Salmonella Weltevreden food poisoning in a tea garden of Assam: An outbreak investigation

Abstract

Background: Salmonella enterica serovar Weltevreden has been a rare cause of acute gastroenteritis occurring worldwide. Here, we report an outbreak of food poisoning in a tea garden.

Objectives: To determine the aetiological agent and risk factors responsible for the outbreak and to take necessary steps for prevention of future outbreaks.

Materials and methods: Affected area was visited by a team of microbiologists for collecting stool samples/rectal swabs from affected patients. Samples were processed by culture followed by confirmation of the isolates biochemically, automated bacterial identification system, conventional serotyping and molecular typing. Water samples were also processed for detection of faecal contamination. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion technique according to the Clinical Laboratory Standard Institute guidelines.

Results: The isolates were confirmed as S. enterica subspecies enterica serovar Weltevreden. They were found sensitive to ampicillin, amoxycillin-clavulanic acid, ciprofloxacin, ofloxacin, norfloxacin, cefotaxime, ceftriaxone, co-trimoxazole and doxycycline. Water samples showed high-level faecal contamination. Source of outbreak was found to be drinking water contaminated with dead livestock. House to house visit was made for early diagnosis and treatment of the cases, awareness campaigning and chlorination of drinking water.

Conclusions: This report emphasises the geographical distribution of this organism in Assam. As S. Weltevreden is widely distributed in domestic animals, people should be made aware of immediate reporting of any unusual death among the livestock and their safe disposal which can significantly reduce the incidence of non-typhoidal salmonellosis in the country.