Cause Of Salmonellosis Research Articles

Retrospective use of whole genome sequencing to better understand an outbreak of Salmonella enterica serovar Mbandaka in New South Wales, Australia.

IntroductionSalmonella enterica serovar Mbandaka is an infrequent cause of salmonellosis in New South Wales (NSW) with an average of 17 cases reported annually. This study examined the added value of whole genome sequencing (WGS) for investigating a non-point source outbreak of Salmonella ser. Mbandaka with limited geographical spread.MethodsIn February 2016, an increase in Salmonella ser. Mbandaka was noted in New South Wales, and an investigation was initiated. A WGS study was conducted three months after the initial investigation, analysing the outbreak Salmonella ser. Mbandaka isolates along with 17 human and non-human reference strains from 2010 to 2015.ResultsWGS analysis distinguished the original outbreak cases (n = 29) into two main clusters: Cluster A (n = 11) and Cluster B (n = 6); there were also 12 sporadic cases. Reanalysis of food consumption histories of cases by WGS cluster provided additional specificity when assessing associations.DiscussionWGS has been widely acknowledged as a promising high-resolution typing tool for enteric pathogens. This study was one of the first to apply WGS to a geographically limited cluster of salmonellosis in Australia. WGS clearly distinguished the outbreak cases into distinct clusters, demonstrating its potential value for use in real time to support non-point source foodborne disease outbreaks of limited geographical spread.

Isolation, Purification, Modeling, and binding site analysis of the Salmonella Bacteriophage ɛ34 repressor for subsequent crystallization and structure‐function studies

The bacteriophage ɛ34 is one of many phages that infect the bacteria Salmonella which is the main cause of salmonellosis (food poisoning). The bacteriophage ɛ34 encodes a protein called the cI repressor that is like other phage repressors. It has a C‐terminal protease domain which is about 80% identical to the repressors of phage λ (which infects E. coli), but its DNA binding N‐terminal portion is only about 50% identical to its closest known relatives in phages λ, and Lex A. This means that the ɛ34 repressor may have the same pathway for inactivation as phage λ, but probably has a different operator binding specificity due to lower sequence homology of its DNA‐binding domain. The N‐terminal DNA‐binding domain is homologous to the Helix‐Turn‐Helix family of DNA‐binding domains.The main goal of this project was to initiate a structure‐function study on the repressor protein of phage ɛ34. The ɛ34 Bacteriophage DNA was first isolated and purified. The gene encoding the bacteriophage ɛ34 repressor was amplified by PCR and cloned into a pET11a vector. The cI repressor, was overexpressed and purified by immobilized metal affinity chromatography and ion exchange chromatography. We also generated a homology model of this protein using the bacteriophage λ as a template in the SWISS‐MODEL homology modelling server. Our models predict a unique structure for the N‐terminal Helix‐Turn‐Helix domain. Finally, we have identified a potential binding site upstream of the cI gene on the Bacteriophage λ DNA. Crystallization trials are currently in progress. This project was done as a collaborative venture between two laboratories, Huntingdon College (Dr. Doba Jackson) and Alabama State University (laboratory of Dr. Robert Villafane). This project is in line with Dr. Robert Villafane's research into the Genomic analysis of bacteriophage ɛ34 of Salmonella enteric serovar Anatum.Support or Funding Information1Department of Chemistry & Biochemistry, Huntingdon College2Department of Biology, Alabama State UniversityThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

An Algerian perspective on non-typhoidal Salmonella infection.

Non-typhoidal Salmonella (NTS) represents a leading cause of food-borne disease worldwide. It is a global public health concern: more than 94 million cases and 115,000 deaths are reported every year, with a disproportionate impact in developing countries. The prevalence of multi-drug-resistant (MDR) Salmonella strains is another major health concern which affects antimicrobial treatment, as many studies report that infections caused by MDR strains are more severe than those caused by susceptible strains. In Algeria, NTS represent one of the primary causes of salmonellosis in both humans and food animal production, especially poultry. Epidemiological surveillance systems and monitoring programs for Salmonella infections are essential requirements to provide data useful for the effective detection and control of Salmonella outbreaks. The present review will supply a perspective on NTS infection, pathogenesis and antimicrobial resistance with a focus on the epidemiology of salmonellosis in Algeria.

Molecular characterization of antimicrobial multi-drug resistance in non-typhoidal Salmonellae from chicken and clam in Mangalore, India.

