Microbiology and Parasitology 1. Which of the following characteristics is used to characterize Staphylococcus aureus? a.“Pitting” on sheep blood agar b. Fermentation of mannitol c. Positive catalase test d. Positive coagulase test 2. To differentiate between a coagulase – negative staphyloccus species and a micrococcus species, which of the following tests can be used? a. Furazolidone susceptibility b. Catalase c. Novoblocin susceptibility d. Urease 3. A pustule drainage submitted for culture is plated onto primary media. After an 18-h incubation, the sheep blood agar plate reveals a predominance of beta- haemolytic, white porcelain colonies. Gram stain shows gram positive cocci. The colonies test catalase – positive. The most appropriate test for additional identification of the isolate is a. Bacitracin b. Bile esculin c. Bile solubility d. Coagulase 4. A 43-year-old female patient complains of a very sore throat. The throat swab that is submitted for routine culture grows a variety of diphtheroids: alpha, beta and nonhemolytic streptococci; staphylococci and Neisseria. The next step is to a. Report it as normal throat flora b. Ask for a repeat collection to get a better specimen c. Identify the beta – haemolytic streptococcus species d. Identify the neisseria species 5. A nasopharyngeal culture grows a predominance of a beta –hemolytic colony type on sheepbl;ood agar at 18 h. The isolate is susceptible to a 0.04 unit of bacitracin. The most likely identification is beta-hemolytic streptococcus. a. Group A b. Group B c. Group D d. Not group A, B or D 6. Which of the following is not consistent with streptococcus pneumoniae a. Alpha hemolysis on sheep blood agar b. Bile solubility positive c. Gram positive, oval shaped cocci in pairs d. Positive catalase test 7. Neisseria species can be identified an differentiated by a. Bile-esculin hydrolysis Listeria monocytogenes d. Escherichia coli b. Sheep – blood agar d. Throat swab Family characteristics of enterobacteriaceae include a. b. Thioglycollate broth On a sheep blood agar plate. the isolated organism grows on sheep-blood agar as a large. Escherichia coli b. 12. Nasopharyngeal swab d. gray colony. Spore former c. Enterobacter aerogenes d. Aureus The specimen of choice for the isolation of Bordetella pertussis from a suspected case of whooping cough is a. Formation of indophenols oxidase d. In each instance. Additional biochemical results are as follows: Phenylalanine deaminase (PAD): negative Urease: negative Hydrogen sulphide (H2S): negative Omithine decarboxylase: positive Lysine decarboxylase: positive Indole: positive Citrate:Negative. pink colony. S. Blood b. Parainfluenza d. haemophilus influenza satellites around colonies of a. Carbohydrate utilization c. The oxidase-negative. Nitrate test d. gram negative and produces the same biotype and is resistant only to tetracycline. S. CSF c. flat. 10. Oxidase test A small gram positive rod that causes neonatal meningitis and septicaemia is a. H. 9. Agalactiae The X and V factors required for growth of haemophilus influenza are contained in a. Pyogenes c. Fermentation of glucose b. Diptheroids b.8. C. S. The most probable organism is a. Brain/ heart infusion broth b. Chocolate agar c. 11. Enterobacter vulgaris . Diptheriae c. and on MacConkey agar as a large. Enterobacter cloacae c. Failures to reduce nitrates Twenty parents on a surgical ward develop urinary tarct infections after catheterization. 13. lactose positive colony type on Macconkey agar that is indole – negative and citrate – positive. gram-negative rod gives the following biochemical reactions: Phenylalanine deaminase (PAD): positive Ornithine: positive Hydrogen sulphide (H2S)P: positive Indole: negative Urease: positive Citrate: positive Lysine: negative. Enterobacter aerogenes 15. The organism described is: a. Urinary tract 16. and non-motile is a. and retype in Salmonella polyvalent antiserum d. Citrobacter freundi b. Pseudomonas 19. Clostridium perfringens appears as a . Other characteristic observations are: Triple sugar iron K/K Motility: positive Oxidase: positive Oxidative/fermentation glucose: oxidative utilization only The most probable genus of this isolate is a. After 48 h of incubation on anaeropbic sheep-blood agar. What is the next step in the definitive identification of this organism? a. and proteus species are common flora of the a. A gram-negative rod is isolated from a patient with second. K.and third-degree burns. A discharge from an infected ear grows a colorless colony type of MacConkey agar that swarms on sheep-blood agar. Escherichia coli b. Boil a saline suspension of the organism for 15 min. A mucoid. This oxidase-negative. Proteus mirabilis d. Retest the isolate using the individual somatic antisera from each sergroup. Proteus vulgaris 17. cool. Pneumonia c. Gastrointestinal tract b. Escherichia. Superficial skin surfaces d. The isolate produces a bluish green pigment and a characteristic fruity odor. Respiratory tract c. Alcaligenes c. Report the organism as a Salmonella polyvalent O-positive species and send the isolate elsewhere for additional identification b. Morganella morganii c. A gram – negative rod biochemically compatible with the genus salmonella fails to agglutinate in the polyvalent somatic antisera for Salmonella serotyping. A through E 18. Enterobacter cloacae d.14. Klebsiella. Acinetobacter b. Wash a suspension of the isolate in saline and retest it in the Salmonella polyvalent antiserum c. Moraxella d. Use of a refrigerated centrifuge with bucket covers b. flat colony with a double zone of hemolysis b. RED c. microerophilic environment d. Gray. streptococci and Neisseria will be stained. Purple and purple c. Use of concentrated potassium hydroxide for decontamination procedure d. iNcubation at 35-37oC b.20. Buffer b. Large. a. Differential and enriched . Decontaminant c. the N-acetyl-L cysteine serves as a a. butyrous. 