarrhea should be tested for which sugar before sending it to a reference laboratory for serologic testing?

answer

Sorbitol fermentation

question

Care must be taken before identifying biochemical isolates of shigella because serological cross reactions occur :

answer

e-coli,
shigella and e-coli are alot alike

question

Which species of shigela is most commonly associated with diarrheal disease in the united states.

answer

S. sonnei
Most active of the lot, orinthene decarboxylase and B-dgalactose activity

question

Which of the following test best differentiates shigella species from e-coli.

answer

Lactose, indole, ONPG and motility (ecoli)are, shigella isnt

question

Which genera of enterobacteriaceae are usually non-motile at 36C.

answer

Shigella , Klebsiella and Yersinia. But dont forget...Yersinia can be motile at 22C.

question

Fever , abdominal cramping , watery stools, and fluid and electrolyte loss preceeded by bloody stools 2-3 days before is charateristic of shigallosis but may also result form infection with

answer

Campylobacter...

question

Cold enrichment of feces (incubation at 4 C) in a phosphate buffered saline prior to subculture onto enteric media enhances the recovery of

answer

Yersinia enterocolitica.
this is the one that can live in the red blood cell bag

question

Which group of test along with clonial morphology on primary media aids most in the rapid identification of the enterobacteriaceae

answer

indole , oxydase, MacConkey and Blood agar plates

question

A routein complete stool culture procedure should include media for the isolation of e-coli O157 H7 as well as:

answer

Salmonella, Shigella, Yersinia, Campylobacter and S. aureus.

question

Which group of test best identifies Morganella and proteus?

answer

Motility, urease and PAD.

question

Which group of test best identifies enterobacter aerogenes from Edwardsella tarda?

answer

Hydrogen sulfied (H2S) production, sucriose fermentation, indole, and VP.
H2s and indole= Tarda
sucrose and VP and citrate= E. aerogene

question

Enterobacter sakazakii can best be differentiated from enterobacter cloacae by its,

answer

Yellow pigmentation and negative sorbitol fermentation.

question

Members of the genus Cedecea are best differentiated from serratia spp. by which test result?

answer

Negative Dnase. Serratia is Dnase positive.

question

a gram negative rod is recovered from a catherized urine sample from a nursing home patient, The lactose negative isolate tested postive for indole, urease, ornithine decarboxylase , and PAD and negative for H2S the most probable identificatin is :

answer

Morganella.
(Indole, PAD and ornithine decarboxylase positive) not proteus tho.

question

Which single test best separates Klebsiella Oxytoca from K. pneumonia,

answer

indole...

question

What organism found in normal fecal flora may be mistaken , biochemically for the genus Yersinia?

answer

Proteus spp. are urease positive lactose negative and motile, remember yersinia is motle at 22C tho...

question

WHY might it be necessary for both pink (lactose positive) colonies and colorless (lactose negative) colonies from an initial stool culture on MacConkey agar to be subcultured and tested further for possible pathogens.

answer

Pathogenic e-coli can be both pink and colorless on MacConkey agar.

question

Which agar that is used for routien stool culture is the medium of choice for the isolation of Yersinia strains from stool specimens?

answer

MacConkey agar. Although CIN is the best for the isolation of yersinia..

question

Which organism is sometimes mistaken for salmonella and will agglutinate in salmonella polyvalent antisera.

answer

C, freundii both are H2S, indole, VP and PAD NEGATIVE also

question

A bloody stool from a 26 year old woman with 3 days of diarrhea showed the following results at 48 hours after plated on the following media: MacConkey: little normal flora with many non-lactose fermenting colonies. Hektoen enteric agar: Many blue green colonies. Campylobacter blood agar and C difficile agar: no growth Clear colonies from MacConkey tested negative for oxidase indole, urease, motility, and H2S. The most likely identificaion is:

answer

Shigella. Shigella and campylobacter cause bloody diarrhea but Campy does not grow on MacConkey.

question

What organisms are generraly positive for B-galactosidase?

answer

E-coli.

question

In the Kauffamn White Schema, the combined antigens used for serological identification for salmonella spp. are?

answer

O, VI, and H antigens.
O= heat stabile
VI or (K) = capsular polysaccharide
H= Flageller (heat labile)

question

The drugs of choice for treatment of Enterobacteriaceae are

answer

Aminoglycosides, trimethoprim-sulfamathoxazole, third generation cephalosporins.

question

A shiga like toxin (verotoxin) is produced mainly by which Enterobacteriaceae

answer

E-coli. O157H7 is the toxin most often associated with bloody diarrhea.

question

Infections caused by Yersinia Pestis are rare in the united states. Those cases that do occur are most frequently located in which region?

answer

New mexico, california and arizona.

