Med Bac exam 3 Quizzes and exercises
When three tubes of cerebrospinal fluid are received in the laboratory they should be distributed to the various laboratory sections as follows: a. #1 Hematology, #2 chemistry, #3 microbiology b. #1 chemistry, #2 microbiology, #3 hematology c. #1 microbiology, #2 hematology, #3 chemistry d. #1 chemistry, #2 hematology, #3 microbiology
#1 chemistry, #2 microbiology, #3 hematology
The expected colony count in a suprapubic urine from a healthy individual is: a 0 CFU/mL b 100 CFU/mL c 1,000 CFU/mL d 100,000 CFU/mL
0 CFU/mL
which of the following microorganisms can make up normal vaginal flora? 1. Lactobacilli 2. Coagulase-negative staphylococci 3. Corynebacterial a. 1 only b. 1 and 2 c. 2 only d. 1, 2, and 3
1, 2, and 3
The colony count from a suprapubic urine culture growing 10 colonies of Staphylococcus saprophyticus is: a. 0 CFU/mL b. 100 CFU/mL c. 1000 CFU/mL d. 100000 CFU/mL
1000 CFU/mL
With regard to blood cultures, which blood to broth ratio is most conductive to growth? a. 1:1 b. 1:2 c. 1:10 d. 10:1
1:10
A clean-catch urine culture (obtained with a 0.001 mL calibrated loop) grows 60 colonies of E. coli. Which of the following represents the final colony count in CFU/mL? a. 60 CFU/mL b. 600 CFU/mL c. 6000 CFU/mL d. 60000 CFU/mL
60000 CFU/mL
A clean-catch urine sample from a nursing home patient is cultured using a 0.001 mL loop. It grows 67 colonies of a lactose fermenter that has the biochemical reactions shown below: TSI: A/A Oxidase: negative Motility: positive Indole: negative Citrate: positive VP: positive Lysin decarboxylase: negative Ornithine decarboxylase: positive Urea: Negative What should the microbiologist report? a. 670 CFU/mL Serratia marsecens b. 6700 CFU/mL Providencia stuartii c. 67000 CFU/mL Enterobacter cloacae d. 67000 CFU/mL Klebsiella oxytoca
67000 CFU/mL Enterobacter cloacae
If a blood agar plate and an EMB plate are both inoculated with 0.001 ml of urine, and 90 colonies of Staph aureus grew on the blood agar plate, what should be reported? a. 90 colony forming units/mL of Staphylococcus aureus b. 90,000 colony forming units/mL of Staphylococcus aureus c. 9,000 colony forming units/mL of Staphylococcus aureus d. 9 colony forming units/mL of Staphylococcus aureus
90,000 colony forming units/mL of Staphylococcus aureus
The bacterial species on the surface of the MacConkey agar plate shown in this photograph, a coccobacillary non-fermenter and a common cause of nosocomial hospital-acquired pneumonia can be presumptively identified as: a. Acinetobacter baumannii b. Burkholderia cepacia c. Moraxella catarrhalis d. Neisseria lactamica
Acinetobacter baumannii
The Gram stain from a blood culture shows gram-positive cocci in chains. The subcultured plates from the blood culture bottle show no growth. Additional testing should be done to detect the presence of: a Staphylococcus saprophyticus b Aerococcus urinae c Abiotrophia defectiva d Streptococcus pneumoniae
Abiotrophia defective
In the microbiology laboratory, the following specimens are received at the same time. Which specimen is classified as a level 1 specimen, requiring immediate processing? a. Catheter tip for quantitation b. Swab in transort medium c. Amniotic fluid d. Unpreserved feces
Amniotic fluid
The colonies growing on the surface of this 5% sheep blood agar plate, with B-hemolysis, were recovered from a throat swab of a 19-year-old girl with acute pharyngitis. Gram stain revealed club-shaped Gram positive bacilli with rudimentary branching. What is this species? a. Arcanobacterium hemolyticum b. Strepotococcus pyogenes c. Listeria monocytogenes d. Corynebacterium pseudodiphtheriticum
Arcanobacterium hemolyticum
A 22-year-old female presents to the emergency room with a hot, painful, swollen right elbow and no visible signs of injury. The physician suspects septic arthritis. Which of the following patient history questions may reveal valuable information that could lead to the potential pathogen? a. Have you been bitten by a cat recently? b. Have you had joint replacement surgery in the recently past? c. Have you been in a fist fight recently? d. Are you sexually active?
