AAB MT Microbiology 2023 |215 questions with 100% correct answers

What term describes the morphology of organisms that vary in shape and size? Pleomorphic Capsules are the basis of which test? Serotyping A mucoid colony on blood agar medium indicates that which of the following characteristics may be present? Organism has a capsule. What are dark staining granules called? Metachromatic Which of the following organisms are non-motile? Shigella and Klebsiella In the bacterial growth cycle, growth ceases because nutrients are exhausted or toxic metabolic products have accumulated in which phase? Stationary phase Which of the following genera of bacteria form spores? Bacillus and Clostridium What term is used to describe bacteria that grow in the absence of atmospheric oxygen and obtain oxygen from oxygen-containing compounds? Anaerobes What is the temperature at which bacteria grow best known as? Optimum On blood agar plates a small zone of alpha hemolysis surrounded by a zone of beta hemolysis after refrigeration is known as what type of hemolysis? Alpha-prime hemolysis What is the most effective method of sterilization? Autoclaving Which of the following is used for quality control for the dry heat oven? Bacillus subtilis Media that cannot be heated can be sterilized by what alternate method? Filtration Which one of the following disinfectants is the most effective germicide against bacteria, spores, tubercle bacilli, fungi, and viruses? Chlorine What is a term that describes a process or treatment that renders a medical device, instrument, or environmental surface safe to handle? Decontamination What color do gram-positive bacteria stain? Purple Acid-fast bacteria appear what color microscopically? Red Acid-fast organisms in tissue are best stained by which of the following methods? Kinyoun Which of the following should be used to remove antimicrobials before culturing? Antimicrobial removal device Which statement concerning sodium polyanethol sulfonate (SPS) is NOT true? Activates some antimicrobials What are some functions of sodium polyanethol sulfonate (SPS)? Prevents blood from clotting, prevents phagocytosis, and neutralizes the bactericidal effect of human serum. What is the most abundant normal flora in throat cultures? Alpha-hemolytic streptococci Why is it recommended to stab the blood agar plate when setting up throat cultures? Some streptococci may not produce beta hemolysis under aerobic conditions. What is the most common pathogen is throat cultures? Streptococcus pyogenes Nasopharangeal swabs are recommended for the detection of which carriers? H. influenzae, N. meningitidis, and B. pertussis Why is a first morning urine specimen preferred for urine cultures? Specimen is more concentrated. What indicates vaginal or urethral contamination of urine? Greater than 10 squamous epithelial cells per hpf. How are smears of cerebrospinal fluid prepared? Centrifuged CSF sediment Smears of CSF are usually stained with which stain? Gram stain Which of the following tests for bacterial antigen on cultures isolated from CSF is more sensitive and faster? Latex agglutination tests Which of the following is not the cause of a venereal disease? Haemophilus aegyptius A positive coagulase test is observed for which of the following? Clotting of plasma What is the preferred method of differentiating S. aureus from S. epidermidis? Coagulase test A colony of nonhemolytic, catalase-positive, coagulase negative, GPC is most likely to be which organism? Staphylococcus epidermidis When performing a bacitracin differentiation test for Group A beta-hemolytic streptococci, disks should be used that have how many units? 0.02-0.04 unit Hippurate hydolysis is used to differentiate which organisms? Group A streptococci from Group B streptococci If pneumococci are resistant to penicillin, then they should be tested for which of the following? Beta-lactamase production Beta-lactamases Enzymes produced by some bacteria which provide resistance to beta-lactam antibiotics like penicillins, cephamycins, and carbapenems. Common Beta-lactamase positive organisms S. epidermidis, P. aeruginosa, K. pneumoniae, and E. coli What is the most probably identity of a bile-esculin positive, beta-hemolytic streptococci that grows in 6.5% NaCl? Enterococci The bile-esculin test is used to differentiate which two organisms? Group D Streptococci and Enterococci An oxidase-positive, Gram-negative cocci from a throat culture might be which organism? Neisseria Oxidase test A test used in microbiology to determine if a bacterium produces certain cytochrome c oxidases. The reagent is a dark-blue to maroon color when oxidized, and colorless when reduced. Oxidase-positive organisms Neisseria, Moraxella, H. pylori, V. cholera, C. jejuni, Aeromonas, and L. pneumophila Oxidase-negative organisms Enterobacteriaceae (Salmonella, E. coli, Y. pestis, Klebsiella, Shigella, Proteus, Enterobacter, Serratia, and Citrobacter) and Haemophilus A fastidious, oxidase-positive, Gram-negative cocci from a rectal swab might be presumptively identified as which organism? Neisseria gonorrhoeae