Recovery of Salmonella isolated from eggs and the commercial layer farms

Mei Long,Wenwen Deng,Shuliang Liu,Xiaoling Ao,Li Chen,Guoyan Wu,Hongning Wang,Yubao Yan,Menggen Ma,Likou Zou,Siyue Zhao,Margaret A Davis,Bei Li,Lisa Jones,Shujuan Chen,Li He,Hua Yu,Kang Zhou,Anyun Zhang

doi:10.1186/s13099-017-0223-8

Abstract

BackgroundSalmonella is recognized as a common bacterial cause of foodborne diarrheal illness worldwide, and animal or its food products have been the most common vehicles of the Salmonella infections. This study aimed to investigate the distribution of Salmonella in two commercial layer farms and to determine the genetic relatedness between these strains. The Salmonella isolates were serotyped by slide agglutination using commercial antisera and analyzed for genetic relatedness using pulsed-field gel electrophoresis (PFGE).ResultsThe internal environment had the highest prevalence of Salmonella (14/15, 93.3%), followed by external environment (60/96, 62.5%) and egg samples (23/84, 27.3%). The prevalence of Salmonella in the environment was significantly higher than that in egg samples (p < 0.05). The occurrence of Salmonella in the internal environment (93.3%) was relatively higher than in the external environment (55.6–77.2%). The 111 isolates were distributed among 15 PFGE types, and the PFGE results suggested that there existed cross-contamination between these strains not only from eggs, but also from the environments.ConclusionsThe findings indicated ongoing Salmonella cross-contamination inside or outside of the layer farms, and that Salmonella could also spread along the egg production line.

Highlights

Salmonella is recognized as a common bacterial cause of foodborne diarrheal illness worldwide, and animal or its food products have been the most common vehicles of the Salmonella infections
Recovery of Salmonella isolates from eggs A total of 23 Salmonella isolates were recovered from 84 egg samples with the prevalence of 27.3%
Four serotypes were detected in 23 Salmonella isolates from egg samples

Summary

Introduction

Salmonella is recognized as a common bacterial cause of foodborne diarrheal illness worldwide, and animal or its food products have been the most common vehicles of the Salmonella infections. Salmonella enterica is recognized as one of the most common bacterial cause of human diarrheal illness worldwide, which has been a considerable burden to public health and economic loss. Salmonella-related infections have been associated with $365 million in annual direct medical costs [2]. In the European Union, 99,020 food-borne cases caused by Salmonella were reported in 2010 [3]. Salmonella outbreaks are commonly associated with consumption of contaminated food, such as poultry meat and eggs, which have been identified as the important vehicle for human salmonellosis [5, 6]

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