MLT 141 Unit 1-5

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The major difference between gram-positive and gram-negative bacteria is that:
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The autoclave sterilizes material by:applying moist heat at high temperatures and increased pressureStandard Precautions in the microbiology laboratory apply to:clinical specimens that contain blood or body fluids.A cleaning solution used on the laboratory bench top to kill bacteria that are potentially harmful to humans would be called a(n):disinfectant.A cleaning solution used on the venipuncture site to avoid skin contamination of the blood sample is called a(n):antiseptic.Direct examinations such as the Gram stain serve what purpose?To give the physician an early indication of what may be wrong with the patientWhich type of media is designed to support the growth of a wide range of microorganisms?NutritiveWhich type of media is designed to distinguish microorganisms on the basis of certain growth characteristics?DifferentialWhich type of media is designed to support the growth of one group of organisms, but not another, by containing antimicrobials, dyes, or alcohol?SelectiveIncreased concentrations of CO2 (5% to 10%) and approximately 15% O2 produce an environmental condition that best suits which type of organism?CapnophilesColonies of Streptococcus pneumoniae appear -hemolytic on blood agar media. Which one of the following statements explains this discrepancy?No discrepancy is present. S. pneumoniae should be -hemolytic on blood agar.Which specimen culture, if positive, should be immediately reported to the clinician?BloodThe first step in the Gram-stain sequence is the application of _______, which is the primary stain.crystal violetThe most critical step in the Gram stain is the application of the:Gram's decolorizer.Organisms that have nutritional needs that are relatively complex and require extra media components to be used for growth are called:fastidious.The most medically important bacteria sought in the medical laboratory are cultivated using incubators with temperatures maintained in what range?35C to 37CA catalase test was performed from a sheep blood agar plate on a colony of streptococci, and bubbling was observed. Which of the following statements explains this discrepancy?The colony may have been contaminated with sheep red blood cells, causing a false-positive result.Antimicrobial agents that inhibit bacterial growth but generally do not kill the organism are known as:bacteriostatic.Antimicrobial agents that usually kill target organisms are said to be:bactericidal.The primary goal of antimicrobial susceptibility testing is to:determine whether the pathogen expresses resistance to the potential therapeutic antimicrobial agents.The minimum inhibitory concentration (MIC) result recorded in antimicrobial testing can be defined as the:lowest antimicrobial agent concentration that completely inhibits visible bacterial growth.The species of Staphylococcus, which is one of the most important human pathogens, is:Staphylococcus aureus.Which group of bacteria is described as catalase positive and is gram-positive cocci that grow facultatively anaerobic and form grapelike clusters?StaphylococcusThe first identification test performed on a clinical isolate of gram-positive, catalase-positive cocci would likely be the:coagulase test.The staphylococci that is more likely to cause uncomplicated urinary tract infections in nonhospitalized hosts, especially sexually active young women, is:S. saprophyticus.Which of the following organisms best describes a catalase-negative, gram-positive coccus that is -hemolytic on sheep blood agar, and bacitracin positive?Streptococcus pyogenesWhich species of bacteria is responsible for causing diseases such as rheumatic fever, glomerulonephritis, and exudative pharyngitis?S. pyogenesThe bacterial species that can be described as able to hydrolyze hippurate, is -hemolytic, is a major cause of neonatal meningitis and sepsis, and is a producer of the Christie, Atkins, Munch-Petersen (CAMP) factor is:S. agalactiae.When performing the CAMP test, what bacteria is streaked down the middle?S. aureusThe major etiologic agent of bacterial endocarditis in the United States is:Viridans streptococci.What morphologic feature is a major consideration in determining an identification scheme for streptococci?Hemolytic patternA) Name the reagent used in the catalase test. B) Describe a positive catalase test. C) Staphylococcus is a catalase__________ and Streptococcus is catalase_______.A) Hydrogen peroxide B) Effervescent/violent bubbling C) positive and negativeA) Why is sheep blood recommended for the isolation of streptococci?To observe hemolysisDescribe the following type of hemolytic reactions seen on blood agar:A). Alpha: incomplete clearing- green effect B). Beta: complete clearing C). Gamma: no clearing1.) A gram stain from sputum specimen showing mostly diplococcic GPC would benefit from what test? 2.) What organisms are we trying to ID/differentiate?1.) P disk/Optochin 2.) P disk +______S.pneumoniae____ P disk - viridans group