Phenotypic and Genotypic Characterization ofSalmonella entericaSerovar Enteritidis Isolates Associated with a Mousse Cake–Related Outbreak of Gastroenteritis in Ningbo, China

Abstract

Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis) is a major pathogen responsible for causing the largest number of sporadic cases and outbreaks of human salmonellosis worldwide. In this study, an outbreak of Salmonella Enteritidis involving 112 cases in Ningbo, China was investigated with a combination of genotypic subtyping methods and phenotypic analysis. The pulsed-field gel electrophoresis and multilocus variable-number tandem-repeat analysis profiles showed that most of the outbreak clinical isolates (22/23) were indistinguishable from each other and were identical to the isolates obtained from implicated mousse cakes, demonstrating that this outbreak of gastroenteritis was caused by Salmonella Enteritidis-contaminated mousse cakes. Moreover, all isolates, irrespective of source, had an identical antibiotic susceptibility pattern. Five virulence-associated genes in Salmonella pathogenicity islands and the plasmid-associated virulence genes spvB/C were present in both the food and clinical isolates. Importantly, all of these isolates can survive well under low-temperature treatment, indicating that manufacturers of foodstuffs with raw ingredients (not subjected to thermal processing) should use an effective approach to prevent or eliminate the microbial hazards to public health.

Genetically Similar Isolates ofSalmonella entericaSerotype Enteritidis Persistent in China for a Long‐Term Period

“…The clinical information of patients included age (mean: 37.5, ranging from 15 to 62 y old), gender (44 males and 20 females). Particularly, of the 72 strains, 47 were isolated from 2 outbreaks, that is, Outbreak A (16 isolates and 75 patients in 2004) and Outbreak B (31 isolates and 210 patients in 2013) (Zhou and others ). The incriminated foods were chickens and dessert cakes for Outbreak A and Outbreak B, respectively.…”

Rapid Multilateral and Integrated Public Health Response to a Cross-City Outbreak of Salmonella Enteritidis Infections Combining Analytical, Molecular, and Genomic Epidemiological Analysis

“…Enteritidis infections ( Braden, 2006 ), outbreaks associated with shell eggs have continued to occur, including a nationwide outbreak that triggered a recall of 500 million eggs ( Kuehn, 2010 ). Food products of egg origin used as an ingredient during preparation, such as mousse cake ( Zhou et al, 2015 ) and egg sandwiches ( Wei et al, 2014 ; Guo et al, 2015 ), were frequently implicated as sources of S . Enteritidis infections.…”

Integrated Whole-Genome Sequencing Infrastructure for Outbreak Detection and Source Tracing of Salmonella enterica Serotype Enteritidis

“…In 2010, a nationwide foodborne outbreak associated with contaminated eggs triggered a recall of 500 million eggs in the United States (Kuehn, 2010). Large-scale outbreaks have also been documented in China in recent years, associated with the consumption of egg sandwiches and mousse cakes (Guo et al, 2015;Zhou et al, 2015).…”