HSS1100 midterm 2 – Flashcards

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question
Which plasmid are the exotoxins for Bacillus anthracis encoded on? Name these 3 exotoxins.
answer
-plasmid pX01
-edema factor EF
-protective antigen PA
-lethal factor LF
question
Name an atibiotic used to treat anthrax
answer
-penicillin
-doxycyline
-ciprofloxacin
-levofloxacin
question
true or false?

Bacillus cereus is motile and resistant to penicillin
answer
True
question
Name and describe the two enterotoxins responsible for food poisoning associated with bacillus cereus
answer
Heat labile: nausea, abdominal pain, diarrhoea, lasts 12-24 hours
Heat stabile: SEVERE nausea and vomitting, short incubation
question
Are Clostridium bacteria aerobic or anaerobic microorganisms?
answer
Anaerobic
question
Name the diseases/clinical presentations of a Clostridium spp. infection
answer
-botulism
-tetanus
-gas gangrene
-pseudomembranous colitis
question
Why does Clostridium botulinum cause food poisoning from a lethal neurotoxin (what does the neurotoxin do?)
answer
Neurotoxin blocks Ach release in the autonomic nervous system which causes flaccid muscle paralysis
question
How do you treat adult botulism?
answer
-antitoxin
-respiratory support
question
What is a known cause of adult botulism?
answer
-smoked fish
-improperly canning vegetables
question
What is a known cause of infant botulism?
answer
-honey contaminated with spores
question
What are the clinical presentations of a 19 month old with botulism?
answer
2-3 days of constipation,trouble swallowing, and muscle weakness
question
How does Clostridium tetani infect a human?
answer
-rusty nail puncture wound
-skin trauma
question
What is the exotoxin made by Clostridium tetani and what does it cause?
answer
-tetanosporin
causes: sustained contraction of skeletal muscles, severe muscle spasms, lock jaw, an risus sardonicus
question
What does Clostridium perfringens cause and what are the 2 classes of infection associated with this?
answer
-gas gangrene
1) wound infection/cellulitis
2)clostridial myonecrosis
question
What does Clostridium difficile cause?
answer
-antibiotic-associated pseudomembranous colitis
question
Which exotoxins are released by Clostridium difficile and what do they cause?
answer
Toxin A: diarrhoea
Toxin B: cytotoxic to colon cells
question
What is the treatment of antibiotic-associated pseudomembranous colitis?
answer
-discontinue current antibiotic regimen
-administer metronizadole or vancymycin BY MOUTH
question
Name 2 non-spore forming rods
answer
-Listeria monocytogenes
-Corynebacterium diptheriae
question
Where is Listeria monocytogenes found?
answer
-soft cheeses
-pate
-cold cuts
-unpasteurized milk
question
True or falseListeria monocytogenes is a facultative intracellular aerobe?
answer
True!
question
Which Gram-positive bacilli crosses the 3 protective barriers (blood-brain, GI, feto-placental)
answer
Listeria monocytogenes
question
Which antibiotics are used to treat Listeria monocytogenes?
answer
ampicillin or trimethoprim-sulfamethoxazole
question
The exotoxin of which microorganism causes damage to heart and neural cells?
answer
Corynebacterium diptheriae
question
How to you treat diptheriae?
answer
1)antitoxin
2)penicillin or erythromycin
3)DPT vaccine
question
What are the 4 major groups of Enterics?
answer
-Enterobacteriaceae
-Vibronaceae
-Pseudomonadaceae
-Bacterioidacaea
question
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?
answer
EMB Media:
-lactose fermenters are dark purple/black. Inhibits Gram-positive bacteria

MacConkey Media:
-lactose fermenters are pink-purple
-Inhibits Gram-positive bacteria
question
What are 4 ways to biochemically classify Enterics?
answer
-H2S production
-Hydrolysis of urea
-liquiefy gelatin
-decarboxylation of amino acids
question
What family does Salmonellae belong to?
answer
Enterobacteriaceae
question
Is Salmonella able to ferment lactose? (What colour would it be on MacConkey agar?)
answer
-unable to ferment lactose
-beige
question
Which serovars of Salmonella enterica cause Enterocolitis?
answer
Enteritidis
Typhimurium
question
Which serovars or Salmonella enterica cause Enteric Fever?