question

A leg culture from a nursing home patient grew gram negative rods on MacConkey Agar as pink to dark pink oxidase negative colonies. Given the following results, which is the most likely organism? TSI=A/A Indole=Neg MR=Neg Citrate= + VP = + H2S= Neg Urease = Neg Motility = Neg.Resisant to carbenicillin and ampicillin. IMVC ==++

answer

Klebsiela pneumonia. are ==++ while e-coli are ++==.

question

Four blood cultures were taken over a 24 hour period from a twenty year old woman with severe diarrhea. the cultures grew motile (room temperture)_ gram negative rods. A urine specimen obtained by catherterization also showed gram negative rods, 100,000 col/mL. Given the following results, which is the most likely organism : TSI=A/A gas Indole= + VP= neg MR=+ H2S=neg Citrate =Neg Urease=Neg Lysine= + (++==)

answer

E=coli. E-coli ++== S typhi =+== Y enterocolitica V+== P vulgaris ++== (just like e-coli)

question

A stool culture form a 30 year old man suffeing from bloody mucoid diarrhea gave the following results on differential enteric media: Mac agar= clear colonies XLD agar= clear colonies Salmonella shigella agar+ small clear colonies. Which test are most appopriate for identification of this enteric pathogen?

answer

TSI, Moility, indole, urease, Shigella typing with polyvalent sera.

question

A leg culture from a hospitalized 70 year old diabetic man grew motile, lactose negative colonies on MacConkey agar, Given the following biochemical reactions at 24 hours what is the most probable organism? H2S, TSI=Neg Indole=Neg MR=Neg VP=+ PAD= Neg Dnase=+ Citrate=+ Urease=Neg

answer

Serratia marcescens remember this is Dnase positive...

question

Three blood cultures taken from a 30 year old cancer patient recieving chemo therapy and admitted with a urinary tract infection grew lactose negative, motile, gram negative rods prior to antibiotic therapy. Given the followig biochemical reactions, which is the most likely organism? H2S, TSI= neg Indole= + MR=+ Dnase=+ VP=neg Citrate=Neg Urease=+ Gelatin hydrolase =+ Ornithine decarboxylase=Neg.

answer

Proteus vulgaris ..... look for this in immunocompromised patients.

question

Three consecutive stool cultures from a 25 year old patient produced scant normal fecal flora on MacConkey and Hektoen agars. However colonies on CIN agar (cefsoledin-irgasan novobiocin) displayed bulls eye colonies after 48 hours incubation. The patient had been suffering from entercolitis with fever, diarrhea, and abdominal pain for 2 days. What is the most likely identification of this gram negative rod.

answer

Yersinia entercolitica. CIN + yersinia = bulls eye colonies.

question

A 6 year old female patient was admitted to the hospital following two days of severe diarrhea. Cultures from three consecutive stool samples contained blood and mucus. Patient history revealed a hamburgar lunch at a fast food restuant 3 days earlier . Which pathogen is most likely responsible for the following results Growth on XLD agar= yellow colonies. HE agar= yellow colonies Mac agar= light pink and dark pink and many colonies. Mac with sorbitol, few dark pink and many colorless colonies.

answer

E-coli O157 H7.

question

Following a two week camping trip in the southwest a 65 year old male patient was hospitalized with a high fever and inflammatory swelling of the axilla and groin lymph nodes, several blood cultures were obtained, resulting in growth of gram negative rods resembling closed saftey pins. The organism grew on MacConkey agar showing nonlactose fermenting colonies. testing demonstrated a non-motile rod that was chemically inert. The most likely identification is

answer

YERSINIA PESTIS.

question

The majority of clinical laboratories with a microbiology department should have the capability of serotyping which pathogenic Enterobacteriaceae

answer

E-coli O157 H7, Salmonella spp. and Shigella spp.

question

Direct spread of pneumonic plague disease occurs by which route.

answer

Inhalation of contaminated airborne droplets.

question

What are the most appropriate screening test to presumtivaly differentiate and identify the nonfermentative gram negative bacilli (NFB) from the enterobacteriaceae?

answer

Oxidase TSI, nitrate reduction, growth on MacConkey agar.

question

Presumptive test used for the pseudomonas spp. are:

answer

Oxidase, oxidaton fermentation (OF) glucose (OPEN), OF glucose (sealed), motility, pigment production.

question

Which test are most appropriate to differentiate between Pseudomonas aeruginosa and Pseudomonas putida?

answer

Mannitol, nitrate reduction and growth at 42C.

question

Which group best differentiates Acinetobacter baumanni from P. aeruginosa

answer

Oxidase, motility, nitrate reduction.

question

In addition to motility, which test best differentiates Acinetobacter spp. and Alcalienes spp.

answer

Oxidase. Acinetobacter is non motile and oxidase negative.

question

The most noted differences between P. aeruginosa and S. maltophillia are:

answer

Oxidase, 42C growth and polor tuft of flagella. S. maltophillia is oxidase neative, does not grow at 42 and is motile by a polor tuft of flagella.

