Gastrointestinal tract infections. Diarrhea. S tool consistency – liquid , half-liquid , mushy Abnormal stool volume >300g/ 24 h Abnormal frequency Contains pus , blood , mucus , flaked epithelium Green, grey , grey-yellow.
Most bacterial pathogens that are ingested never reach the intestinal tract the normal gastric acid barrier.
1)by a shift in delicate balance of bidirectional water and electrolytes fluxes in the upper small bowel by intraluminal toxins or minimally invasive organisms
2)by inflammatory of cytotoxic destruction of the ileal or colonic mucosa
3)by penetration through an intact mucosa to the reticuloendothelial system
These three types can be distinguished by a quick simple examination. Mucus from a fresh stool specimen is mixed with a drop of methylene blue and examinated for the presence of fecal leucocytes.
2) The presence of polymorphonuclear leucocytes documents an inflammatory or invasive process that usually arises from colon or distal small bowel. Agents that cause an inflammatory colitis may require specific antimicrobial intervention as well as supportive fluid therapy
3)Caused by organisms that penetrate the intact intestinal mucosa often in the distal small bowel to multiply in the lymphatic or reticuloendothelial cells. This usually results in a febrile systemic illness with or without diarrhea
The classic example is Salmonella typhi. If diarrhea is present mononuclear leukocytes may be found in the stools of these patients
Shigella, Salmonella, Campylobacter
EIEC, Clostridium difficile
Cholera, ETEC, EPEC, toxin-typefoodpoisoning, rotavirus, adenovirus, Cryptosporidia, Giardia
non-inflammatoryintheearlystageswhendueto Shigella, Salmonella and Campylobacter
Fever,tenesmussuggests an inflammatory protocolitis
Blood-EHEC or amebiasis
Seafood-Vibrio or Norwalk-like viruses
Antibiotics- Clostridium difficile, salmonellosis.
Travel-ETEC, Norwalk-like, rotaviruses, parasitic (Giardia, Strongloides, Entamoeba, Cryptosporidium)
Outbreak- Staphyloccousaureus, Bacillus cereus, anisakiasis, Clostridium perfrigens ,Cryptosporidium, ETEC, Vibrio, Salmonella, Campyolobacter ,Shigella, EIEC.
1) 3,5 gNaCl + 2.5g NaHCO3 + 1.5g KCl + 20g glucose /1 liter of boiledwater
2) 3 leveltablespoons of sugar + ¾ teaspoon salt + ½ teaspoonsodiumbicarbonate
1 cup orangejuice and water to 1 liter
3) 1 levelteaspoon salt + 8 levelteaspoon of sugar per liter of water 1 cup orangejuiceortwobananas for potassium
40g cerealflour (rice,maize,wheat,potato) for glucose
Caution : beforegivingthe drink tasteit and be sureitis no moresaltythantears.
In othercasessuspect :
Invasivesalmonellosis , cholera, severeyersiniosis, giardiasis, amoebiasis, traveller’sdiarrhea
Transmission : inadequately cooked contaminated food , hen’s eggs (infected via the oviduct) raw milk ; turtles
Diagnosis : stool culture
1st week- fever , headache, malaise, constipation, unproductive cough, relative bradycardia
2nd week- continuous fever, apathy, diarrhea, abdominal distension,
‘rose spots’ (30%), splenomegaly (75%)
3rd week- continuous fever, delirium, drowsiness, gross abdominal distension, ‘pea soup’ diarrhea
4th week- gradual improvement in all symptoms.
Antibiotics: ciprofloxacin in adults or third-generation cephalosporin in children (ceftriaxone), chloramphenicol ,TMP/SMX
Transmission: faecal-oral, waterborne, foodborne, sexually –oral-anal contacts
Flies may spread infection in the tropics.
Invasion of lower intestines,ileum and colon,mucosal inflammation and secretion
EPEC-adhere to smallintestinalmucosalcellsdissolution of microvilli
ETEC action of twotoxins-A net increaseinintestinalsecretion
EIEC-invadesileal and colonicmucosainflammation and dysenterylikeillness
Action of cholera toxin (enterotoxin)throughstimulation od adenylatecyclase
Important : adequate disposal of human faeces during an epidemic
Thethridleadingparasiticcause of deathafter malaria and schistosomatosis
40.000-100.000 deathsannuallyinthe developing countries
Reiter’s syndrome (reactive arthritis) may develop after infection with Salmonella,Yersinia,Campylobacter,Shigella as well as after nonfoodborne infections such as nongonococcalurethritis and Cyclospora infections.
1) polyatrhritis 2) urethritis 3) conjunctivitis
DIAGNOSIS : diarrhea ormegacolontoxicumwithoutanyotherreason plus one of threebelow :
1)Demonstration of C.difficiletoxininstoolspecimen
2)Sigmoidoscopicchanges –colitis pseudomembranosa
3)Histopathologicallyconfirmed colitis pseudomembraosa
-may be presentafter one dayor 10 weeksafterfinishingantibiotic
Patientwith C. difficileshould be isolated for 48 afterdiarrehahasfinished
Outbreaks of staphylococcal food poisoning -ham,poultry,potato and egg salads,cream-filled pastries which are thought to be contaminated during preparation by a food handler.
Food handler’s hand has a purulent skin lesion (true in minority).
Long incubation Bacillus cereus-meat or vegetable dishes. BUT ALSO this bacteria is being a frequent contaminant of raw meats,vegetables,milkproducts.