answer
Typhi
Paratyphi
question
List some common symptoms of Enterocolitis
answer
-nausea
-vomiting
-profuse diarrhoea
-abdominal pain
-fever
-chills
-headache
-myalgia
question
How does someone get Enterocolitis?
answer
Ingestion of food (pultry, meat, eggs, milk)contaminated with Salmonella enterica serovar enteritidis or typhimurium
question
How is Enterocolitis spread?
answer
person-to-person
question
Why are antibiotics not recommended for Enterocolitis?
answer
antibiotics makes it take longer for the bacteria to exit your system and does not lessen the time of the illness
question
How long do chronic carriers of Enteric Fever excrete bacteria? Convalescent carriers?
answer
chronic: 6 months to lifelong
convalescent: 3 months
question
How is Enteric Fever diagnosed?
answer
isolation of bacteria from blood (1st week) and stool and urine (2nd and 3rd week)
question
What colour would Escherichia coli be on MacConkey agar?
answer
pink/purple
question
Which microorganism causes Hamburger disease?
answer
E. coli O157:H7
question
Which antibiotics are used to treat Listeria monocytogenes?
answer
ampicillin or trimethoprim-sulfamethoxazole
question
The exotoxin of which microorganism causes damage to heart and neural cells?
answer
Corynebacterium diptheriae
question
List some common symptoms of Enterocolitis
answer
-nausea
-vomiting
-profuse diarrhoea
-abdominal pain
-fever
-chills
-headache
-myalgia
question
How does someone get Enterocolitis?
answer
Ingestion of food (pultry, meat, eggs, milk)contaminated with Salmonella enterica serovar enteritidis or typhimurium
question
How is Enterocolitis spread?
answer
person-to-person
question
Why are antibiotics not recommended for Enterocolitis?
answer
antibiotics makes it take longer for the bacteria to exit your system and does not lessen the time of the illness
question
How long do chronic carriers of Enteric Fever excrete bacteria? Convalescent carriers?
answer
chronic: 6 months to lifelong
convalescent: 3 months
question
How is Enteric Fever diagnosed?
answer
isolation of bacteria from blood (1st week) and stool and urine (2nd and 3rd week)
question
What colour would Escherichia coli be on MacConkey agar?
answer
pink/purple
question
Which microorganism causes Hamburger disease?
answer
E. coli O157:H7
question
What does Shigellae cause?
answer
acute diarrhoea with mucous, pus, and blood
question
Is there a vaccine for Shigellae?
answer
No.
question
What percent of people does a dose of 10^5 of Shigella infect? A dose of 10^9?
answer
10^5 = 25%
10^9 = 95%
question
What does Vibrio cholerae cause?
answer
cholera: acute GI illness
question
How does the enterotoxin for Vibrio cholerae work?
answer
-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
question
Campylobacter is part of the normal flora in who/what?
answer
birds and domestic animals
question
Which micro-organism is a major cause of human enteritis?
answer
Campylobacter
question
How do you treat a Pseudomonas infection?
answer
Treatment is difficult because all Pseudomonas spp. are resistant to many antibiotics
question
What are the similarities between Pseudomonas aeruginosa and Pseudomonas cepacia?
answer
-respiratory pathogen in patients with cystic fibrosis
-opportunistic pathogen
-Gram-negative rods
question
Name a common contaminant (micro-organism) of saline solutions and water.
answer
Pseudomonas cepacia
question
Which micro-organism is part of the normal nasopharyngeal flora of adults and children?
answer
Haemophilus influenzae
question
Can Haemophilus influenzae cause increased bronchial inflammation in patents that already have chronic bronchitis?
answer
Yes.
question
True or falseThere is currently no vaccine for Haemophilus influenzae in Canada.
answer
False.
question
Which micro-organism causes nosocomial infections and was linked to infant illness from powdered formula?
answer
Enterobacter spp.
question
Helicobacter pylori is the most common cause of which stomach illness?
answer
stomach ulcers
question
Which treatment is reccomended for a Helicobacter pylori infection?
answer
Triple therapy treatment: antibitocs and proton pump inhibitors.
question
What are the 4 virulence factors for Bordetella pertussis?
answer
-Pertussis toxin
-Extra cytoplasmic adenylase cyclase
-Filamentous hemagglutinin
-Tracheal cytotoxin
question
Where is Legionella pneumophila found?
