HSS1100 midterm 2 – Flashcards
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| Which plasmid are the exotoxins for Bacillus anthracis encoded on? Name these 3 exotoxins. |
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| -plasmid pX01 -edema factor EF -protective antigen PA -lethal factor LF |
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| Name an atibiotic used to treat anthrax |
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| -penicillin -doxycyline -ciprofloxacin -levofloxacin |
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| true or false? Bacillus cereus is motile and resistant to penicillin |
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| True |
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| Name and describe the two enterotoxins responsible for food poisoning associated with bacillus cereus |
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| Heat labile: nausea, abdominal pain, diarrhoea, lasts 12-24 hours Heat stabile: SEVERE nausea and vomitting, short incubation |
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| Are Clostridium bacteria aerobic or anaerobic microorganisms? |
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| Anaerobic |
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| Name the diseases/clinical presentations of a Clostridium spp. infection |
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| -botulism -tetanus -gas gangrene -pseudomembranous colitis |
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| Why does Clostridium botulinum cause food poisoning from a lethal neurotoxin (what does the neurotoxin do?) |
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| Neurotoxin blocks Ach release in the autonomic nervous system which causes flaccid muscle paralysis |
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| How do you treat adult botulism? |
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| -antitoxin -respiratory support |
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| What is a known cause of adult botulism? |
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| -smoked fish -improperly canning vegetables |
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| What is a known cause of infant botulism? |
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| -honey contaminated with spores |
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| What are the clinical presentations of a 19 month old with botulism? |
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| 2-3 days of constipation,trouble swallowing, and muscle weakness |
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| How does Clostridium tetani infect a human? |
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| -rusty nail puncture wound -skin trauma |
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| What is the exotoxin made by Clostridium tetani and what does it cause? |
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| -tetanosporin causes: sustained contraction of skeletal muscles, severe muscle spasms, lock jaw, an risus sardonicus |
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| What does Clostridium perfringens cause and what are the 2 classes of infection associated with this? |
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| -gas gangrene 1) wound infection/cellulitis 2)clostridial myonecrosis |
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| What does Clostridium difficile cause? |
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| -antibiotic-associated pseudomembranous colitis |
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| Which exotoxins are released by Clostridium difficile and what do they cause? |
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| Toxin A: diarrhoea Toxin B: cytotoxic to colon cells |
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| What is the treatment of antibiotic-associated pseudomembranous colitis? |
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| -discontinue current antibiotic regimen -administer metronizadole or vancymycin BY MOUTH |
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| Name 2 non-spore forming rods |
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| -Listeria monocytogenes -Corynebacterium diptheriae |
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| Where is Listeria monocytogenes found? |
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| -soft cheeses -pate -cold cuts -unpasteurized milk |
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| True or falseListeria monocytogenes is a facultative intracellular aerobe? |
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| True! |
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| Which Gram-positive bacilli crosses the 3 protective barriers (blood-brain, GI, feto-placental) |
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| Listeria monocytogenes |
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| Which antibiotics are used to treat Listeria monocytogenes? |
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| ampicillin or trimethoprim-sulfamethoxazole |
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| The exotoxin of which microorganism causes damage to heart and neural cells? |
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| Corynebacterium diptheriae |
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| How to you treat diptheriae? |
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| 1)antitoxin 2)penicillin or erythromycin 3)DPT vaccine |
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| What are the 4 major groups of Enterics? |
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| -Enterobacteriaceae -Vibronaceae -Pseudomonadaceae -Bacterioidacaea |
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| Which media are used to discriminate bacteria that ferment lactose and which colour are lactose fermenters on these media? Also, do they inhibit Gram-positive or Gram-negative bacteria? |
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| EMB Media: -lactose fermenters are dark purple/black. Inhibits Gram-positive bacteria MacConkey Media: -lactose fermenters are pink-purple -Inhibits Gram-positive bacteria |
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| What are 4 ways to biochemically classify Enterics? |
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| -H2S production -Hydrolysis of urea -liquiefy gelatin -decarboxylation of amino acids |
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| What family does Salmonellae belong to? |
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| Enterobacteriaceae |
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| Is Salmonella able to ferment lactose? (What colour would it be on MacConkey agar?) |
