Transmission Of Salmonellae Research Articles

Comparison of microbiological, pathological, and zootechnical aspects between broiler chickens and turkeys challenged with Salmonella Heidelberg

Salmonella remains the second most common cause of gastrointestinal illness in the United States, European Union and other regions of the globe. In the food chain, poultry, especially turkeys and chickens, are considered significant contributors to salmonellosis in humans, as their intestinal tracts are often colonized with Salmonella . Due to changes in the prevalence of serovars, Salmonella Heidelberg ( SH ) has gained prominence, especially in the United States and Brazil, where outbreaks have occurred in recent years. The transmission of salmonella can occur by different routes, whether by infected breeding flocks, previously infected flocks, contaminated food or water. Thus, eliminating the bacteria from the installations can be a difficult task. In this sense, several countries have implemented salmonella control programs on poultry farms, in order to reduce its presence. Our study demonstrated that, despite the similarity between bird species and their rearing systems, turkeys are more sensitive to the Heidelberg serovar, especially in relation to microbiological contamination of internal organs and elimination of the agent into the environment. This information is extremely relevant for the poultry industry, enabling it to improve biosecurity programs in this species.

Examination of common swifts (Apus apus) for salmonella shedding in the area of Hannover, Lower Saxony, Germany.

The available literature indicates a high prevalence of the zoonotic pathogen Salmonella (S.) enterica serovar Infantis in the common swift (Apus apus). This long-distance migrant, which only consumes aerial plankton, can reach high population densities in places with suitable breeding sites. Dedicated competent private persons take part in the hand rearing of juvenile common swifts in wildlife rescue centres, which unavoidably results in close contact with these avian patients. For this reason, we examined common swifts for shedding of Salmonella spp. In the years 2014 and 2019, intestinal swabs or fresh faeces of common swifts (2014: n = 54; 2019: n = 62) were examined microbiologically (DIN EN ISO 6579; Annex D) in the area of Hannover, Lower Saxony, Germany. Salmonella spp. could not be detected in any of the examined common swifts within the investigation period and the studied area in 2014 and 2019. The results illustrate that the common swift is unlikely to be a natural reservoir of Salmonella spp. For the transmission of salmonella by swifts the local conditions with the corresponding environmental impact seem to play a significant role, and the risk of transmission should be assessed according to the region to be examined.

Research Note: Contamination of eggs by Salmonella Enteritidis and Salmonella Typhimurium in experimentally infected laying hens in indoor cage-free housing

Contaminated eggs are a leading source of human Salmonella infections and this problem continues to challenge public health authorities and egg industries around the world. Salmonella invasion of the ovaries and oviducts of infected laying hens can result in bacterial deposition inside the edible portions of developing eggs. The introduction, persistence, and transmission of salmonellae in commercial egg-laying flocks are influenced by flock management practices, but the food safety ramifications of different types of laying hen housing remain unresolved. The present study assessed the frequency of internal contamination of eggs after experimental Salmonella Enteritidis and S. Typhimurium infection of laying hens in indoor cage-free housing. Groups of 72 hens were housed on wood shavings in isolation rooms simulating commercial cage-free barns with community kick-out nest boxes and perches and 1/3 of the hens in each room were orally inoculated with 8.0 × 107 cfu of 2-strain mixtures of either S. Enteritidis (2 rooms) or S. Typhimurium (2 rooms), and the entire internal contents of all eggs laid 5 to 30 d postinoculation in nest boxes or on the flooring substrate were cultured to detect Salmonella. Contaminated eggs were laid between 8 and 28 d postinoculation. The overall incidence of S. Enteritidis isolation from eggs (3.41%) was significantly (P = 0.0005) greater than S. Typhimurium (1.19%). The contamination frequencies associated with the 2 egg collection locations were not significantly different (P > 0.05). These results demonstrate that oral infection of a relatively small proportion of laying hens in indoor cage-free housing with invasive Salmonella serovars can result in the production of internally contaminated eggs at low frequencies over a period of nearly a month postinoculation.