question

Which pseudomonas is usually associated with a lung infection related to cystic fibrosis?

answer

P. aeruginosa

question

A nonfermenter recovered from an eye wound is oxidase positive , motile with polor monotricious flagella and grows at 42. colonies are dry wrinkled or smooth , buff to light brown in color and are difficult to remove from the agar. In which DNA homology group shoould this organism be placed?

answer

Pseudomnas stutzeri

question

Which organisms is associated with immunodeficency syndrome and meliodosis (a gladers like disease in south east asia and northern australia.

answer

Burkholderia (P.) pseudomallei
Vietnameese time bomb

question

Which biochemical test are needed to differentiate Burkholderei (P.) cepatia from S. (X) maltophilia

answer

Pigment on blood agar, oxidase and DNase

question

The following results were obtained from a pure culture of gram negative rods recovered from the pulmonary secreations of a 10 year old cystic fibrosis patient with pneumonia. Oxidase pos motility pos glucose OF open pos Gelatin hydrolysis pos pigment red Arginine dihydrolase pos growth at 42 pos flagella polor and monotricious.

answer

Pseudomonas aeruginosa

question

Alcaligenes fecalis (formerly A. ordrans) is distinguished from bordatella bronchioseptica with which test?

answer

Urase rapid.
Alcaligenes fecalis is negative and bordatella bronchioseptica is urease positive.

question

Flavobacterium spp. are easily distinguished from acinetobacter sppp. by which two test?

answer

Oxidase and growth on Macconkey agar.

question

A gram negative cocobacillus was recovered on chocolate agar from the CSF of an immunocompromised patient. The organism was non motile and positive for indophenonoxidase but failed to grow on macconkey agar. The organism was highly susceptible to pennicillin. The most probable identification is.

answer

Moraxella lacunata.
involved in infections with immunosuppressed. highly susceptible to pennicillin.

question

Centramede agar is used as a selective isolation agar for:

answer

Pseudomonas aeruginosa

question

A specimen form a 15 year old female burn patient was cultured after debridement, and the following results were obtained. Oxidase positive Lysine decarboxylase negative Catalase positive motility positive Ornithene decarboxylase negative Glucose positive for oxidation (open tube) Arginine dihydrolase positive Maltose negative for open tube pennicillin resistant Aminoglycosides susceptible colitan susceptible

answer

Pseudomonas aeruginosa

question

A yellow pigment producing organism that is oxidase positive, nonmotile and does not grow on macConkey is

answer

Flavobacterium menenigiosepticum

question

Which reagent is used to develop a red color indicative of a positive reaction in the nitrate test?

answer

Sulfanillic acid and alpha- napthylamine

question

A culture from an intra abdominal abcess produced orange tan colonies on blood agar that gave the following results Oxidase positive Nitrate reduction positive KIA alk/alk H2S pos Motility single polor flagellum DNase positive Ornithene decarboxylase positive The most likely identification is

answer

Shewanella (pseudomonas ) putrifaciens

question

Flavobacteriun spp. and B. cepacia are easily differentiated by:

answer

Motility. cepacia are motile flavobacterium are nonmotile

question

A 15 year old female complained of severe eye irritation after removing her soft contact lenses. A swab of the infected right eye was obtained by a opthamologist who ordered a culture and sensitivities. the culture was plated on blood agar and macconkey agar . At 24 hours the growth of a gram negative rod that test cytochrome oxidase positive was noted . The muller hinton sensitivity plate showed a bluish green lawn of growth that proved highly resistant to most antibiotics tested except amikacin , tobramycin and ciprofloxacin. the most likely identification is

answer

Pseudmonas aeruginosa.

question

What pseudomonas spp. is associated with the following virulence factors. enterotoxin A, endotoxins, proetolytic enzymes, antimicrobial resistance and production of alginate?

answer

P. aeruginosa

question

A 20 year old horse groomer exhibited a glanders like infection. His history indicated he had suffered open wounds on his hands two weeks before the swelling of his lymph nodes. A gram negative rod was recovered from a blood culture that grew well on blood and macconkey agars. Most of the biochemical test were negative, including the cytochrome oxidase test. What is the most likely identification?

answer

Burkholderia mallorii

question

A vietmnam war veteran presented with a glanders like infection (meliodosis). Several blood culters produced gram negative rods that were cytochrome oxidase positive, oxidized glucose and xylose, and grew at 42. the most likely organism is

answer

Burkholderia pseudomallei

question

Cytochrome oxidase positive, nonfermentive gram negative bacilli were recovered from the stool of a cystic fibrosis patient. The isolates produced wet(mucoidy) colonies on blood aagar. Which identification is most likely?

answer

Pseudomonas aeruginosa.

question

A visitor to south america who returned with diarrhea is suspected with being infected with V. cholerae. Select the best medium for the recovery and identification of this organism.

