Association between Indoor Environmental Contamination by Salmonella enterica and Contamination of Eggs on Layer Farms

Gole, Vaibhav C.; Torok, V. A.; Sexton, Margaret; Caraguel, Charles; Chousalkar, Kapil K.

doi:10.1128/jcm.00816-14

Cited by 41 publications

(52 citation statements)

References 27 publications

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“…The predominant Salmonella serovars isolated during this study were S. Mbandaka and S. Typhimurium phage type 135. S. Mbandaka was the predominant pathogen in our previous longitudinal study conducted on cage farms (11,28). S. Mbandaka has not been associated with egg-related Salmonella outbreaks in Australia.…”

Section: Discussionmentioning

confidence: 65%

“…It is not clear why MLVA type 03 12 09 11 523 was isolated more frequently (from 59 human cases from 2013 to 2015) than MLVA type 03 12 09 10 523 isolated from the same flock. Our previous report suggested that MLVA profiles of S. Typhimurium isolated from cage farms and human Salmonellosis cases were similar (11). Although a majority of the previous studies were focused on S. enterica serovar Enteritidis, the results of these studies were highly variable.…”

Section: Discussionmentioning

confidence: 98%

“…A previous epidemiology study in cage production systems found that the odds of an eggshell testing positive for Salmonella were higher when the environmental samples, such as fecal, egg belt, and dust samples, tested positive for Salmonella (11). However, little attention has been given to estimating the prevalence of Salmonella on eggs collected from free-range production systems or to determining the factors responsible for contamination.…”

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confidence: 99%

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Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

Gole

Woodhouse

Caraguel

et al. 2017

Appl Environ Microbiol

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The current study investigated the effect of environmental stressors (i.e., weather changes) on Salmonella shedding in free-range production systems and the correlations with behavioral and physiological measures (i.e., fecal glucocorticoid metabolites). This involved longitudinal and point-in-time surveys of Salmonella shedding and environmental contamination on four commercial free-range layer farms. The shedding of Salmonella was variable across free-range farms and in different seasons. There was no significant effect of season on the Salmonella prevalence during this investigation. In this study, the combined Salmonella most probable number (MPN) counts in environmental (including feces, egg belt, dust, nest box, and ramp) samples were highest in samples collected during the summer season (4th sampling, performed in February). The predominant serovars isolated during this study were Salmonella enterica serovar Mbandaka and Salmonella enterica serovar Typhimurium phage types 135 and 135a. These two phage types were involved in several egg product-related Salmonella outbreaks in humans. Multilocus variablenumber tandem-repeat analysis (MLVA) results indicated that MLVA types detected from human food poisoning cases exhibited MLVA patterns similar to the strains isolated during this study. All Salmonella isolates (n ϭ 209) were tested for 15 different genes involved in adhesion, invasion, and survival of Salmonella spp. We also observed variations for sopA, ironA, and misL. There were no positive correlations between fecal corticosterone metabolite (FCM) and Salmonella prevalence and/or shedding in feces. Also, there were no positive correlations between Salmonella prevalence and Salmonella count (log MPN) and any of the other welfare parameters.IMPORTANCE In this study, the welfare of laying hens and Salmonella shedding were compared over a prolonged period of time in field conditions. This study investigated the long-term shedding of Salmonella serovars in a free-range egg production system. Given that there is increasing demand for free-range eggs, it is essential to understand the risks associated with such a production system.

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Section: Discussionmentioning

confidence: 65%

Section: Discussionmentioning

confidence: 98%

mentioning

confidence: 99%

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Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

Gole

Woodhouse

Caraguel

et al. 2017

Appl Environ Microbiol

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“…It is important to state that the probability of an eggshell being Salmonella spp. positive is higher when environmental samples are positive for the bacteria (GOLE et al, 2014).…”

Section: Discussionmentioning

confidence: 97%

Microbiological vulnerability of eggs and environmental conditions in conventional and free-range housing systems

