Talk:Escherichia coli
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Below is the text from three electronic flashcards I made from lecuture notes from two different microbiology classes. If nobody else is able to do so, I will translate this data into coherent English sentences as I find time. maveric149
Escherichia coli
1) Gram reaction? Gram -
2) Catalase reaction? Catalase +
3) Microscopic appearance? Rod
4) Colony characteristics? Colilert Test+ : yellow & fluoresce
5) Isolation? Fecal coliforms can grow @44.5°C,
inoculum? media? conditions?
Colilert Test: -ase = E. Coli enzyme
ONPG + ß-galactosidase ––> ONP(bright yellow) + G MUG + ß-D-glucuronidase ––> MU(fluoresces @340nm) + G
incubate 24 hrs @ 35°C
Colilert Test
ONPG Ortho-nitro-phenol-ß D-Galactopyronoside
ß galactosidase is an enzyme of E. Coli that can cleave the bond between ONP & G in ONPG (this bond is similiar to the bond between Glucose & Galactose)
MUG 4-methyl-umbelliferone-ß D-Glucuronide
Escherichia coli 1
1) Natural environment is ... large intestine of mammals
2) Dominant types are.... non pathogenic
3) Serology (# of Serogroups) = O (174), & H (flagellar, 56)
4) How many types are pathogenic.= 5 (3 are of most concern)
5) Ones that are of most concern
Enterotoxigenic E. coli (ETEC) ¹
Enteropathogenic E. coli (EPEC) ²
Enterohemorrhagic E. coli (EHEC)
¹ Major cause of death in 3rd world. Travelers & child diarrhea. Heat labile toxin & heat stable toxin.
² Cause of severe diarrhea in children & travelers.
Escherichia coli 2
1) How is O157:H7 different?
does not ferment sorbitol in 24hrs,
MUG negative, doesn't grow well at 44-45°C, acid tolerant
2) Properties of EHEC?
>100 known serotypes (O157:H7), hemolytic uremic syndrome (HUS -- 3-5% deathrate), low dose, onset 3-8 days, sm intestine infector
3) Symptoms of O157:H7? Severe abdominal pain, bloody diarrhea, vomiting, low to no fever. Last 6-8 days. Produces shiga-like toxins (aka verotoxins)
Why was "Escherichia coli" moved here? We don't generally abbreviate genus/species names here; why do it in this case? --LDC
- Because "Escherichia" is hardly ever used -- even by microbiologists (let alone everyone else). --mav
While it's certainly true that E. coli is an indicator species for fecal contamination of water, when we do surface water or treated wastewater sampling we are actually looking for total coliforms -- many species; occasionally also for fecal strep. There is some indication, though it's controversial, that the ratio of fecal coliforms to streptococci present can indicate whether the source is likely to be human (e.g., failing septic systems) vs. animal (e.g., agricultural runoff). When a drinking water utility reports a positive sample to us (e.g., contamination due to line break, etc.), presence or absence of E. coli is noted. Uyanga 14:44, 29 Aug 2003 (UTC)
Changes to text on E.coli and UTI
Just to explain the changes I've made to the para on UTI and E.coli. I've downgraded the importance of honeymoon cystitis a little. While intercourse can be a precipitating factor in UTI I don't think it's a major cause and may be largely aprocryphal. In practice there always 'seems' to be a large sex imbalance in the incidence of UTI (biased heavily to females) but as I understand it, over a lifetime the risk is about even. Male and female are equal up to age 10 or so, females then lead up to about 55/60 years (short urethra, pregnancy) then males suffer more (prostate, general aging, hospitalisation etc). I'll try to back this up with some figures if I can.
I'll try and add something about what makes E.coli (or at least some strains of E.coli) such good uropathogens as well, when I can.
Didn't sign that last contribution.Tim 21:12, 14 Nov 2004 (UTC)
- from Journal of Gender Specific Medicine. 2000 Nov-Dec;3(8):27-34. (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11253265&dopt=Abstract) "Urinary tract infections (UTIs) are more common among women than men, although the prevalence in elderly men and women is similar." Matt 17:21, 26 May 2005 (UTC)