Salmonella Typhimurium infections transmitted by chlorine-pretreated clover sprout seeds.

Raw seed sprouts have caused numerous outbreaks of enteric infections. Presoaking seeds in a 20,000 mg/liter (ppm) calcium hypochlorite solution before sprouting is recommended to reduce bacterial contamination and infection risk. In 1999, the authors investigated an outbreak of Salmonella serotype Typhimurium infections in Colorado. In a case-control study, they matched 20 cases with 58 controls by age, sex, and telephone prefix; 10 (52%) of 19 cases and no controls recalled eating raw alfalfa-style sprouts in the 5 days before the patient's illness (p < 0.00001). Traceback implicated clover sprouts grown from seeds shared by two sprouters. The time period and region over which these sprouts were sold matched the occurrences of 112 culture-confirmed illnesses. Only one of the sprouters presoaked seeds as recommended, and fewer infections were attributable to this sprouter (0.29 vs. 1.13 culture-confirmed infections/50-pound (110.1-kg) bag of seed). After recall of the implicated sprouts and seed, S. Typhimurium illnesses declined. Contaminated raw clover sprouts can cause outbreaks of enteric illness. Presoaking contaminated seeds in a 20,000 mg/liter calcium hypochlorite solution reduces, but does not eliminate, the risk of infection. Until safer production methods are developed, persons eating raw sprouts continue to risk developing potentially serious gastrointestinal illness.

An outbreak of salmonellosis among children attending a reptile exhibit at a zoo.

OBJECTIVE: In January 1996, an outbreak of diarrhea caused by Salmonella Enteritidis occurred in children attending a Komodo dragon exhibit at a metropolitan zoo. We sought to determine the extent of the outbreak and mode of transmission. STUDY DESIGN: A case-control study was conducted. Controls were randomly selected from zoo membership lists and matched to patients by age group and date of exhibit visit. RESULTS: Of 65 patients identified, 39 had confirmed and 26 had suspected cases. The median age was 7 years (range, 3 months to 48 years); 55% were enrolled in the case-control study. No patients and two (4%) controls reported touching a dragon; however, 83% of patients but only 52% of controls touched the wooden barrier that surrounded the dragon pen (odds ratio = 4.0, 95% CI 1.2 to 13.9). Washing hands at the zoo after visiting the dragons was highly protective (OR = 0.14, 95% CI 0.03 to 0.7). Cultures from the patients, one dragon, and the exhibit barriers yielded Salmonella Enteritidis, phage type 8. On the basis of an attack rate of 4.3% among exhibit attendees under 13 years old on whom data were collected, we estimate that 315 additional cases of salmonellosis occurred among visitors in this age group. CONCLUSION: This large outbreak demonstrates the importance of environmental contamination in the transmission of Salmonella from reptiles, and the protective value of hand washing. Recommendations regarding reptile exhibits and reptilian pets should emphasize this indirect route.

Confirmation of the Syva MicroTrak enzyme immunoassay for chlamydia trachomatis by Syva Direct Fluorescent Antibody Test.

BACKGROUND AND OBJECTIVES: The Syva Micro Trak enzyme immunoassay (EIA) is used widely for screening women infected with Chlamydia trachomatis. Confirmatory tests used in conjunction with EIA screening have shown that false-positive results are common. GOALS: To evaluate the specificity of the Syva MicroTrak EIA by confirmation of positive specimens with the Syva Direct Fluorescent Specimen Test. STUDY DESIGN: Of 6,039 endocervical specimens collected from women attending Colorado family planning clinics, 328 positive EIA results (5.4%) were obtained by Syva MicroTrak EIA. A random subset of 136 positive specimens was tested by Syva Direct Specimen Test. Twenty of 136 specimens (14.7%) negative by Syva Direct Specimen testing were also tested by Syva blocking antibody tests (9 of 20 positive, 45%) and Roche Amplicor polymerase chain reaction (PCR; 6 of 20 positive, 30%). Of 20 specimens positive by Syva MicroTrak EIA and negative by Syva Direct Specimen Test, 11 (55%) were also negative by blocking antibody and PCR, including three specimens with initial EIA sample-to-cutoff ratios greater than 2. CONCLUSIONS: Confirmatory testing of Syva MicroTrak EIA positive specimens with Syva Direct Specimen Test showed that 14.7% were false positive. Coupling the Syva Direct Specimen test with either blocking antibody or PCR reduces the rate of false-positive results to 8%.