15. What techniques are necessary for weak D testing?

6. Why is testing for Rh antigens and antibodies different from ABO testing?

14. What does the genotype —/— represent in the Rh system?

16. A patient types as AB and appears to be Rh positive on slide typing. What additional tests should be performed for tube typing?

7. Testing reveals a weak D that reacts 1+ after indirect antiglobulin testing (IAT). How is this result classified?

2. How is an individual with genotype Dce/dce classified?

4. Which donor unit is selected for a recipient with anti-c?

13. What antibodies could an R1R1 make if exposed to RR22 blood?

1. A complete Rh typing for antigens C, c, D, E, and e revealed negative results for C, D, and E. How is the individual designated?

17. According to the Wiener nomenclature and/or genetic theory of Rh inheritance:

8. What is one possible genotype for a patient who develops anti-C antibody?

3. If a patient has a positive direct antiglobulin test, should you perform a weak D test on the cells?

11. Which offspring is not possible from a mother who is R1R2 and a father who is R1r?

12. Why is testing a pregnant woman for weak D not required?

18. The Wiener nomenclature for the E antigen is:

20. Which technology may report an Rh-weak D positive as Rh negative?

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

10. A patient tests positive for weak D but also appears to have anti-D in his serum. What may be the problem?

7. Which of the following reagents is added to detect the production of indole?

9. Lysine iron agar (LIA) showing a purple slant and a blackened butt indicates:

4. At which pH does the methyl red (MR) test become positive?

10. Putrescine is an alkaline amine product of which bacterial enzyme?

19. A physician orders 2 units of leukocyte-reduced red blood cells. The patient is a 55-year-old male with anemia. He types as an AB negative, and his antibody screen is negative. There is only 1 unit of AB negative in inventory. What is the next blood type that should be given?

8. Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of:

2. The ortho-nitrophenyl-β-galactopyranoside (ONPG) test is most useful when differentiating:

21. Cold enrichment of feces (incubation at 4°C) in phosphate-buffered saline prior to subculture onto enteric media enhances the recovery of:

11. Which genera are positive for phenylalanine deaminase?

1. Biochemically, the Enterobacteriaceae are gram-negative rods that:

20. Fever, abdominal cramping, watery stools, and fluid and electrolyte loss preceded by bloody stools 2–3 days before is characteristic of shigellosis but may also result from infection with:

9. A patient developed a combination of Rh antibodies: anti-C, anti-E, and anti-D. Can compatible blood be found for this patient?

19. Which genera of Enterobacteriaceae are usually nonmotile at 36°C?

13. The malonate test is most useful in differentiating which members of the Enterobacteriaceae?

5. A positive Simmons citrate test is seen as a:

15. 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 serotyping?

12. Kligler iron agar (KIA) differs from triple-sugar iron agar (TSI) in the:

25. Which group of tests best differentiates Enterobacter aerogenes from Edwardsiella tarda?

3. The Voges–Proskauer (VP) test detects which end product of glucose fermentation?

18. Which of the following tests best differentiates Shigella species from E. coli?

28. Which of the following organisms is often confused with the Salmonella species biochemically and on plated media?

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

17. Which species of Shigella is most commonly associated with diarrheal disease in the United States?

22. Which group of tests, along with colonial morphology on primary media, aids most in the rapid identification of the Enterobacteriaceae?

14. Which genera of the Enterobacteriaceae are known to cause diarrhea and are considered enteric pathogens?

23. A routine, complete stool culture procedure should include media for the isolation of E. coli O157:H7 as well as:

31. Which of the following organisms, found in normal fecal flora, may be mistaken biochemically for the genus Yersinia?

26. Enterobacter sakazakii can best be differentiated from Enterobacter cloacae by which of the following characteristics?

16. Care must be taken when identifying biochemical isolates of Shigella because serological cross reactions occur with:

33. Which agar that is used for routine stool cultures is the medium of choice for the isolation of Yersinia strains from stool specimens?

30. Which single test best separates Klebsiella oxytoca from K. pneumoniae?

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

34. Which organism is sometimes mistaken for Salmonella and will agglutinate in Salmonella polyvalent antiserum?

36. Which of the following organisms are generally positive for β-galactosidase?

24. Which group of tests best identifies the Morganella and Proteus genera?

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

29. A gram-negative rod is recovered from acatheterized urine sample from a nursing home patient. The lactose-negative isolate tested positive for indole, urease, ornithine decarboxylase, and phenylalanine deaminase and negative for H2S. The most probable identification is:

38. The drugs of choice for treatment of infections with Enterobacteriaceae are:

40. Infections caused by Yersinia pestis are rare in the United States. Those cases that do occur are most frequently located in which region?

37. In the Kauffmann–White schema, the combined antigens used for serological identification of the Salmonella spp. are:

43. A stool culture from a 30-year-old man suffering from bloody mucoid diarrhea gave the following results on differential enteric media: MacConkey agar = clear colonies; XLD agar = clear colonies; Hektoen agar = green colonies; Salmonella–Shigella agar = small, clear colonies Which tests are most appropriate for identification of this enteric pathogen?