answer

TCBS agar. The growth of yellow colonies on TCBS agar, citrate utilization and acid from sucrose is diagnostic for V.C

question

A curved gram negative rod producing oxidase positive colonies on blood agar was recovered from a stool culture. Given the following results what is the most likely identification?, VP NEG TCBS AGAR GREEN COLONIES, UREASE NEGATIVE LYSINE POS, ARGININE NEGATIVE, INDOLE POSITIVE LACTOSE NEGATIVE, KIA ALK/ACID STRING TEST NEGATIVE,

answer

TCBS AGAR GREEN COLONIES,
VIBRIO PARAHEMOLYTICUS

question

A gram negative S shaped rod recovered from selective media for Cappylobacter species gave the following results.CAt pos, Oxidase pos, motility pos, hippurate hydrolysis pos, Growth at 42C pos, Nalidixic acid susceptible, grape order negative.

answer

Campylobacter jujeni are the ones that hydrolyze hippurate

question

What atmospheric condition is needed to recover Campylobacter spp. from specimens inoculated onto a Campy-selective agar at 35C and 42C

answer

5% O2, 10%CO2, and 85% N2.

question

Which group of test best differentiates Helicobacteer pylori from C.jejuni

answer

Urease, nitrate and HIPPURATE HYDROLYSIS.(jejuni)

question

Which of the following test test should be done first in order to differentiate Pleasiomonas shigellosis from Shigella species on selective enteric agar?

answer

Oxidase... P. shigellosis is a lactose nonfermenter that will resemble Shigella spp. on macconkey agar
P. shigellosis is the only enterobacteriacae that is oxidase positive

question

What is the best two test to differentiate A. hydrophillia from P. shigellosis

answer

DNase and VP. Both of these bacteria cause diarreah grow well on enteric agar , and may be confused with enterobacteriaceae, Both organisms are positive for oxidase, motility, indole, and lysine decarboxylase. A. hydrophillia is beta hemolytic on blood agar.

question

Which genus ( in which most species are oxidase and catalase positive) of small gram negative cocobacillus is mainly associated with animals but may cause endocarditus, bacteremia and wound and dental infections in humans.

answer

Actinobacillus ( its main habitat is the mouth)

question

Which of the following test may be used to differentiate Cardiobacterum hominus from Actinobacillus spp.

answer

Indole. Cardiobacterum hominus is a gram negative cocobacillus similar to Actinobacillus it is a cause of endocarditus. c. hominus are oxidase positive and negative for nitrate reduction.

question

A mixture of slender gram negative rods and cocbacilli with rounded ends was recovered from blood culture following a patients root canal surgery. Given the following results after 48 hours what is the most llikely organism. cat neg, Ornithine pos, urease neg, lysine pos, oxidase pos, X and V requirement Neg, Indole neg, growth on blood and chocolate agar pos ( with PITTING) of the agar, Carbohydrate neg, growth on Macconkey agar neg.

answer

Eikenella corrodens

question

Kingella Kingae is usually associated with which type of infection?

answer

Endocarditus. King the big one...

question

Cultures obtained from a dog bite wound produced yellow, tan and slightly pink colonies on blood and chocolate agar with a margin of finger like projections. appearing as a film around the colonies. Given the following results at 24 hours, which is the most likely organism? oxidase pos, cat pos, growth on macconkey neg, motility neg.

answer

Capnophaga. normal flora in humans , however infectious from a dog bite.

question

Smooth gray colonies showing no hemolysis are recovered from an infected cat scratch on blood agar and chocolate agar. The organisma are gram negative pleomorphic rods that are both catalase positive and oxidase positive. The most likely organism is

answer

Pasturella...cat scratch

question

Which media should be used to recover bordetella pertusis from nasopharangel specimens,

answer

Bordet gengou agar

question

Which media is recommended for the recovery of brucella spp from blood and bone marrow.

answer

Biphasic castenega bottles with brucella broth.

question

In addition to CO2 requirements and biochemical characeristics, brucella melitensis and brucella abortus are differential by growth on media containing which two dyes.

answer

Basic fusion and thionin
Abortus is negative for thionin.

question

Which of the following amino acids are required for the growth of francisella tularensis

answer

Cystiene and cystine

question

Which medium is best for recovery of legionella pneumophilia from clinical specimens.

answer

Buffered charcoal yeast extract agar.
CYE agar

question

Haemophilus influenza, which requires X and V factors for growth, can be differentiated from subspecies Haemophilus aegyptis by which two test?

answer

Indole and xylose.

question

Haemophilus spp. that requires the V factor (NAD) are easily recovered from which agar plate.

answer

Chocolate, the V factor is NAD must be released from RBCS before it can be assimilated by Haemophilus sp.
the RBCs are lysed in chocolate agar.

question

Which of the folowing products is resopnsible for satellite growth of heamophylilus spp. around colonies of staphylococcus and Neisseria spp. on sheep blood agar.

