Background

Acute Gastrointestinal infections may be caused by a variety of agents, including bacteria, viruses, and protozoa. However, only a few agents have been documented in nosocomial transmission (Table 5) Nosocomial transmission of agents that cause gastrointestinal infections usually results from contact with infected individuals, from consumption of contaminated food, water, or other beverages, or from exposure to contaminated objects or environmental surfaces. Airborne transmission of small round-structured viruses (Norwalk-like viruses) has been postulated but not proved. Inadequate handwashing by health care personnel and inadequate sterilization or disinfection of patient-care equipment and environmental surfaces increase the likelihood of transmission of agents that cause gastrointestinal infections. Generally, adherence to good personal hygiene by personnel before and after all contacts with patients or food and to either standard or contact precautions will minimize the risk of transmitting enteric pathogens.

Laboratory personnel who handle infectious materials also may be at risk for occupational acquisition of gastrointestinal infections, most commonly with Salmonella typhi. Although the incidence of laboratory-acquired S. typhi infection has decreased substantially since 1955, infections continue to occur among laboratory workers, particularly those performing proficiency exercises or research tests. Several typhoid vaccines are available for use in laboratory workers who regularly work with cultures or clinical materials containing S. typhi. The oral live-attenuated Ty21a vaccine, the intramuscular Vi capsular polysaccharide vaccine, or the subcutaneous inactivated vaccine may be given. Booster doses of vaccine are required at 2- to 5-year intervals, depending on the preparation used. The live-attenuated Ty21a vaccine should not be used for immunocompromised persons, including those known to be infected with HIV.

Personnel who acquire an acute gastrointestinal illness (defined as vomiting, diarrhea, or both, with or without associated symptoms such as fever, nausea, and abdominal pain) are likely to have high concentrations of the infecting agent in their feces (bacteria, viruses, and parasites) or vomitus (viruses and paraites). It is important to determine the etiology of gastrointestinal illness in health care personnel who care for patients at high risk for severe disease (e.g., neonates, elderly persons, and immunocompromised patients). The initial evaluation of personnel with gastroenteritis needs to include a thorough history and determination of the need for specific laboratory tests, such as stool or blood cultures, staining procedures, and serologic or antigen-antibody tests.

After resolution of some acute bacterial gastrointestinal illnesses, some personnel may have persistent carriage of the infectious agent. Once the person has clinically recovered and is having formed stools, however, the risk of transmission of enteric pathogens is minimized by adherence to standard precautions.In addition, appropriate antimicrobial therapy may eradicate fecal carriage of Shigella or Campylobacter. In contrast, antimicrobial or antiparasitic therapy may not eliminate carriage of Salmonella or Cryptosporidium. Moreover, antimicrobials may prolong excretion of Salmonella and lead to emergence of resistant strains. However, transmission of Salmonella to patients from personnel who are asymptomatic carriers of Salmonella has not been well documented. In general, antimicrobial therapy is not recommended, unless the person is at high risk for severe disease. When antibiotics are given, stool cultures should be obtained at least 48 hours after completion of antibiotic therapy.

Restriction from patient care and the patient's environment or from food handling is indicated for personnel with diarrhea or acute gastrointestinal symptoms, regardless of the causative agent. Some local and state agencies have regulations that require work exclusion for health care personnel, food handlers, or both who have gastrointestinal infections caused by Salmonella or Shigella. These regulations may require such personnel to be restricted from duty until results of at least two consecutive stool cultures obtained at least 24 hours apart are negative.

Recommendations

a. Vaccinate microbiology laboratory personnel who work with S. typhi on a regular basis, according to published guidelines. Category II

b. Pending their evaluation, exclude personnel with acute gastrointestinal illnesses (vomiting or diarrhea, with or without other symptoms such as nausea, fever, or abdominal pain) from contact with patients and their environment or from food handling. Category IB

c. Consult local and state health authorities regarding work restrictions for patient care personnel or food handlers with enteric infections. Category IB

d. Determine the etiology of gastrointestinal illness among personnel who care for patients at high risk for severe disease. Category IB

e. Allow personnel infected with enteric pathogens to return to work after their symptoms resolve, unless local regulations require exclusion from duty. Category II

f. Ensure that personnel returning to work after a gastrointestinal illness practice good hygienic practices, especially handwashing, to reduce or eliminate the risk of transmission of the infecting agents. Category IB

g. Do not routinely perform follow-up cultures or examinations of stool for enteric pathogens other than Salmonella to determine when the stool is free of the infecting organism, unless local regulations require such procedures. Category IB

h. Do not perform routine stool cultures on asymptomatic health care personnel, unless required by state and local regulations. Category IB

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