15 psi at 200oF for 15 min d. BLUE b. mucoid colony witha zone of alpha hemolysis d. 10 psi at 121oC for 10 min c. Colony with a pearllike surface and a single sone of beta hemolysis Isolation of campylobacter jejuni from a patient with gastroenteritis is optimized by a. All of the following are standard protocol for processing this specimen except: a. An anaerobic environment without CO2 In the N-acetyl-L-cysteine-alkali method of processing sputum specimens for mycobacterial culture. 23. nonhemolytic colony with a glistening surface c. White. 21. respectively a. PUrple and red b. 10 psi at 220oF for 10 min When acetone – alcohol is inadvertently omitted from the gram – stain procedure. Selective enrichment in selenite broth c. COLORLESS d. Use of both liquid and solid media for setup of AFB culture c. GREEN MacConkey agar is sued for isolation of members of the family enterobacteriaceae because the medium ios a. Digestant d. Use of a laminar flow biological safety cabinet for processing the specimen Routine sterilization of artificial culture media by autoclaving is recommended at a. Inhibitory and differential b. 25. 24. Red and red d. Red and purple He color of a non acid fast bacilluys following the acid-alcohol steop and before conterstanding in the acid-fast stain procedure a. pH stabilizer A sputum specimen is submitted to the laboratory accompanied by a request for an AFB culture. 15 psi ast 121oC for 15 min b. 22. 26. If the specimen cannot be oplated immediately. 28. c. Enriched and selective d. Streptococcus pneumoniae from alpha-hemolytic streptococci c. P-aminodimethylbenzadehyde c. Citrate is the only source of carbon in the medium c. Decarboxylase lysine c. 33. In the 35oC incubator . Sulfanilic acid and alpha – napthylamine b. In the refrigerator c. Group D enterococci from group-D nonenterococci A lysine-iron agar (LIA) slant shows a red slant over a yellow butt. 2:1 c. Ferric chloride To eliminate the antibacterial properties of blood and simultaneously introduce an adequate volume of blood for recovery of microorganisms from septicaemia. Enterobacteriaceae from non-Enterobacteriaceae d. Peritoneal fluid d. Produce H2S Which of the following statements regarding Simmmon’s citrate agar is incorrect a. 10:1 Which of the following specimens is acceptabkle for the evaluation of clinically important anaerobes a. This reaction indicates that the organism a. Glucose is the carbohydrate in the medium d. the recommended blood-tobroth ratio in the blood-culture bottle is approximately a. Deaminase lysine b. Catalase-positive Streptococcus species from catalase-negative Staphylococcus species b. it should be held a. Alpha-naphthol and potassium hydroxide d. 1:10 d. At room temperature d. Selective and supplemented Ethylhydrocupreine hydrochloride (optochin) is a chemical used to differentiate a. 32. In the freezer b. Superficial wound A urine is received in the laboratory for culture. Growth on the slant is interpreted as a positive reaction The reagent(s) used to detect a positive phenylalanine –deaminase reaction is (are) a. Feces b.27. 29. Sputum c. 30. 31. 1:2 b. Ferments lactose d. Blue color is an alkaline reaction b. E of Mueller-hinton media b.coli 37. Paeilomyces c. Pyogenes 36. The pair of organisms that would provide a good positive and negative control for phenylethyl – alcohol “(PEA) blood agar is a. Catalase S. Rhodotorula d. Cryptococcus b. Incubation in 8-10% CO2 35. Clear and dissolve debris d. PSeudomonas aeruginosa and Escherichia coli b. The function of 10% potassium hydrosxxide in the direct examination of skin. The most likely identification of this isolate is a. Aureus S. Fix preparation for subsequent staining 40. Trichosporonm beigelli . hair and nail scrapings is to a. Scopulariopsis 38. Indole E. Coli d. Saccharomyces 39. This isolate most likely belongs to the genus a. On lactopherol cotton blue prparationm. A potentially pathogenic yeast that is normal flora in the oropharyngeal cavity and may produice thrush is a. skin. Haemop-hilus influenzae and Streptococcus pyogenes c. blue – green spores. swollen – tipped conidiophores bear sterigmata and conidia in chains. A fungal colony grows rapidly on Sabouraud’s dextrose agar as a white colony tyope with a dense production of aerial. Standardized testing conditions for the Kirby-Bauer agar-disk diffusion antimicrobial susceptibility test include all of the following except: a. Standard inoculums size c. Epidermidis d. Aspergillus b. Staphylococcus aureus