Pathogen Safety Data Sheets: Infectious Substances – Escherichia coli, enterotoxigenic

PATHOGEN SAFETY DATA SHEET - INFECTIOUS SUBSTANCES

SECTION I - INFECTIOUS AGENT

NAME: Escherichia coli, enterotoxigenic

SYNONYM OR CROSS REFERENCE: ETEC ^{Footnote 1Footnote 2}, intestinal pathogenic E. coli ^{Footnote 2}, enteric pathogen ^{Footnote 2}.

CHARACTERISTICS: Enterotoxigenic Escherichia coli (ETEC) are in the family Enterobacteriaceae ^{Footnote 3}. The bacteria are gram negative, rod shaped, non-spore forming, motile with peritrichous flagella or nonmotile, and grow on MacConkey agar (colonies are 2 to 3 mm in diameter and red or colorless) ^{Footnote 4}. They are able to grow under aerobic and anaerobic conditions ^{Footnote 1}, and produce two types of enterotoxin: heat-labile (LT) (oligomeric) and heat-stable (ST) (monomeric) ^{Footnote 2Footnote 3}.

SECTION II - HAZARD IDENTIFICATION

PATHOGENICITY/TOXICITY: Patients with ETEC enteritis usually have an abrupt onset of watery diarrhea that does not contain blood, pus, or mucus (nondysenteric) ^{Footnote 1}. The diarrhea is usually mild to moderate in severity, but some patients may have severe fluid loss ^{Footnote 1}. Low-grade fever, nausea, and abdominal pain may also be present ^{Footnote 5}. Dehydration may become severe or life threatening in neonates and children, necessitating aggressive fluid and electrolyte replacement ^{Footnote 2}. A self-limited course, with resolution in 2-5 days, is most common in adult travelers who acquire the disease ^{Footnote 1}, though some strains of the organism may produce a disease lasting much longer, with a median duration of illness of 7 days ^{Footnote 6}. There are an estimated 800,000 deaths each year due to ETEC ^{Footnote 7}.

EPIDEMIOLOGY: Human diarrhea caused by ETEC is the most common disease caused by pathogenic E. coli strains ^{Footnote 7}. It is estimated that there are more than 650 million cases of ETEC infection each year ^{Footnote 7}. ETEC infections are most common in developing countries that lack appropriate sanitation and drinking-water treatment facilities ^{Footnote 1Footnote 2} but are now considered a re-emerging food- and water-borne disease in developed nations as well. In developing nations disease occurs at any time of the year, but incidence peaks in the warm, wet seasons that favor environmental bacterial replication ^{Footnote 1}. ETEC is a disease of young children in developing nations ^{Footnote 2}. The percentage of ETEC in children with diarrhoea varies from 10-30% ^{Footnote 8}. In endemic areas, 20–40% of diarrhea cases are due to ETEC ^{Footnote 8}. Several studies suggest that 20–60% of travellers from developed countries experience diarrhoea when visiting the areas where ETEC infection is endemic ^{Footnote 8}. Furthermore, several outbreaks have occurred on cruise ships, which appear to constitute a fairly frequent setting for disease caused by this organism ^{Footnote 9}. Outbreaks of ETEC caused by endemic strains, rather than association with travel, have occurred in the U.S.^{Footnote 10-Footnote 12} and Denmark ^{Footnote 13Footnote 14}. As with travel-associated diarrhea, disease caused by ETEC in developed nations tends to strike older children and adults.

HOST RANGE:Humans (principally neonates and travelers from non-endemic areas) ^{Footnote 7} and animals (production animals and postweaning diarrhea in swine) ^{Footnote 7}. ETEC have been strongly associated with cattle ^{Footnote 15}, though the role of cattle as a source of strains for human infection is currently unclear.

INFECTIOUS DOSE: The infectious dose of ETEC in adult is estimated to be at least 10⁸ organisms, but the young, the elderly and the infirm may be susceptible to lower numbers ^{Footnote 16}.

MODE OF TRANSMISSION: ETEC are spread primarily by the fecal-oral route and are most common in developing countries that lack appropriate sanitation and drinking-water treatment facilities ^{Footnote 17}. The most important mode of transmission is contaminated, improperly treated drinking water ^{Footnote 1Footnote 2}. Fruits and vegetables that are washed with contaminated water and not cooked also serve as vehicles of transmission ^{Footnote 1Footnote 2}. Person-to-person spread is uncommon ^{Footnote 17}.

INCUBATION PERIOD: The incubation period is short at between 14 and 30 hours ^{Footnote 5}.