It has been isolated from 25% of dried foods such as seasoning mixes,spices,dried potatoes and from more than 50% of dried beans and cereals.
Undercooked ground beef, lettuce, apple cider, alfaalfa sprouts, venison, and salami.
Healthy cattle commonly carry E.coli O157 –H7 in their intestines and execrate it in manure. Produce may be contaminated with E.coli O157 –H7 through use of manure as fertilizer or use water in processing that has been contaminated with fecal matter. Consumption of contaminated swimming water or drinking water.
Salomenlla- poultry , beef, egg, dairy products or produce. Internally contaminated shell eggs cause many outbreaks of infections with Salmonella serotype Enteritidis.
Fresh produce melons, tomatoes, raw milk, unpasteurized orange juice, alfalfa sprouts, contaminated chocolate candy, peanut snacks, cereals.
Crabs brought in travelers language from Latin America have caused cholera in the US.
most of ten associated with the ingestion of low-acid ph>4.4 home canned vegetables, fruits, fish. Honey was the source of Clostridium botulinum in some cases of infant botulism.
Norovirus –contamination of food by an ill food handler. Less commonly contaminations of shellfish, salads, imported frozen raspberries.
Cyclospora- infections were linked to consumption of raspberries imported from Central America.
Outberaks have been also associated with mesclun lettuce mix.
NAUSEA AND VOMITING WITNIN 1 TO 6 HOURS–caused by a performed enterotoxin
Bacillus cereus-type 1- short incubaton
In these two-vomiting and fever infrequently.
Vomiting in 1/3 of affected persons suggests that these organisms are not involved.
Bacillus cereus- type -2 long incubation
Incubation 8-16 hours.
Diarrhea 96% + abdominal cramps 96% + sometimes vomiting and rarely fever
Clostridium perfrigens- toxins produced in vivo, accounting for the longer incubation period.
The most common symptoms are abdominal cramps and diarrhea although nausea may occur, vomiting and fever are uncommon- less then <10%
5 types of toxin have been described. Type A is almost always the toxin causing food poisoning. The enterotoxin is active throughout the small intestine, with greatest activity in ileum in which net serretion of sodium and fluid and inhibitition of chloride and glucose absorption occur. ; it damages epithelial cells at villus tips.
Salmonella, Shigella, Campylobacter jejuni, Vibroparahaemoliticus, E.coli.
bloody diarrhea and vomiting occur in a varying proportion of patients
C.jejuni is most common foodborne bacterial pathogen-in contrast to the illnesses caused by other org. food poisoning caused by C.jejuni is chracterizied by longer incubation period, 3-4 days
Salmonella is second most common bacterial pathogen
associated with foodborne outbreaks ; median incubation period 6-48 h
E.coli O157-H7 like C.jejuni 3-4 days.
enterotoxigenic strains of E.coli, V.parahaemoliticus, V. cholera non O1 and in endemic areas V.cholerae O1 and O 139, C.jejuni, Salmonella, Shigella.
enterotoxines synthesized in vivo are responsible for the syndrome caused by V.cholerae O1 and V.cholerae non O1 and enterotoxigenic strains of E.coli.
when Salmonella, Shigella, V.parahaemoliticus –enterotoxigenic or cytotoxic substances
severe cholera : profuse watery diarrhea accompanied by musclar cramps
Cholera -5 days
V.cholerae non O1-2-12 days
other resolve within 72-96 h
Norovirusesthe most common of known foodborne pathogens
causing 2/3 of all foodborne illnesses caused by known pathogens.
vomiting and diarrhea are often the presenting symptoms, onset 1-2 days after exposure
watery, nonbloody diarrhea, abdominal pain, nausea.
vomiting more common among children, diarrhea more likely to predominate in adults.
fever 1/3 to ½ and is low grade
It is impossible to distinguish beweennoroviruses and some bacterial causes of gastroenteritis, such as ETEC for a single patient based on clinical course.
Criteria that suggest noroviruses:
1) failure to detect a bacterial or parasitic pathogen in stool specimens
2)occurance of vomiting >50% of patients
3)mean duration 12-60 h
4)mean incubation 24-48 h
The syndrome of hemorrhagic colitis has been linked to Shiga toxin-producing strains of E.coli most often serotype O157-H7.These strains produce cytotoxins that affect Vero kidney cell cultures and are neutralized by antiserum to Shiga toxin. (Shiga toxins and verotoxines)
The toxins are absorbed from the gut and damage vascular endothelial cells in target organs such as gut and kidney.
Severe abdominal cramps and diarrhea which is initially watery but may be grossly bloody.
uncomplicated infection remain afebrile
mean incubation 3-8 days
Duration of uncomplicated 1-12 days
development of fever and leukocytosis may herald HUS.Children mortality 3-5 %
HUS occurs in 8% of infections in children,with onset about 1 week after the beginning of diarrheal illness.
other E.coliserogroups that produce Shiga toxins can also cause hemorrhagic colitis and HUS.
Rarelyinfantsayswallowsporeswhichlatergerminate and producetoxin.toxigenesiscannotoccurinmatureadultguts.
Guillan-Barre syndrome- in contrast to botulism,this syndrome is usually manifested by an ascending paralysis accompanied by sensory findings ad abnormal nerve conduction velocity.
Listeriosis typically affects pregnant women, fetuses, persons with compromised immunity-fever, myalgis, bacteriemia, meningitis.
foods cold processd meats and dairy products.
incubation period 2-6 weeks
Vibriovulnificuscause fulminate myonecrosis or primary bacteriemia after ingestion of raw oysters