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| -unable to ferment lactose -beige |
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| Which serovars of Salmonella enterica cause Enterocolitis? |
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| Enteritidis Typhimurium |
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| Which serovars or Salmonella enterica cause Enteric Fever? |
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| Typhi Paratyphi |
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| List some common symptoms of Enterocolitis |
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| -nausea -vomiting -profuse diarrhoea -abdominal pain -fever -chills -headache -myalgia |
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| How does someone get Enterocolitis? |
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| Ingestion of food (pultry, meat, eggs, milk)contaminated with Salmonella enterica serovar enteritidis or typhimurium |
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| How is Enterocolitis spread? |
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| person-to-person |
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| Why are antibiotics not recommended for Enterocolitis? |
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| antibiotics makes it take longer for the bacteria to exit your system and does not lessen the time of the illness |
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| How long do chronic carriers of Enteric Fever excrete bacteria? Convalescent carriers? |
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| chronic: 6 months to lifelong convalescent: 3 months |
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| How is Enteric Fever diagnosed? |
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| isolation of bacteria from blood (1st week) and stool and urine (2nd and 3rd week) |
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| What colour would Escherichia coli be on MacConkey agar? |
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| pink/purple |
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| Which microorganism causes Hamburger disease? |
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| E. coli O157:H7 |
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| Which antibiotics are used to treat Listeria monocytogenes? |
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| ampicillin or trimethoprim-sulfamethoxazole |
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| The exotoxin of which microorganism causes damage to heart and neural cells? |
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| Corynebacterium diptheriae |
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| List some common symptoms of Enterocolitis |
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| -nausea -vomiting -profuse diarrhoea -abdominal pain -fever -chills -headache -myalgia |
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| How does someone get Enterocolitis? |
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| Ingestion of food (pultry, meat, eggs, milk)contaminated with Salmonella enterica serovar enteritidis or typhimurium |
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| How is Enterocolitis spread? |
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| person-to-person |
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| Why are antibiotics not recommended for Enterocolitis? |
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| antibiotics makes it take longer for the bacteria to exit your system and does not lessen the time of the illness |
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| How long do chronic carriers of Enteric Fever excrete bacteria? Convalescent carriers? |
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| chronic: 6 months to lifelong convalescent: 3 months |
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| How is Enteric Fever diagnosed? |
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| isolation of bacteria from blood (1st week) and stool and urine (2nd and 3rd week) |
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| What colour would Escherichia coli be on MacConkey agar? |
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| pink/purple |
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| Which microorganism causes Hamburger disease? |
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| E. coli O157:H7 |
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| What does Shigellae cause? |
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| acute diarrhoea with mucous, pus, and blood |
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| Is there a vaccine for Shigellae? |
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| No. |
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| What percent of people does a dose of 10^5 of Shigella infect? A dose of 10^9? |
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| 10^5 = 25% 10^9 = 95% |
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| What does Vibrio cholerae cause? |
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| cholera: acute GI illness |
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| How does the enterotoxin for Vibrio cholerae work? |
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| -enterotoxin binds cells in small intesting -cells secrete chlorides -this decreases Na+ absorption -water accumulates in gut = watery diarrhoea -can lead to severe dehydration and death if untreated |
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| Campylobacter is part of the normal flora in who/what? |
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| birds and domestic animals |
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| Which micro-organism is a major cause of human enteritis? |
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| Campylobacter |
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| How do you treat a Pseudomonas infection? |
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| Treatment is difficult because all Pseudomonas spp. are resistant to many antibiotics |
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| What are the similarities between Pseudomonas aeruginosa and Pseudomonas cepacia? |
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| -respiratory pathogen in patients with cystic fibrosis -opportunistic pathogen -Gram-negative rods |
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| Name a common contaminant (micro-organism) of saline solutions and water. |
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| Pseudomonas cepacia |
