Flashcards
Enterics II
Cards in this deck (88)
- 1What are the microbiological features of Salmonella?- gram-negative rods
- facultative anaerobes
- oxidase negative
- lactose negative
- motile (phase variable)
- hydrogen sulfide producers - 2What are types of Salmonella host ranges?broad and narrow
- 3broad-host-range Salmonellainfect diverse animal species; typically cause gastroenteritis in humans
- 4What are the Salmonella serotypes with a broad-host-range?S. Typhimurium
S. Enteritidis - 5narrow-host-range Salmonellaspecifically adapted to a preferred host and rarely manifest as gastroenteritis
- 6What are the diseases caused by non-Typhoid serotype Salmonella?gastroenteritis and bacteremia
- 7What are the symptoms of gastroenteritis?medium volume, watery diarrhea
fever
nausea
vomiting - 8What are the clinical characteristics of gastroenteritis?- 12-48 hour incubation period (longer with a lower infectious dose
- 3-7 day duration
- self-resolving
- carriage in stool 4-5 weeks post-resolution - 9What are the clinical characteristics of bacteremia?- approx. 8% of patients with non-typhoidal salmonellosis
- secondary focal infections in 5-10% of cases (adults)
- AIDS patients at high risk (recurrent bacteremia AIDS-defining)
- host adapted serotypes S. Choleraestitis & S. Dublin (have higher propensity often without antecedent gastroenteritis - 10What is the incidence of non-typhoidal serotype Salmonella in the US?- 40-50,000 reported cases/yr (1-1.5 million actual)
- highest incidence: in children < 5 yrs old & elderly
- seasonal pattern: late summer, early fall - 11How is non-typhoidal serotype Salmonella transmitted?contaminated food and water
eggs and poultry most commonly
a vast array of foods - 12What is the infectious dose of non-typhoidal serotype Salmonella?10^6 to 10^8
- 13How is non-typhoidal serotype Salmonella isolated and identified?1. plate fecal specimen on selective/differential media
2. biochemical test of lac negative isolates
3. determine serotype - 14What is the treatment and prevention of non-typhoidal serotype Salmonella?- fluid & electrolyte replacement
- antimicrobial treatment (1. non therapeutic value for uncomplicated gastroenteritis and 2. preemptive treatment of patients at high risk of bacteremia)
- proper food preperation & storage prevents infection - 15What are the diseases associated with typhoidal serotype Salmonella?enteric (typhoid) fever and chronic asymptomatic carriage
- 16What are the clinical characteristics of enteric (typhoid) fever?- severe systemic illness with protracted (3-4 weeks)
- insidious onset, headache, anorexia, myalgia 10-14 days post-exposure
- gastroenteritis symptoms ~ 1 week later
- occasional maculopapular rash on trunk "rose spots"
- 10-15% mortality in untreated cases
- milder cases with S. Paratyphi - 17What are the clinical characteristics of chronic asymptomatic carriage?- excretion of the organism in stool for >1 yr
- 1-4% of untreated typhoid patients
- gallbladder primary reservoir - 18How are S. Typhi and S. Paratyphi (typhoidal serotype) transmitted?fecal contamination of food and water
- 19What is the reservoir of S. Typhi and S. Paratyphi (typhoidal serotype Salmonella)?humans
- 20What is the US incidence of S. Typhi and S. Paratyphi (typhoidal serotype Salmonella)?400-500 cases/yr
75% traveler's disease - 21What is the global incidence of S. Typhi and S. Paratyphi (typhoidal serotype Salmonella)?~10-20 million cases/yr (80% caused by S. Typhi)
~200,000 deaths/yr - 22What are the treatment and preventative measures for typhoid serotype Salmonella"?- fluid & electrolyte replacement
- antimicrobial treatment (reduces complications and mortality/variable sensitivity)
- proper sanitation and water treatment
- vaccine recommended for traveler - 23What is the vaccine for typhoid serotype Salmonella?Typbar-TCV
- 24What is Typbar-TCV and its properties?Vi capsule polysaccharide conjugated to tetanus toxoid
- infants
- long lasting
- prequalified by WHO in 2017 - 25What are the microbiological features of the genus Yersinia?- gram negative rod
- facultative anaerobe
- oxidase negative
- lactose negative
- bipolar staining
- nonmotile @ 37 degrees Celcius
- motile @ 25 degrees Celcius
psychrophilic (grow @ 4 degrees Celcius) - 26What are the clinically significant species of Yersinia?- Yersinia enterocolitica
- Yersinia pseudoturberculosis