answer

NAD.
Beta hemolysins lyse the RBCs and release the NAD

question

Which of the following plates should be used in order to identify Haemophilus haemolyticus.and Haemophilus parahaemolyticus?

answer

Horse blood agar and muller hinton agar with X and V factor added.
you need something with hemolysis to tell the two apart. haemolyticus is hemolytic.

question

The majority of Haemophilus influinza infections are caused by which of the following capsular serotypes?

answer

b

question

Which Haemophilus species is generally associated with endocarditus.

answer

Haemophilus aphrophilus.

question

Which Haemophilus species is difficult to isolate and recover form genital ulcers and swollen lymph nodes.

answer

H. ducreyi

question

Which of the following is characteristic of strains of haemophilus influenza that are resistant to ampicillin?

answer

Production of beta lactamase enzyme. Roughly 20% of h. flu strains produce B-Lactamase, which hydrolyses and inactivates the beta lactam ring of ampicillin and penicillin.

question

A small gram negative cocobacilla recovered from a CSF of a two year old. gave the following results indole pos, Glucose acid, X requirement positive, V requirement positive, Urease positive, lactose neg, sucrose neg, hemolysis neg,

answer

not hemolyticus.... because not hemolyzed... INFLUENZA

question

The delta ALA test (for porphyrins) is a confirmatory procedure for which test used for the identification of haemophylus species.

answer

X factor.... you could make a mistake because you could have picked a hemolytic bacteria or scooped up some agar..

question

The test used most often to separate the Micrococcaceae family from the streptococcus family is

answer

Catalase. 3%

question

Micrococcus and staphylococcus species are differentiated by which test?

answer

Fermentation of glucose (OF)tube Miicrococcus dont ferment. (closed tube)

question

Lysostaphin is used to differentiate staphylococcus from which other genus

answer

Micrococcus.
staphylococcus is susceptible to lysostaphin

question

Which of the following is used to identify Staphylococcus aureus?

answer

Slide coagulase, tube coagulase and latex agglutination.

question

Which of the following enzymes contribute to the virulence of staph auerus

answer

Haluronidase and beta lactamase.

question

Which staphylococcus species in addition to staph aureus also produces coagualse

answer

S intermedius

question

Staphyococcus epidermidis (coagulase negative) is recovered from which of the following sources.

answer

Prostetic heart valves, Intervenous catheters , Urinary tract. 50-80% of all coagulase negative staph.

question

Slime production is associated wiith which staphylococcus species.

answer

S. epidermidis. produces extracellular slime that enhaces the adheasion

question

Strains of staphylococcus species resistant to the beta lactam antibiotics by standardized disc diffusion and broth microdilution susceptibility methods are called

answer

Heteroresistant.

question

Staphylococcus saprophyticus is best differentiated from staphylococcus epidermidis by resistance to

answer

5 micrograms of novobiocin.

question

The following results were observed by using a tube coagulase test coagulase at 4 hours positive. Coagulase at 18 hours negative. Novobiacin sensitive Hemolysis on blood agar positive. Mannitol salt positive DNase positive

answer

Staphylococcus aureus can produce fibrinolysins that dissolve the clot formed by the coagulase enzyme. it is still positive.

question

Staphylococcus aureus recovered from a wound culture gave the following antibiotic sensitivity pattern by the standardized kirby bauer method Pennicillin R, Ampicillin S, Cephalothin R, cefoxitin R, Vancoumycin S, Methcillin R, What is the drug of choice for treating this patient

answer

Vancoumycin

question

Which of the following test should be used to differentiate Staphylococcus aureus from Staphylococcus intermedius

answer

Acetoin

question

A gram positive coccus recovered from a wound ulcer from a 31 year old diabetic patient showed pale yellow creamy. beat hemolytic colonies on blood agar. given the following results what is the most likely identification. Cat pos, Glucose OF positive open tube, negative sealed tube. Mannitol salt Neg slide coagulase neg.

answer

Micrococcus is sealed tube NEGATIVE remember that.

question

Urine culture from a catheter from an 18 year old female patient produced more than 100,000 col/mL on a CNA plate. Colonies were catalase pos. coagulase neg by the latex agglutination slide method as well as the tube coagulation test . The best singular test for identification is.

answer

Novobiocin susceptibiity.

question

A staphylococcus spp. recovered from a wound (cellulitus) was negative for the slide coagulase test (clumping factor) and negative for novobiocin resistance. The next test needed for identification is

answer

tube coagulase, Beta hemolysis on blood agar, Mannitol salt agar plate,

question

Furazolidone susceptibility is a test used to differentiate

answer

Staphylococcus from micrococcus spp. Staphylococcus are susceptible giving zones of inhibition that are 15 mm or greater.

question

Bacitracin resistance (0.04 unit) is used to differentiate:

answer

Planococcus from micrococcus.

