Breast-feeding decreases the risk of sporadic salmonellosis among infants in FoodNet sites.

Among the population of the Foodborne Diseases Active Surveillance Network (FoodNet) surveillance areas ("FoodNet sites") in 1996, children under 12 months of age had the highest incidence of sporadic salmonellosis. We conducted a case-control study in 5 FoodNet sites to identify risk factors for sporadic infant salmonellosis. A case patient was a child under 12 months of age with a laboratory-confirmed, nontyphoidal serogroup B or D Salmonella infection. Twenty-two case patients were matched with 39 control subjects by age and either telephone exchange or vital record birth list. In a multivariate analysis, case patients were more likely to have a liquid diet containing no breast milk than a liquid diet containing only breast milk (matched odds ratio, 44.5; P=.04). Case-patients were more likely to reside in a household where a member had diarrhea (matched odds ratio, 13.2; P=.01). To decrease their infants' risk of salmonellosis, mothers should be encouraged to breast-feed their infants. Caretakers of infants should learn about salmonellosis, hand washing, and safe preparation of formula and solid food.

Chicken consumption is a newly identified risk factor for sporadic Salmonella enterica serotype Enteritidis infections in the United States: a case-control study in FoodNet sites.

The sources of sporadic Salmonella enterica serotype Enteritidis (SE) infections in the United States are unclear. To determine risk factors for sporadic SE infection, we conducted a population-based case-control study in 5 Foodborne Disease Active Surveillance Network surveillance areas. During the 12-month study, 396 cases of SE infection were ascertained. Among the 182 case patients and 345 controls, SE infection was univariately associated with international travel (matched odds ratio [MOR], 61; 95% confidence interval [CI], 8-447), eating undercooked eggs (MOR, 2.2; 95%CI, 1-5), and eating chicken prepared outside of the home (MOR, 2.2; 95% CI, 1.3-3.4). Multivariate analysis revealed that eating chicken outside of the home remained the only significant risk factor for illness (MOR, 2.0; 95% CI, 1.1-3.6). Chicken consumption has not previously been identified in the United States as a risk factor for SE infection. Measures to prevent SE infections include educating consumers and food handlers about food safety and interventions to decrease contamination of eggs and poultry.

Farm visits and undercooked hamburgers as major risk factors for sporadic Escherichia coli O157:H7 infection: data from a case-control study in 5 FoodNet sites.

In 1996, active surveillance in 5 Foodborne Diseases Active Surveillance Network (FoodNet) sites revealed up to a 9-fold difference in Escherichia coli O157:H7 (O157) infection incidence between sites. A matched case-control study of sporadic O157 cases was conducted in these sites from March 1996 through April 1997. Case subjects were patients with non-outbreak-related diarrheal illness who had O157 isolated from their stool samples. Control subjects were healthy persons matched by age and telephone number exchange. Overall, 196 case patients and 372 controls were enrolled. O157 infections were associated with farm exposure, cattle exposure, eating a pink hamburger (both at home and away from home), eating at a table-service restaurant, using immunosuppressive medication, and obtaining beef through a private slaughter arrangement. Variations in cattle exposures may explain a part of the regional variability of O157 infection incidence. O157 control measures should focus on reducing risks associated with eating undercooked hamburger, dining at table-service restaurants, and farm exposures.

Fluoroquinolone-resistant Campylobacter infections: eating poultry outside of the home and foreign travel are risk factors.

A 12-month, population-based, case-control study of Campylobacter infections was conducted at Foodborne Disease Active Surveillance Network surveillance areas during 1998-1999. Of 858 Campylobacter isolates tested for antimicrobial susceptibility to the fluoroquinolone ciprofloxacin, 94 (11%) were resistant. Travel outside of the United States was reported by 27 (42%) of 64 patients with fluoroquinolone-resistant Campylobacter infection and by 51 (9%) of 582 patients with fluoroquinolone-susceptible Campylobacter infection (odds ratio [OR], 7.6; 95% confidence interval [CI], 4.3-13.4). When patients with domestically acquired fluoroquinolone-resistant Campylobacter infection were compared with matched healthy control subjects in a multivariate analysis, those infected were 10 times more likely to have eaten chicken or turkey cooked at a commercial establishment (18 [55%] of 33 case patients vs. 7 [21%] of 33 controls; matched OR, 10.0; 95% CI, 1.3-78). Although travel outside of the United States was associated with fluoroquinolone-resistant Campylobacter infection, most infections among study participants were domestically acquired. This study provides additional evidence that poultry is an important source of domestically acquired fluoroquinolone-resistant Campylobacter infection. Control measures should include efforts to improve food handling in commercial establishments.

Prolonged diarrhea due to ciprofloxacin-resistant campylobacter infection.

BACKGROUND: Campylobacter causes >1 million infections annually in the United States. Fluoroquinolones (e.g., ciprofloxacin) are used to treat Campylobacter infections in adults. Although human infections with ciprofloxacin-resistant Campylobacter have become increasingly common, the human health consequences of such infections are not well described. METHODS: A case-control study of persons with sporadic Campylobacter infection was conducted within 7 FoodNet sites during 1998-1999. The E-test system (AB Biodisk) was used to test for antimicrobial susceptibility to ciprofloxacin; ciprofloxacin resistance was defined as a ciprofloxacin minimum inhibitory concentration of > or =4 microg/mL. We conducted a case-comparison study of interviewed persons who had an isolate tested. RESULTS: Of 858 isolates tested, 94 (11%) were ciprofloxacin resistant. Among 290 persons with Campylobacter infection who did not take antidiarrheal medications, persons with ciprofloxacin-resistant infection had a longer mean duration of diarrhea than did persons with ciprofloxacin-susceptible infection (9 vs. 7 days [P=.04]). This difference was even more pronounced among the 63 persons who did not take antidiarrheal medications or antimicrobial agents (12 vs. 6 days [P=.04]). In a multivariable analysis-of-variance model, the persons with ciprofloxacin-resistant infection had a longer mean duration of diarrhea than did the persons with ciprofloxacin-susceptible infection (P=.01); this effect was independent of foreign travel. The association between ciprofloxacin resistance and prolonged diarrhea is consistent across a variety of analytical approaches. CONCLUSIONS: Persons with ciprofloxacin-resistant Campylobacter infection have a longer duration of diarrhea than do persons with ciprofloxacin-susceptible Campylobacter infection. Additional efforts are needed to preserve the efficacy of fluoroquinolones.