answer
-water
-shower heads
-water tanks
-air cooling/heating tanks
question
Is the exposure of Legionella pneumophila by person-to-person transmission, aerosol, or both?
answer
aerosol ONLY.
question
What are the 4 steps of the Ziehl-Neelsen technique?
answer
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
question
What does Mycobacterium tuberculosis cause?
answer
Chronic, slow-progressing pulmonary infection (tuberculosis)
question
How long does it take to see M. tuberculosis colonies on a plate?
answer
4-6 weeks
question
Which medium is used to grow Mycobacterium tuberculosis?
answer
Lowenstein-Jensen medium
question
True or false?
Clostridium perfringens is the leading cause of death world-wide from a single infection?
answer
False. Mycobacterium tuberculosis holds this record.
question
Discuss the stages of Primary Tuberculosis
answer
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!
question
Describe the Mantoux test for TB.
answer
Tuberculin solution is injected INTRADERMALLY. Wait 48-72 hours, check for induration. Record diameter of induration. >10mm positive 5-9mm doubtful, <4mm negative
question
True or falseM. marinum and M. fortuitum are indistinguishable from TB
answer
True!
question
What are the two types of leprosy caused by Mycobacterium leprae?
answer
-Tuberculoid leprosy
-Lepromatous leprosy
question
Discuss Tuberculoid leprosy and Lepromatous leprosy.
answer
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
question
What does Treponema pallidum cause?
answer
Syphillis
question
Is Treponema pallidum unculturable in vitro or in vivo?
answer
in vivo
question
Since Treponema pallidum is almost invisible under the Gram stain, the Geimsa stain, and the Ziehl-Neelsen stain, what can you use?
answer
Dark field microscopy
question
Discuss the stages of Syphilis
answer
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
question
Since latent Syphilis is non-transmittable after 4 years, can it still cause a congenital infection?
answer
Yes.
question
Discuss the Non-treponemal (VDRL, RPR, Wassermann) tests for Treponema pallidum
answer
-Non-specific: uses cardiolipin as antigen
-screening
-positive in early stages
question
Discuss the treponemal tests for Treponema pallidum
answer
-Specific: uses treponemal extracts
-FTA-ABS: Fluorescent Treponemal Antibody Absorption
-MHA-TP: Microhemagglutination of T. pallidum
-used to confirm positive VDRL
question
Which micro-organism causes Lyme disease?
answer
Borrelia burgdorferi
question
Which parts of the body does Borrelia burgdorferi affect?
answer
-skin
-joints
-nervous system
-heart
question
Is Borrelia burgdorferi common in Canada and rare in the USA or rare in Canada and common in the USA?
answer
-common in US and rare in Canada
question
Name an antibiotic used to treat Lyme disease
answer
-doxycyline
-amoxicilin
-cefuroxime
question
Can Chlamydiae make their own ATP?
answer
Nope.
question
Can Clamydiae grow on artificial media?
answer
Nope.
question
What does Chlamydiae cause in males and in females?
answer
males: urethritis
females: cervicitis
question
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) ?
answer
-prostatitis
-epididymitis
question
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?
answer
Chlamydia trachomatis
question
Which micro-organism is responsible for being the leading cause of blindness in the Middle East, North Africa and South East Asia?
answer
Chlamydia trachomatis
question
What does Chlamydia pneumoniae cause?
answer
-sub-clinical infections
-respiratory tract infections
-mild pneumonia
question
Which micro-organism is a bird pathogen that can be transmitted to humans and causes Pneumonia or Endocarditis?
answer
Chlamydia psittaci
question
Are Mycoplasma or Mycobacterium the smallest free-living bacterium?
answer
Mycoplasma
question
Is it true that Mycoplasma lack a true cell wall?
answer
Yes it is.
question
Which micro-organism is the primary cause of atypical pneumonia?
answer
Mycoplasma pneumoniae
question
Are Genital Mycoplasma (M. hominis, Ureaplasma urealyticum) part of normal genital flora?
answer
Yes they are.
question
List the levels (depth) of infection by fungal pathogens
answer
-Superficial
-Cutaneous
-Subcutaneous
-Systemic
question
What are Dimorphic fungi?
