Identification of botulinum toxin type in clinical samples and foods in Iran

Botulism is a serious neuroparalytic disease caused by toxins of Clostridium botulinum. Botulinum toxin is produced under anaerobic conditions and is one of the most dangerous toxin in the world. Rapid diagnosis of botulism is very essential for successful therapy. In this study, we reviewed data of cases of botulism in Iran from April 2004 through March 2010.

From a total of 1140 samples of suspected botulism samples, 477 serum, 294 stool, 111 gastric secretions, and 258 food samples were collected from 21 provinces. These samples belonged to 432 distinct patients. All samples were tested for botulism by mouse bioassay, a gold standard method for detection of botulism.

From 1140 received samples, 64 (5.6 %) positive samples of botulism were identified. Of these, 14 (21.8 %) cases had toxin type A, seven (11 %) cases had toxin type B, 22 (34.3 %) cases had toxin type E, and seven (11 %) cases had toxin type AB. The toxin type could not been identified in 14 (21.8 %) cases. The highest positive results were in Gilan, Tehran, Golestan, and Hamedan provinces. Seafoods and locally- made cheese were the most implicated foods in type E and type A botulism, respectively.

Accurate and rapid diagnosis of botulism is very important because every case of botulism can be a public health emergency. During the study period, the median number of positive cases per year was 2.7 (range: one to18). Therefore, it is suggested that all clinicians are required to submit the collected samples from patients with botulism symptoms to the botulism reference laboratory for specific diagnosis and confirmation of botulism.