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| Which micro-organism is part of the normal nasopharyngeal flora of adults and children? |
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| Haemophilus influenzae |
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| Can Haemophilus influenzae cause increased bronchial inflammation in patents that already have chronic bronchitis? |
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| Yes. |
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| True or falseThere is currently no vaccine for Haemophilus influenzae in Canada. |
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| False. |
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| Which micro-organism causes nosocomial infections and was linked to infant illness from powdered formula? |
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| Enterobacter spp. |
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| Helicobacter pylori is the most common cause of which stomach illness? |
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| stomach ulcers |
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| Which treatment is reccomended for a Helicobacter pylori infection? |
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| Triple therapy treatment: antibitocs and proton pump inhibitors. |
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| What are the 4 virulence factors for Bordetella pertussis? |
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| -Pertussis toxin -Extra cytoplasmic adenylase cyclase -Filamentous hemagglutinin -Tracheal cytotoxin |
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| Where is Legionella pneumophila found? |
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| -water -shower heads -water tanks -air cooling/heating tanks |
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| Is the exposure of Legionella pneumophila by person-to-person transmission, aerosol, or both? |
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| aerosol ONLY. |
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| What are the 4 steps of the Ziehl-Neelsen technique? |
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| 1) Ziehl-Neelsen carbol fuschsin to the slide for 5 minutes while applying heat 2) Follow with a gentle wash with water to cool the slide 3)Acid alcohol is now added to decolorize the slide 4) Wash the slide in water again and counterstain with methylene blue for 12 minutes |
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| What does Mycobacterium tuberculosis cause? |
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| Chronic, slow-progressing pulmonary infection (tuberculosis) |
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| How long does it take to see M. tuberculosis colonies on a plate? |
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| 4-6 weeks |
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| Which medium is used to grow Mycobacterium tuberculosis? |
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| Lowenstein-Jensen medium |
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| True or false? Clostridium perfringens is the leading cause of death world-wide from a single infection? |
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| False. Mycobacterium tuberculosis holds this record. |
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| Discuss the stages of Primary Tuberculosis |
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| 1)Aerosol inhalation 2)Bacteria multiply in alveoli 3)Macrophage ingestion of bacilli and formation of primary complex 4)Foci of infection in lungs (may be spread to kidneys, bones, and meninges) ~~~~~6 weeks later~~~~~~~ 5) CMI is fully active, infection has stopped (majority of cases) 6) Some bacilli survive, reactivation several months to years later. ***Steps 5) and 6) are where you would get a positive tuberculin test! |
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| Describe the Mantoux test for TB. |
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| Tuberculin solution is injected INTRADERMALLY. Wait 48-72 hours, check for induration. Record diameter of induration. >10mm positive 5-9mm doubtful, <4mm negative |
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| True or falseM. marinum and M. fortuitum are indistinguishable from TB |
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| True! |
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| What are the two types of leprosy caused by Mycobacterium leprae? |
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| -Tuberculoid leprosy -Lepromatous leprosy |
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| Discuss Tuberculoid leprosy and Lepromatous leprosy. |
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| TL: visible nerve enlargement, few erythromatous plaques, few bacilli in infected tissues, many lymphocytes and granulomas, low infectivity LL: no visible nerve enlargement, many erythromatous nodules, many bacilli in infected tissue, high infectivity |
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| What does Treponema pallidum cause? |
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| Syphillis |
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| Is Treponema pallidum unculturable in vitro or in vivo? |
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| in vivo |
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| Since Treponema pallidum is almost invisible under the Gram stain, the Geimsa stain, and the Ziehl-Neelsen stain, what can you use? |
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| Dark field microscopy |
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| Discuss the stages of Syphilis |
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| Primary Syphilis: -Appearance of chancre 3-4 weeks after infection -Fluid from lesion contains bacteria seen under dark field microscopy Secondary Syphilis: -6 weeks after appearance of chancre -generalized local rash -mucosal lesions with many treponemes *Spontaneous remission may occur after primary OR secondary phase Latent Syphilis: -no symptoms of infection -non-transmittable after 4 years -congenital infection may occur Late Syphilis: -obliterative endarteritis -can involve skin, mucosae, nervous system, cardiovascular system and tissues |
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| Since latent Syphilis is non-transmittable after 4 years, can it still cause a congenital infection? |
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| Yes. |
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| Discuss the Non-treponemal (VDRL, RPR, Wassermann) tests for Treponema pallidum |
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| -Non-specific: uses cardiolipin as antigen -screening -positive in early stages |