Are you sexually active?
Which one of the following methods is the best way to confirm your patient's identity? a. Look at the sign on the patient's door or above the patient's bed. b. Ask the patient to state his/her name, and check the atient's armband, comparing the full name and medical record number to that shown on your preprinted collection list. c. Ask the patient to confirm his/her name as in the following example: "is your name Ms. Smith?" d. First collect the blood specimen, then establish patient identity, then label with the correct reprinted computer generated label
Ask the patient to state his/her name, and check the atient's armband, comparing the full name and medical record number to that shown on your preprinted collection list.
Which of the following organisms dislay the characteristic "Medusa head" on 5% sheep blood agar (SBA) after 18 hours of incubation at 35 C? a. Yersinia pestis b. Bacillus anthracis c. Francisella tularensis d. Brucella abortus
Bacillus anthracis
Which of the following organisms is considered a contaminant when isolated from blood cultures and is part o fnormal skin flora? a. Bacillus subtilis b. Salmonella typhi c. Bacillus anthracis d. Pseudomonas aeurginosa
Bacillus subtilis
The following statements regarding automated identification systems are correct EXCEPT: a. May misidentify the biological threat agents b. Designed to identify raidly growing microorganisms c. Likely to produce aerosols during set-up d. Can reliably identify Francisella tularensis
Can reliably identify Francisella tularensis
Which culture medium is specifically formulated to recover Salmonella typhi from stool specimens? a. Selenite broth b. Bismuth sulfite agar c. Salmonella/Shigella (SS) agar d. Deoxycholate citrate agar
Bismuth sulfite agar
Biochemical reactions of an organism are consistent with Salmonella. A suspension is tested in polyvalent antiserum A through G and in Vi antiserum. There is agglutination in the Vi antiserum only. What should be done next? a. Boil suspension of the organism for 10 minutes to inactivate the Vi antigen b. Test organism with individual antisera for agglutination c. Report "no Salmonella isolated" d. Repeat biochemical identification of the organism
Boil suspension of the organism for 10 minutes to inactivate the Vi antigen
A 5-year-old nonimmunized male with a persistant cough, fever, and flulike symptoms was admitted to the hospital. Nasopharyngeal swabs were cultured on 15% blood, chocolate, Bordet-Genjou, and Regan-Lowe (with 10% charcoal) agars. All media grew a gram-negative coccobacillus. Carbohydrate and biochemical tests were negative. What is the most likely identification? a. Haemophilus influenza b. Bordetella pertussis c. Haemophilus parainfluenzae d. Bordetella bronchiseptica
Bordetella pertussis
A patient was admitted to the hospital for fevers, chills, weight loss, headaches, and fatigue. The patient mentioned that he had cut his hand while hunting wild boar a couple of weeks ago. Blood cultures were received in the microbiology laboratory and several days later a bone marrow specimen on the patient was received. The blood culture was positive after 5 days and the bone marrow grew a small, convex, smooth colony after 48 hours on sheep blood and chocolate agar. A gram stain was performed and demonstrated small Gram negative coccobacilli organisms. Which of the following organisms is the cause of infection for this patient? a. Bacillus anthracis b. Brucella suis c. Acinetobacter species d. Moraxella species
Brucella suis
What organism produced outside a bioterrorism event causes glanders disease? a. Burkholderia mallei b. Francisella tularensis c. Yersinia pestis d. Variola virus
Burkholderia mallei
What is the one principle that is conserved between all continuous monitoring blood culture systems? a. pH detection b. H2 detection c. O2 detection d. CO2 detection
CO2 detection
A large container of peritoneal fluid is received in the laboratory (about 50 mL). How should the tech process this sample for aerobic culture? a. Use a sterile pipette and add a drop of fluid per agar plate b. Insert a swab into the specimen container and inoculate all agar plates c. Centrifuge the specimen and use the sediment to inoculate the agar plates d. Add 1 mL of saline to 1 mL of fluid, vortex, and inoculate plates
Centrifuge the specimen and use the sediment to inoculate the agar plates