COMMUNICABILITY: Person-to-person infection can occur, but is uncommon because the infectious dose is high. ^{Footnote 1Footnote 18}

SECTION III - DISSEMINATION

RESERVOIR: Humans ^{Footnote 7} and animals (especially post weaning pigs) ^{Footnote 7}.

ZOONOSIS: None reported ^{Footnote 19}.

VECTORS: None.

SECTION IV - STABILITY AND VIABILITY

DRUG SUSCEPTIBILITY/RESISTANCE: Susceptible to carbapenem, fosfomycin-trometanol, nitrofurantoin, and bovine apo-lactoferrin ^{Footnote 2Footnote 20}. E. coli can be resistant to chloramphenicol, β lactams, nalidixic acid, ampicillin, and ciprofloxacin ^{Footnote 2}. Fluoroquinolones such as ciprofloxacin enhance toxin production.

SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to a combination of 2,2-dibromo-2-cyanoacetamide (DBA) with sodium iodide (20:80 parts), iodine, 2 % glutaraldehyde, quaternary ammonium (20°C, 0.5 min), hypochlorite (0.525%, 20°C, 0.5 min), phenolic (20°C, 0.5 min), and ethyl alcohol (70%, 20°C, 0.5 min) ^{Footnote 21-Footnote 23}.

PHYSICAL INACTIVATION: Ozone can inactivate E. coli ^{Footnote 24}. E. coli are also sensitive to heat treatment, especially at temperatures of 70°C or higher ^{Footnote 19Footnote 25}.

SURVIVAL OUTSIDE HOST: E. coli can survive for 1.5 hours to 16 months on dry inanimate surfaces ^{Footnote 26}.

SECTION V – FIRST AID / MEDICAL

SURVEILLANCE: Monitor for symptoms. Stool culture is a common method used to identify E. coli ^{Footnote 27}. ETEC can be detected using non-radioactively labeled oligonucleotides DNA probes and PCR targeted against the LT and ST genes ^{Footnote 1Footnote 2}. ELISA can also be used to detect LT and ST ^{Footnote 1Footnote 2}.

Note: All diagnostic methods are not necessarily available in all countries.

FIRST AID TREATMENT: Treatment with trimethoprim/sulfamethoxazole (TMP-SMX) or quinolones reduces the duration of diarrhea ^{Footnote 18}. Treatment of fluid and electrolyte loss is usually achieved through oral rehydration ^{Footnote 1Footnote 19}. The use of the World Health Organization Oral Rehydration Salts (ORS) solution has been recommended ^{Footnote 1}. Intravenous rehydration may be necessary for infants, individuals with excessive vomiting, or those with severe dehydration ^{Footnote 1}. Bismuth subsalicylate may decrease the amount of diarrhea and the duration of disease ^{Footnote 1}. Antimicrobial therapy is generally not indicated, because of the self-limited nature of this disease ^{Footnote 1}.

IMMUNIZATION: There are currently no vaccines approved for human use against the diarrheagenic E coli ^{Footnote 1}.

PROPHYLAXIS: TMP-SMX is recommended for a short term (< 2 weeks) for those at a high risk of disease ^{Footnote 18}. Bismuth subsalicylate provides some prophylactic benefit, but should not be used as a substitute for other preventive measures ^{Footnote 1}.

SECTION VI - LABORATORY HAZARDS

LABORATORY ACQUIRED INFECTIONS: 12 cases of laboratory acquired infections with E. coli have been reported, the majority have been caused by enterohemorrhagic E.coli (EHEC) ^{Footnote 28}.

SOURCES/SPECIMENS: Stools and fecally contaminated material ^{Footnote 1Footnote 2}.

PRIMARY HAZARD: Ingestion ^{Footnote 28}.

SPECIAL HAZARD: None.

SECTION VII – EXPOSURE CONTROLS / PERSONAL PROTECTION

RISK GROUP CLASSIFICATION: Risk Group 2 ^{Footnote 29}.

CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures ^{Footnote 30}.

PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable ^{Footnote 30}. Eye protection must be used where there is a known or potential risk of exposure to splashes.

OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC) ^{Footnote 30}. The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities.

SECTION VIII – HANDLING AND STORAGE

SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up ^{Footnote 30}.

DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing ^{Footnote 30}.

STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labeled ^{Footnote 30}.

SECTION IX - REGULATORY AND OTHER INFORMATION

REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.

UPDATED: December 2011

PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada

Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright ©
Public Health Agency of Canada, 2011
Canada