question

Which of the following test will rapidly differentiate micrococci from staphylococci?

answer

Modified Oxidase.

question

Streptococcus species exhibit the following properties.

answer

Facultative anaerobe, oxidase negative, catalase negative.

question

Which group of streptococci is associated with erythrogenic toxin prodction?

answer

Group A
A RED FACE,

question

A four fold rise in titer of which antibodies is the best indicator of a recent infection with group A beta hemolytic streptoocci?

answer

Anti-streptolysin O

question

Bacitracin A disks (0.04 unit) are used for the presumptive identification of which grop of beta hemolytic streptococci.

answer

Group A

question

Trimethoprim-sulfamethoxazole (SXT) disks are used along with bacitracin disks to differentiate which streptococci

answer

beta hemolytic streptococci.
ONLY

question

Beta hemolytic streptococci not of group A or B usually exhibit which of the following reactions.

answer

SXT Susceptible
bacitracin is variable

question

A false positive camp test for the pesumptive identifivcation of group B strep may occur if the plate is incubated in

answer

a candle jar or CO2 incubator. It must be incubated in ambieant air. CAMP in air,

question

Which test is used to differentiate the viridans strep from the group D strep. and enterococci?

answer

Bile esculin test. can they grow in the presence of bile. group D can and cause a blackened butte. Viridans strep are negative.

question

The bile soluability test causes the lysis of

answer

Strep pneumo

question

S. pneumoniae and the viridans strep can be differentiated by which test

answer

Optichin. inhibits s pneumo but NOT the viridans.

question

The salt tolerance test (6.5% salt broth ) is used to presumptivily identify

answer

Enterococcus fecalis

question

In addition to Enterococcus feacalis, which other strep will grow in 6.5% salt broth

answer

B... salty Balls

question

The quelling test is used to identify which streptococcus spp.

answer

S. pneumoniaea

question

The L-pyrrolidonyl B-napthylamide (PYR) hydrolysis test is a presumptive test for which streptococcus.

answer

Group A and group D enterococcus.

question

A pure culture of beta hemolytic strep recovered from a leg wound ulcer gaqve the following reactions. CAMP neg Hippurate hydrolysis negative Bile esculin negative 6.5% salt negative PYR neg Bacitracin R Optichin R SXT sensitive

answer

Non-grp A, non-grp B, Non-grp D.

question

Beta hemolytic streptococci, more than 50,000 col/mL were isolated from a urinary tract catheter. given the following reactions, what is the most likely identification?
CAMP neg
Hippurate hydrolysis pos/neg
Bile soluability neg
6.5% pos
PYR pos
bile esculin pos
SXT R Bacitracin R Optichin R

answer

Enterococcus fecalis

question

Nutritionally variant streptococcus (NVS) require specific thiol compoundsn cysteine, or the active form of vitamine B6, Which test supplies these requirements?

answer

Staphlococcus cross streak accross the NVS innoculum, provides the nutrients needed, Very small colonies of NVS can be seen growing adjacent to the staphylococci streak on the blood agar plate in a manner similar to the satellite phenomenon of haemophylus spp. around S. aureus

question

Many alpha hemolytic strep recovered from a wound were found to be pennicillin resistant Given the following results What is the most likely identification? Bile esculin pos PYR pos 6.5% salt pos Hippurate hydrol pos
Bile solubility neg
SXT resistant

answer

E. faecalis the key is the penicillin resistance...

question

Which two test best differentiates S. bovis (group D streptococcus , enterococcus) from strep salivarius

answer

Starch hydrolysis and acid production from mannitol. S. bovis and S. salivarius are similar... only S. bovis is positive for mannitol and starch reactions.

question

Two blood cultures on a newborn grew beta hemolytic strep with the following reactions CAMP test pos Hippurate hydreol pos Bile solubility neg
Bacitracin R Bile esculin Neg PYR neg SXT R

answer

Group B S. agalactiae are resistant to both bacitracin and SXT.

question

MTM medium is used primarily for the selective ecovery of which organism from genital specimens?

answer

N. gonorrheae

question

Variaton in coloney types seen with fresh isolates of Niesseria gonorrhoeae and sometime with Niesseria meningitidis are the result of:

answer

Multiple nutritional requirements, Pili on the cell surface, and use of a transparent meduim.

question

Gram negative dipilococci recovered from an MTM plate and giving a positive oxidase test can be presumptively identified as:

answer

Neisseria gonorrhea, Neisseria meningitidis, Neisseria lactamica.

question

The superoxol test is used a a rapid presumptive test for

answer

Neisseria gonorrheae

question

Nonpathogenic Moraxella spp. capable of growing on selective media for Neisseria can be differentiated from Neisseria spp. by which test?

answer

10-unit penicilin disk.

