An Outbreak of Foodborne Botulism in Surat Thani Province, Thailand, 2012

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Jpn. J. Infect. Dis., 66, 353-354, 2013 Laboratory and Epidemiology Communications An Outbreak of Foodborne Botulism in Surat Thani Province, Thailand, 2012

Piyada Wangroongsarb1*, Chutima Jittaprasartsin1, Karun Suthivarakom1, Thanitchai Kamthalang1, Seesaiy Yeesoonsang2, and Somchai Sangkitporn1 1National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi; and 2The Office of Disease Prevention and Control, Department of Disease Control, Ministry of Public Health, Phitsanulok, Thailand Communicated by Keigo Shibayama (Accepted April 30, 2013)

Between October 25–November 22, 2012, two scribed by Holdeman et al. (2), toxin assessment using a patients were admitted to the Koh Samui Hospital, mouse bioassay (3), and assessment using enzyme- Surat Thani Province, Thailand for suspected food- linked immunosorbent assay (ELISA) (Centers for borne botulism. On October 25, a 41-year-old man Disease, Control and Prevention, Atlanta, Ga., USA). (Patient 1) was admitted with ametropia, dysphagia, Toxin detection procedure also included a neutraliza- dysarthria, glossoplegia, nausea, and vomiting. The tion test using a mouse bioassay. Our results from these following day, he experienced dyspnea and was subse- suspected samples are summarized in Table 1. Isolated quently ventilated to support breathing and was trans- bacteria were identified by botulinum neurotoxin genes ferred to the intensive care unit. The need for respirato- (boNT) and BoNT/B subtyping according to the ry support indicated the severity of the illness, and its methods of Lindstr äom et al. (4) and Umeda et al. (5). rate of progression was suspected of a reaction to toxin The following primers were used for multiplex PCR ingestion. On October 27, 2012, a serum sample was typing: B-forward (5?-GATTTTTGGGGAAATCTTT- collected for botulinum diagnosis before treatment with 3?), B1-reverse (5?-CCAATTACATCCCAATTTTAA an antitoxin. On November 1, 2012, serum and stool A-3?), B2-reverse (5?-GTATAGTTTTGTAAAATTCA samples were also collected from this patient for botuli- TTAGAATCATA-3?), and Osaka05-reverse (5?-TCT num diagnosis. Our patient eventually recovered; TCCTTTTTCTTAAAATTTTTAAG-3?). Analysis of however, he was under medical observation until the boNT/B2 amplicon (370 bp) from strain Surat Tha- November 22, 2012. ni 2012 was confirmed by a band in lane 7 (Fig. 1). We On October 25, 2012, Patient 1's wife (a 37-year-old were able to identify the bacteria isolated from a stool woman [Patient 2]) experienced vomiting, two episodes sample as Clostridium botulinum type B2. Unfortunate- of diarrhea, xerostomia, and ametropia/diplopia. She ly, we could not isolate the same bacterial species from was admitted to the hospital on October 26, 2012, with the suspected food (home-made fermented crab chief complains of diplopia, syncope, and vertigo. Ini- preserved with salt). The other suspected food item tially, she was diagnosed with hypertension drug absti- (fermented bamboo shoots preserved with salt) was not nence and later foodborne botulism was suspected. Se- collected in this investigation. Neurotoxin assessment rum sample was collected from Patient 2 for botulism using a mouse bioassay was recommended as the diag- diagnosis, and she was treated with botulinum antitox- nostic standard method due to its high sensitivity (0.01 in. By October 30, 2012, Patient 2 recovered, but she ng/ml of specimen eluate). Naturally, the prevalence of was kept under medical observation until November 14, viable C. botulinum spore contamination in food sam- 2012. ples is generally relatively low (10–1,000 spores/kg), For a definitive diagnosis of botulism, the National and the unsuitable growing conditions such as low pH, Institute of Health (NIH) of Thailand received samples moisture content, NaCl content, inappropriate temper- on November 5, 2012, which included 1 stool sample, 4 ature, and growth of other bacterial species could act to sera samples, and 6 suspected food samples (steamed suppress C. botulinum viability and may have led to the bamboo shoot, 2 samples; fermented fish, 1 sample; failure of C. botulinum detection in the suspected food and fermented crab, 3 samples). Both patients con- specimens (6). In addition, toxin-type can differ in any sumed portions of all of the suspected food samples on of the multiple steps between toxin ingestion and nerve October 24, 2012. Sample screening was performed on receptor binding, including the rate of absorption from the basis of isolation and identification methods of the gut or the speed of toxin binding to the nerve termi- Dowell and Hawkins (1), biochemical testing as de- nals (7). We concluded that the etiological agent of foodborne infection in Surat Thani Province was due to infection of C. botulinum type B2 (Table 1). *Corresponding author: Mailing address: National Institute In April 1998, an outbreak of C. botulinum infection of Health, Department of Medical Sciences, Ministry of occurred in Thawanpha District, Nan Province, Public Health, 88/7 Soi Bamrajnaradura, Nonthaburi Thailand that involved 9 cases (8). In March 2006, an 11000, Thailand. Tel: ＋66 2951 0000-11 Fax: ＋66 2591 outbreak of 209 botulism cases occurred in Banluang 5449, E-mail: piyada.w＠dmsc.mail.go.th District, Nan Province, Thailand due to the consump-

353 Table 1. Summary of foodborne botulism in Thailand, 2012, using isolation, ELISA, mouse bioassay, and molecular technique

Laboratory examination

Province/ Mouse bioassay ELISA outbreak Sample (no. of samples) period Neutralization test Isolation BoNT/B Toxicity Antitoxin type ABEF subtyping test ABEF

Surat Thani/ Patient1,41yr October 25– Serum (2) － ND －－－－－－ November 22, 2012 Stool (1) ＋ DADD ＋ B2 Patient2,37yr Serum (2) － ND －－－－－ Food Steamed bamboo shoot (2) － ND －－－－－ Fermented crab (lot. 1) ＋ DADD－－－－－－ Fermented crab (lot. 2, 3) － ND －－－－－ Fermented fish (1) － ND －－－－－

yr, years; ND, not done; D, dead; A, alived; ＋, positive; －, negative.

tions.

Acknowledgments We thank Dr. Jirawan Arayapong for her investigation and collaboration in the surveillance. Especially we thank Dr. Rama Murthy from National Institute of Cholera and Enteric Diseases, India for his helpful comments on this manuscript.

Conflict of interest None to declare.

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