Detection of Zoonotic Antibiotic Resistant Salmonella spp. Carrying Virulence Genes in Rural Mus musculus, Golestan Province, North of Iran

Background and aims: Salmonella spp. infect cold-blooded and warm-blooded animals and may cause a worldwide zoonotic disease, salmonellosis, in infected animals. Rodents can be Salmonella carriers without any signs of salmonellosis. The frequency of salmonella contamination, the presence of virulence genes (SpvR and SpvB) and antibiotic resistance pattern of isolated Salmonella were studied in rural Mus musculus to reveal the possible role of them in Salmonella dissemination in Golestan province. Methods: A total of 190 wet rectal swabs of M. musculus were obtained from rural areas of Golestan province with different climate conditions. The swabs were cultured and positive samples were serotyped and their antibiotic resistance patterns were studied. The presence of Salmonella and virulence genes was analyzed by SpvR and SpvB genes primers, respectively. Results: Salmonella spp. were detected in 15 (7%) of 190 fecal samples by bacterial culture and PCR. S. enteritidis (n=9) and S. typhimurium (n=6) were identified. The highest and lowest frequencies were detected in humid (13.1%) and arid areas (3.1%), respectively. SpvR and SpvB genes were diagnosed in 10 of 15 (66.6%) isolated Salmonella. The highest resistance of detected Salmonella spp. was observed against streptomycin (53%). All the isolates were sensitive to chloramphenicol, gentamicin and trimethoprim. Conclusion: The Salmonella contamination in sampled house mice indicates that native people should be made aware of the risk of Salmonella infection and possible ways of salmonella transmission through rodents. In addition, the application of appropriate therapeutic approaches to prevent the spread of antibiotic resistant Salmonella is recommended.

Are We Ready for Bioterrorism? Health Personnel were Affected by Contaminated Meat Cooked at a Daily Routine Hospital Kitchen

Introduction:Salmonellae are gram-negative motile bacilli. The transmission of salmonellae to a susceptible host usually occurs from the consumption of contaminated foods. Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts four to seven days, but can be severe enough to require hospitalization.Aim:Describe a hospital kitchen based mass foodborne infection.Methods:Descriptive analysis of the foodborne infection event.Results:310 health personnel were contaminated from lunch that was cooked at our hospital kitchen. On that day 70 patients came to the emergency department for complaints of vomiting, fever, and diarrhea. During the next two days, we canceled all planned surgical operations. At the second day, we followed 80 patients and third day 150 patients came to our emergency services. Our emergency services and ıntensive care units were blocked because of personnel illness. We examined all patients, got blood tests and stool stains and cultures. Because of this mass casualty contamination, our infection control committee gave formal information that suspicious of Salmonellosis. 13 of 310 infected health personnel were hospitalized. They got intravenous saline and electrolytes support like calcium and potassium. After two days we got Results of stool cultures, there was inoculation of Salmonella types. None of them died.Discussion:We realized that we are not ready for mass casualty incidents like this contamination. Because our patient flow was really blocked. We had to call in new doctors and nurses from different hospital staffs. The event was similar to bioterrorism conditions and we suddenly have to put in place hospital disaster plans at the beginning of decontamination. This situation made us to recognize bioterrorism agents like Salmonella types. We have to raise awareness of the community about chemical, biological, radiological and nuclear agents attacks.

Prevalence of salmonella in camel’s meat and liver at Belbeis, Sharkia Governorate, Egypt

The aim of this study was to detect the prevalence, serotypes, and public health importance of salmonella in camel meat and liver in Belbeis, Sharkia Governorate, Egypt. A total of 200 samples were obtained from apparently healthy slaughtered camels comprising of meat and liver (100 of each) and examined to detect non lactose fermenting dark center colonies. Out of the 200 examined samples, 37 were Salmonella positive (28 meat and 9 liver samples) with a prevalence rate of 18.5%. The identified serotypes were Salmonella Enteritidis (62.1%) and Salmonella Typhimurium (37.9%). This study revealed that camel play an important role in transmission of salmonella to human thus special precaution and hygienic measures must be applied in abattoir during evisceration and dressing of carcasses.