question

A gram stain on a uretheral discharge from a man showing extracellular and intracellular gram-negative diplococci within segmeneted neutrophils is presumptive for

answer

Neisseria gonorrheae. this is not true for weomen

question

The beta-galactosidase test aides in the identifiation of which Neisseria

answer

Neisseria lactamica.

question

Cystine tryptic digest (CTA) media used for identification of Neisseria spp. should be inoculated and cultured in:

answer

A non-CO2 incubater at 35C for up to 72 hours.

question

Culture on MTM media of a vaginal swab produced several colonies of gram negative dipilococci that were catalase and oxidase positive and superoxol negative. Given the folowing reactions what is the most likely identification.? glocose pos sucrose neg lactose pos maltose pos fructose neg

answer

Neisseria Lactamica is the only spp that grows on MTM and utilizes LACTOSE

question

Sputum from a patient with pneumonia produced many colonies of gram negative diplococci on a chocolate plate that were also present in fewer numbers on MTM after 48 hours. What is the most likely identification? Cat pos oxi pos DNase pos tributyrin hydrolysis pos Glu neg suc neg Lac neg Mal neg Fru neg

answer

Moraxella catarralis stunted growth on MTM, DNase pos.

question

Anaerobes.
A large gram positive spore forming rod growing on blood agar as large raised beta hemolytic colonies that spread and appear frosted green gray glass is most likely a

answer

Bacillus sp.

question

Bacillus anthracis and Bacillus cereus can best be differentiated by which test

answer

Motility and beta hemolysis on blood agar.

question

What is the specimen of choice for proof of food poisoning by Bacillus cereus

answer

Food

question

Bacillus anthracis culture obtained from a wound specimen produced colonies that had many outgrowths (medusa-head appearance), but were not beta hemolytic on sheep blood agar. What test should be preformed next

answer

penicillin 10unit susceptibility test Bacillus anthracis is susceptible but other Bacillus is not.

question

Which of the following test should be performed for initial differentiation of listeria monocytogenes from group B streptococci.

answer

Gram stain, motility at room temp, catalase.

question

Culture of a finger wound specimen from a meat packer produced short gram positve bacilli on a blood agar plate with no hemolysis. Given the following test results at 48 hours, what is the most likely identification. cat neg H2S/TSI pos Motility wet prep neg Motility media neg bottle brush growth in stab culture.

answer

E. rhusiopathiae

question

A non-sporeforming slender gram positive rod froming palisades and chains was recovered from a vasginal culture grew well on tomato juice agar. The most likely identification is

answer

Lactoacillis

question

A corynebacterium secies recovered from a throat culture is considered a pathogen when it produces

answer

A pseudomembrane in the nasopharynx, an exotoxin, Gray black colonies with a brown halo on tnisdale agar

question

A presumptive diagnosis of gardnerella vaginalis can be made using which of the following findings.

answer

Oxidase and catalase(neg), pleomorphic bacilli heavily colonized on vaginal epithelium Hippurate hydrolysis.

question

A gram positive branching filimentatious organism recovered from a sputum specimen was recovered from a sputum and found to be positive with a modified acid fast stain method. what is most likely?

answer

Nocardia

question

Routein Laboratory testing for treponema pallidum involves:

answer

Serological analysis

question

Spirochetes often detected in the hemotology laboratory, even before the physician suspects the infection are.

answer

Borrelia spp.

question

Which of the following organisms is the cause of lyme disease

answer

Borrelia Burgdorferi

question

The diagnostic method most commonly used for the identification of lyme disease is

answer

serology

question

Primary atypical pneumonia is caused by

answer

Mycoplasm pneumoniae

question

Which organism typically prodices fried egg colonies on agar within 1-5 ays of culture from a genital specimen?

answer

Mycoplasm Hominis

question

The Manganous chloride-urea test is used for the identification of which organism?

answer

Uroplasma urealyticum

question

A gram positive gram variable, beaded organism with diabetic branching was recovered from the sputum fo a 20 year old patient with leukemia. the specimen produced orange glabrous , waxy colonies on middle brook agar that showed partial acid fast staining with the modified kenyoun stain. What is the most likely identification?

answer

Nocardia

question

A direct smear from a nasopharyngeal swab stained with loeffler methylene blue stain showed various letter shapes and deep blue, metachromatic granules,

answer

Cory

question

Which of the following is the best, rapid, noncultured test to preform when gardenerella vaginalis is suspected in a patient with vaginosis

answer

10% KOH, Whiff test...

question

ANAEROBIC BACTERIA. Obligate anaerobes, facultative anaerobes, and microaerophilic are terms referring to bacteria requireing:

answer

Decreased O2

question

Which of the following most affects the oxidation reduction potential (Eh or redox potential) of media for anaerobic bacteria.

answer

PH, PH , PH, PH

question

Which of the following is the medium of choice for the selective recovery of gram negative anaerobes?

