MT AAB Study guide quizlet cards |1764 questions and answers 2023.

What term describes the morphology of organisms that vary in shape and size? Pleomorphic i.e. coccobacilli Bacteriology arrangements: -pairs (diplococci "N. Gon"; diplobacilli -chains (streptococci, streptobacilli) -grape like clusters (staphylococci) -group of four-tetrads (peptococcus) -packets of eight-cuboidal (sarcina) -palisades (corneybacterium) Capsules are the basis of which test? serotyping and identification (capsules are antigenic); they are observed using India ink (negative staining) representative organisms (Strep pneumo, Kleb pneumo, Haemophilus influenza, and Neisseria meningitidius) A mucoid colony on blood agar medium indicates that which of the following characteristics may be present? Organism has a capsule. -it surrounds some bacteria What are dark staining granules called? Metachromatic granunles -affinity for basic dyes -stains such as Albert, Neisser, and methylene blue Which of the following organisms are non-motile? Shigella and Klebsiella (with exception to Salmonella--other "ella" are nonmotile) Shigella (neg) vs Salmonella (pos) Klebsiella (neg) vs Enterobacter (pos) Bacillus anthracis (neg) vs most bacillus species (pos) best observed at 25C 35-37C ,au be inhibitory In the bacterial growth cycle, growth ceases because nutrients are exhausted or toxic metabolic products have accumulated in which phase? Stationary phase (plateau ceases-nutrients exhausted/toxic) Which of the following genera of bacteria form spores? Bacillus and Clostridium endospores-non feeding, non motile, non reproductive -highly resistant to heat, drying, freezing; toxic chemical & radiation. (Sporulating bacteria-bacteria in which spores are forming) What term is used to describe bacteria that grow in the absence of atmospheric oxygen and obtain oxygen from oxygen-containing compounds? Anaerobes Aerobes grows in presence of (free) O2 Capnophiles growth enhanced by increased CO2 aerotolerants does not grow well but tolerate (survive) in presence of oxygen What is the temperature at which bacteria grow best known as? Optimum mesophilic grows best 35-37C; most organisms will grow at 20C thermophilic heat loving (50*55C); autoclaving procedures psychotrophilic cold loving (10C)-blood bank contaminancts 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 -Beta hemolysis (clear, colorless-complete hemolysis) -alpa hemolysis (green, incomplete hemolysis) -Gamma hemolysis (no hemolysis) What is the most effective method of sterilization? Autoclaving (steam at 121C @ 16 lbs pressure for 15-30 min)-**QC Bacillus STEAROTHERMOPHILUS -boiling method (kills all veg-not all spores/viruses (100C for 15-30 min) Under Fractional Sterilization (used to sterilize media containing mile or serum) -alternate heating which kills vegetative cells, followed by incubation when spores germinate, followed by heating, which kills the remaining tyndallization-flowing steam for 30 min on 3 successive days -inspissation-75-80C for 2 hrs on 3 successive days Which of the following is used for quality control for the dry heat oven? Bacillus subtilis Dry Heat method -kills by oxidation -oven 160-180C for 1-2 hours -QUALITY CONTROLS (Bacillus Subtilis) Media that cannot be heated can be sterilized by what alternate method? Filtration asbestos filter-98% effective membrane filter-0.22 micron = 100% bacterial sterility for media that are degraded by heat; Which one of the following disinfectants is the most effective germicide against bacteria, spores, tubercle bacilli, fungi, and viruses? Chlorine (bleach) oxidizes organic matter 2% aqueous glutaraldehyde safe for delicate lensed instruments poor activity against Pseudomonas What is a term that describes a process or treatment that renders a medical device, instrument, or environmental surface safe to handle? Decontamination process can range from sterilization or disinfection to just cleaning with soap and water What color do gram-positive bacteria stain? Purple - Crystal violet (1 min) will stain for gram positive - Mordent iodine (1 min) increases affinity or binding of dye - Decolorizer has 95% alcoholic or aqueous sol'n of dye (2-5 seconds)--most critical step - safranin (counterstain) (1 min) will stain for gram neg bact Acid-fast bacteria appear what color microscopically? Red Hot: Ziehl-Neelson retains the primary dye (carbohlfuchsin) Acid-fast organisms in tissue are best stained by which of the following methods? Kinyoun Cold: Kinyoun also stains acid fast organisms in TISSUE Which of the following should be used to remove antimicrobials before culturing? Antimicrobial removal device (ARD) this is for patients taking antibiotics, can utilize a special broth to remove the antibiotics prior to culture. 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. culture may include anaerobic conditions for Beta Strept 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