A gram stain of a swab of a hand wound reveals: moderate neutrophils no squamous epithelial cells moderate gram-positive cocci in clusters moderate large gram-negative bacilli Select the appropriate media that will selectively isolate each organism a. KV-laked agar, Thayer-Martin b. Sheep blood, MacConkey c. Columbia CNA chocolate d. Columbia CNA, MacConkey
Columbia CNA, MacConkey
Cystine-tellurite blood agar is recommended for the isolation of which organism? a. Yersinia enterocolitica b. Legionelle pneumophilia c. Coynebacterium diphtheriae d. Francisella tularensis
Coynebacterium diphtheriae
If you receive a transudate fluid for a Gram stain and bacterial culture, what is the ideal specimen prepartion method for the gram stain? a. one drop of the original sample on a slide to create an appropriate smear b. Cytocentrifugation to create an appropriate smear c. use two slides smashed together with the orginal sample in between to create an appropriate smear d. dip a swab into the original sample and place it on a slide to creat an appropriate smear
Cytocentrifugation to create an appropriate smear
A susected case of Legionnaires' disease was noted on the request form for a culture and sensitivity ordered on a sputum sample. The patient was a 70-year-old male who presented with a positive serological test for Legionella spp. What is the most efficient way to confirm the infection using the submitted sample? a. Culture the sputum on MacConkey agar b. Gram stain of the sputum c. Acid-fast staining d. Direct immunofluorescent microscopy
Direct immunofluorescent microscopy
A fecal specimen, inoculated to xylose lysine deoxycholate (XLD) and Hektoen enteric (HE) M . produced colonies with black centers. Additional testing results are as follows: Biochemical screen Result Serological test Result glucose positive polyvalent no agglutination H2S positive group A no agglutination lysine decarboxylase positive group B| no agglutination urea negative group C no agglutination ONPG negative group D no agglutination indole positive group V, no agglutination The most probable identification is: a Salmonella enterica b Edwardsiella tarda c Proteus mirabilis d Shigella sonnei
Edwardsiella tarda
An organism has been isolated from teh CSF of a premature newborn. The organism grew in 48 hours on MacConkey and blood agar. Additional reactions include: alk/alk (red/red) on Kligler Iron agar, oxidative utilization of carbohydrates, and a positive indole reaction. Which of the following is the most likely identification? a. Sphingobacterium multivorum b. Bordetella bronchiseptica c. Elizabethkingia (Flavobacterium) meningosepticum d. Stenotrophomonas maltophilia
Elizabethkingia (Flavobacterium) meningosepticum
The organism most commonly associated with neonatal purulent meningitis is: a Neisseria meningitidis b Streptococcus pneumoniae c group B streptococci d Haemophilus influenzae
Group B streptococci
The purpose of the additive SPS (sodium polyanethol sulfonate) that is in continuous monitoring sytem blood culture bottles, is all of the following EXCEPT? a. Inactivates and absorbs out complement b. Inactivates and absorbs out coagulation factors c. Inactivates neutrophils and monocytes d. Inactivates and absorbs out antimicrobial agents
Inactivates and absorbs out antimicrobial agents
Which combination of test/quality control organisms is correct? a. Coagulase: Staphylococcus saprophyticus and Staphylococcus epidermidis b. H2S production: Proteus mirabilis and Salmonella serotype Typhi c. Phenylalanine deamination: Escherichia coli and Yersinia enterocolitica d. Indole: Escherichia coli and Proteus mirabilis
Indole: Escherichia coli and Proteus mirabilis
A medical technologist is working on a stool culture from a patient with severe, bloody diarrhea. She wants to set up biochemicals to differentiate Shigella and E. coli. Which of the following tests would be the most appropriate? a. Hydrogen sulfide, ONPG, motility, urease b. Lactose, indole, ONPG, motility c. Urease, citrate, VP, hydrogen sulfide d. Gas, MR, urease, citrate
Lactose, indole, ONPG, motility
A tech is interpreting a urine culture with a source of suprapubic aspiration. There is one colony of Staphylococcus epidermidis present on the blood agar which was streaked with a 0.01 loop. What should the tech do next? a. List the S. epidermidis as a contaminate from collection b. List and provide a sensitivity for the S. epidermidis c. Report the culture as "no growth" d. Quantitate and report mixed urethral flora
List and provide a sensitivity for the S. epidermidis