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| Discuss the treponemal tests for Treponema pallidum |
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| -Specific: uses treponemal extracts -FTA-ABS: Fluorescent Treponemal Antibody Absorption -MHA-TP: Microhemagglutination of T. pallidum -used to confirm positive VDRL |
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| Which micro-organism causes Lyme disease? |
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| Borrelia burgdorferi |
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| Which parts of the body does Borrelia burgdorferi affect? |
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| -skin -joints -nervous system -heart |
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| Is Borrelia burgdorferi common in Canada and rare in the USA or rare in Canada and common in the USA? |
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| -common in US and rare in Canada |
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| Name an antibiotic used to treat Lyme disease |
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| -doxycyline -amoxicilin -cefuroxime |
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| Can Chlamydiae make their own ATP? |
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| Nope. |
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| Can Clamydiae grow on artificial media? |
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| Nope. |
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| What does Chlamydiae cause in males and in females? |
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| males: urethritis females: cervicitis |
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| John Johnson is infected with Chlamydia trachomatis and does not get treated because he is asymptomatic and does not know he is infected. What can happen to him now (complications) ? |
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| -prostatitis -epididymitis |
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| Jessica Jessmeister presents with chronic pelvic pain, PID, and tubal infertility after having an ectopic pregnancy last year. She is likely suffering complications from an untreated STD caused by which micro-organism? |
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| Chlamydia trachomatis |
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| Which micro-organism is responsible for being the leading cause of blindness in the Middle East, North Africa and South East Asia? |
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| Chlamydia trachomatis |
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| What does Chlamydia pneumoniae cause? |
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| -sub-clinical infections -respiratory tract infections -mild pneumonia |
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| Which micro-organism is a bird pathogen that can be transmitted to humans and causes Pneumonia or Endocarditis? |
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| Chlamydia psittaci |
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| Are Mycoplasma or Mycobacterium the smallest free-living bacterium? |
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| Mycoplasma |
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| Is it true that Mycoplasma lack a true cell wall? |
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| Yes it is. |
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| Which micro-organism is the primary cause of atypical pneumonia? |
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| Mycoplasma pneumoniae |
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| Are Genital Mycoplasma (M. hominis, Ureaplasma urealyticum) part of normal genital flora? |
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| Yes they are. |
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| List the levels (depth) of infection by fungal pathogens |
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| -Superficial -Cutaneous -Subcutaneous -Systemic |
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| What are Dimorphic fungi? |
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| Fungi that grow as either yeast or mold |
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| What are Hyphae? |
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| Threadlike, branching tubules composed of fungal cells attached end to end |
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| What are Molds (mycelia)? |
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| Multicellular colonies composed of clumps of intertwined and branching hyphae |
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| What are Saprophytes? |
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| Fungi that live and use organic matter such as soil, rotten vegetation as their energy source |
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| Michael Michaelson presents with tinea nigra (black coloured painless patches on soles of hands and feet) and is found to have a superficial infection caused by Exophiala werneckii. How can he treat this? |
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| By spreading dandruff shampoo containing selenium sulfide over skin |
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| Cutaneous fungal dermatophytoses secrete the enzyme keratinase. What does this cause for the infected person? |
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| -scaly skin -loss of hair -crumbling of nails *keratinase digests keratin |
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| Which micro-organisms cause subcutaneous fungal infections that cause chromoblastomycosis? |
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| -Phialophora -Cladosporium |
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| Which micro-organism is an occupational hazard to gardeners because it causes subcutaneous fungal infections? |
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| Sporothrix schenckii |
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| Name 3 fungi that cause systemic disease in humans |
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| -Histoplasma capsulatum -Blastomycces dermatitidis -Coccidioides immitis |
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| Which micro-organism causes fungal infection in AIDS patients? |
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| Cryptococcus neoformans |
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| What is the most frequently identified intestinal parasite worldwide? |
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| Giardia lamblia (protozoan) |
