The proper blood-to-broth ratio for blood cultures to reduce the antibacterial effect of serum in adults is:, A. 1:2, B. 1:3, C. 1:10, D. 1:30, The most appropriate method for collecting a urine specimen from a patient with an indwelling catheter is:, A. Remove the catheter, cut the tip, and submit it for culture, B. Disconnect the catheter from the bag, and aseptically collect urine from the terminal end of the catheter, C. Aseptically collect urine directly from the drainage bag, D. Aspirate urine aseptically from the catheter tubing, Which of the following groups of specimens would be acceptable for anaerobic culture?, A. Vaginal swab, eye swab, B. Intraoral surface swab, leg tissue, C. Pleural fluid, brain abscess fluid, D. Urine, sputum, Sodium polyanetholsulfonate (SPS) is used as an anticoagulant for blood cultures 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, The optimal collection of a wound specimen for culture of anaerobic organisms is a:, A. Swab of lesion obtained before administration of antibiotics, B. Swab of lesion obtained after administration of antibiotics, C. Syringe filled with pus, obtained before administration of antibiotics, D. Syringe filled with pus, obtained after administration of antibiotics, The most important variable in the recovery of organisms in adult patients with bacteremia is:, A. A subculture of all bottles at day 5 of incubation, B. The recommended volume of blood cultured, C. Collection of daily blood culture sets for 3 consecutive days, D. Collection of multiple blood culture sets from a single venipuncture, Virus transport medium should contain agents that:, A. Enable rapid viral growth during the transport time, B. Inhibit bacterial and fungal growth, C. Destroy nonpathogenic viruses, D. Inhibit complement-fixing antibodies, A bronchoscopy sample with the request for culture of Legionella is sent to the laboratory. The correct plating protocol is:, A. Culture on thiosulfate citrate bile salt media, B. Incubate the culture media anaerobically, C. Reject the specimen and request a sputum sample, D. Culture on buffered charcoal yeast extract agar with antibiotics, A community hospital microbiology laboratory is processing significant numbers of stool cultures because of an outbreak of diarrhea following heavy rains and flooding. A media that should be incorporated in the plating protocol is:, A. Colistin nalidixic acid for Listeria, B. MacConkey agar with sorbitol for Campylobacter, C. Mannitol salt agar for Enterococcus species, D. Thiosulfate citrate bile salts sucrose for Vibrio species, A male urethral discharge specimen submitted for culture should be inoculated to:, A. Sheep blood and phenylethyl alcohol agars, B. Eosin-methylene blue and sheep blood agars, C. Thioglycolate broth and chocolate agar, D. Chocolate and modified Thayer-Martin agars, Which selective medium is used for the isolation of gram-positive microorganisms?, A. Columbia CNA with 5% sheep blood, B. Trypticase soy agar with 5% sheep blood, C. Eosin methylene blue, D. Modified Thayer-Martin, Campylobacter jejuni isolation requires the fecal specimen be:, A. Inoculated onto selective plating media and incubated in reduced oxygen with added CO₂ at 42°C, B. Stored in tryptic soy broth before plating to ensure growth of the organism, C. Inoculated onto selective plating media and incubated at both 35°C and at room temperature, D. Incubated at 35°C for 2 hours in Cary-Blair media before inoculating onto selective plating media, Which of the following specimen requests is acceptable?, A. Feces submitted for anaerobic culture, B. Foley catheter tip submitted for aerobic culture, C. Rectal swab submitted for direct smear for gonococci, D. Urine for culture of acid-fast bacilli, A cerebrospinal fluid specimen containing only 2 drops of CSF is collected by a lumbar puncture from a febrile 25-year-old male and is submitted for a stat Gram stain and culture. The direct specimen Gram stain is reported as many neutrophils and no microorganisms seen. The remaining drop of CSF should be inoculated to:, A. Blood agar, B. CNA agar, C. Chocolate agar, D. Thayer-Martin agar, A diabetic foot swab from an 82-year-old woman with recurrent infections is submitted for culture. The Gram stain reveals many neutrophils, no squamous epithelial cells, many gram-negative bacilli, many gram-positive cocci in chains. In addition to sheep blood, chocolate and MacConkey agar, the technologist