An outbreak of foodborne botulism in Rome

Objective: Foodborne botulism is caused by consumption of preformed Clostridium botulinum toxins (BoNT) in food. Although rare events, botulism outbreaks, especially those involving commercially prepared products, represent a public health emergency, given the potential for a large number of cases [1]. Case series: In November 2016, a 71-year old male (Case 1) presented to Umberto I Emergency Department (ED) with a 5-day history of diplopia, xerostomia, and constipation. He was afebrile with normal vital signs. Neurological examination confirmed left and right diplopia in the lateral vision, with no deficit in muscles tone, coordination, and osteotendon reflexes. He was held for further tests; the symptoms did not resolve. The Poison Control Center was alerted 2 days later, and a detailed anamnesis and food history revealed a meal consumed 10 days earlier with four friends in a public eatery. One of them was already hospitalized elsewhere for head trauma following a sudden fall, and showed severe weight loss (Case 2). Botulism was considered and then strongly suspected when informed by the local health department of a confirmed case in a patient who ate at the same restaurant on the same day. The remaining three diners were evaluated in our ED shortly after. Two (Case 3 and 4) reported dysphagia, diplopia, and constipation, associated with ptosis in one case. One patient was asymptomatic and discharged. An industrial preparation of vegetables in oil, used as a sandwich filling, was considered the most likely source. Trivalent-Equine Antitoxin (750 IU-anti-A, 500 IU-anti-B, and 50 IU-anti-E per mL) was administered. There was no progression of clinical signs and no one required mechanical ventilation. BoNT-producing clostridia, identified as type B, were detected in fecal samples. Patients were discharged after 12 (Case 1), 19 (Case 2) and 23 days (Case 3 and 4), respectively. In total, the outbreak produced 5 confirmed cases. Conclusion: This report allows the follow considerations: (i) mildly symptomatic botulism cases may escape recognition; (ii) clinicians should be trained to consider a diagnosis of botulism: an initial suspicion may lead to identification of other cases originally misdiagnosed; (iii) collaboration of medical and public health professionals is key to link multiple suspected cases to a common exposure. In summary, secondary prevention, which includes rapid identification, epidemiologic linkages of cases, and control of outbreaks resulting from contaminated food, is beneficialto prevent further spread and reduce morbidity and costs.