45. Three blood cultures taken from a 30-year-old cancer patient receiving chemotherapy and admitted with a urinary tract infection grew lactose-negative, motile, gram-negative rods prior to antibiotic therapy. Given the following biochemical reactions, which is the most likely organism? H2S (TSI) = + Indole = + MR = + VP = Neg Citrate = Neg Urease = + DNase = + Phenylalanine deaminase = + Gelatin hydrolysis = + Ornithine decarboxylase = Neg

41. 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; VP = + Citrate = + H2S = Neg; Urease = + Motility = Neg. Antibiotic susceptibility: resistant to carbenicillin and ampicillin

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

39. The Shiga-like toxin (verotoxin) is produced mainly by which Enterobacteriaceae?

47. A 6-year-old female patient was admitted to the hospital following 2 days of severe diarrhea. Cultures from three consecutive stool samples contained blood and mucus. Patient history revealed a hamburger lunch at a fast-food restaurant 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 colonies Mac with sorbitol agar – few dark pink and many colorless colonies

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

2. For which clinical specimens is the KOH direct mount technique for examination of fungal elements used?

51. Which isolates of the Enterobacteriaceae family most commonly produce extended-spectrum β-lactamase (ESBL)?

50. Direct spread of pneumonic plague disease occurs by which route?

44. A leg-wound 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 = + DNase = + Citrate = + Urease = Neg Phenylalanine deaminase = Neg Ornithine and lysine decarboxylase = + Arginine decarboxylase = Neg Gelatin hydrolysis = +

1. All of the following are examples of appropriate specimens for the recovery of fungi except:

12. Arthroconidia production is used to differentiate which two yeast isolates?

3. The India ink stain is used as a presumptive test for the presence of which organism?

10. Which of the following yeast enzymes is detected using birdseed (niger seed) agar?

11. Which of the following yeasts is characteristically positive for germ tube production?

4. Cutaneous disease involving skin, hair, and nails usually indicates an infection with a:

42. Four blood cultures were taken over a 24-hour period from a 20-year-old woman with severe diarrhea. The cultures grew motile (room temperature), gram-negative rods. A urine specimen obtained by catheterization 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 decarboxylase = + Phenylalanine deaminase = Neg

21. Dimorphic molds are found in infected tissue in which form?

48. Following a 2-week camping trip to the Southwest (US), a 65-year-old male patient was hospitalized with a high fever and an inflammatory swelling of the axilla and groin lymph nodes. Several blood cultures were obtained, resulting in growth of gram-negative rods resembling “closed safety pins.” The organism grew on MacConkey’s agar showing non–lactose-fermenting colonies. Testing demonstrated a nonmotile rod that was biochemically inert. What is the most likely identification?

7. Cornmeal agar with Tween 80 is used to identify which characteristic of an unknown yeast isolate?

13. The urease test, niger seed agar test, and the germ tube test are all used for the presumptive identification of:

5. What is the first step to be performed in the identification of an unknown yeast isolate?

14. Which of the following yeasts produces only blastoconidia on cornmeal Tween 80 agar?

6. An isolate produced a constriction that was interpreted as a positive germ tube, but Candida albicans was ruled out when confirmatory tests were performed. Which of the following fungi is the most likely identification?

20. A blood agar plate inoculated with sputum from a patient with diabetes mellitus grew very few bacterial flora and a predominance of yeast. Given the following results, what is the most likely identification of the yeast isolate? CORNMEAL TWEEN 80 AGAR Germ tube = Neg Pseudohyphae = + Arthroconidia = Neg Blastoconidia = + (arranged along pseudohyphae) Chlamydospores = Neg

8. Blastoconidia are the beginning of which structures?

15. Ascospores are formed by which yeast isolate?

9. An isolate from CSF growing on cornmeal agar produces the following structures. Which tests should be performed next? : Blastoconidia = + Pseudohyphae = Neg Chlamydospores = Neg Arthroconidia= Neg

19. Yeast recovered from the urine of a catheterized patient receiving chemotherapy for cancer gave the following results: What further testing is necessary? CORNMEAL TWEEN 80 AGAR Germ tube = + Blastoconidia = + Pseudohyphae = + Arthroconidia= Chlamydospores Neg = +

22. The mycelial form of which dimorphic mold produces thick-walled, rectangular, or barrel-shaped alternate arthroconidia?

23. The yeast form of which dimorphic fungus appears as oval or elongated cigar shapes?

18. Carbohydrate assimilation tests are used for the identification of yeast isolates by inoculating media:

24. The mycelial form of Histoplasma capsulatum seen on agar resembles:

17. Chlamydospore production is demonstrated by which Candida species?

25. The yeast form of which dimorphic mold shows a large parent yeast cell surrounded by smallerm budding yeast cells?

26. Which group of molds can be ruled out when septate hyphae are observed in a culture?

27. Tinea versicolor is a skin infection caused by:

16. A germ tube–negative, pink yeast isolate was recovered from the respiratory secretions and urine of a patient with AIDS. Given the following results, what is the most likely identification? CORNMEAL TWEEN 80 AGAR Blastoconidia = + Pseudohyphae = Neg Arthroconidia= Neg Urease = +

31. Microscopic examination of a fungus cultured from a patient with athlete’s foot showed large, smooth-walled, club-shaped macroconidia appearing singly or in clusters of two to three from the tips of short conidiophores. The colonies did not produce microconidia. What is the most likely identification?