Of the organisms listed, which is the most likely to be contracted following consumption of unpasteurized milk? a. Erysipelothrix rhusiopathiae b. Listeria monocytogenes c. Corynebacterium Jeikeium d. Pasteurella multocida
Listeria monocytogenes
All of the organisms below are known to cause gastroenteritis, EXCEPT: a. Moraxella catarrhalis b. Campylobacter jejuni c. Vibrio cholerae d. Aeromonas hydrophila
Moraxella catarrhalis
When an epidemiologic survey for the detection of upper respiratory tract carriers of Neisseria meningitidis or Bordetella pertussis is being conducted, the optimal type of specimen to be obtained for culture is a. Anterior nares b. Buccal cavity c. Nasopharyngeal d. Throat
Nasopharyngeal
The most common organism that causes septic arthritis in patients under 30 years of age is: a. Neisseria gonorrhoeae b. Staphylococcus aureus c. Treponema pallidum d. Chlamydia trachomatis
Neisseria gonorrhoeae
a 24-year-old man presents with pain on urination and urethral discharge. a gram stain of the discharge is seen in the image. (grem negative coccobacilli) What is the most likely identification of this organism? a. Acinetobacter baumannii b. Neisseria gonorrhoeae c. Haemophilus ducreyi d. Escherichia coli
Neisseria gonorrhoeae
An 18-year-old boy is admitted to the hospital with suspected meningitis. He is lethargic and presents with a rigid neck. He has not had most of the recommended vaccines from childhood to now. Gram stain of his spinal fluid shows many PMNs with intra- and extracellular gram-negative diplococci. The suspected pathogen is: a. Listeria monocytogenes b. Haemophilus influenzae c. Streptococcus agalactiae d. Neisseria meningitidis
Neisseria meningitidis
The quality of an expectorated sputum is evaluatd based on the a. Amount of bacteria seen in a direct gram stain b. Number of red blood cells in comparison to epithelial cells in a direct gram stain c. Number of white blood cells in comparison to epithelial cells in a direct gram stain d. Viscosity of th esample and macroscopic appearance of blood
Number of white blood cells in comparison to epithelial cells in a direct gram stain
Abiotrophia defectiva (formerly Streptococcus defectivus) and Granulicatella adiacens (formerly S. adjacens, then A. adiacens) are the names currently given to two species of what were previously called nutritionally variant streptococci (NVS). What supplement must be added to the blood culture medium to recover these organisms in cases of "culture-negative endocarditis?" a. Thiamine b. Pyridoxal c. Sodiumpolyanethol sulfonate (SPS) d. Synthetic resins
Pyridoxal
The Streptococcus viridans group, the most common cause of the sub-acute bacterial endocarditis, origniates as part of the normal ____ flora. a. urinary b. Gastrointestinal c. Oral d. Genital
Oral
A physician called the microbiology laboratory and asked what he needed to order to diagnose Bordetella pertussis from a child who had what appeared to be having whooping cough. Which of the following should the physician be told to order? a. Direct fluorescent antibody (DFA) test only b. Culture only c. PCR testing d. IgG and IgM antibody tests
PCR testing
The most common cause of acute meningitis associated with CSF shunts is: a. coagulase-negative staphyloccci b. Naegleria fowleri c. Citrobacter koseri d. Streptococcus pneumoniae
coagulase-negative staphylococci
Prior to receiving antibiotic therapy, a patient had a urinary tract infection with gram-negative motile rods producing the following reactions: indole: positive H2S (TSI): positive MR: positive VP: negative Phenylalanine deaminase: positive Urea: positive Citrate: positive Ornithine decarboxylase: negative Gelatin hydrolysis: positive Based on the reactions above, what organism is MOST likely causing the infection? a. Proteus vulgaris b. Enterobacter cloacae c. Serratia marcescens d. Klebsiella pneumoniae
Proteus vulgaris
Acceptable sources for urine culture from a patient with suspected urinary tract infection include all EXCEPT: a. Suprapubic aspiration b. Straight catheter c. Voided mid-stream clean catch d. Drainage bag from nephrostomy catheter
drainage bag from nephrostomy catheter
A tech is working on a urine culture and finds the following isolates: Escherichia coli: >100000 CFU/mL Enterococcus faecalis: 50000 CFU/mL Klebsiella pneumoniae: 30000 CFU/mL How should the tech continue with the culture work up? a. Quantitate culture and report as mixed urethral flora/contaminants b. Perform sensitivity on the E. coli and list other as contaminants c. Perform sensitivity on the E. coli and K. pneumoniae and list E. faecalis as a contaminant d. Reject culture due to contamination