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| What are the symptoms of acute giardiasis? |
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| -diarrhoea -weight loss -abdominal discomfort -nausea -vomiting |
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| True or falseCysts formed by Giardia lamblia are broken apart in the colon and not excreted. |
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| False! The cysts are shed with faeces. |
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| How would you identify Giardia lamblia in a stool sample (what technology would you use)? |
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| bright-field microscopy or immunofluorecene microscopy |
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| What is possibly the most common sexually transmitted disease worldwide (200 million cases)? |
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| Trichomonas vaginalis |
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| How is Entamoeba histolytica transmitted? |
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| -faecal-oral route (person-to-person) -contaminated water -raw produce -flies |
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| True or falseEntameoba histolytica may spead to the blood to produce liver, lung, or brain abcesses? |
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| True. |
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| Name some ways to control Entamoeba histolytica infections. |
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| -public health education -improved sanitation and water treatment -wash fruits and vegetables |
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| Are Genital Mycoplasma (M. hominis, Ureaplasma urealyticum) part of normal genital flora? |
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| Yes they are. |
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| List the levels (depth) of infection by fungal pathogens |
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| -Superficial -Cutaneous -Subcutaneous -Systemic |
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| What are Dimorphic fungi? |
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| Fungi that grow as either yeast or mold |
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| What are Hyphae? |
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| Threadlike, branching tubules composed of fungal cells attached end to end |
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| What are Molds (mycelia)? |
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| Multicellular colonies composed of clumps of intertwined and branching hyphae |
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| What are Saprophytes? |
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| Fungi that live and use organic matter such as soil, rotten vegetation as their energy source |
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| Michael Michaelson presents with tinea nigra (black coloured painless patches on soles of hands and feet) and is found to have a superficial infection caused by Exophiala werneckii. How can he treat this? |
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| By spreading dandruff shampoo containing selenium sulfide over skin |
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| Cutaneous fungal dermatophytoses secrete the enzyme keratinase. What does this cause for the infected person? |
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| -scaly skin -loss of hair -crumbling of nails *keratinase digests keratin |
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| Which micro-organisms cause subcutaneous fungal infections that cause chromoblastomycosis? |
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| -Phialophora -Cladosporium |
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| Which micro-organism is an occupational hazard to gardeners because it causes subcutaneous fungal infections? |
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| Sporothrix schenckii |
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| Name 3 fungi that cause systemic disease in humans |
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| -Histoplasma capsulatum -Blastomycces dermatitidis -Coccidioides immitis |
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| Which micro-organism causes fungal infection in AIDS patients? |
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| Cryptococcus neoformans |
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| What is the most frequently identified intestinal parasite worldwide? |
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| Giardia lamblia (protozoan) |
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| What are the symptoms of acute giardiasis? |
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| -diarrhoea -weight loss -abdominal discomfort -nausea -vomiting |
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| True or falseCysts formed by Giardia lamblia are broken apart in the colon and not excreted. |
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| False! The cysts are shed with faeces. |
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| How would you identify Giardia lamblia in a stool sample (what technology would you use)? |
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| bright-field microscopy or immunofluorecene microscopy |
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| What is possibly the most common sexually transmitted disease worldwide (200 million cases)? |
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| Trichomonas vaginalis |
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| How is Entamoeba histolytica transmitted? |
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| -faecal-oral route (person-to-person) -contaminated water -raw produce -flies |
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| True or falseEntameoba histolytica may spead to the blood to produce liver, lung, or brain abcesses? |
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| True. |
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| Name some ways to control Entamoeba histolytica infections. |
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| -public health education -improved sanitation and water treatment -wash fruits and vegetables |
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| Cats are the only definitive host of which parasite? |
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| Toxoplasma gondii |
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| Which parasite causes encephalitis, myocarditis, and pneumonia in an immunocompromised host? |