might also process a(n):, A. Anaerobic blood agar plate, B. BCYE agar plate, C. CNA agar plate, D. XLD agar plate, Which of the following is the most appropriate specimen source and primary media selection?, A. CSF: Columbia CNA, MacConkey, B. Endocervical: chocolate, Martin Lewis, C. Sputum: sheep blood, Thayer-Martin, KV-laked blood, D. Urine: sheep blood, chocolate, Columbia CNA, Which of the following is the most appropriate organism and media combination?, A. Vibrio species—Skirrow, B. Enterohemorrhagic E. coli—phenylethyl alcohol (PEA), C. Campylobacter species—charcoal yeast extract, D. Yersinia enterocolitica—cefsulodin-irgasan-novobiocin (CIN), A Gram stain from 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, An organism that must be incubated in a microaerophilic environment for optimal recovery is:, A. Campylobacter jejuni, B. Escherichia coli, C. Pseudomonas aeruginosa, D. Proteus mirabilis, Vibrio parahaemolyticus is best isolated from feces on:, A. Eosin methylene blue (EMB) agar, B. Hektoen enteric (HE) agar, C. Salmonella-Shigella (SS) agar, D. Thiosulfate citrate bile salts (TCBS) agar, Media used to support growth of Legionella pneumophila should contain the additives:, A. X and V factors, B. Hemin and vitamin K, C. Charcoal and yeast extract, D. Dextrose and laked blood, The best medium for culture of Bordetella pertussis is:, A. Phenylethyl alcohol agar, B. Potassium tellurite blood agar, C. Regan-Lowe agar, D. Tinsdale agar, A 21-year-old patient presents with pharyngitis. A throat swab is collected and submitted for anaerobic culture. This specimen should be:, A. Set up immediately, B. Rejected as unacceptable, C. Inoculated into thioglycolate broth, D. Sent to a reference laboratory, An antibiotic used to suppress or kill contaminating fungi in media is:, A. Amphotericin B and penicillin, B. Chloramphenicol, C. Cycloheximide, D. Streptomycin, A sputum specimen is received for culture and Gram stain. The Gram-stained smear is seen in the image (total magnification 100x). The technologist's best course of action would be to:, A. Inoculate appropriate media and incubate anaerobically, B. Inoculate appropriate media and incubate aerobically, C. Call the physician and notify him of this "life-threatening" situation, D. Call the patient care area and request a new specimen, A vaginal/rectal swab is collected from a pregnant patient to screen for group B Streptococcus colonization. The best medium to inoculate the specimen to is:, A. CNA agar, B. LIM broth, C. Sheep blood agar, D. Thioglycolate broth, When processing a patient specimen for Gram stain and culture, the proper use of a biological safety cabinet includes:, A. Bringing into the cabinet all required media and equipment just prior to setting up each individual specimen, B. Keeping the ultraviolet light on for the first 30 minutes of working in the cabinet, C. Not using any heat generating equipment such as open flames or microburner/incinerators, D. Not disrupting the air curtain barrier by keeping air flow and exhaust grills unobstructed, A wound specimen grows 2 colony types on sheep blood agar and 1 clear colony type on MacConkey agar. Colony type #1 swarming over entire plate, Gram stain: gram-negative bacilli; colony type #2 white colony, Gram stain: gram-positive cocci in clusters. The best way to isolate colony type #2 from colony type #1 is to subculture:, A. Colony #1 to sheep blood and chocolate agars, B. Colony #1 to sheep blood and/or MacConkey agar, C. Colony #2 to sheep blood and chocolate agars, D. Colony #2 to CNA and/or PEA agar, A differential medium that can be used as a primary isolation agar producing predictable colored colonies that can be distinguished from other organism colony types describes:, A. Buffered charcoal yeast extract agar, B. Blood phenylethyl alcohol agar, C. Campylobacter blood agar, D. Chromagar, Anticoagulants acceptable for use with blood, bone marrow and synovial fluid specimens that are to be cultured include:, A. EDTA and sodium citrate, B. Heparin and sodium citrate, C. Sodium polyanethol sulfonate (SPS) and heparin, D. Sodium polyanethol sulfonate (SPS) and EDTA, Appropriate culture requirements for a specimen from a patient suspected of having tularemia include:, A media with cysteine such as buffered charcoal yeast extract agar, B. Colistin nalidixic acid agar, C. Mueller-Hinton agar with 5% sheep blood agar, D. Regan-Lowe media, The primary isolation