Quantitate culture and report as mixed urethral flora/contaminants
A very bloody stool is received by the laboratory. The following day a pathogenic strain of E. coli is isolated. Which sugar should this isolate be tested against to begin the identification process? a. Mannitol b. Sorbitol c. Lactose d. Arabinose
Sorbitol
A tech is reviewing a gram stain from a positive blood culture bottle. The background on the stain shows pink debris and the tech thinks that there is also gram-negative bacilli but is having difficulty differentiating the artifact and possible organisms. What could the tech do next to help determine if bacteria are present in the blood culture bottle? a. Stain with Wright-Giemsa b. Stain with Acridine Orange c. Use Calcofluor White d. Stain with Periodic Acid-Schiff
Stain with Acridine orange
Each of the bacterial species listed below may be associated with culture-negative endocarditis except: a. Cardiobacterium hominis b. Streptococcus abiotropha c. Brucella abortis d. Staphylococcus epidermidis
Staphylococcus epidermidis
The most frequent cause of prosthetic heart valve infection occuring within 2-3 months after surgery is: a. Streptococcus pneumoniae b. Streptococcus pyogenes c. Streptococcus aureus d. Staphylococcus epidermidis
Staphylococcus epidermidis
A urine culture from a 23-year-old female grew a catalase-positive gram-positive coccus (>100,000 cfu/mL), which would most likely be a. Enterococcus faecalis b. Streptococcus bovis group c. Streptococcus viridans d. Staphylococcus saprophyticus
Staphylococcus saprophyticus
A 67-year-old man was seen in the emergency room complaining of cough, fever, and piercing right posterior chest pain. X-ray of the chest revealed consolidation of the right middle lobe of the lung. Sputum culture grew the bacterial species shown in the upper photograph. The lower photomicrograph illustrates a gram-stain of the sputum specimen. The most likely cause of the pneumonia is: a. Klebsiella pneumoniae b. Enterococcus faecalis c. Staphylococcus intermedius d. Streptococcus pneumoniae
Streptococcus pneumoniae
The most frequent cause of bacterial meningitis in adults and in children is: a. Streptococcus neumoniae b. Neisseria meingitidis c. Haemophilus influenzae d. Escherichia coli
Streptococcus pneumoniae
Which of the following organisms is the leading cause of bacterial meningitis in infants, young children, and adults in the United States? a. Haemophilus influenzae b. Neisseria meningitidis c. Pediococcus spp. d. Streptococcus pneumoniae
Streptococcus pneumoniae
A blood culture bottle with macroscopic signs of growth is gram stained and the technician notes small, curved gram-negative bacilli resembling "gull wings". It is subcultured to blood and chocolate agar, and incubated aerobically and anaerobically. After 24 hours, no growth is apparent. The next step should be to: a. Subculture the bottle, adn incubate in microaerophilic conditions b. assume the organism is nonviable, adn ask for repeat specimen c. utilize the oxidase and indole to test aeromonas d. subculture the bottle to a medium containing X and V factors
Subculture the bottle, adn incubate in microaerophilic conditions
A urine specimen, from a premature infant, was sent for culture to the microbiology laboratory and it grew out 30000 CFU/mL of a coagulase negative staphylococcus. The physicican felt that the growth was skin contamination as the urine was collected in a U-bag that was attached around the infant's genitalia area. The physician sent a second specimen for culture and it was reported as no growth after 48 hours. Which of the following specimens is the most probable specimen type for the second specimen that was sent to the microbiology laboratory for culture? a. Straight Catheterized Urine b. Clean-catch midstream urine c. Suprapubic Bladder Aspiration Urine d. Indwelling Catheter Urine
Suprapubic bladder aspiration urine
A patient came into the emergency department with a swollen knee and the physician drained 20 mL of fluid from the patient's knee. What is the name of the fluid collected? a. Pleural fluid b. Ascitic fluid c. Synovial fluid d. Pericardial fluid
Synovial fluid
When vitreous fluid is collected, it must be transported to the laboratory within 15 minutes and set up immediately for culture. This specimen type must be handled with care as this specimen type is not easy to obtain. What body site is this specimen collected from? a. lungs b. ear exudate c. eye d. heart
eye
