Patogenic E.coli Strain in Tajikistan
Role of enteropathogenic E.coli O157-H7 in structure of acute intestinal diseases and study of etio-pathogenic characteristics of the pathogen in the Republic of Tajikistan
Tech Area / Field
- MED-DIS/Disease Surveillance/Medicine
3 Approved without Funding
Republican Center for State Sanitary Epidemiological Control, Tajikistan, Dushanbe
- Department of the Army / Armed Forces Institute of Medical Sciences, USA, DC, Washington
Project summaryThere is increasing recognition of a widening array of enteric pathogens associated with illnesses of the gastrointestinal tract. Along with well-known microorganisms – Salmonella, Shigella and rotaviruses, agents such as enterohemorrhagic E.coli, Cyclospora, Cryptosporidium, Giardia, Campylobacter jejuni, Clostridium difficile, caliciviruses and other enteric virus patogens are increasing cause of acute diarrheal illnesses. Within the last years acute intestinal infections (All) have been widely spread in Tajikistan.
Recent studies of diarrhea diseases structure in Tajikistan have shown that E.Coli have been detected in 46.1% of all (1068 positive out of 2319 samples) investigated stool samples in 2009 in the frame of the project.
E. coli O157:H7 was first recognized as a food borne pathogen in 1982 during an investigation into an outbreak of hemorrhagic colitis (bloody diarrhea) associated with the consumption of contaminated hamburgers (Riley, et al., 1983). The following year, Shiga toxin (Stx), produced by the then little-known E. coli O157:H7, was identified as the real culprit.
In the ten years following the 1982 outbreak, approximately thirty E. coli O157:H7 outbreaks were recorded in the United States (Griffin & Tauxe, 1991). The actual number that occurred is probably much higher because E. coli O157:H7 infections did not become a reportable disease (required to be reported to public health authorities) until 1987 (Keene et al., 1991 p. 60, 73). As a result, only the most geographically concentrated outbreaks would have garnered enough attention to prompt further investigation (Keene et al., 1991 p. 583). It is important to note that only about 10 percent of infections occur in outbreaks, the rest are sporadic.
It is estimated that 85 percent of E. coli O157:H7 infections are food borne in origin (Mead, et al., 1999). In fact, consumption of any food or beverage that becomes contaminated by animal (especially cattle) manure can result in contracting the disease. Foods that have been identified as sources of contamination include ground beef, venison, sausages, dried (non-cooked) salami, unpasteurized milk and cheese, unpasteurized apple juice and cider (Cody, et al., 1999), orange juice, alfalfa and radish sprouts (Breuer, et al., 2001), lettuce, spinach, and water (Friedman, et al., 1999). Pizza and cookie dough have also been identified as sources of E. coli outbreaks.
The infection is sometimes fatal, particularly in children. Outbreaks of infection, generally associated with beef, have been reported in Australia, Canada, Japan, United States, in various European countries, and in southern Africa. Outbreaks have also implicated alfalfa sprouts, unpasteurized fruit juice, lettuce, game meat and cheese curd.
Type O157:H7 strains produce several cytotoxins, neurotoxins, and enterotoxins, including Shiga toxin, and cause bloody diarrhea, which, in 2 to 7% of cases, lead to hemolytic-uremic syndrome Such strains have most often been acquired from undercooked ground beef but may also be acquired from infected people by the fecal-oral route when hygiene is inadequate.
E. coli O157:H7 typically causes acute bloody diarrhea, which may lead to hemolytic-uremic syndrome. Symptoms are abdominal cramps and diarrhea that may be grossly bloody. Fever is not prominent. Diagnosis is by stool culture and toxin assay.
E. coli O157:H7 infection typically begins acutely with severe abdominal cramps and watery diarrhea that may become grossly bloody within 24 h. Some patients report diarrhea as being “all blood and no stool,” which has given rise to the term hemorrhagic colitis. Fever, usually absent or low grade, occasionally reaches 39° C. Diarrhea may last 1 to 8 days in uncomplicated infections.
About 5% of cases (mostly children < 5 yr and adults > 60 yr) are complicated by hemolytic-uremic syndrome which typically develops in the 2nd week of illness. Death may occur, especially in the elderly, with or without this complication.
This project provides opportunity for microbiological research on isolation and identification of entero hemorrhagic E. coli E. coli O157: H7 from the biological material from patients with uncomplicated diarrhea, acute intestinal infections with hemo colitis and the development of hemolytic uremic syndrome, from contacts in the focuses, as well as food products and water .
Only 51,2 % of Tajik population have access to piped water, and for the last years, this percentage for the rural population has a tendency to reduction (35,3 %). Source of water for 48.2 % population are open water sources. More than 80 % of water pipe do not respond to the sanitary norms, do not have sanitary protection zones, completed system and disinfection means for drinking water supplied to the population, and necessary complex of treatment facilities.
Around 80 % of piped networks are depreciated, and is in unsatisfactory sanitary and technical conditions. In separate cities and districts, piped water is supplied with frequent interruptions.
Tube water sources used by population for drinking and consumption purposes are exposed to contamination due to overloaded drainage system, different domestic and factory wastes.
Critical to development a cost-effective approach to the evaluation and management of infectious diarrhea is the selective use of available diagnostic methods, therapies, and preventive measures.