answer
Fungi that grow as either yeast or mold
question
What are Hyphae?
answer
Threadlike, branching tubules composed of fungal cells attached end to end
question
What are Molds (mycelia)?
answer
Multicellular colonies composed of clumps of intertwined and branching hyphae
question
What are Saprophytes?
answer
Fungi that live and use organic matter such as soil, rotten vegetation as their energy source
question
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?
answer
By spreading dandruff shampoo containing selenium sulfide over skin
question
Cutaneous fungal dermatophytoses secrete the enzyme keratinase. What does this cause for the infected person?
answer
-scaly skin
-loss of hair
-crumbling of nails

*keratinase digests keratin
question
Which micro-organisms cause subcutaneous fungal infections that cause chromoblastomycosis?
answer
-Phialophora
-Cladosporium
question
Which micro-organism is an occupational hazard to gardeners because it causes subcutaneous fungal infections?
answer
Sporothrix schenckii
question
Name 3 fungi that cause systemic disease in humans
answer
-Histoplasma capsulatum
-Blastomycces dermatitidis
-Coccidioides immitis
question
Which micro-organism causes fungal infection in AIDS patients?
answer
Cryptococcus neoformans
question
What is the most frequently identified intestinal parasite worldwide?
answer
Giardia lamblia (protozoan)
question
What are the symptoms of acute giardiasis?
answer
-diarrhoea
-weight loss
-abdominal discomfort
-nausea
-vomiting
question
True or falseCysts formed by Giardia lamblia are broken apart in the colon and not excreted.
answer
False! The cysts are shed with faeces.
question
How would you identify Giardia lamblia in a stool sample (what technology would you use)?
answer
bright-field microscopy or immunofluorecene microscopy
question
What is possibly the most common sexually transmitted disease worldwide (200 million cases)?
answer
Trichomonas vaginalis
question
How is Entamoeba histolytica transmitted?
answer
-faecal-oral route (person-to-person)
-contaminated water
-raw produce
-flies
question
True or falseEntameoba histolytica may spead to the blood to produce liver, lung, or brain abcesses?
answer
True.
question
Name some ways to control Entamoeba histolytica infections.
answer
-public health education
-improved sanitation and water treatment
-wash fruits and vegetables
question
Are Genital Mycoplasma (M. hominis, Ureaplasma urealyticum) part of normal genital flora?
answer
Yes they are.
question
List the levels (depth) of infection by fungal pathogens
answer
-Superficial
-Cutaneous
-Subcutaneous
-Systemic
question
What are Dimorphic fungi?
answer
Fungi that grow as either yeast or mold
question
What are Hyphae?
answer
Threadlike, branching tubules composed of fungal cells attached end to end
question
What are Molds (mycelia)?
answer
Multicellular colonies composed of clumps of intertwined and branching hyphae
question
What are Saprophytes?
answer
Fungi that live and use organic matter such as soil, rotten vegetation as their energy source
question
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?
answer
By spreading dandruff shampoo containing selenium sulfide over skin
question
Cutaneous fungal dermatophytoses secrete the enzyme keratinase. What does this cause for the infected person?
answer
-scaly skin
-loss of hair
-crumbling of nails

*keratinase digests keratin
question
Which micro-organisms cause subcutaneous fungal infections that cause chromoblastomycosis?
answer
-Phialophora
-Cladosporium
question
Which micro-organism is an occupational hazard to gardeners because it causes subcutaneous fungal infections?
answer
Sporothrix schenckii
question
Name 3 fungi that cause systemic disease in humans
answer
-Histoplasma capsulatum
-Blastomycces dermatitidis
-Coccidioides immitis
question
Which micro-organism causes fungal infection in AIDS patients?
answer
Cryptococcus neoformans
question
What is the most frequently identified intestinal parasite worldwide?
answer
Giardia lamblia (protozoan)
question
What are the symptoms of acute giardiasis?
answer
-diarrhoea
-weight loss
-abdominal discomfort
-nausea
-vomiting
question
True or falseCysts formed by Giardia lamblia are broken apart in the colon and not excreted.
answer
False! The cysts are shed with faeces.
question
How would you identify Giardia lamblia in a stool sample (what technology would you use)?