Which test can be used to diagnose infection and confrim eradication of Helicobacter pylori? a. Dnase b. Hippurate hydrolysis c. String test d. Urea breath test
Urea breath test
A tech in the laboratory receives a cerebrospinal fluid (CSF) culture for Gram stain and culture. What steps are needed for the best slide preparation of the specimen? a. Use a sterile swab to spread CSF on the slide b. Use a sterile swab to obatin CSF and roll swab back and forth on the slide c. Use cytocentrifugation to prepare the slide d. Place a portion of sample on the slide, press a second slide onto the sample, and pull the slide away to provide a thin film of the sample
Use cytocentrifugation to prepare the slide
A technologist is reading a gram stain from a CSF and observes many intracellular gram-negative diplococci. Which set of chemistry and hematology CSF results would most likely be seen in someone with this type of infection? a. WBC increased, glucose increased, protein increased b. WBC decreased, glucose decreased, protein decreased c. WBC increased, glucose decreased, protein increased d. WBC decreased, glucose increased, protein decreased
WBC increased, glucose decreased, protein increased
All of the following are examples of preanalytic errors, EXCEPT: a. Misidentified patient b. Underfilled tube c. Prolonged tourniquet application d. Wrong test performed
Wrong test performed
An 8-year-old girl is admitted to the hospital with a 3-day history of fever, abdominal pain, diarrhea, and vomitting. A stool culture grows many lactose-negative colonies that yielded the laboratory results shown in this table: Oxidase: negative TSI: alkaline/acid Indole: negative Urea: positive Citrate: positive Ornithine decarboxylase: positive Sucrose: positive H2S: negative Motility at 25 C: positive The most probably identification of this organism is: a. E. coli b. Providencia stuartii c. Yersinia enterocolitica d. Edwardsiella tarda
Yersinia enterocolitica
Which of the following organisms causes an acute mesenteric lymphadenitis in adults that closely mimics the symptoms of appendicitis? a. Salmonella typhimurium b. Plesiomonas shigelloides c. Yersinia enterocolitica d. Listeria monocytogenes
Yersinia enterocolitica
A gram negative rod exhibiting bipolar staining was isolated from sheep blood agar after 24 hours of incubation. Oxidase: negative Urease: negative Catalase: positive Indole: negative Which of the following species is most probable? a. Brucella species b. Yersinia pestis c. Bacillus anthracis d. Francisella tularensis
Yersinia pestis
Throughout history, plague pandemics have killed millions Transmission of the human plague may still occur through bites of rodent fleas or contact with infected animals. What is the causative agent of plague? a. Vibrio cholerae b. Bacillus anthracis c. Clostridium botulinum d. Yersinia pestis
Yersinia pestis
The diagnosis of Neisseria gonorrhoeae in female is best made from a. clinical history b. an endocervical culture c. a gram stain of cervical secretions d. examination for clue cells
an endocervical culture
A budding yeast with pseudohyphae and clusters of gram-positive staphylococci were observed in a gram stain smear prepared from a positive blood culture. What is the MOST likely source of the infection? a. Urinary tract b. An indwelling catheter c. lung abscess d. subcutaneous cellulitis
an indwelling catheter
A CSF specimen is received from a patient with suspected meningitis. Positive gram stain, along with the results shown here suggest what type of condition? elevated WBC count Neutrophils predominant Marked protein elecation Marked glucose decrease Lactate level = 37 mg/dL a. Viral meningitis b. CSF leakage c. Multiple sclerosis d. Bacterial meningitis
bacterial meningitis
Since Brucella species are facultative intracellular organisms that infect the reticuloendothelial system, specimens of choice for recovery include: a. urine and feces b. blood and bone marrow c. bronchoalveolar lavage and sputum d. seminal fluid or vaginal fluid
blood and bone marrow
Osteomyelitis can only be diagnosed by collection and subsequent culture of a sample collected from which source? a. bone b. CSF c. blood d. urine
bone
An immunosuppressed patient with a CSF shunt is exhibiting symptoms of a shunt infection. When performing a gram stain, the organism observed in teh image to the right is seeen. What is the most likely identity of this organism? (image description: large, budding gram positive cocci) a. candida sp. b. Staphylococcus sp. c. E. coli d. Enterococcus sp.