and WS. Kill contaminating bacteria c. Oxidase Pseudomonas aeruginosa E. Coli proteus vulgaris c. Geotrichum c. Gram stain E. Penicillium d. Incubation at 35oC d. Eneterococcus and E.coli Neisseria meningitides b. Reserve fungal elements b. A saprobic yeast that inhabits airborne dust. and mucosa grows rapidly and oproduces an orange – to – red color. Which of the following organism will give the appropriate positive and negative reactiosn for quality control of the test listed Positive Negative a.34. Trichuris trichuria The direct iodine preparation is best used to detect protozoan a. Increased acidity due to the release of penicillin acid . Albicans c. Cryptococcus neoformans d. In general. Zone of susceptibiklity around an ampicillin disk b. Entamoeba c. The most probable identity of the cyst is a. Entamoeba histolytica b. The parasite is a. Geotrichum In an iodine preparation of feces. Ascaris b. 43. b. Cysts d. Hookworm c. 70oC Procedure that directly determines beta lactamas eproduction by microorganism is based on detection of a(n) a. 35oC b.41. Ascaris lumbricoides d. Are true bacteria b. Giardia d. Entamoeba coli d. C. 20oC d. Produce intracellular inclusions d. 46. 47. the optimal temperature for holding this specimen is a. 42. Zone of inhibition around an oxacillin disk c. Are obligate intracellular organisms c. Plasmodium Chlamydia differ from viruses in that chlamydiae a. Trophozoites c. Enterobius vermicularis b. with one flattened side and usually. Are isolated in tissue – culture systems A specimen for viral culture is collected on a Friday and must be held for processing until the next day. Entamoeba hartmanni The infective stage of this parasite consists of an egg with a thin hyaline shell. an amoebic cyust appears to have a single nucleus with a large karyosome and chromatin bodies do not appear along the nuclear membrane. 45. Iodamoeba butschii c. 44. A large glycogen mass that stains reddish brown occupies the cytoplasm. a fully developed larva within. Larvae Parasites that are detected by direct visualization in the peripheral blood smear are a. 4oC c. Eggs b. The catalase test is positive and modified oxidas etest is negative. Increase in pH due to teh reduction of iodine In a broth-dilution method of antimicrobial susceoptibility testing. now they present with different clinical symptoms. Micrococcus sp. Colorless c. 51. The agent that produces the toxin is a. Glucose degradation . Clostridium tetani d. Clostridium botulinum c. The sister complains of fever and joint pains and has carditis. 53. colonies of Vibrio cholera appear a. Inhibitory concentration d. white and beta hemoplytic. S. Bacteriocidal concentration c.ts-sucrose (TCBS) agar. Scarlet efever and erysipelas Purulent material is obtained from a carbuncle and submitted for bacterial cuklture. Saprophyticus On thiosulfate-citrate-bile-sal. Although the slide coagulase test is negative. d. the tube with the lowest concentration of antimicrobial in which there is no visible growth is the minimal a. The most probable identity iof this sioalte is a. Bacillus cereus b.epidermidis d. The brother displays edema and hypertension.48. Lethal concentration This adult disease results from performed neurotoxin that is ingected and causes symptoms of neuromuscular flaccid paralysis. The single best test to distionguish between these organisms is a. 52. S. S. Both had antecedent sore throats about 2 to 3 weeks earlier that grew beta – haemolytic streptococci. Aureus c. Antimicrobial concentration b. Glomerulonephritis and rheumatic fever c. b. Olive green d. The disease that these siblings have are most likely a. The culture shows growth in the primary broth and on the sheep – blood agar plate and no growth on teh <acConkey agar plate. Rheumatic fever and scarlet fever d. The direct smear reveals many gram – positive cocci adn WBCs. and RBC casts are seen in the urine. Black A gram-negative coccobacillary organism that is isolated from synovial fluid on chocolate agar resembles either a moraxella species or Neisseria gonorrhoeae. 50. Erysipelas and glomerulonephritis b. Yellow b. the tube coagulase test is positive. The colonies on the blood agar plate are butyrons. 49. Staphylococcus aureus Two siblings arrive at the emergency room. Beta hemolysis b. The direct gram’s stain of tyhe CSF reveals small gram positive rods and numerous WBCs. urease – positive in 1 to 2 h. . Hippurate hydrolysis d. The isolate produces catalase. Blood cultures from this patient yield an organism that shows the following characteristics: requires an atmosphere of 10% CO2. small translucent colonies with narrow zone of beta hemolysis grow on sheepblood agar. Metachromatic granulation c. Tumbling motility b. A dair farmer weho has an intermittent fever. progressive weakness and night sweats is suspected of having undulant fever. Motility d. A lumbar puncture is performed on an 82-year-old woman who is receiving immunosuppressive therapy. H2S production on TSI agar 55. At 18 h. grows in the presence of thionine dye but not in the presence of fuchsin. Identification of this isolate could be made by demonstration of a. Which of the following is described there a.c. Oxidas eproduction 54.