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Your patient has impetigo, a skin infection caused by Staphylococcus aureus.  You test bacteria grown from fluid from the lesions for antibiotic sensitivity. Impetigo lesions What is an antibiotic, tested here, that could be used to treat the patient’s infection, effectively? a. ampicillinb. Bactrimc. streptomycin [antibiotic] What is the name of the enzyme that bacteria use to degrade penicillin and other antibiotics of its class? a. β-lactamaseb. hexose kinasec. glucose-6-phosphate dehydrogenased. RuBisCo [enzyme] Among the antibiotics tested listed, above, which one works by inhibiting a metabolic/biochemical pathway? a. aminoglycosideb. beta-lactamc. macrolided. sulfonamide (eg., Bactrim) [metabolic] What is the most common mechanism of resistance to sulfonamide antibiotics such as Bactrim? [Bactrim] a.  beta-lactamase b.  bypass c.  efflux pumps d.  carbapenimase  

Your friend recently returned from a tour of South America, and has been complaining of the sensation of something wiggling beneath their scalp.  This is what you remove from their head (see below)!  (2 points, total) What is the technical term for insect larvae growing in mammal flesh?  [larvae] What is a medical use for insect larvae growing in mammal flesh?  [medical]

Which MR tube (see below) is positive? a. left tubeb. right tube [MRtube] What is the name of the fermentation pathway that produces a positive MR test? a. 2,3-butanediol fermentationb. ethanol fermentationc. lactic acid fermentationd. mixed acid fermentation [MRpathway] Which VP tube (see below) is positive? a. Tube Ab. Tube B [VPtube] What is name of the fermentation pathway that produces a positive VP test? a. 2,3-butanediol fermentationb. ethanol fermentationc. lactic acid fermentationd. mixed acid fermentation [VPPathway]

How does UV radiation inhibit microbial growth? a. denatures protein by oxidation of amino acid R groupsb. denatures protein by reaction with amino acid sulfhydryl (SH-) groupsc. causes DNA strand gaps and breaksd. causes the formation pyrimidine (eg., thymine) dimers [UV] How does ionizing radiation (eg., X rays) inhibit microbial growth? a. denatures protein by oxidation of amino acid R groupsb. denatures protein by reaction with amino acid sulfhydryl (SH-) groupsc. causes DNA strand gaps and breaksd. causes the formation of pyrimidine (eg., thymine) dimers [ionizing] If an organism is an endospore-former (eg., Bacillus anthracis), at what phase of its growth would it be most resistant to UV radiation?  [resistant] a.  lag phase b.  log phase c.  plateau phase d.  decline/death phase

For much of the 20th century, people who lived in the Southern United States were stereotyped as being slow-witted and lazy.  However, it is believed that much of this behavior was due to infestation with hookworm which can cause severe anemia due to it feeding on the host’s blood.  What is the proper name (Genus and specific epithet) of this parasite?

SARS-CoV-2 variants (mutants) can be detected using the RT-PCR test.  What is the name of the phenomenon by which the variants are detected (1 point), and why does this phenomenon occur (up to 3 points)?

You are working with a patient in the community clinic who complains of a sore throat (see below for a picture of the patient’s throat).  You submit throat swabs to the clinical lab for culturing and identification.  See below for results of lab tests. Growth on blood agar – note clear zone around colonies Gram stain – note chains of purple cocci Catalase test – no bubbles What is the proper name of the bacterium that is the most likely cause of the patient’s distress? a. Staphylococcus aureusb. Staphylococcus epidermidisc. Streptococcus pneumoniaed. Streptococcus pyogenes [propername] What do we mean when we say “beta-hemolysis”? a. lysis of red blood cells with incomplete degradation of hemoglobinb. lysis of red blood cells with no degradation of hemoglobinc. lysis of red blood cells with complete degradation of hemoglobind. no lysis of red blood cells or hemoglobin [beta-hemolysis] What do we mean when we say “alpha-hemolysis”? a. lysis of red blood cells with incomplete degradation of hemoglobinb. lysis of red blood cells with no degradation of hemoglobinc. lysis of red blood cells with complete degradation of hemoglobind. no lysis of red blood cells or hemoglobin [alpha-hemolysis]

What enzyme is necessary to produce a positive “I” test? a. glucose-6-phosphate dehydrogenaseb. hexose kinasec. tryptophanased. tyrosinase [enzyme] Which area of the dry slide (see below) shows a positive ‘I” test? a. top left cornerb. bottom left corner [Indole] Which Simmon’s citrate tube (see below) is positive? a. Tube 1b. Tube 2 [citrate] What must an organism be able to do to produce a positive citrate test? a.  have tryptophanase b.  have catalase c.  have citrase d.  have lactase [positive]

To prevent heartworm, cats and dogs should receive appropriate prophylactic medication.  What is the proper name  of the parasite responsible for heartworm? [heartworm] a.  Schistosoma mansoni b.  Dirofilaria immitis c.  Arthrobotrys d.  Echinococcus granulosarum To which major group of helminths does the heartworm parasite belong?  [majorgroup] a.  Annelida b.  Cestodes c.  Nematodes d.  Trematodes How is this parasite transmitted?  [transmission] a.  fleas b.  mosquitoes c.  biting flies d.  ticks

Below, left, is a fecal smear of a patient suffering from abdominal pain, nausea, and vomiting following a stay in an area where human feces (“night soil”) are used to fertilize crops.  Below, right, is an image of the adult parasite that the patient passed in their stool.  (2 points, total) What is the proper name (Genus + specific epithet) of the pathogen causing this patient’s illness?  [parasitename] What can be a complication requiring surgery of having a large number of this parasite in one’s intestines?  [complication]