candida
Gram stain examination from a blood culture bottle shows dark blue, spherical organisms in clusters. Growth on sheep blood agar shows small, round, pale yellow colonies. Further tests should include: a catalase production and coagulase test b bacitracin susceptibility and serological typing c oxidase and deoxyribonuclease reactions d Voges-Proskauer and methyl red reactions
catalase production and coagulase test
Four specimens are received in the laboratory at the same time. The specimens are: Urine in specimen cup for urine culture Feces in preservative for stool culture Cerebrospinal fluid for culture Synovial Fluid for culture Which specimen should be processed first? a. urine b. feces c. cerebrospinal fluid d. synovial fluid
cerebrospinal fluid
Bacterial vaginosis is best diagnosed with: a. culture b. "sneeze" test c. Gram stain d. serology
gram stain
A stool specimen can be suspected of harboring Vibrio cholerae if it possesses which of the following characteristics? a. If the stool is well-formed and shows blood streaks b. If the stool is soft, dark, and positive for occult blood. c. if the ftool contains a high concentration of segmented neutrophils d. if the stool is watery with a high pH and flecks of mucous
if the stool is watery with a high pH and flecks of mucous
When following sentinel laboratory procedures and protocols, any isolate that cannot be ruled out as one of the "select agents" that might be used in acts of bioterrorism should be: a. immediately identified to the species level and reported to the LRN reference laboratory b. Definitively characterized as a "select agent" c. subjected to confirmatory testing in-house d. immediately referred to the nearest LRN reference laboratory
immediately referred to the nearest LRN reference laboratory
Blood culture bottles used in continuous monitoring systems, such as the BacTec, uses resins or charchoal to do which of the following? a. Inactivates and absorbs out complement b. Inactivates and absorbs out coagulation factors c. Inactivates neutrophils and monocytes d. Inactivates and absorbs out antimicrobial agents
inactivates and absorbs out antimicrobial agents
Sodium Polyanethol Sulfonate (SPS) is used as an anticoagulant for blood culture because it: a. Inactivates penicillin and cephalosporins b. prevents clumping of red cells c. inactivates neutrophils and components of serum complement d. facilitates growth of anaerobes
inactivates neutrophils and components of serum complement
Beta-hemolytic gram-positive cocci are isolated from the cerebrospinal fluid of a 2-day-old infant with signs of meningitis. The isolate grows on sheep blood agar under aerobic conditions and is resistant to a bacitracin disc. Which of the following should be performed for the identification of the organism? a. Oxidase production b. Catalase formative c. Latex antigen grouping d. Esculin hydrolysis
latex antigen grouping
A tech is working on a urine culture and finds the following isolate: Escherichia coli: 5000 CFU/mL How should the tech continue with the culture work up? a. perform sensitivity on E. coli b. reject the culture due to contamination c. report the culture as no growth d. list the E. coli as a possible contaminant
list the E. coli as a possible contaminant
Cerebrospinal fluid test results that are most consistent with viral meningitis include: a. decreased protein level b. increased glucose level c. increased lactate level d. lymphocytes predominant
lymphocytes predominant
When a corrected report needs to be made, which of the following is required? a. Correct the report and release results b. remove the erroneous report from the patient's record c. notify the physician of the erroneous report d. reissue the report; nothing else needs to be done
notify the physician of the erroneous report
Critical values not reported in a timely manner is an example of a laboratory error made during which phase of laboratory testing? a. centrifugation b. analytic c. postanalytic d. preanalytic
postanalytic
The saying, "if it wasn't recorded, it never happened" holds true in the microbiology laboratory because accrediting agencies require that detailed and accurate records be maintained. All of the following are purposes of record retention within the microbiology laboratory EXCEPT? a. Records provide a paper or electronic audit trail b. Records serve as a point of reference c. Records assit in identifying trends d. records are not important as computers store all the data
records are not important as computers store all the data
Gram positive cocci isolated from a catheterized urine culture on a 76-year-old male gave the following reactions: blood agar: creamy, white, opaque colonies which are not hemolytic catalase: positive slide coagulase negative tube coagulase negative novobiochin susceptible the next action that the medical laboratory professional should take is to: a. report the isolate as coagulase negative staphylococcus b. report the isolate as staphylococcus epidermidis c. report the isolate as staphylococcus saprophyticus d. perform further testing to speciate the organism