of Neisseria gonorrhoeae requires:, A. Anaerobic conditions, B. Starch media, C. Carbon dioxide, D. Blood agar, Acceptable specimen sources for culture of anaerobic bacteria includes:, A. Sputum, B. Stool, C. Suprapubic bladder aspiration, D. Vaginal, In general, anaerobic infections differ from aerobic infections in which one of the following?, A. They usually respond favorably to aminoglycoside therapy, B. They usually arise from exogenous sources, C. They are usually polymicrobial, D. Gram stains of specimens are less helpful in diagnosis, An expectorated sputum is sent to the laboratory for culture from a patient with respiratory distress. The direct specimen Gram stain shows many squamous epithelial cells (>25/lpf) and rare neutrophils. This Gram stain is most indicative of:, A. A pneumococcal pneumonia, B. An anaerobic infection, C. A Haemophilus pneumonia, D. Oropharyngeal flora, Upon review of a sputum Gram stain, the technician notes that all the neutrophil nuclei in the smear stained dark blue. The best explanation for this finding is the:, A. Iodine was omitted from the staining procedure, B. Slide was inadequately decolorized with acetone/alcohol, C. Sputum smear was prepared too thin, D. Cellular components have stained as expected, The image depicts a Gram stain (final magnification 1000x) of a knee fluid from a patient who has recently undergone knee replacement surgery. The best interpretation of this Gram stain is:, A. Gram-positive cocci suggestive of Staphylococcus, B. Gram-positive bacilli suggestive of Corynebacterium, C. Gram-positive bacilli suggestive of Listeria, D. Gram-positive cocci suggestive of Streptococcus, The principal difference between the Ziehl-Neelsen acid-fast stain technique and the Kinyoun acid-fast stain technique is the:, A. Type of dyes used, B. Type of microscope used to interpret stained smears, C. Strength of acid decolorizer, D. Use of heat to allow the dye to penetrate organism, Relapsing fever in humans is caused by:, A. Borrelia recurrentis, B. Brucella abortus, C. Leptospira interrogans, D. Spirillum minus, Three sets of blood cultures are obtained from an adult patient with fever and suspected endocarditis. Growth in one aerobic bottle is seen after 5 days incubation, and the Gram stain is seen in the image. This indicates that:, A. There is low-grade bacteremia, B. The organism is most likely a contaminant, C. The patient has a line infection, D. The blood culture bottles are defective, 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, 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 agglutination test for Protein A, B. Bacitracin susceptibility and latex grouping, C. Oxidase and indole reactions, D. Voges-Proskauer and methyl red reactions, Gram-positive cocci in chains are seen on a Gram stain from a blood culture. The organism grows as a beta-hemolytic colony. Further tests that could be performed include:, A. PYR, bacitracin, and hippurate, B. Catalase and agglutination test for Protein A, C. Oxidase and mass spectrometry, D. Voges-Proskauer and methyl red, "Nutritionally variant" streptococci are:, A. Enterococci, B. Group D enterococci, C. Beta-hemolytic streptococci, D. In the genera Granulicatella and Abiotrophia, The most frequent cause of prosthetic heart valve infections occurring within 2-3 months after surgery is:, A. Streptococcus pneumoniae, B. Streptococcus pyogenes, C. Staphylococcus aureus, D. Staphylococcus epidermidis, Gram-positive cocci isolated from a blood culture have the characteristics: optochin susceptibility: negative; bacitracin (0.04 U) susceptibility: negative; bile esculin hydrolysis: negative; hippurate hydrolysis: positive; catalase: negative. This organism is most likely:, A. Staphylococcus aureus, B. Streptococcus pneumoniae, C. Streptococcus pyogenes, D. Streptococcus agalactiae, During the previous month, Staphylococcus epidermidis has been isolated from blood cultures at 2-3 times the rate from the previous year. The most logical explanation for the increase in these isolates is that:, A. The blood culture media are contaminated with this organism, B. The hospital ventilation system is contaminated with Staphylococcus epidermidis, C. There has been a break in proper skin preparation before drawing blood for culture, D. A relatively virulent isolate is being spread from patient to patient, A 55-year-old man becomes septic after a triple bypass procedure. Gram-positive cocci in