Molecular cloning of peptidyl-prolylcis-trans isomerase B gene (cyclophilins B) from poultry isolate Salmonella typhimurium

Salmonellosis is considered as one of the widest spread foodborne zoonosis in industrialized as well as developing countries. It is most frequently found in the gastrointestinal tracts of animals and has been commonly associated with foods such as raw meat, poultry, eggs and dairy products. Poultry and poultry products are supposed to make up fifty percent of the total vehicle of transmission of salmonella. In this study, we reported the cloning and sequence analysis of cyclophilin gene (ppiB) from Salmonella Typhimurium. The resultant PCR fragment of 495bp was cloned and the sequencing data revealed 100% homology between ppiB sequences from Salmonella Typhimurium strain E-3232 and ppiB sequences of standard reported strain (Salmonella typhimurium str. LT2) in NCBI data base. This submitted sequence in Gene bank was having accession no. KR149241. The ppiB sequence has also shown 90–100% homology with another Salmonella serovars, which suggests that ppiB gene of Salmonella, is highly conserved in the majority of the pathogenic Salmonella. PPIase is most likely involved in a wide range of biochemical and physiological processes.

Investigating the prevalence of Salmonella in dogs within the Midlands region of the United Kingdom.

BackgroundThe intimate relationship between dogs and their owners has the potential to increase the risk of human exposure to bacterial pathogens. Over the past 40 years, there have been several reports on transmission of salmonellae from dogs to humans. This study therefore aimed to determine the prevalence of Salmonella in the faeces of dogs from the Midlands region of the United Kingdom to assess exposure risk and potential for zoonotic transmission.ResultsA total of 436 apparently healthy dogs without diarrhoea from households (n = 126), rescue centres (n = 96), boarding kennels (n = 43), retired greyhound kennels (n = 39) and a pet nutrition facility (n = 132) were investigated for Salmonella shedding. Faecal samples were processed by an enrichment culture based method. The faeces from one dog (0.23 %; 95 % confidence limit 0.006 %, 1.27 %) was positive for Salmonella. The species was S. enterica subspecies arizonae.ConclusionThis study showed that the prevalence of Salmonella from faeces from apparently healthy dogs from a variety of housing conditions is low; however, Salmonella shedding was still identified.

Epidemiology of Poultry Salmonellosis: A Review

Salmonellosis is one of the major foodborne disease of significant public health concern. Salmonellosis is considered as one of the most wide spread foodborne zoonosis in industrialized as well as developing countries. It is commonly found in the gastrointestinal tracts of animals and has been commonly associated with foods such as raw meat, poultry, eggs and dairy products. Poultry and poultry products derived from poultry are believed to make up fifty percent of the total vehicle of transmission of salmonella. Typhoid and non-typhoid salmonellosis remain major public health problems and are clearly the most economically important food borne disease. In many countries, the incidence of salmonellosis has markedly increased; however, paucity of good surveillance data exists. Salmonella has five different pathogenicity islands that encodes the majority of the virulence genes used for invasion and evasion of the host. The purpose of this review is to discuss the epidemiology, salmonella pathogenicity islands, invasion, molecular diagnosis, and global regional control and prevention strategies.

English

Salmonella is one of the most important pathogens associated with gastrointestinal infections in warm-blooded animals. Lizards have been incriminated in the transmission ofSalmonellae and other enteric pathogens through contaminated soil, food, or water. In the current study, we characterized a Salmonella isolate, recovered from the small intestine of an Agama agama lizard captured in a poultry pen from Teaching and Research Farm, University of Ibadan, Nigeria. The characterization was based on serotyping, polymerase chain reaction (PCR)-based confirmation of the serotype, multiplex PCR identification of selected beta-lactam genes associated with 3rd generation cephalosporin resistance and pathogenicity experiment of the isolate in pullet. Our work identified the isolate asSalmonella enterica serotype Pullorum that had apparently lost its fimbriae 1 antigen due to sub-culturing prior to serotyping. The isolate also carried transferable 3rd generation cephalosporin resistant genes and produced 28% mortalities in 16 weeks old birds during 21days pathogenicity experimentation. This work reveals the potential roles of Agama agama lizards regarding the epidemiology of Salmonella infections and possible involvement in the spread of antibiotic drug resistant pathogens in poultry.   Key words: Salmonella, Agama agama, 3rd generation - cephalosporins, Nigeria.