strep__Bacteria described as being coryneform have which of the following morphologic features?Resemble and are often referred to as Chinese lettersThe organism that exhibits characteristic end-over-end tumbling motility when incubated in nutrient broth at room temperature for 1 to 2 hours is:Bacillus anthracis.Patients who are immunocompromised and women who are pregnant should avoid eating soft cheeses such as Mexican-style, feta, Brie, Camembert, and blue-veined cheeses to prevent:food-borne listeriosis.Clue cells are associated with which gram-positive bacilli?G. vaginalisThese organisms metabolize glucose to lactic acid, producing an acidic pH within the female vaginal cavity that inhibits the growth of pathogenic bacteria.Lactobacillus spp.Common name when coryneform bacteria are normal skin floradiptheroidsHow is Bacillus transmitted?Cannot transmit human to human. Ingest or inhale spores. Ingest preformed toxins. Skin infection from sporesHow does Bacillus appear on gram stain and what feature on gram stain will confirm the genus?Large GPR If see spores inside the GPR, confirms genus1.) Major pathogen in this genus is: Bacillus anthracis 2.) What specimen source is it OFTEN isolated in first? BLOOD 3.) What are the diseases it causes? Anthrax Skin form, pulmonary form-inhaled (woolsorter disease), GI form-ingested1.) Bacillus anthracis 2.) BLOOD 3.) Anthrax, Skin form, pulmonary form-inhaled (woolsorter disease), GI form-ingested2 key features that distinguish the major Bacillus pathogen from the ordinary species:Non-beta hemolytic and Non-motileWhat does Listeria look like on colony growth and what are some biochemical reactions used for ID?Colony growth-Looks like beta strep. But is GPR, Catalase +, and motile at RT (Umbrella motility)Why is Listeria dangerous in pregnant women/effects on baby.In pregnant women, it causes an influenza like illness and can cross the placenta and if untreated may lead to fetal infection, abortion, stillbirth, or premature birth. Major, but not most common, cause of neonatal menigitisWhat types of food production is Lactobacillus an important part of?Beer, pickles, yogurt, dairy, sourdough bread starter etcWhere is Lactobacillus normal flora?NF in mouth (but can cause dental cavities), GI tract, and genital tract of femalesFor the most part, all Enterobacterales are positive for which biochemical reactions?Glucose, catalase, and reduce nitrates to nitritesMost strains of Escherichia coli that are identified on selective and differential media from the appropriate sources can be presumptively identified based on which characteristic?Spot indole-positiveThe swarming gram-negative bacillus that can be presumptively identified on the basis of a positive indole test is:Proteus vulgaris.A gram-negative bacillus that is hydrogen sulfide (H2S)-positive, citrate-positive, spot indole-negative, and associated with gastroenteritis in the United States is most likely:Salmonella enteritidis.E. coli would appear what color on HE agar?yellowA green colony with a black center is isolated on HE agar from a stool specimen. It is most likely which organism?Salmonella spp.MacConkey-sorbitol agar is useful for detecting pathogenic strains of:E. coli.The most common etiologic agent associated with urinary tract infections is:E. coli.Enterobacteriaceae are motile by _______ flagella. Nonmotile members are:peritrichous Klebsiella & Shigella. Some strains of Escherichia, Salmonella, & Yersinia (at 35o)MUG test important to differentiate between:ordinary E.coli + and STEC strains of E. coli negWhich test separates K. pneumonia from K. oxytocae?IndoleMost common food born gastroenteritis in the US is caused by: It is transmitted by: Types of food found in:Salmonella ingestion of foods if animal origin or water contaminated by animal contact eggs, chicken, unpasteurized milk, fruits & vegs with feces cotaminationTyphoid fever is what organism?Salmonella enteric, serotype typhiTyphoid fever is found 1st in what specimen?bloodCausative agent of plague is?Yersinia pestisSelective agar for Yersinia from stools?CINFrequent flora of the GI tract are:. coliforms... E.coli, Proteus, KlebsiellaWhat genera of the Enterobacteriaceae are enteric pathogens & cause diarrhea?Some strains of E. coli, Salmonella, SHigella, YersiniaMost common organism isolated in fecal specimens:E. coliWhich organism is oxidase-negative, oxidizes glucose, and is a nonlactose fermenter?AcinetobacterNot including organisms in the Enterobacteriaceae family, the most common gram-negative bacilli encountered in clinical specimens are:Pseudomonas.The disease referred to as melioidosis is caused by which one of the following?Burkholderia pseudomalleiProfuse watery diarrhea (i.e., "rice water stools"), leading to dramatic fluid loss, severe dehydration, and hypotension that frequently leads to death, is the hallmark of which toxin activity?Cholera toxin (CT)The selective medium, thiosulfate citrate bile salts sucrose (TCBS) agar, is especially formulated for isolating what pathogen from stool cultures?VibrioThe transmission of Vibrio spp. to humans is by:ingestion of contaminated seafood or water.