answer
bright-field microscopy or immunofluorecene microscopy
question
What is possibly the most common sexually transmitted disease worldwide (200 million cases)?
answer
Trichomonas vaginalis
question
How is Entamoeba histolytica transmitted?
answer
-faecal-oral route (person-to-person)
-contaminated water
-raw produce
-flies
question
True or falseEntameoba histolytica may spead to the blood to produce liver, lung, or brain abcesses?
answer
True.
question
Name some ways to control Entamoeba histolytica infections.
answer
-public health education
-improved sanitation and water treatment
-wash fruits and vegetables
question
Cats are the only definitive host of which parasite?
answer
Toxoplasma gondii
question
Which parasite causes encephalitis, myocarditis, and pneumonia in an immunocompromised host?
answer
Toxoplasma gondii
question
How is Malaria transmitted?
answer
-Anopheline mosquitos
-blood transfusion/shared needles
-congenital infection
-"airport malaria"
question
What are SEVERE symptoms of Malaria?
answer
-seizures
-coma
-renal failure
-respiratory failure
question
Is drug resistance a serious or mild problem with Malaria?
answer
Serious!!
question
What is the most common symptom of Cryptosporidium spp.?
answer
water diarrhoea
question
Which parasite causes chronic, debilitating, and potentially life threatening symptoms in the immunocompromised?
answer
Cryptosporidium spp.
question
True or falseDrug treatment is available for Cryptosporidium spp.?
answer
NO!
question
Is Cryptosporidium an arthropod, protozoan, or helminth?
answer
protozoan
question
Which part of the body does Cryptosporidium infect?
answer
typically the intestinal epithelial cells of the small intestine
question
What is the numerically most important mode of transmission for Cryptosporidium?
answer
WATER
question
How is C. Parvum spread?
answer
-person-to-person
-autoinfection
-zoonotic
question
Cattle serve as an important reservoir host for which parasite?
answer
C. parvum
question
True or falseExposure to temperatures above 40 degrees C and below 0 degrees celcius will kill the oocysts of C. parvum?
answer
False! above 60 and below -20
question
The infection caused by Cyclospora cayetanensis, cyclosporiasis, is effectively treated with which antibiotic?
answer
trimethoprim-sulfamethoxazole (bactrim)
question
Pinworms (Enterobius vermeicularis) affect up to what percent of school-aged children in North America?
answer
50%
question
True or falseEnterobius vermicularis is more of a nuisance than a health problem.
answer
True!
question
Scotch-tape test of the perianal area can diagnose which parasitic infection?
answer
Pinworms
question
Which parasite fits this description: small roundworm found worldwide in many carnivorous and omnivorous animals, including humans.
answer
Trichinella spp.
question
How is Trichinella spp. transmitted?
answer
Through ingestion of larvae in raw or poorly cooked meat
question
Matching:
__A domestic form
__B wild form
__C bears,humans, walrus
__D humans, horses, swine

1)Trichinella spiralis
2)Trichinella nativa
answer
A)1
B)2
C)2
D)1
question
Name a very large intestinal nematode
answer
Ascaris lumbricoides
question
What is the most common human helminth infection?
answer
Ascaris lumbricoides
question
How is Ascaris lumbricoides diagnosed?
answer
stool examination for the presence of eggs
question
Most cases of which parasite arise from home-prepared sushi, sashimi, and ceviche?
answer
Anisakiasis simplex (aka whale worm or herring worm)
question
What are the definitive hosts of Anisakiasis simplex?
answer
-dolphins
-whales
-porpoises
question
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?
answer
Anisakiasis
question
Which tapeworm is 10 meters long?
answer
Diphyllobothrium spp.
question
How is Diphyllobotrium spp. transmitted?
answer
Through the consumption of raw or poorly cooked freshwater fish containing infective larvae
question
Which tapeworms can grow up to 20 meters in length?
answer
Taenia spp.
question
Taenia saginata, Taenia solium.
Which is a beef tapeworm and which is a pork tapeworm?
answer
saginata is beef
solium is pork
question
Which tapeworm causes neurocysticercosis (intracranial hypertension, hydrocephalus, convulsive seizures)?
answer
T. solium
question
What are Schistosoma?
answer
Blood flukes.
They are free-swimming larvae in fresh water that penetrate skin and develop in blood vessels surrounding intestine or bladder
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