report the isolate as coagulase negative staphylococcus
Gram stain of a spinal fluid revealed pleomorphic, gram-negative rods. Colonies that appeared on chocolate agar after 24 hours of incubation were gray, opaque, and medium in size. A musty odor was noted when the plate was opened. Gram stain of the colonies on chocolate agar showed small, gram-negative coccobacilli. No growth was seen on sheep blood or MacConkey agar. The next step taken by the technologist to identify this isolate would be to show that the organism: a. Ferments lactose and produces indole b. decarboxylates lysine c. requires cysteine d. requires X and V factors
requires X and V factors
Isolation of Neisseria gonorrhoeae A. Is enhanced by cold enrichment B. Requires incubation under increased CO2 C. From contaminated sited is made easier by the use of CIN agar D. Is not affected if clinical specimen is refrigerated before culturing
requires incubation under increased CO2
When an unpreserved urine specimen cannot be cultured immediately, which storage method is most appropriate? a. stored at room temperature for up to 8 hours b. stored in the freezer for up to 24 hours c. stored in the incubator for up to 8 hours d. stored in the refridgerator at 4 C for up to 24 hours
stored in the refridgerator at 4 C for up to 24 hours
All of the following pose a significant risk of transmitting bloodborne pathogens, EXCEPT? a. bloody urine b. semen c. pleural fluids d. sweat
sweat
An expectorated sputum specimen is received for culture at your laboratory. You are preparing to make slides and inoculate the media and are observing the gross appearance of the specimen. The specimen is a mixture of watery, bloody, and purulent material. Which area(s) of the specimen is most likely indicated for culture and slides? a. any area is acceptable for culture and slide preparation b. only the watery portion of the specimen is most indicated for culture and slide preparation c. the bloody and purulent areas of the specimen are most idicated for culture and slid preparation d. an equal sampling of the watery, bloody, and purulent areas is most indicated for culture and slide prepartion
the bloody and purulent areas of the specimen are most idicated for culture and slid preparation
Upon review of a sputum Gram stain, the technician notes that the nuclei of all of the neutrophils present in the smear are staining dark blue. The best explanation for this finding is: a. the iodine was omitted from the staining procedure b. the slide was inadequately decolorized with acetone/alcohol c. the sputum smear was prepared too thin d. the cellular components have stained as expected
the slide was inadequately decolorized with acetone/alcohol
A vaginal swab for anaerobic culture is received in the laboratory. How should this specimen be handled? a. the specimen should be processed for culture b. the specimen should be rejected c. the order should be changed to an aerobic culture d. the specimen should be discarded
the specimen should be rejected
Organisms such as coagulase-negative Staphylococcus, Corynebacterium, and alpha streptococcus species are all found on the skin and represent normal skin flora. All of the following are functons of normal skin flora EXCEPT? a. They provide substances that are toxic to other organisms b. They inhibit the growth of more harmful microorganisms c. They provide a level of immunity to protect against the formation of infections d. They aid in the transmission of nosocomial infections
they aid in the transmission of nosocomial infections
What is the role of a sentinel laboratory within the Laboratory Response Network (LRN)? a. to make the decision that a bioterrorism event has occured and notify the press b. to rule out critical biological agents or to refer them to a Laboratory Response Network (LRN) reference laboratory c. to detect and confirm (rule-in) the presence of a threat agent d. to test environmental samples during a susected bioterrorism event
to rule-out critical biological agents or to refer them to a Laboratory Response Network (LRN) reference laboratory
A 25-year-old female presented in the emergency room with an acute urethral discharge of two days duration. The image shows the Gram-stained smear that was obtained. Many polymorphonuclear leukocytes and intracellular and extracellular gram-negative diplococci were observed. Based on the clinical history and the Gram stain obsevation, what diagnosis can be made? a. Neisseria gonorrhoeae infection b. Moraxella species infection c. Unable to determine the cause of infection d. trichomonas vaginalis infection
unable to determine the cause of infection
A woman came to see her physician as she was having vaginal/vulvar itching and some pain upon urination. To obtain a diagnosis of a yeast infection, which of the following is the test of choice? a. fungal culture b. wet preparation c. routine vaginal culture d. nucleic acid base test
wet preparation