clusters produce beta-hemolytic, catalase-positive colonies on sheep blood agar. Identify the organism and confirmatory test., A. Staphylococcus aureus and latex agglutination, B. Streptococcus pyogenes and PYR, C. Streptococcus agalactiae and latex agglutination, D. Enterococcus faecium and PYR, A patient with a prosthetic heart valve visits the dentist. She presents 2 weeks later with a high fever, chills, and shortness of breath and receives a diagnosis of subacute endocarditis. Which organism would be expected to grow?, A. Staphylococcus lugdunensis, B. Staphylococcus saprophyticus, C. Viridans streptococci, D. Streptococcus agalactiae, A blood culture from a 64-year-old male with lymphoma is positive at 18 hours. The organisms are nonlactose fermenting gram-negative bacilli on MacConkey agar. Oxidase: negative; TSI: alkaline/acid, no H₂S; motility: positive; indole: positive; citrate: positive; ornithine decarboxylase: negative; urea: positive; phenylalanine deaminase: positive; VP: negative. The genus is:, A. Morganella, B. Proteus, C. Providencia, D. Serratia, 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, incubated aerobically and anaerobically. After 24 hours, no growth is apparent. The next step should be to:, A. Subculture the bottle, and incubate in microaerophilic conditions, B. Assume the organism is nonviable, and ask for repeat specimen, C. Utilize the oxidase and indole test to detect Aeromonas, D. Subculture the bottle to a medium containing X and V factors, Which of these specimen types is considered to be the most sensitive for the recovery of Brucella in cases of chronic infection?, A. Blood, B. Urine, C. Bone marrow, D. Lymph node, A college student attends a beach party where raw oysters and other shellfish are consumed. The next day, he has symptoms of septicemia. Oxidase: positive; MacConkey agar: pink colonies; O/129 (150 μg): susceptible. The most likely organism is:, A. Aeromonas hydrophila, B. Pseudomonas putida, C. Serratia marcescens, D. Vibrio vulnificus, The laboratory receives a blood culture from a veterinarian who has been ill for many weeks with fevers, arthritis, and fatigue. The blood culture is positive after 5 days. Gram stain: small, gram-negative coccobacilli; sheep blood agar: growth after 48 hours with small, smooth, raised colonies. What should the microbiologist do next?, A. Consider the growth contamination and perform another Gram stain, B. Perform biochemical identification for HACEK organisms, C. Perform identification and susceptibility testing using an automated system, D. Take extra safety precautions for possible Brucella, Cutibacterium (formerly Propionibacterium) acnes is most often associated with:, A. Food poisoning, B. Post-antibiotic diarrhea, C. Tooth decay, D. Blood culture contamination, Which one of the following anaerobes is inhibited by sodium polyanethol sulfonate (SPS)?, A. Bacteroides fragilis, B. Cutibacterium acnes, C. Peptostreptococcus anaerobius, D. Veillonella parvula, A patient has a suspected diagnosis of subacute bacterial endocarditis. His blood cultures grow non-spore-forming pleomorphic gram-positive bacilli only in the anaerobic bottle. What test(s) will give a presumptive identification?, A. Beta-hemolysis and oxidase, B. Catalase and spot indole, C. Esculin hydrolysis, D. Hydrolysis of gelatin, Microorganisms resembling Mycoplasma pneumoniae have been isolated from the blood of patients treated with antibiotics that:, A. Complex with flagellar protein, B. Interfere with cell membrane function, C. Inhibit protein synthesis, D. Interfere with cell wall synthesis, 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, The organism most commonly associated with neonatal purulent meningitis is:, A. Neisseria meningitidis, B. Streptococcus pneumoniae, C. Group B streptococci, D. Haemophilus influenzae, 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 identification?, A. Oxidase production, B. Catalase formation, C. Latex antigen grouping, D. Esculin hydrolysis, A 4-year-old is admitted with symptoms of meningitis, and a Gram stain of the CSF reveals small, pleomorphic, gram-negative coccobacilli. After 24 hours at 35°C, small, moist, gray colonies are found on the chocolate agar plate only. Which biochemical data would be consistent with this isolate?, A. CTA dextrose positive; CTA maltose-positive; ONPG-negative, B. Sodium hippurate hydrolysis-positive; A disc negative; CAMP test positive, C. X