afebrile watery diarrhea Flashcards
cholera is.
acute illness via enterotoxin colonizing mucosal surface of small bowl
rapid loss of fluid and e-lytes–>hypovolemic shock, metab. acidosis, death
Vibrio cholerae
G-, ox positive facultative anaerobe, salt-loving, curved rod
common H Ag
EC, noninvasive
biofilm matrix proteins: RbmA, Bap1, RbmC
main V. cholera O Ag type
Type O1
O139 as well
Cholera-like illness serotypes
O141, O75 (US) O37, O10, O12, O6, O14 (world) serotype changes from lateral transfer of gene cassettes El Tor strain pandemic, Haiti epidemic inc. virulence
new strain of cholera resistant to ?? found in ??
2 super bug genes
strain name??
3rd generation Abs, India
New Delhi Metallo B-lactamase-1 (blaNDM-1)
plasmid-med B lactamase-1 (blaDHA-1)
O1 El Tor Ogawa
V. cholera transmission: different infectious doses for person-person vs environ. spread
person-person
hyperinfectious state of rice-water feces for 5 hours
from environment, food-borne, contam. food/water
high infectious does: 10^6-8 bac
V. cholera spread in ?? mos
risk factor ??
warm mos: that don't have an "R" contaminate shellfish (w/bicarb or food: inf. dose drops to 10^4)
cholera is a ??? therefore multiply in and adhere to ?? producing ??
toxemia, sm. intestine, CT enterotoxin
V. cholera O1 virulence factors
TCP*
CT-1, CT-2*
MARTX toxins
*not all genes that carry 1 or both(1st 2) of these genes cause cholera
cholera vir. factor: TCP
toxin co-reg common pili
need for colonization and is attach. site for CTX? (lysogenic phage containing genes encoding cholera toxin)
cholera virulence factors: CT-1 and CT-2
cholera enterotoxins
cause of diarrhea, heat-labile, bind Gm1 ganglioside–>inactivation of GTPase–>inc. cAMP production–>hyper sec. of Cl- and bicarb–>H2O follows from cell
cholera virulence factor: MARTX toxin
multifunctional-autoprocessing repeats-in-toxins
produced by most isolates
disrupts actin cytoskeleton–>either? allows colonization/reduces functionality of innate immune cells preventing clearance, aides extra intestinal survival
rel. to C. diff toxin B
immunity to V. cholera: both ?? and ??
vaccines cross-protect for ??
CD4+ T-cell dependent, IgA
ETEC, O1, NOT O139
V. cholera s/s
mild diarrhea–>fatal (hypovolemic shock, hemoconc., K depletion, loss of bicarb, sev. acidosis
V. cholera incubation period
diarrhea time frame
fever ?
disease course ?
1-5 days, then abrupt
diarrhea for 1-3 days
typically NO fever
may run 1-7 days
classic V. cholera presentation
effortless vomiting, watery diarrhea (“rice water” appearance, flecks of floating mucus), musc. crapms, poor turgor, “absent” periph. pulse, sunken eyes, wrinkled skin, cyanosis, fishy odor–>60% mort. w. out tx!
V. cholera dx
abrupt afebrile watery diarrhea assoc. with eating shellfish
10^6-10^8 vibrios/mL in rice stools (microscopic)
Cx: spec. request media
serology: rapid slide test, serotype
V. cholera ddx
all abrupt afebrile diarrhea
base ddx on epidem: food hx, incub. period
V. cholera tx
abx?
enteric isolation
initial rehydration IV: 5gm NaCl 4 gm NaHCO3, 1 gm KCl in 1L H20
oral admin of gluc-e-lyte solution, amylase-res. starch (SCFA-prod in colon, stim. Na absorption)
abx only for sev. dehydration, also Zn supple.
V. cholera ppx
handle food properly!
vaccine for travel to endemic area
Enterotoxigenic E. coli (ETEC)
what color on McConkey?
G- rod, motile by flagella (H Ag) or non-motile, non-fastidious, facultative anaerobe, oxidase negative
coliform: ferments lactose with acid and gas production
PINK on McConkey agar
ETEC happens in who?
passed how?
associations?
traveler’s diarrhea, weanling diarrhea, food and water borne outbreaks ww
fecal-oral, reservoir is GIT of humans/animals
no gender/season assoc
risk factor: poor sanitation
ETEC has ?? that allows them to attach to sm. bowel and secrete ?? causing mucosal cells to secrete fluids and e-lytes
fimbriae
enterotoxins
ETEC virulence factors
colonization factor Ag (CFA) fimbriae: adherence
enterotoxins:
LT (heat labile): like Cholera toxin (CT), inc. cAMP
ST (heat stable): binds GC–>inc. cGMP–>phos/act. Cl channel–>Cl secretion, inhib. of Na uptake
what can provide partial immunity to ETEC??
what else provides some protection??
cholera vaccine bismuth subsalicylate (4tabs/day) +/- abx for travelers
ETEC self-limiting?
yes
ETEC infectious dose??
onset??
duration?? fever?
HIGH: 10^6-10^8
abrupt onset: 1-2 day incubation period
diarrhea for 1-3 days, no fever
ETEC dx: Cx?
ddx
Cx not useful
any afebrile short term diarrhea: cholera, aeromonas, FB agents, use epi to rank
ETEC tx
abx?
fluid/e-lyte replacement
abx in sev. cases
Enteroaggregative E. coli (EAEC)
adhere to epithelial cells: HEp-2 in a “stacked-brick” pattern
unknown how it causes diarrhea, new strains can produce Shiga toxins
cause persistent watery diarrhea
reservoir: human GIT
aeromonas hydrophila
resistant to ??
oxidase positive
Chlorine and refrigeration/cold temps
aeromonas causes what??
transmitted how ??
live where ??
up to 13% reported gastroenteritis cases in US
fecal-oral
fresh water, ubiquitous: environ/clinic/food
can survive and multiply at low temps
unknown infectious dose
aeromonas produces…
for how long??
how?
profuse afebrile watery diarrhea
about 3 days duration
produces enterotoxin (like CT)
aeromonas dx: Cx?
ddx
Cx on blood agar with ampicillin
Cholera, ETEC (travs diarrhea) any fresh/brack water contam. food-assoc. afebrile diarrhea of short duration
aeromonas tx
aeromonas is typically ??
rehydration
MDR