- Yersinia pestis - 27What is the reservoir of Y. enterocolitis and Y. pseudotuberculosis?wild and domestic animals and environment
- 28What is the common transmission vehicles of Y. enterocolitis and Y. pseudotuberculosis?raw uncooked pork
unpasteurized milk/milk products
stored blood - 2 cases/year - 29What is the incidence and epidemiology of Y. enterocolitis and Y. pseudotuberculosis?more common in colder climates (Canada, Northern Europe)
most cases in children
serotypes O3 & O9 in Europe
serotype O3 in Canada
serotype O8 in the US
~ 150 confirmed cases/yr in US - 30What is the pathogenicity of Y. enterocolitis and Y. pseudotuberculosis?can survive in macrophages
similar to S. Typhi - 31What are the microbiological features of the genus Vibrio?- gram negative curved rod
- single polar flagella
- facultative anaerobes
- oxidase positive (distinguishes from Enterobacteriaceae
- most species are halophilic (except V. cholera) - 32halophilicrequires high salt concentration for growth
- 33What are the clinically significant species of Vibrio?V. cholera
V. parahaemolyticus
V. vulnificus - 34What is unique about the genome of V. cholerae?bipartite genome
- 35What is a bipartite genome?the genome is segmented into two segments (referred to as DNA A and DNA B) that are packaged into separate particles
- essential genes on each segment - 36What is the clinical presentation of V. cholera?- asymptomatic to severe, rapidly fatal, dehydrating diarrhea
- characterized by rice-water stool
- extensive fluid & electrolyte loss leading to hypovolemic shock, hypokalemia, and metabolic acidosis
- mortality up to 60% if untreated
- mortality < 1% with treatment - 37hypovolemicdecreases blood volume
- 38hypokalemiadecreased potassium levels
- 39metabolic acidosislow blood pH
- 40What is the reservoir of V. cholera?estuarine environment
- 41What are the transmission vehicles of V. cholerae?contaminated water and food (sea food)
- 42What is the infectious dose of V. cholerae?~ 10x8 bacteria
- 43What is the incidence of V. cholerae?US: low, 2-13 cases/yr - traveler's disease
global: > 500,000 cases reported/yr
endemic regions - symptomatic cases 2-15 yr olds
epidemic regions - all age groups at risk
7 pandemics since 1817 - 44What is the strain (serotype) association of pandemics and epidemics of V. cholerae?- all prior pandemics and epidemics due to serotype O1 (Yemen)
- epidemic ~ 20 yrs ago secondary to serotype O139 (Bengal) - 45What is the name of the phage that encodes the pathogenicity of V. cholerae?CTX phi
- 46What does the V. cholerae phages encode for and its characteristics?encodes cholera toxin
binds TCP pilus
absent from most environmental isolates
viable non-culturable - 47What are the diagnostics techniques used to identify V. cholerae?- movement of the bacteria via darkfield microscopy
- culture fecal specimens on TCBS agar
- fluorescent antibodies
- biochemical verification and serotype O1 & O139 - 48What is the treatment for V. cholerae?- fluid & electrolyte replacement
- antibiotics reduce the duration of symptoms and shedding
- antibiotic sensitivity varies - 49What are the preventative measures of V. cholerae?- proper sanitation and water treatment facilities
- oral vaccines - 50What are the oral vaccines of V. cholerae?- DUKORAL
-Shanchol/mORCVAX/Euvichol
-Vaxchora - 51What is DUKORAL?killed whole cell w/recombinant B subunit for serotype O1 strains
- 60% efficacy - 52What is Shanchol/mORCVAX/Euvichol?killed whole cells for serotypes O1 and O139
- 53What is Vaxchora?live attenuated oral vaccine
FDA approved in 2016 - 54What are the clinical presentations of V. parahaemolyticus?- explosive watery diarrhea (sometimes bloody)
- a headache
- cramps
-nausea
- occasionally septicemia - 55What is the treatment of V. parahaemolyticus?self-resolving
- 56What is the reservoir for V. parahaemolyticus?marine environment
- 57What is the transmission route of V. parahaemolyticus?raw sea food
- 58What is the prominent serotype of V. parahaemolyticus and where is it geographically located?O3:K6
Japan - 59What are the two toxins that V. parahaemolyticus produces?TDH
TRH - 60What is TDH and what bacteria produces it?thermostable direct hemolysin
V. parahaemolyticus - 61What is TRH and what bacteria produce it?TDH-related hemolysin
V. parahaemolyticus - 62What are the human infections that occur from V. vulnificus?- rapidly progressing necrotic wound infections
