An outbreak of foodborne botulism associated with food sold at a salvage store in Texas.

Foodborne botulism is caused by potent neurotoxins of Clostridium botulinum. We investigated a large outbreak of foodborne botulism among church supper attendees in Texas. We conducted a cohort study of attendees and investigated the salvage store that sold the implicated foods. We identified 15 cases of botulism (40%) among 38 church supper attendees. Nine patients (60%) had botulinum toxin type A detected in stool specimens. The diagnosis was delayed in 3 cases. Fifteen (63%) of 24 attendees who ate a chili dish developed botulism (relative risk, undefined; P<.001). The chili dish was prepared with "brand X" or "brand Y" frozen chili, "brand Z" canned chili, and hot dogs. An unopened container of brand X chili yielded type A toxin. Brand X chili was purchased at a salvage store where perishable foods were inadequately refrigerated. Our investigation highlights the need to improve clinicians' awareness of botulism. More rigorous and more unannounced inspections may be necessary to detect food mishandling at salvage stores.

Evaluation and interlaboratory validation of a selective agar for phosphatidylinositol-specific phospholipase C activity using a chromogenic substrate to detect Listeria monocytogenes from foods.

Phosphatidylinositol-specific phospholipase C (PI-PLC) activity is a potential virulence factor and is exhibited only by the Listeria species Listeria monocytogenes and Listeria ivanovii. A chromogenic substrate for the direct detection of PI-PLC activity is available in a new medium (BCM L. monocytogenes plating agar). The use of a chromogenic substrate offers a mechanism with which to directly screen for L. monocytogenes and L. ivanovii other than the esculin used in Oxford (OXF) and Palcam (PAL) agars, which screen for all Listeria species. The specificity levels of BCM plating agar and of BCM confirmation and rhamnose agars were evaluated with 107 Listeria and 10 Bacillus species isolates. In addition, BCM L. monocytogenes plating agar was compared with standard Listeria selective agars (OXF and PAL agars) with regard to the recovery of L. monocytogenes from 2,000 food and environmental samples obtained from eight participating laboratories. A Listeria species was isolated from at least one of the agars in 209 analyses, and L. monocytogenes was isolated in 135 of these analyses. In 27 of the analyses in which L. monocytogenes was isolated, one or more of the selective differential agars used failed to isolate L. monocytogenes, and therefore the results of these analyses were discrepant. Relative to a reference method involving the use of all three agars (OXF, PAL, and BCM agars), the OXF-BCM, PAL-BCM, and OXF-PAL combinations had sensitivities of 99.3, 99.2, and 90.2%, respectively. In statistical analyses of the different combinations of agars, the OXF-BCM and BCM-PAL combinations were found to be superior to the OXF-PAL combination for the detection of L. monocytogenes.