Term
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Definition
- may not have any diarrhea or vomiting
- dysentary may be present
- fecal leukocytes present
- blood in stool
- fever |
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Term
Inflammatory gastroenteritis pathogens |
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Definition
- Salmonella sp.
- Shigella sp.
- Campylobacter sp.
- Yersinia enterocolitica
- Vibrio parahaemolyticus
- Francisella tularensis
- EIEC
- EHEC
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Term
Salmonella sp. (general, habitat) |
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Definition
Gram -, rods, motile, facultative anaerobes, non-lactose fermenting
Habitat:
- typhi = human
- enteritidis and choleraesuis = intestines of animals |
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Term
Salmonella sp.: transmission |
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Definition
Fecal-oral route
animals to humans (Turtles)
animal food products to humans |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
-sensitive to killing by gastric acid
-attach to gastric epithelial cells in sm. intestine and colon -> bacterial type III secretory system injects bacterial proteins into host cells -> internalization -> replication in vacuoles -> cell lysis -> enter mesenteric lymph nodes and blood stream -> fever, ab pain, diarrhea |
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Term
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Definition
used by Salmonella sp.
-bacterial needle that injects effector proteins into host cell |
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Term
Salmonella enteritidis: Virulence |
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Definition
-inflammatory diarrhea due to invasion of intestinal epithelial cells
-controlled by vagocytic defenses
-risk in immunocompromised for disseminated disease |
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Term
Salmonella typhi: pathogenesis |
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Definition
-cause enteric fever (typhoid fever)
-fever, nonproductive cough, bloody diarrhea, ab pain, rose spots on skin |
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Term
Salmonella typhi: Virulence |
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Definition
-invasive intracellular pathogen
-reaches blood stream (better than other Salmonella sp.)
-little diarrhea
-enteric fever
-involvement of other organs |
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Term
Salmonella: Clinical manifestations - Enteritis |
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Definition
- most common form of salmonellosis
- symptoms occur 6 - 48 hrs after injestions
- nausea, ab cramps, vomiting, nonbloody diarrhea
- fever, headache, myalgias
Symptoms last 2 days - 1 wk |
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Term
Salmonella: Clinical manifestations - septicemia |
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Definition
- higher risk in pediatric, geriatric and immunocompromised
- clinical presentation like all Gram (-) sepsis |
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Term
Salmonella: clinical manifestations - Enteric fever |
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Definition
S. typhi = typhoid fever
others = paratyphoid fever
-bacteria pass through the gastric epithelial cells and are engulfed by macrophages
-Symptoms:
- 10 - 14 days after ingestions
- fever, headache, myalgias, malaise, anorexia for 1 wk followed by diarrhea
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Term
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Definition
Non-lactose fermenter = colorless on MacConkey agar
motile
H2S+
enteritidis - isolated from stool
typhi - isolated from stool OR blood
fewer rectal leukocytes than shigellosis |
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Term
Shigella Sp.: general, habitat, transmission |
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Definition
General:
Gram -, bacilli, non-motile, non-lactose fermenter
resistant to stomach acids = only 10 - 20 bacilli needed to cause disease
Habitat:
human and primate intestines
invades and survives in cytoplasm
Transmission:
fecal-oral, P2P
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Term
|
Definition
-produces shiga toxin (exotoxin, cytotoxic to epithelial cell)
-attach and penetrate GI epithelial cells and M cells (use Type III)
-multiply intracellularly, spread to contiguous cells (use hemolysin to escape cell)
-use host cell actin for transport |
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Term
|
Definition
-isolation from stool
-nonlactose fementer
Distinctive features from Salmonella:
-non-motile
-H2S negative
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Term
Shigellosis: clinical manifestations |
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Definition
-incubation period 36 - 72 hrs
-fever, cramping ab pain (both non specific)
-dysentary 2 days later
-watery diarrhea |
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Term
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Definition
-usually self limited
-prevent P2P spread
-fluid and electrolyte replacement for severe cases
-antidiarrheal compunds contraindicated (b/c they inhibit peristalsis = can't get rid of toxin) |
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Term
Campylobacter sp: general |
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Definition
General:
gram -, curved or comma shaped, microaerophilic, motile rods
can suvive intracellularly in monocytes and intestinal epithelial cells -> tissue necrosis and cell death
can travel to blood stream
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Term
Campylobacter sp: habitat and transmission |
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Definition
habitat: intestinal tract of animals
transmission:
-fecal-oral route
-transmitted ny contraminated food; more common in summer |
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Term
Campylobacter sp: incidence |
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Definition
leading cause of bacterial diarrheal illness in US