Outbreak of Salmonellosis Linked to Live Poultry from a Mail-Order Hatchery

BackgroundOutbreaks of human salmonella infections are increasingly associated with contact with live poultry, but effective control measures are elusive. In 2005, a cluster of human salmonella Montevideo infections with a rare pattern on pulsed-field gel electrophoresis (the outbreak strain) was identified by PulseNet, a national subtyping network.MethodsIn cooperation with public health and animal health agencies, we conducted multistate investigations involving patient interviews, trace-back investigations, and environmental testing at a mail-order hatchery linked to the outbreak in order to identify the source of infections and prevent additional illnesses. A case was defined as an infection with the outbreak strain between 2004 and 2011.ResultsFrom 2004 through 2011, we identified 316 cases in 43 states. The median age of the patient was 4 years. Interviews were completed with 156 patients (or their caretakers) (49%), and 36 of these patients (23%) were hospitalized. Among the 145 patients for whom information was available, 80 (55%) had bloody diarrhea. Information on contact with live young poultry was available for 159 patients, and 122 of these patients (77%) reported having such contact. A mail-order hatchery in the western United States was identified in 81% of the trace-back investigations, and the outbreak strain was isolated from samples collected at the hatchery. After interventions at the hatchery, the number of human infections declined, but transmission continued.ConclusionsWe identified a prolonged multistate outbreak of salmonellosis, predominantly affecting young children and associated with contact with live young poultry from a mail-order hatchery. Interventions performed at the hatchery reduced, but did not eliminate, associated human infections, demonstrating the difficulty of eliminating salmonella transmission from live poultry.

Comparison of the Prevalence of Salmonella Infection in Layer Hens from Commercial Layer Farms with High and Low Rodent Densities

A comparison on the prevalence of Salmonella infection in layer hens from commercial layer farms with high and low rodent densities was investigated. Out of 280 laying hens sampled from three commercial layer farms with high rodent densities, Salmonella enterica subsp. enterica serovar Enteritidis (Salmonella Enteritidis) was isolated from 20 (7.14%) hens and Salmonella enterica subsp. enterica serovar Infantis (Salmonella Infantis) from three (1.07%) hens. In contrast, layer hens sampled from four commercial layer farms with low rodent densities were negative for any salmonellae. Significant differences (P < 0.05) in the isolation rates of Salmonella from various organs of infected layer hens were also noted. For Salmonella Enteritidis, liver (55.0%) and the oviduct (55.0%) had the highest isolation rates while all Salmonella Infantis isolates were from the oviduct. Pulsed field gel electrophoresis (PFGE) analysis of BlnI-digested chromosomal DNA of Salmonella Enteritidis isolated from layer hens and rodents showed similar patterns. PFGE analysis of Salmonella Infantis isolated from layer hens, rodents, eggs, and the environment yielded identical patterns. In this study, the significantly higher prevalence rate (P < 0.05) of Salmonella Enteritidis and Salmonella Infantis in layer hens from high rodent density farms could be attributed to the high rodent population density. The persistent Salmonella Enteritidis and Salmonella Infantis infection inside layer houses may have been amplified by the increasing numbers in the rodent population over the years, which increased the opportunity for environment-rodent-chicken interaction and the transmission of salmonellae to chickens. Monitoring of salmonellae from rodents inside poultry premises is recommended to be an effective additional tool in the assessment of the Salmonella status of layer flocks.

The Global Burden of NontyphoidalSalmonellaGastroenteritis

To estimate the global burden of nontyphoidal Salmonella gastroenteritis, we synthesized existing data from laboratory-based surveillance and special studies, with a hierarchical preference to (1) prospective population-based studies, (2) "multiplier studies," (3) disease notifications, (4) returning traveler data, and (5) extrapolation. We applied incidence estimates to population projections for the 21 Global Burden of Disease regions to calculate regional numbers of cases, which were summed to provide a global number of cases. Uncertainty calculations were performed using Monte Carlo simulation. We estimated that 93.8 million cases (5th to 95th percentile, 61.8-131.6 million) of gastroenteritis due to Salmonella species occur globally each year, with 155,000 deaths (5th to 95th percentile, 39,000-303,000 deaths). Of these, we estimated 80.3 million cases were foodborne. Salmonella infection represents a considerable burden in both developing and developed countries. Efforts to reduce transmission of salmonellae by food and other routes must be implemented on a global scale.

