Laboratory Practices for Stool‐Specimen Culture for Bacterial Pathogens, IncludingEscherichia coliO157:H7, in the FoodNet Sites, 1995–2000

Abstract

In 2000, we surveyed microbiologists in 388 clinical laboratories, which tested an estimated 339,000 stool specimens in 1999, about laboratory methods and policies for the routine testing of stool specimens for Salmonella, Shigella, Campylobacter, and Vibrio species, Yersinia entercolitica, and Escherichia coli O157:H7. The results were compared with those of similar surveys conducted in 1995 and 1997. Although these laboratories reported routinely testing for Salmonella, Shigella, and Campylobacter species, only 57% routinely tested for E. coli O157:H7, 50% for Y. entercolitica, and 50% for Vibrio species. The mean proportions of stool specimens that yielded these pathogens were as follows: Campylobacter, 1.3% of specimens; Salmonella, 0.9%; Shigella, 0.4%; and E. coli O157:H7, 0.3%. The proportion of laboratories that routinely tested for E. coli O157:H7 increased from 59% in 1995 to 68% in 2000; however, the proportion of stool specimens tested decreased from 53% to 46%. E. coli O157:H7 should be routinely sought in stool specimens submitted for microbiologic culture.

Four-Year Experience with Simultaneous Culture and Shiga Toxin Testing for Detection of Shiga Toxin-Producing Escherichia coli in Stool Samples

“…Our results demonstrated an overall STEC isolation rate of 0.24% (0.2% for O157 and 0.04% for non-O157), which is lower than the national isolation rate of 0.72 per 100,000 population reported in 2009 (CDC [http://www.cdc.gov/ncezid/dfwed/PDFs /national-stec-surv-summ-2009-508c.pdf]) but closer to the isolation rate range of 0.26 to 1 per 100,000 population reported in North Carolina in 2009 (2), to 0.13% in the southeast region of the United States from 1990 to 1992 (4), and to the 0.3% national annual rate from 1995 to 2000 (5). Indeed, isolation rates differ considerably by state: states in the upper Midwest have the highest STEC O157 isolation rates (range, 1.01 to 5.3%), with much lower rates in states in the South (range, 0.0 to 1.0 per 100,000 population) (2).…”

Prevalence and Characterization of Shiga-Toxin O157:H7 and Non-O157:H7 EnterohemorrhagicEscherichia ColiIsolated from Different Sources

“…transmission of Stec occurs through contaminated foods, such as ground beef, through contaminated water and by person-to-person spread (52,55). in some countries, o157:h7 (o157) is the most common serotype of Stec (26) and is the serotype most often associated with hUS (57). Approximately 150 non-o157 Stec serotypes also cause diarrheal disease (44,50).…”

Foodborne Illness Acquired in the United States—Major Pathogens

“…However, for infections with L. monocytogenes, M. bovis, and V. vulnifi cus and severe infections with hepatitis A virus, we assumed high rates of medical care seeking (i.e., we assumed that 100% of persons with M. bovis infection and 90% with L. monocytogenes, V. vulnifi cus, or severe hepatitis A virus infections sought care) and specimen submission (100% for hepatitis A virus and M. bovis, 80% for others). We accounted for percentage of laboratories that routinely tested for speci¿ c pathogens (25%-100%) and test sensitivity (28%-100%) by using data from FoodNet (10,11) and other surveys of clinical diagnostic laboratory practices (online Technical Appendix 3). For the 5 pathogens for which data were from outbreaks only, we used the nontyphoidal Salmonella spp.…”