most common cause in udnerdeveloped countries
3-5 days after ingestion; diseasse only if penetrates the mucouse layer and invades GI epithelial cells |
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Term
Campylobacter sp: virulence |
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Definition
-flagella
-adherence factors
-heat labile toxin = watery diarrhea
-ingestion by host cells = inflammatory colitis
-can also produce shiga toxin
-inflammatory and bloody diarrhea |
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Term
Campylobacter sp: clinical manifestations |
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Definition
anywhere from 7 days to chronic infection
periumbilical cramping, intense abdominal pain that mimics appendicitis, malaise, myalgias, headache, vomiting
watery diarrhea = most common
inflammatory bowel disease |
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Term
Campylobacter sp: detection |
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Definition
Detection:
-WBC in feces
-isolation in stool: requires growth on Campy or Skirrow media
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Term
Yersinia enterocolitica: general, habitat, transmission |
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Definition
general:
aerobic, gram (-), bacilli
habitat: domestic and farm animals
transmission: fecal-oral route |
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Term
Yersinia enterocolitica: pathogenesis |
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Definition
invades mucosa of terminal ileum -> painful enlargement of mesenteric lymp nodes
- mistaken for appendicitis
- causes inflammatory and bloody diarrhea
transmitted by contaminated meat products, mostly during winter (can grow at 4 degrees C) |
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Term
Yersinia enterocolitica: virulence and clinical manifestations |
|
Definition
virulence:
-heat stable enterotoxin -> inflammatory and bloody diarrhea
clinical:
-febrile illness with abdominal pain
-can mimic appendicitis
-lasts 2 - 3 weeks
-common in infants, occasional septicemia |
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Term
Yersinia enterocolitica: detection |
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Definition
isolation from stool and blood |
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Term
|
Definition
gram (-), motile, bacilli
found in fresh, salt and chlorinated water habitats
very resistant to temperatures and chemicals
Aerolysin cytotoxic toxin (ACT)
opportunistic pathogen in immune compromised |
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Term
|
Definition
small, curved, gram (-), bacilli, single flagellum |
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Term
V. cholerae: virulence, transmission |
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Definition
virulence:
-produces cholera toxin - activates adenylate cyclase to increase cAMP -> voluminous, watery diarrhea
transmission:
-contaminated water or food (shellfish or crabs) |
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Term
Vibro cholerae: pathogenesis |
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Definition
-colonizes small bowel
-acute illness due to enterotoxin production
-severe form: rapid loss of liquid and electrolytes; hypovolemic shock, metabolic acidosis and death
-acid sensitive = requires a lot to cause disease |
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Term
Cholera toxin (enterotoxin) |
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Definition
- A-B type toxin
- A increases adenylate cyclase activity -> increase in cAMP |
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Term
Vibro cholera: clinical manifestations |
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Definition
-abrupt, watery diarrhea (rice water)
-vomiting following diarrhea
-cyanotic, sunken eyes, high voice, unobtainable BP, etc. all because of severe dehydration |
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Term
Vibrio cholera: diagnosis |
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Definition
-rice water stools
-stool culture on thiosulfate-citrate-bile salt-sucrose agar (TCBS); colonies are yellow, other Vibrio are green |
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Term
|
Definition
-hemolytic strains are most virulent
-enterotoxin production -> moderate bowel inflammation; mild to moderately severe diarrhea
-halophilic (salt-loving); grows in marine environments
-found in raw or undercooked shellfish
-colonizes small intestine |
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Term
Vibrio parahaemolyticus: Transmission, clinical manifestions, diagnosis |
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Definition
Transmission:
-ingestion of inadequately cooked seafood or sushi
clinical: watery diarrhea, ab cramps, nausea, vomiting, bloody diarrhea (sometimes)
diagnosis: green on TCBS agar |
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Term
Enterotoxigenic E. Coli (ETEC) |
|
Definition
-Non-invasive = do not see fecal WBC's
-colonize sm. intestine
-common cause of traveler's diarrhea
-produce cholera-like (heat-labile) toxin and a heat-stable toxin -> both lead to watery diarrhea (secretion of Cl- -> osmotic diarrhea)
-abrupt onset watery diarrhea, lasts less than 24 hrs after initiation of fluid replacement |
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Term
Enteropathogenic E. Coli (EPEC) |
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Definition
-non-invasive = do not see WBC in stool
-no known toxin
-adheres to epithelial cells in Sm. intestine and disrupts microvilli (effacement)
-type III secretory system
-makes its own receptor
- when it binds to cell it forms pedestals
-watery diarrhea with mild inflammation, infants <6 m.o. |
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Term
Enteroaggregative E. Coli (EAggEC) |
|
Definition
-non-invasive = do not see WBC in stool
3 stages:
- adhere to mucosa
- enhanced mucus production encases bacteria enabling biofilm formation
- elaboration of cytotoxin, damages intestinal cells
-may colonize sm. and lg. intestine
-cause of a more persistent diarrhea |