answer

Kanamycin-vancoumycin (KV agar)

question

Anaerobic bacteria are routinely isolated from all of the following except:

answer

Urinary tract infections

question

Methods other than packaged microsystems used to identify Anaerobic bacteria include

answer

GLC gas liquid chromotography

question

Which broth is used for the cultivation of Anaerobic bacteria in order to detect the volitile fatty acids as an aide to identification?

answer

Prereduced peptone yeast extract glucose

question

A gram positive spore forming bacillus growing on sheep blood agar anaerobically produces a double zone of beta hemolysis and is positive for lecthinase what is ID?

answer

C. perfringens

question

Egg yolk agar is used to detect which enzyme produced by Clostridium?

answer

Lecithinase

question

Which of the following organisms will display lipase activity on egg yolk agar

answer

C. botulism C. sporogenes C. novyi

question

Which spore type and location is found on C. tetani.

answer

Round terminal.

question

Gram positive bacilli recovered from two blood cultures from a 60 year old diabetic gave the following results. Spores seen neg hemolysis + double zone Motility neg Lectithinase positive Volitile acids by GLC = acetic acid and butyric acid.

answer

C. perfringenes

question

What mechanism is responsible for botulism in infants caused by C. botulism

answer

Ingestion of spores in food or liquid.

question

The classic form of foodborne botulism is characteristic by the ingestion of

answer

preformed toxin in food.

question

Which test is performed in order to confirm an infection with C. botulinum

answer

Toxin neutralization.

question

Which Clostridium spp. causes pseudomembraneous colitis or antibiotic associated colitus?

answer

C. difficile

question

Identification of Clostridium tetani is based on

answer

Clinical findings

question

Obligate anaerobic gram negative bacilli that do not form spores grow well in 20% bile and are resistant to penicillin-2 unit disks are most likely:

answer

Bacteroides

question

Which Bacteroides spp. is noted for pitting of the agar and is sensitive to penicillin 2-unit disks

answer

B. ureolyticus

question

Which gram negative bacilli produce black pigment and brick red flouresence when exposed to an ultra violet light source?

answer

Porphyromonas spp. and Prevotella

question

The following characteristics of an obligate anaerobe gram negative bacilli best describe which genera :

Gram stain: long slender rods with pointed ends.
Clolnial appearance dry bread crumbs or fried egg appearace.
Penicillin 2-unit disks: susceptible

answer

Fusobacterium

question

Which one is not an anaerobic cocci that stains gram positive?
Peptococcus
Peptostreptococcus
streptococcus
Veillonella spp

answer

Veillonella spp

question

The gram positive non-spore forming anaerobic rods most frequently recovered from blood cultures as a contaminant are:

answer

Proprionibacterium acnes

question

Which Clostridium Spp. is most often recovered from a wound infection with gas gang green?

answer

C. perfringenes

question

Gram stain of a smaear taken from periodontal pockets of a 30 year old man with poor dental hygene showed sulfer granules containing gram positive rods (short diptheroids and some branched filiments). Colonies on blood agar resembled molor teeth in formation, The most likely organism is:

answer

Actinomyces israelli

question

Antimicrobial susceptibility testing of anaerobes is done by which of the following methods?

answer

Micro-tube broth dilution

question

MYCOBACTERIA 7.8 Harr

The best specimen for the recovery of mycobacteria from a sputum sample is:

answer

First morning specimen

question

What concentration of sodium hydroxyide (NaOH) is used to prepare a working decontamination solution for the processing of not normally sterile specimens for mycobacteria:

answer

4% NaOH

question

Which is the most appropriate non-selective medium for the recovery of mycobacteria from a heavily contamnated specimen?

answer

Petragnanis agar

question

Mycobacteria stained by Ziehl-Neelsen or Kinyoun methods with methylene blue counter stain are seen microscopically as:

answer

Bright red rods against a blue background

question

Acid fast of a smear prepared from a digested sputum showed slender, slightly curved, beaded red mycobacterial rods. Growth on middlebrook 7H10 slants produced buff colored microcolonies with a surpentine pattern after 14 days at 37C. Niacin and nitrate reduction test were positive. What is it?

answer

M. tuberculosis

question

Which organism associated with cattle, causes tuberculosis in humans, especially in regions where dairy farming is prevelent?

answer

Mycobacterium bovis

question

What organism are used as controls for rapid growers and slow growers?

answer

Mycobacterium fortuitum and Mycobacterium tuberculosis

question

What Mycobacterium is produced pigmented colonies in the dark (is a scotochromogen)?

answer

M. szulgai

question

What Mycobacterium is associated with a skin infection:

answer

Mycobacterium marinum
Mycobacterium haemophilum
Mycobacterium ulcerans

not

Mycobacterium kansasii

question

All of the following Mycobacterium spp. produce the enzyme to convert niacin to niacin ribonucleotide except:

answer

M. tuberculosis

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