- fulminant septicemia - 63What is the epidemiology of fulminant septicemia in those exposed to V. vulnificus?- 50% mortality
- 80% occurrence in male
- 93% occurs with consumption of raw oysters
- 95% of those infected have pre-existing liver conditions - 64How are those commonly infected with V. vulnificus?fishmongers
oyster shuckers
results of occupational hazard - 65What are the other species of Vibrio cause infections in humans?V. alginolyticus
V. hollisae
V. mimicus
V. fluvialis
V. furnissii
V. damsela - 66What are the microbiological features of the genus Campylobacter?- gram negative
- 0.3-0.6 micron diameter
- curved/helical rod
- single polar flagellum
- microaerophilic (5-7% oxygen)
- oxidative metabolism (do not utilize carbohydrates)
- optimal growth at 42 degrees (some species)
- oxidase positive
- polysaccharide capsule (phase variable) - 67What is the disease presentation of Campylobacter infection?bloody diarrhea
abdominal cramping
frequent bowel movements (~10-20/day)
last for about 3-4 days
self-resolving - 68What are the transmission vehicles of Campylobacter?undercooked poultry
raw milk
surface water
beef, clams, and cheese
direct contact with infected animals & pets - 69What is the US incidence of Campylobacter?~ 1.5-2 million vases/yr
seasonal, summer to early fall
higher in rural communities - 70What is the global incidence of Campylobacter?pervasive
symptomatic in children
asymptomatic in adults - 71What genus of bacteria rivals Campylobacter in disease incidence in the U.S.?Salmonella
- 72What are the sequalae diseases associated with a Campylobacter infection?- Guillain-Barre syndrome
- reactive arthritis
- inflammatory bowel disease - 73What is Guillain-Barre syndrome and its epidemiology?flaccid peripheral neuropathy due to inflammatory demyelination
- approx. 1 in 2000 C. jejuni infections
- 30-66% of cases have previous C. jejuni infections
-sialic acid containing LOS - 74What occurs secondary to sialic acid-containing LOS?induces cross-reactive antibodies
"molecular mimicry" - 75What is LOS stand for and mean?lipodigosaccharide
similiar to LPS, but lacking outer O-antigen repeats - 76What are the isolation and identification methods of Campylobacter?1. direct examination of feces
2. culture stools (blood)
3. bacteriological filter which has a very small diameter - 77What is the treatment and prevention for a Campylobacter infection?- self-resolving
- fluid and electrolyte replacement
- anitmicrobioal treatment in severe cases and bacteremic patients
- prevented by proper hygeine and food preperation - 78Why is the treatment of a Campylobacter infection with vaccines problematic?- > 90 somatic O antigents
-resistant to quinolones - 79What are the microbiological features of Helicobacter?- gram negative helical rod
- motile by polar flagella
- microaerophilic
- urease positive
- oxidase positive
- high genetic variability - 80What is the disease presentation of H. pylori?- results in life long gastric colonization
- initial acquisition can be asymptomatic or cause gastritis
- main cause of gastric ulcers - 81What is the reservoir for H. pylori?humans
- 82How is H. pylori transmitted?fecal-oral & oral-oral
clusters within family - 83What is the US incidence of H. pylori infection?- increase with age
- inversely related to socio-economic status - 84What is the global incidence of a H. pylori infection?- >70% carriage by age 10 in developing regions
- 85What is a possible occurrence with treatment of H. pylori?can cause esophageal reflux that can cause esophageal cancer
- 86What is the only bacterium that is considered to be a gastric carcinogen?H. pylori
- 87What are the isolation and identification methods for H. pylori?1. histological examination of gastric biopsy (gold standard, but invasive)
2. culture of biopsy on specialized media (2 week incubation period)
3. urease test via biopsy or breath test (isotopically labeled CO2)
4. stool antigen tests (commercially available) - 88What are the treatment and prevention methods of H. pylori?-7-10 day regimen with proton pump inhibitor, macrolide and beta lactam
- benefit/risk assessment
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- Flashcards on Enterics II, created by Kerra Washington on 06/11/2018.
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- Kerra Washington · Nov 2018
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- Nov 12, 2018
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