GI 6 Flashcards
similar to shigellosis but less severe ..and what does shigellosis have that this condition does not
enteroinvasive e. coli (EIEC)
does not have a shiga toxin
pathogenesis of enteroinvasive e. coli (EIEC)
invades the enterocytes of LI (like shigellosis)
what are the different types of salmonella genus based on
Vi antigens (capsular)
3 clinical manifestations of salmonella
gastroenteritis, septicemia/bacterial, enteric (typhoid) fever
bacteria associated enteric typhoid fever
Salmonella Typhi
tests that you order for the different symptoms of salmonella
- enterocolitis: positive in stool culture soon after test but not seen in blood
- septicemia/bacteremia: pos in blood culture during high fever and sometimes seen in stool
- enteric typhoid fever: pos in blood culture for 1st and 2nd week then pos from 2nd week and on in stool
pathogenesis of salmonella
they all will invade SI and sometimes LI but only septicemia/bacteremia will go the lymphatics then enter the blood and become systemic
what harbors salmonella that leads to enterocolitis/gastroenteritis
it is food borne infection and seen mainly in dairy/poultry products
who is mainly infected with reptile associated salmonella
infants and children through direct or indirect contact
who in the US is infected with enteric typhoid fever
those that have travelled to Asia, Mexico, and India
what occurs if enteric typhoid fever goes systemic
it can enter the liver/gall bladder and replicate in the bile and then bile enter the SI and reinfects leading to inflammation and ulceration
of course if it gets to SI –> seen in feces
types of people who are important/dangerous in the transmission of typhoid fever
carriers because they have no symptoms but yet shed and infect others
how can you prevent transmission of typhoid fever
take out the gall bladder so there will be no site for microbe to multiply and shed in feces
how do you isolate and detect salmonella
use McConkey’s agar or S-S agar (salmonella -shigella agar)
what do you see on S-S agar for salmonella
colorless/pale because salmonella does not do lactose fermentation
how do you differentiate salmonella from shigella
salmonella is motile while shigella is not
salmonella uses gas from glucose
salmonella does H2S production and shigella does not (with the exception of s. flexnieri)
diagnostic feature of s. typhi
- S-S agar
- history of travel to endemic areas like Asia, Mexico, and India
- Positive widal reaction
- gram neg, motile bacteria
morphological feature of campylobacter
gram neg, motile, microaerophilic, does not ferment CH2O, and catalase positive
carrier of campylobacter coli
pigs
in general, how does one get infected with campylobacter
fecal contaminated water
unpasteurized milk
raw/partially cooked poultry
toxins of campylobacter
- endotoxin
- enterotoxin –> watery diarrhea
- cytotoxin: verotoxin (similar to shiga toxin) –> bloody diarrhea
clinical symptoms of campylobacter
symptoms begin 3-5 days after ingestion
- pyrexia (raised temp - fever)
- prostration
- abdominal pain
- diarrhea
complications of campylobacter
- reactive arthritis
- guillian barre (aka acute motor axonal neuropathy) which is a symmetric ascending paralysis
detection of c. jejuni
fecal specimen culture –> gram neg, motile, catalase pos, microaerophilic, needs 10% CO2
Yersinia enterolytica is common in what age group
children under the age of 7
what other condition rivals yersinia enterolytica
salmonella acute gastroenteritis because of commonality in cooler climates
yersinia is a pyschrotroph - facultative psyhcrophile
pathogenesis of yersinia enterolytica
releases a ST enterotoxin that increases cGMP –> watery diarrhea
induces invasive inflammation in the distal ileum and adjacent tissues and mesenteric lymph node hence mimicking appendicitis
treatment of yersinia enterolytica
doxycycline and oxytetracycline
complication of yersinia enterolytica
post-infective reactive arthritis (autoimmunity arthritis)
what are the non cholera vibrios
v. parahemolyticus
v. alginolyticus
v. vulnificus
v. cholerae (non toxigenic v. cholerae)
features of non cholerae vibrios
not agglutinated by anti 01 sera halophilic organisms (common coastal waters)
how does one get vibrio parahemolyticus and in what area of the world is it common
from eating raw or undercooked seafood
common in Japan - they eat raw fish (sushi)
how does one get infected with vibrio vulnificus
eating raw oysters
clinical features of vibrio vulnificus
it is a virulent strain
get intense skin lesions –> gastroenteritis and severe bacteremia
how do you diagnose vibrio
screening stool for oxidase activity
TCBS agar - thiosulfate citrate bile salt sucrose agar –> sucrose negative will be vibrio parahemolyticus and vibrio vulnificus
what does enteroaggregative possess
AAF - aggregative adherence factor
another name for STEC - shiga toxin producing e. coli
VTEC - verotoxin producing e. coli
what can STEC/VTEC cause
hemorrhagic colitis
hemolytic uremic syndrome
thrombotic thrombocytopenia purpura
which one of the STEC/VTEC affect adults and which children and which elderly
hemorrhagic colitis - adults
hemolytic uremic syndrome - children
thrombotic thrombocytopenia purpura - elderly
toxin released by VTEC/STEC
verotoxin released and it causes inhibition of protein synthesis (which is why it is called shiga like toxin e coli)
worst thing you can do in patients with VTEC/STEC and why
treat them with antibiotics because the killed organism will release more toxin causing even more damage
what is screened for in routine stool culture? what if it is bloody?
routine - campylobacter, shigella, salmonella
if bloody - STEC/VTEC
complication of a pseudopod forming protozoa
entamoeba histolytica
toxic megacolon
how does one get infected with balantidum coli
contaminated water or food by pig feces
pathogenesis of balantidum coli
you ingest cyst –> becomes trophozoite which invades the SI –> into LI to invade colon –> shed cyst and trophozoite in the feces
diagnosis of balantidum coli
ciliated trophozoite in the feces because cysts are not frequent
manifestations of ascaris lumbricoides and treatment
asymptomatic –> but could be pulmonary symptoms
treat with albendazole
how would you describe the ascaris lumbricoides worm
large white/pink adult worm that is 15-25 cm long
clinical manifestation of trichuris trichuria especially in children
asymptomatic with peripheral blood eosinophilia
in children - iron deficiency and growth retardation
treatment of trichuris trichura
albendazole just like ascaris (both are worms that gives you eosinophilia)
manifestation of anyclostoma duodenale nectar americanus
iron deficiency and protein energy malnutrition especially in children and women of child bearing age
treatment of ancylostoma duodenale nectar americanus
albendazole and iron replacement