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Term
Diagnosis and treatment of inflammatory E. coli infections |
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Definition
Diagnosis:
-isolation on MacConkey's Agar (like Vibro)(lactose fementer)
Tx: fluid and electrolytes, antibiotics |
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Term
Enteroinvasive E. coli (EIEC) |
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Definition
-similar pathogenesis as for Shigella infections
-results in watery diarrhea and dysentery
-sporadic outbreaks in infants and children |
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Term
Enterohemorrhagic E. coli (EHEC) |
|
Definition
-mostly infects lg. bowel
-kidney damage due to Shiga toxin
Clinical manifestations:
-Hemolytic colitis: severe crampy ab pain, watery diarrhea followed by bloody diarrhea, no fever
-Hemolytic Uremic Syndrome: triad of acute renal failure, thrombocytopenia and microangiopathic hemolytic anemia |
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Term
Diagnosis and Treament of Invasive E. coli infections: EHEC |
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Definition
Dx:
-carbohydrate sorbitol must be included in the medium
-inability to ferment sucrose
-ELISA detection of Shiga Toxins 1 and 2 in stool
Tx: Avoid antibiotics |
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Term
Listeria monocytogenes: Listeriosis |
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Definition
-usually mild diarrhea but systemic symptoms are prominent
-pathogen can break into cytoplasm and divide
-major risk is maternal infection during pregnancy
-serious in immunocompromised |
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Term
Three most common causes of acute infectious diarrhea |
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Definition
Salmonella, Shigella, Campylobacter |
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Term
|
Definition
- MOST common in uncomplicated outpatient UTI's
- Gram (-), motile, bile tolerant, lactose fermenting
- Lab ID: pink on MacConkey Agar
- transmission: part of normal flora
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Term
E. coli: Virulence Factors |
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Definition
- adherence to urethroepithelial cells via fimbriae (pyelonephritis strains are the most adherent)
- endotoxin
- some strains have capsule adhesion
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Term
|
Definition
UPEC
- adhere to urethroepithelial cells
- increased serum resistance
- increased hemolysin production
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Term
Staphylococcus saprophyticus |
|
Definition
- 5-15% of cystitis cases in young, sexually active women
- gram (+), cocci in clusters
- transmission: normal flora of skin and GU mucosa
- prevention: urination after intercourse
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Term
Staphylococcus saprophyticus: Lab ID |
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Definition
- white colonies on blood agar
- catalase (+)
- coagulase (-)
- mannitol non-fermenter
- Novobiacin resistant (distinguishes from other coagulase (-) staph)
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Term
Staphylococcus epidermidis |
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Definition
- nosocomial UTI pathogen
- white colonies on blood agar
- Catalase (+)
- Coagulase (-)
- mannitol non-fermenter
- novobiacin sensitive
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Term
Staphylococcus epidermidis: pathogenesis and tx/px |
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Definition
- Pathogenesis: slime production and biofilm formation; colonizes catheters and prostheses
- Tx/Px: MDR strains exist so use catheter care
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Term
|
Definition
- common in pts with recurrent infections, instrumented or have anatomic defects
- normal flora of UG tract
- MDR (vanco)
- fomerly classified in Streptococcus
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Term
|
Definition
- produces ureases which cause pyelonephritis
- Highly motile (swarmer) - able to ascend the ureter against the flow of urin
- Gram (-), rod
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Term
Proteus mirabilis: virulence and lab ID |
|
Definition
Virulence Factors:
Lab ID:
- non-lactose fermenting
- urease (+)
- indole (-)
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|
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Term
|
Definition
- common in pts with recurrent infections, instrumented or have anatomic defects
- Gram (-) rod, motile
- lactose fermenter
- MDR
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|
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Term
|
Definition
- common in pts with recurrent infections, instrumented or have anatomic defects
- nosocomial pathogen
- inherently resist to many antibiotics
- Gram (-), rods, motile, aerobe
- ubiquitous distribution in soil and water
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Term
Psuedomonas aeruginosa: lab ID |
|
Definition
- oxidase (+) (distinguishes from E. coli)
- pigment production
- fimbriae for adherence
- endotoxin
- biofilm formation (attaches to catheters)
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|
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Term
|
Definition
- nosocomial UTIs
- Gram (-), non-motile, lactose fermenter
- Transmission: normal flora, able to survive in moist environments (hands)
- virulence: capsule, endotoxin, fimbriae
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|
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Term
|
Definition
- gram (-), bacillus, facultative anaerobe
- normal GI flora in small numbers
- environmental bacteria
- opportunistic pathogen (nosocomial)
- characteristic red pigment
- lactose - , indole - , urease - , motile, H2S -
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|
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Term
|
Definition
- common in hospitalized pts who are on broad-spectrum antibiotics and have a bladder catheter
- diabetic pts
- immunosuppressed pts
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