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| Toxoplasma gondii |
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| How is Malaria transmitted? |
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| -Anopheline mosquitos -blood transfusion/shared needles -congenital infection -"airport malaria" |
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| What are SEVERE symptoms of Malaria? |
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| -seizures -coma -renal failure -respiratory failure |
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| Is drug resistance a serious or mild problem with Malaria? |
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| Serious!! |
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| What is the most common symptom of Cryptosporidium spp.? |
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| water diarrhoea |
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| Which parasite causes chronic, debilitating, and potentially life threatening symptoms in the immunocompromised? |
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| Cryptosporidium spp. |
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| True or falseDrug treatment is available for Cryptosporidium spp.? |
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| NO! |
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| Is Cryptosporidium an arthropod, protozoan, or helminth? |
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| protozoan |
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| Which part of the body does Cryptosporidium infect? |
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| typically the intestinal epithelial cells of the small intestine |
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| What is the numerically most important mode of transmission for Cryptosporidium? |
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| WATER |
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| How is C. Parvum spread? |
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| -person-to-person -autoinfection -zoonotic |
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| Cattle serve as an important reservoir host for which parasite? |
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| C. parvum |
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| True or falseExposure to temperatures above 40 degrees C and below 0 degrees celcius will kill the oocysts of C. parvum? |
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| False! above 60 and below -20 |
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| The infection caused by Cyclospora cayetanensis, cyclosporiasis, is effectively treated with which antibiotic? |
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| trimethoprim-sulfamethoxazole (bactrim) |
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| Pinworms (Enterobius vermeicularis) affect up to what percent of school-aged children in North America? |
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| 50% |
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| True or falseEnterobius vermicularis is more of a nuisance than a health problem. |
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| True! |
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| Scotch-tape test of the perianal area can diagnose which parasitic infection? |
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| Pinworms |
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| Which parasite fits this description: small roundworm found worldwide in many carnivorous and omnivorous animals, including humans. |
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| Trichinella spp. |
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| How is Trichinella spp. transmitted? |
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| Through ingestion of larvae in raw or poorly cooked meat |
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| Matching: __A domestic form __B wild form __C bears,humans, walrus __D humans, horses, swine 1)Trichinella spiralis 2)Trichinella nativa |
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| A)1 B)2 C)2 D)1 |
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| Name a very large intestinal nematode |
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| Ascaris lumbricoides |
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| What is the most common human helminth infection? |
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| Ascaris lumbricoides |
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| How is Ascaris lumbricoides diagnosed? |
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| stool examination for the presence of eggs |
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| Most cases of which parasite arise from home-prepared sushi, sashimi, and ceviche? |
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| Anisakiasis simplex (aka whale worm or herring worm) |
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| What are the definitive hosts of Anisakiasis simplex? |
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| -dolphins -whales -porpoises |
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| Since drug treatment is not effective and symptoms are often mistaken for appendicitis, diagnosis is difficult and exploratory surgery may be required thanks to which parasite? |
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| Anisakiasis |
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| Which tapeworm is 10 meters long? |
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| Diphyllobothrium spp. |
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| How is Diphyllobotrium spp. transmitted? |
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| Through the consumption of raw or poorly cooked freshwater fish containing infective larvae |
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| Which tapeworms can grow up to 20 meters in length? |
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| Taenia spp. |
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| Taenia saginata, Taenia solium. Which is a beef tapeworm and which is a pork tapeworm? |
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| saginata is beef solium is pork |
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| Which tapeworm causes neurocysticercosis (intracranial hypertension, hydrocephalus, convulsive seizures)? |
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| T. solium |
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| What are Schistosoma? |
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| Blood flukes. They are free-swimming larvae in fresh water that penetrate skin and develop in blood vessels surrounding intestine or bladder |
