Foodborne and Waterborne Infections in Elderly Community and Long-Term Care Facility Residents, Victoria, Australia

Martyn D. Kirk

, Joy Gregory, Karin Lalor, Gillian V. Hall, and Niels Becker

Author affiliations: Australian National University, Canberra, Australian Capital Territory, Australia (M.D. Kirk, G.V. Hall, N. Becker); Department of Health, Melbourne, Victoria, Australia (J. Gregory, K. Lalor)

Abstract

We calculated rates of foodborne and waterborne infections reported to the health department in Victoria, Australia, during 2000–2009 for elderly residents of long-term care facilities (LTCFs) and the community. We used negative binomial regression to estimate incidence rate ratios, adjusting for age, sex, and reporting period. We analyzed 8,277 infections in elderly persons. Rates of campylobacteriosis, legionellosis, listeriosis, toxigenic Escherichia coli infections, and shigellosis were higher in community residents, and rates of Salmonella infection were higher in LTCF residents. Each year, 61.7 Campylobacter infections were reported per 100,000 LTCF residents, compared with 97.6 per 100,000 community residents. LTCF residents were at higher risk for S. enterica serotype Typhimurium associated with outbreaks. Rates of foodborne infections (except salmonellosis) were similar to or lower for LTCF residents than for community residents. These findings may indicate that food preparation practices in LTCFs are safer than those used by elderly persons in the community.

Infectious disease incidence varies with age, and elderly persons are considered more vulnerable than younger persons to foodborne and waterborne infections (1,2). In many countries, elderly persons unable to care for themselves live in long-term care facilities (LTCFs) where they receive assistance with meals, daily living, and health care (3). Food preparation practices and various exposures in LTCFs may modify the risk of foodborne and waterborne infections in these residents (4,5) when compared with elderly persons living in the community, who may have less safe food preparation practices (6–8).
A variety of pathogens transmitted by food or water, including Campylobacter sp., Clostridium perfringens, Cryptosporidium sp., Legionella spp., and Shigella sp., and various serotypes of Salmonella enterica can infect humans (9,10). Foodborne and waterborne infections predominantly manifest in elderly persons as gastroenteritis but, depending on the infectious agent, can result in pneumonia, bacteremia, and meningitis (11,12). Elderly persons can become infected by ingesting contaminated water or food or, as with Legionella spp., inhaling contaminated aerosols (13). Some infections are predominantly foodborne; others can be acquired from infected persons or animals or through contact with contaminated environments (4).
These agents can manifest as outbreaks in facilities, leading to community concern about the safety of residents (14,15). Although most outbreaks of gastroenteritis in LTCFs are spread from person to person and are generally mild (16), such outbreaks do result in higher case-fatality rates (CFRs) among residents (17). As a result, regulatory agencies in many countries have mandated programs to manage food safety in facilities. To prevent legionellosis in residents, health agencies commonly provide advice about disinfection of hot water systems that can be reservoirs for Legionella spp (13).
Few studies have compared the incidence of infections caused by agents that can be transmitted by contaminated food or water consumed by elderly persons living in LTCFs and in the community. One study in the United States estimated that the lower limit of the death rate for nursing home residents from gastroenteritis of unknown etiology was 38.91 (95% CI 38.55–39.27) per 100,000 persons per year, compared with an estimated upper limit of 8.50 (95% CI 8.47–8.53) per 100,000 persons >65 years of age living in the community (18). Little examination has been done of the incidence of sporadic foodborne or waterborne diseases in institutionalized elderly persons. To address this gap, we estimated rates of reported infection in persons >65 years of age living in Victoria, Australia, infected with any of 7 different pathogens according to whether they lived in a government-subsidized LTCF or in the community, and we examined the effect of age on incidence of disease. These pathogens were Campylobacter sp., Cryptosporidium sp., Legionella spp., Listeria sp., Salmonella enterica, Shiga toxin–producing Escherichia coli (STEC), and Shigella sp.