29. An organism cultured from the skin produces colonies displaying a cherry-red color on Sabouraud dextrose agar after 3–4 weeks and teardrop-shaped microconidia along the sides of the hyphae. The most likely identification is:

37. Which Aspergillus species, recovered from sputum or bronchial mucus, is the most common cause of pulmonary aspergillosis?

36. Which dematiaceous mold forms flask-shaped phialides, each with a flask-shaped collarette?

30. Which Microsporum species causes an epidemic form of tinea capitis in children?

28. Which of the following structures is invaded by the genus Trichophyton?

32. Which Trichophyton species causes the favus type of tinea capitis seen in the Scandinavian countries and in the Appalachian region of the United States?

34. A mold that produces colonies with a dark brown, green-black, or black appearance of both the surface and reverse side is classified as a:

38. A hyaline mold recovered from a patient with AIDS produced rose-colored colonies with lavender centers on Sabouraud dextrose agar. Microscopic examination showed multiseptate macroconidia appearing as sickles or canoes. What is the most likely identification?

42. A bone marrow sample obtained from an immunocompromised patient revealed small intracellular cells using a Wright’s stain preparation. Growth on Sabouraud–dextrose agar plates of a mold phase at 25°C and a yeast phase at 37°C designates the organism as dimorphic. The mold phase produced thick, spherical tuberculated macroconidia. What is the most likely identification?

35. A rapidly growing hyaline mold began as a white colony but soon developed a black “pepper” effect on the agar surface. The older colony produced a black matte, making it resemble a dematiaceous mold. What is the most likely identification?

33. The Hair Baiting Test is used to differentiate which two species of Trichophyton that produce red colonies on Sabouraud agar plates?

45. A bone marrow specimen was obtained from an immunocompromised patient who tested positive for HIV. The organism grew rapidly at 3 days showing a mold form (at 25°C), displaying conidiophores with four to five terminal metulae with each having four to six phialides. The conidia at the end of the phialides were oval and in short chains. They appear as a fan or broom when viewing under 10× and 40×. At 37°C, the yeast form grew more slowly, showing conidia that formed hyphal elements breaking at the septa to produce oval arthroconidia. This thermodimorphic mold is most likely:

39. Material from a fungus-ball infection produced colonies with a green surface on Sabouraud agar in 5 days at 30°C. Microscopic examination showed club-shaped vesicles with sporulation only from the top half of the vesicle. This hyaline mold is most probably which Aspergillus spp.?

44. Upon direct examination of a sputum specimen, several spherules were noted that contained endospores. Growth on Sabouraud–dextrose agar showed aerial mycelial elements. The septate hyphae produced barrel-shaped arthroconidia. What is the most likely identification?

43. A lung biopsy obtained from an immunocompromised patient showed many “cup-shaped” cysts (gray to black) in a foamy exudate (green background) using Gomori methenamine silver (GMS) stain. The organism cannot be cultured because it does not grow on routine culture media for molds. The patient was diagnosed with pneumonia that resisted antibiotic treatment. The most likely identification is?

41. An India ink test was performed on CSF from an HIV-infected male patient. Many encapsulated yeast cells were seen in the centrifuged sample. Further testing revealed a positive urease test and growth of brown colonies on niger-seed agar. The diagnosis of meningitis was caused by which yeast?

46. What is the specimen of choice for the initial diagnosis of Pneumocystis jirovecii (carinii) in an immunocompromised patient, such as someone with AIDS?

47. A transplant patient is suspected of having invasive aspergillosis on the basis of clinical and radiological findings. Which specimen is best for the initial identification of aspergillosis by soluble antigen testing?

49. A thermally dimorphic fungus shows a filamentous mold form with tuberculate macroconidia at room temperature, and a yeast form above 35°C. Which organism best fits this description?

40. A rapidly growing nonseptate mold produced colonies with a gray surface resembling cotton candy that covered the entire plate. Microscopic examination revealed sporangiophores arising between, not opposite, the rhizoids and producing pear-shaped sporangia. What is the most likely identification?

50. SITUATION: After a vacation to the Southwestern United States, a midwesterner complained of flulike symptoms with fever, chills, nonproductive cough, and chest pain. Microscopic exam of sputum, cleared with KOH, revealed large, thick-walled spherules containing endospores. Upon culture, the mold phase showed septate hyphae and alternating barrel-shaped arthroconidia. Which organism is most likely the cause of this pneumonia?

48. What is the most common cause of mucormycosis infection in humans?