factor: no growth; V factor: no growth; XV factor: growth; horse blood: no hemolysis, D. Catalase-positive; esculin hydrolysis-positive; methyl red positive; "umbrella" motility at 22°C positive, A technologist is reading a Gram stain from a CSF and observes many intracellular gram-negative diplococci. Which set of CSF results would most likely be seen?, A. Result a (increased WBC, increased glucose, increased protein), B. Result b (decreased WBC, decreased glucose, decreased protein), C. Result c (increased WBC, decreased glucose, increased protein), D. Result d (decreased WBC, increased glucose, decreased protein), An 18-year-old boy is admitted with suspected meningitis. He is lethargic and presents with a rigid neck. He has not had most recommended vaccines. 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, A 25-year-old man who had recently worked as a steward on a transoceanic grain ship presented with high fever, diarrhea and prostration. Axillary lymph nodes are hemorrhagic and enlarged. A Wright-Giemsa stain of the aspirate shows bacilli that are bipolar, resembling safety pins. The most likely identification is:, A. Brucella melitensis, B. Streptobacillus moniliformis, C. Spirillum minus, D. Yersinia pestis, Anaerobic gram-positive bacilli with subterminal spores are isolated from a peritoneal abscess. The colony has a swarming appearance. The most likely identification is:, A. Bacillus cereus, B. Clostridium septicum, C. Eggerthella lenta, D. Bifidobacterium dentium, A Gram stain of a peritoneal fluid shows large gram-positive bacilli. There is 3+ growth on anaerobic media only, with colonies producing a double zone of hemolysis. To assist with identification, the microbiologist could:, A. Determine if the organism ferments glucose, B. Perform the oxidase test, C. Set up egg yolk agar plate, D. Test for bile tolerance, An organism from a peritoneal abscess is isolated on kanamycin-vancomycin laked blood agar and grows black colonies on BBE agar. It is nonpigmented, catalase-positive, and indole-negative. The genus is:, A. Acidaminococcus, B. Bacteroides, C. Porphyromonas, D. Prevotella, Thin, gram-negative bacilli with tapered ends isolated from an empyema specimen grow only on anaerobic sheep blood agar. They are indole-positive, lipase-negative, and inhibited by 20% bile. The most probable identification is:, A. Bacteroides distasonis, B. Prevotella melaninogenica, C. Fusobacterium nucleatum, D. Clostridium septicum, A 10-year-old child with cystic fibrosis presents with cough and shortness of breath. Her sputum Gram stain is seen in the image. The best medium and incubation condition to optimize recovery of the organism is:, A. MacConkey agar incubated in CO₂, B. Tinsdale agar incubated in ambient air, C. Chocolate agar incubated in CO₂, D. CNA agar incubated in ambient air, A sputum culture from an alcoholic seen in the ER grows gray, mucoid, stringy colonies on sheep blood agar. The isolate grows readily on MacConkey agar and forms mucoid, dark pink colonies. ONPG: positive; indole: negative; glucose: positive; oxidase: negative; citrate: positive; VP: positive. The organism is most likely:, A. Edwardsiella tarda, B. Klebsiella pneumoniae, C. Escherichia coli, D. Proteus vulgaris, A patient with a nosocomial pneumonia has a sputum Gram stain showing many neutrophils and numerous small gram-negative coccobacilli. The organism grows as a mucoid, hemolytic colony on blood agar and as a colorless colony on MacConkey agar. Oxidase: negative; catalase: positive; nitrate: negative; ONPG: negative; ornithine decarboxylase: negative; lysine decarboxylase: negative. The organism is:, A. Stenotrophomonas maltophilia, B. Alcaligenes faecalis, C. Moraxella lacunata, D. Acinetobacter baumannii, Serum samples from a patient with pneumonia demonstrate a rising antibody titer to Legionella. A BAL specimen has a positive antigen test for Legionella, but no organisms are recovered on buffered charcoal yeast extract medium after 2 days of incubation. The best explanation is that the:, A. Antibody titer represents an earlier infection, B. Positive antigen test is a false-positive, C. Specimen was cultured on the wrong media, D. Culture was not incubated long enough, A 17-year-old female with cystic fibrosis is diagnosed with pneumonia. A sputum sample grows gram-negative bacilli with yellow, smooth colonies. Oxidase: positive; TSI: alk/alk; glucose: oxidized; fluorescence: negative; lysine decarboxylase: positive. The most likely organism is:, A. Burkholderia cepacia, B. Klebsiella pneumoniae, C. Shewanella putrefaciens, D. Stenotrophomonas maltophilia, A college student who recently studied abroad in Southeast Asia is admitted with a diagnosis of "glanders-like" infection (melioidosis). A sputum specimen grows small, gram-negative bacilli that are positive for oxidase, reduce nitrate to gas, and oxidize glucose, lactose, and mannitol. The most likely organism is:, A. Stenotrophomonas maltophilia, B. Burkholderia pseudomallei, C. Pseudomonas aeruginosa, D. Acinetobacter baumannii, An organism previously thought to be nonpathogenic, Moraxella catarrhalis, is now known to be associated with opportunistic respiratory infection. Characteristic identification criteria include:, A. Beta-lactamase-negative, B. Butyrate esterase-positive, C. Gram-negative bacilli, D. Oxidase-negative, An organism recovered from a sputum has the following characteristics: growth at 6 days on BCYE agar with CO₂ at 35°C; Gram stain: delicate branching gram-positive bacilli; modified acid-fast stain: branching, filamentous, "partially" acid-fast bacterium. These results are consistent with:, A. Nocardia, B. Mycobacterium, C. Actinomyces, D. Streptomyces, The Gram stain of drainage from a pulmonary sinus tract shows many WBCs and 3+ branching gram-positive bacilli. Colonies grow only on anaerobic media after 3 days incubation. They are yellow-tan and have a molar tooth appearance. The most likely genus is:, A. Actinomyces, B. Bacteroides, C. Fusobacterium, D. Nocardia, A 1-2 mm translucent, nonpigmented colony, isolated from an anaerobic culture of a lung abscess, fluoresces brick-red under ultraviolet light. A Gram stain reveals coccobacilli. Growth in bile: inhibited; vancomycin: resistant; kanamycin: resistant; colistin: susceptible; catalase: negative; esculin hydrolysis: negative; indole: negative. The identification is:, A. Bacteroides ovatus, B. Cutibacterium acnes, C. Prevotella melaninogenica, D. Porphyromonas asaccharolytica, Psittacosis is transmissible to man via contact with:, A. Insects, B. Birds, C. Cattle, D. Dogs, Which 2 diseases are usually preceded by infection with the organism seen in the image?, A. Rheumatic fever, undulant fever, B. Glomerulonephritis, rheumatic fever, C. Rheumatic fever, tularemia, D. Glomerulonephritis, undulant fever, A common cause of acute exudative pharyngitis is:, A. Staphylococcus aureus (beta-hemolytic), B. Streptococcus pneumoniae, C. Streptococcus agalactiae, D. Streptococcus pyogenes, A 15-year-old is admitted to the ER with severe sinusitis. Aspiration specimens from the nasal passage reveal a pure culture of alpha-hemolytic, depressed center colonies with a distinctive mucoid appearance on a blood agar plate. Which of the following could aid in identification?, A. Bile solubility, optochin sensitivity, B. Hippurate hydrolysis, bile esculin, C. Bacitracin sensitivity, Lancefield grouping, D. PYR positivity, catalase negativity, A 6-year-old male presents with a severe case of tonsillitis. The physician collects a throat swab and orders a GAS probe test. The probe comes back negative. A culture is requested. Results: catalase: negative; bacitracin disk: sensitive; hippurate hydrolysis: negative; CAMP test: negative; PYR: negative; Gram stain: gram-positive cocci in chains. Which organism is most likely causing the tonsillitis?, A. Group A beta-hemolytic streptococci, B. Group B beta-hemolytic streptococci, C. Group C beta-hemolytic streptococci, D. Group D beta-hemolytic streptococci, Small, pleomorphic gram-negative bacilli are isolated from an eye culture. They grow only on chocolate agar and are oxidase-variable. The most likely organism is:, A. Acinetobacter lwoffii, B. Haemophilus influenzae, C. Stenotrophomonas maltophilia, D. Pseudomonas aeruginosa, An isolate on chocolate agar from a patient with epiglottitis is suggestive of Haemophilus species. Additional testing shows that the isolate required NAD for growth and is nonhemolytic. The organism is most likely Haemophilus:, A. haemolyticus, B. ducreyi, C. influenzae, D. parainfluenzae, A 3-year-old unimmunized female presents to the ER with a severe cough, fever, and flu-like symptoms. A nasopharyngeal swab is planted on chocolate, Bordet-Gengou, and Regan Lowe media. After 5 days, colonies grow on all media, with growth on Bordet-Gengou described as "drops of mercury." The