Report of Neonatal Meningitis Due to Salmonella enterica Serotype Agona and Review of Breast Milk-Associated Neonatal Salmonella Infections

We present the first documented case of Salmonella enterica serotype Agona meningitis in a 6-day-old baby. S. enterica serotype Agona was isolated concurrently from infant cerebrospinal fluid and parental fecal samples, and Salmonella was isolated from breast milk. The role of breast milk in transmission of Salmonella enterica is discussed.

Multilocus sequence typing supports the hypothesis that cow- and human-associated Salmonella isolates represent distinct and overlapping populations.

A collection of 179 human and 156 bovine clinical Salmonella isolates obtained from across New York state over the course of 1 year was characterized using serotyping and a multilocus sequence typing (MLST) scheme based on the sequencing of three genes (fimA, manB, and mdh). The 335 isolates were differentiated into 52 serotypes and 72 sequence types (STs). Analyses of bovine isolates collected on different farms over time indicated that specific subtypes can persist over time on a given farm; in particular, a number of farms showed evidence for the persistence of a specific Salmonella enterica serotype Newport sequence type. Serotypes and STs were not randomly distributed among human and bovine isolates, and selected serotypes and STs were associated exclusively with either human or bovine sources. A number of common STs were geographically widespread. For example, ST6, which includes isolates representing serotype Typhimurium as well as the emerging serotype 4,5,12:i:-, was found among human and bovine isolates in a number of counties in New York state. Phylogenetic analyses supported the possibility that serotype 4,5,12:i:- is closely related to Salmonella serotype Typhimurium. Salmonella serotype Newport was found to represent two distinct evolutionary lineages that differ in their frequencies among human and bovine isolates. A number of Salmonella isolates carried two copies of manB (33 isolates) or showed small deletion events in fimA (nine isolates); these duplication and deletion events may provide mechanisms for the rapid diversification of Salmonella surface molecules. We conclude that the combined use of an economical three-gene MLST scheme and serotyping can provide considerable new insights into the evolution and transmission of Salmonella.

Vertical and Horizontal Transmission ofSalmonellaWithin Integrated Broiler Production System

Salmonella remains one of the leading causes of food-borne illness in the United States, and many key questions regarding the introduction and persistence in animal production systems still remain. In order to understand the ecology of Salmonella within an integrated commercial broiler production system, 289 Salmonella enterica were recovered from two integrated poultry farms during the production and processing of seven consecutive flocks. The variety and prevalence of Salmonella serotypes differed between farms. Overall, 15 serotypes were identified, with the most common being Typhimurium (55%), Montevideo (7.9%), Kentucky (9%), and Enteritidis (9.7%). Salmonella Typhimurium and Enteritidis isolates recovered from processed carcasses from Farm One were further characterized using pulsed-field gel electrophoresis (PFGE), and were shown to be indistinguishable from isolates recovered from the poultry house environment and mice trapped on this farm. Additionally, the same broiler S. Typhimurium and S. Enteritidis strains, identified by PFGE, were also isolated from samples taken at a company breeder farm, suggesting vertical transmission of these Salmonella serotypes in this poultry production system. Results indicate that management practices at the breeder level may have a profound effect on the transmission and persistence of salmonellae within an integrated production system, as well as on the potential contamination of poultry-derived products.