Galvão

Biondo

Possebon

et al. 2018

SCA

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Although Brazil is currently the world's eighth largest egg exporter, the shift of consumers towards free-range eggs may present new sanitary challenges. This study aims to evaluate the microbiological vulnerability of eggs and environmental conditions in a farm certified for both conventional and freerange systems using two standard methods (enterobacteria counting and Salmonella spp. survey). Two high-producing farms were selected for this study, one under both conventional and freerange systems at the same place as the test farm, and another under conventional system only as a control farm. Enterobacteriaceae counts were determined for eggshells; and detection of Salmonella spp. was conducted in eggs, nest box material, feeder, and sponge samples from water dispensers, feeders, production plant, besides water samples from nipple dispensers and artesian well. The average enterobacteria count (log CFUmL -1 ) was 0.09 for conventional and 1.73 for free-range systems (p < 0.001). While Salmonella spp. was not detected in the conventional system but was present in one feeder and three eggshells from the free-range system. Therefore, the conventional system demonstrated better hygiene-sanitary status than the free-range one. Moreover, controlling food safety should always be considered when improving animal welfare. Key words: Enterobacteria. Food safety. Microbial contamination. Public health. Salmonella spp. ResumoApesar do Brasil ser considerado o oitavo maior exportador mundial de ovos, mudanças nas preferências dos consumidores relacionadas a ovos produzidos em sistemas de pastejo livre, podem representar novos desafios sanitários. Neste estudo o objetivo foi avaliar a vulnerabilidade microbiológica dos ovos e ambiente de produção numa fazenda certificada para sistema convencional e de pastejo livre, utilizando dois métodos considerados padrão (contagem de Enterobactérias e pesquisa de Salmonella). Duas fazendas de alta produção de ovos foram selecionadas para o estudo, sendo que uma delas continha o sistema convencional e também o sistema de pastejo livre de criação na mesma localidade. A segunda fazenda (sistema convencional) foi utilizada como controle. A enumeração de enterobactérias

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“…Fecal pellets were collected from each mouse at 3, 6, 9, 12, 15, and 18 days postinfection (p.i.) and processed for isolation of challenge isolates by culture (fecal enrichment method) according to a previously described method (4,19).…”

Section: Methodsmentioning

confidence: 99%

Pathogenicity of Salmonella Strains Isolated from Egg Shells and the Layer Farm Environment in Australia

McWhorter

Davos

Chousalkar

2015

Appl Environ Microbiol

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bIn Australia, the egg industry is periodically implicated during outbreaks of Salmonella food poisoning. Salmonella enterica serovar Typhimurium and other nontyphoidal Salmonella spp., in particular, are a major concern for Australian public health. Several definitive types of Salmonella Typhimurium strains, but primarily Salmonella Typhimurium definitive type 9 (DT9), have been frequently reported during egg-related food poisoning outbreaks in Australia. The aim of the present study was to generate a pathogenicity profile of nontyphoidal Salmonella isolates obtained from Australian egg farms. To achieve this, we assessed the capacity of Salmonella isolates to cause gastrointestinal disease using both in vitro and in vivo model systems. Data from in vitro experiments demonstrated that the invasion capacity of Salmonella serovars cultured to stationary phase (liquid phase) in LB medium was between 90-and 300-fold higher than bacterial suspensions in normal saline (cultured in solid phase). During the in vivo infection trial, clinical signs of infection and mortality were observed only for mice infected with either 10 3 or 10 5 CFU of S. Typhimurium DT9. No mortality was observed for mice infected with Salmonella serovars with medium or low invasive capacity in Caco-2 cells. Pathogenicity gene profiles were also generated for all serovars included in this study. The majority of serovars tested were positive for selected virulence genes. No relationship between the presence or absence of virulence genes by PCR and either in vitro invasive capacity or in vivo pathogenicity was detected. Our data expand the knowledge of strain-to-strain variation in the pathogenicity of Australian egg industry-related Salmonella spp. Salmonella is one of the most common causes of food-borne infection worldwide. In Australia, the egg industry is periodically implicated in cases of Salmonella food poisoning (1). Uncooked or partially cooked foods containing raw egg as an ingredient accounted for 14% of food-borne outbreaks in 2006, 13% in 2007, and 28% in the first quarter of 2008 (2). It has been shown that some Salmonella serovars, such as Salmonella enterica serovar Enteritidis, have the capacity to infect developing eggs within the oviduct, and therefore contaminated eggs act as an ecological amplifier (3). It is believed that this could then facilitate the dissemination of Salmonella into the food chain and its eventual transmission to humans. These studies, however, for the most part have been focused on Salmonella Enteritidis with limited investigation of S. enterica serovar Typhimurium. The dramatic increase in Salmonella Enteritidis infections occurring in overseas countries has not been observed in Australia (4). Salmonella Typhimurium and other nontyphoidal Salmonella spp., however, have become a major concern for the Australian egg industry.S. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts (5). There are several definitive types of S...

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Association between Indoor Environmental Contamination by Salmonella enterica and Contamination of Eggs on Layer Farms

Cited by 41 publications

References 27 publications

Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

Dynamics of Salmonella Shedding and Welfare of Hens in Free-Range Egg Production Systems

Microbiological vulnerability of eggs and environmental conditions in conventional and free-range housing systems

Pathogenicity of Salmonella Strains Isolated from Egg Shells and the Layer Farm Environment in Australia

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