Gram stain shows minute coccobacilli that are catalase-positive and oxidase-positive. The most likely identification is:, A. Bordetella parapertussis, B. Yersinia pestis, C. Francisella tularensis, D. Bordetella pertussis, A Gram stain performed on a sinus aspirate reveals gram-negative diplococci and PMNs. Oxidase testing is positive and carbohydrate degradation tests are inert. The organism most likely is:, A. Neisseria lactamica, B. Moraxella catarrhalis, C. Neisseria meningitidis, D. Neisseria sicca, Establishing the pathogenicity of a microorganism isolated from a child's throat and identified as Corynebacterium diphtheriae would depend upon:, A. The morphological appearance as revealed by Gram stain, B. The type of hemolysis on blood agar, C. A positive toxigenicity test, D. The appearance of growth on Tinsdale tellurite agar, Chlamydia trachomatis infections have been implicated in:, A. LGV and conjunctivitis, B. Gastroenteritis and urethritis, C. Neonatal pneumonia and gastroenteritis, D. Neonatal meningitis and conjunctivitis, A liquid fecal specimen from a 3-month-old infant is submitted for culture. The stool culture should detect Salmonella, Shigella and:, A. Campylobacter species, B. Clostridium botulinum, C. Entamoeba hartmanni, D. Enterotoxigenic Escherichia coli, When performing a stool culture, a colony type typical of an enteric pathogen is subcultured on a blood agar plate. TSI: acid butt, alkaline slant, no gas, no H₂S; phenylalanine deaminase: negative; motility: nonmotile; serological typing: Shigella flexneri (subgroup B). The serological typing is verified with new kit and controls. The best course of action would be to:, A. Report the organism as Shigella flexneri without further testing, B. Verify reactivity of motility medium with positive and negative controls, C. Verify reactivity of the TSI slants with positive and negative controls for H₂S production, D. Verify reactivity of phenylalanine deaminase with positive and negative controls, MacConkey media for screening suspected cases of hemorrhagic E. coli O157:H7 must contain:, A. Indole, B. Citrate, C. Sorbitol, D. Lactose, An isolate from a stool culture gives: MacConkey agar: colorless colonies; Hektoen agar: yellow-orange colonies; TSI: acid slant/acid butt, no gas, no H₂S; urea: positive. These screening reactions are consistent with which enteric pathogen?, A. Yersinia enterocolitica, B. Shigella sonnei, C. Vibrio parahaemolyticus, D. Campylobacter jejuni, Which of the following organisms can grow in the small bowel and cause diarrhea in children, traveler's diarrhea, or a severe cholera-like syndrome through the production of enterotoxins?, A. Yersinia enterocolitica, B. Escherichia coli, C. Salmonella typhi, D. Shigella dysenteriae, Shigella species characteristically are:, A. Urease-positive, B. Nonmotile, C. Oxidase-positive, D. Lactose fermenters, Gram-negative bacilli have been isolated from feces, and the confirmed biochemical reactions fit those of Shigella. The organism does not agglutinate in Shigella antisera. What should be done next?, Test the organism with a new lot of antisera, B. Test with Vi antigen, C. Repeat the biochemical tests, D. Boil the organism and retest with the antisera, Biochemical reactions of an organism are consistent with Shigella. A suspension is tested in antiserum without resulting agglutination. However, after 15 minutes of boiling, agglutination occurs in group-D antisera. The Shigella species is:, A. dysenteriae, B. flexneri, C. boydii, D. sonnei, An 8-year-old girl is admitted with a 3-day history of fever, abdominal pain, diarrhea, and vomiting. A stool culture grows many lactose-negative colonies. Oxidase: negative; TSI: acid slant/acid butt; indole: negative; urease: positive; ornithine decarboxylase: positive; sucrose: positive; H₂S: negative; motility at 25°C: positive. The most probable identification is:, A. Escherichia coli, B. Providencia stuartii, C. Yersinia enterocolitica, D. Edwardsiella tarda, A fecal specimen inoculated to XLD and HE produced colonies with black centers. Additional testing: Glucose fermentation: positive; H₂S: positive; lysine decarboxylase: positive; urea: negative; ONPG: negative; indole: positive; polyvalent through group Vi: no agglutination. The most probable identification is:, A. Salmonella enterica, B. Edwardsiella tarda, C. Proteus mirabilis, D. Shigella sonnei.

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