Differences and similarities among experts’ opinions on Salmonella enterica dynamics in swine pre-harvest

A workshop was conducted to elicit expert opinion on infection status and transmission of salmonella in pigs at the farm of origin, during transport and during lairage. A second objective was to compare opinions regarding risk factors for salmonella introduction and control at the farm level between experts from different countries. Thirty-six experts from 11 countries filled in a paper-and-pencil questionnaire during an international conference. Experts from all countries agreed on the risk of salmonella introduction related to live animals and the importance of general hygiene and all-in/all-out management for salmonella control. However, workshop participants from Denmark put more weight on factors related to feed while experts from USA rated factors related to rodents and people contact higher. The experts believed that 21–33% of pigs coming from a chronically infected farm would be infected with salmonella, but only one-third of the infected pigs would be shedders. Regarding transport and lairage, the US participants believed that contamination was occurring in the majority of pigs regardless of initial infection status and particularly during lairage; in contrast, the Danish experts were more optimistic with respect to the contamination and infection risk. US experts believed that the incidence of salmonella shedding would be high among pigs infected during transport and lairage and that an important proportion of ‘carrier’ pigs would start shedding. Our results reflect the differences in the level of salmonella infection and implemented control strategies between countries as well as the different philosophies that professionals have. The differences in opinion regarding salmonella dynamics could be due either to true differences in risk as a consequence of distinct management and transport practices in Denmark and USA or to a difference in perception.

Dynamics of Salmonella Contamination in a Commercial Quail Operation

Control of carcass contamination requires knowledge of the source and dynamics of spread of Salmonella in commercial poultry production. We examined Salmonella contamination at a U.S. commercial quail operation. Pulsed-field gel electrophoresis (PFGE) was used to type isolates in order to trace Salmonella throughout this production environment. During a 6-mo survey, Salmonella serotypes hadar, typhimurium, typhimurium variant Copenhagen, and paratyphi were encountered within this poultry operation. Ninety-four percent of the Salmonella isolated from breeder and production houses and from carcass rinses belonged to Salmonella serotypes typhimurium variant Copenhagen and hadar. There were six distinct S. typhimurium variant Copenhagen genetic types, as identified by PFGE, present within this particular poultry operation. Seventy-nine percent of S. typhimurium variant Copenhagen identified from the environment of the breeder and production houses produced the same PFGE pattern. Thirty-eight percent of S. typhimurium Copenhagen isolated from carcass rinses and the breeder house shared the same PFGE DNA pattern. This study demonstrates the transmission of salmonellae throughout this production environment, from the breeders to their progeny and to the birds ultimately processed for human consumption.

A model for evaluating intervention strategies to control salmonella in the poultry meat production chain.

A model of the transmission of salmonella through the poultry meat production chain is developed, to predict the effects of intervention strategies for salmonella control. The model first describes the situation before intervention in terms of salmonella prevalences at flock level and some transmission parameters. After single control measures are translated into effects on these transmission parameters, the effects of sets of control measures (intervention strategies), can be calculated with the model. As research data are lacking, the model input parameters were derived from expert opinion. As an example, the effects of two intervention strategies proposed for the Dutch poultry industry are predicted. A sensitivity analysis is performed to indicate where the most effective control measures may be expected. Additionally, the reliability of the model predictions is studied by an uncertainty analysis. The use of the model as a tool for policy makers deciding about salmonella control strategies is discussed.

Effect of Simultaneous or Delayed Competitive Exclusion Treatment on the Spread of Salmonella in Chicks

Exposure of newly hatched chicks in the hatchery to salmonellae results in the establishment of seeder chicks with fecal shedding and the transmission of salmonellae to other contact chicks in the broiler house during growout. This study investigated the protective effect of treatment with a characterized competitive exclusion culture, CF3 on the transmission of Salmonella from seeder to contact chicks when CF3 treatment occurred simultaneously with seeder challenge or when treatment was delayed until 24 hr after challenge. Delayed treatment failed to prevent the establishment of seeder chicks, but did significantly (P≤.005) reduce the spread of Salmonella from seeder to non-challenged contact chicks. Simultaneous Salmonella challenge and CF3 treatment significantly (P≤.005) decreased the establishment of seeders and was highly effective in preventing the spread of Salmonella from seeder to contact chicks. The results demonstrated that treatment on the day of hatch can significantly help to reduce seeder establishment and the spread of Salmonella from seeders to highly susceptible contact chicks.