Salmonella enterica has been documented as one of the leading causes of salmonellosis throughout the world and is most commonly associated with the consumption of contaminated food products. Thus, this research was aimed at studying the antimicrobial susceptibility pattern and detection of quinolone resistance in Salmonella spp isolated from food of animal origin. Thirty-six Salmonella isolates comprising 8 from poultry and 28 from seafood (clams) were identified, serotyped and characterized for their antimicrobial susceptibility against 10 different antibiotics. Plasmid DNA was isolated from all the isolates by alkaline lysis, quinolone resistant non-typhoidal S. Weltevreden were examined for mutation in the DNA gyrase coding gene. Among the 36 Salmonella isolates, 20 were S. weltevreden (8 from poultry and 12 from seafood) and 16 were S. Typhimurium (from seafood). All the isolates showed multiple resistance to nalidixic acid, tetracycline, co-trimoxazole and nitrofurantoin, but, interestingly, the isolates were 100% susceptible to ampicillin, chloramphenicol and gentamicin. Resistant isolates from the study carried the genes responsible for resistance to respective antibiotics. The strain S130 isolated in the study showed single point mutation, Asp87Gly, at position 87 in quinolone resistance determining region. It revealed mutation in quinolone resistance determining region as a cause for quinolone resistance in non-typhoidal Salmonellae. The occurrence of genes accountable for plasmid mediated resistance to quinolones (viz., qnrA, qnrB and qnrS) in plasmid of non-typhoidal Salmonellae isolates provides evidence for plasmid mediated quinolone resistance.

Salmonella enterica serovar Typhimurium utilizes the ClpPX and Lon proteases for optimal fitness in the ceca of chickens

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a leading cause of salmonellosis. Poultry and poultry products are implicated in transmission of Salmonella to humans. In 2013, an outbreak of S. Typhimurium occurred that comprised 39 states within the United States and was associated with backyard flocks of chickens. Colonization of the avian host by S. Typhimurium requires numerous genetic factors encoded within the bacterium. Of particular interest are genetic factors induced by alternative sigma factors within S. Typhimurium since these genetic elements are important for adaptation to different environmental stresses. The heat shock response is a dedicated change in gene regulation within bacteria in response to several stresses, specifically growth at 42°C. Because chickens have a higher body temperature than other animals (42°C) the hypothesis was tested that components of the heat shock response are important for optimal fitness within the chicken. To this end, deletion of the heat shock proteases clpPX (BTNC0022) or lon (BTNC0021) was accomplished and the bacterial fitness in vivo was compared to the “wild-type” strain (NC1040) using a competition assay. One-day-old chicks were orally gavaged with an equal mixture of NC1040 and either BTNC0022 or BTNC0021. Quantification of viable bacteria over time by using plate counts indicated that deletion of either heat shock protease resulted in significantly reduced colonization of the chicken ceca compared to the wild-type strain. To satisfy the molecular Koch's postulates, clpPX and lon mutants were complemented in trans using a low-copy number plasmid for additional in vivo experiments. Complementation studies confirmed the importance of either heat shock protease to colonization of the chicken ceca. This report demonstrated that both ClpPX and Lon were important for optimal fitness within chickens. Moreover, these results suggested that components of the heat shock may be critical factors used by S. Typhimurium for colonization of poultry. The use of feed additives or other treatments that inactivate or inhibit ClpPX or Lon may reduce the bacterial burden of S. Typhimurium in poultry.

Higher Storage Temperature Causes Greater Salmonella enterica Serovar Typhimurium Internal Penetration of Artificially Contaminated, Commercially Available, Washed Free Range Eggs

Foodborne salmonellosis is a major public health concern, with contaminated eggs identified as a significant source of infection. In Australia, the most prevalent cause of salmonellosis from eggs is Salmonella enterica subsp. enterica serovar Typhimurium. This study explored the effect of temperature after 1, 7, 14, 21, and 28 days of storage on commercially available washed free range eggs, artificially contaminated with Salmonella Typhimurium on the external surface. At each time point, the external surface of the egg, the crushed eggshell, and the internal egg yolk and albumen were analyzed for Salmonella. After 28 days of storage, 25% of eggs stored at 4°C, 50% of eggs stored at 14°C, and 100% of eggs stored at 23 and 35°C were internally contaminated with Salmonella. After 1 day of storage, more than 50% of all eggs had Salmonella present in the crushed shell after the external surface had been disinfected with ethanol. This is the first study to demonstrate that refrigeration reduced the potential for Salmonella Typhimurium to penetrate the eggshell membrane and internally contaminate table eggs commercially available in Australia. It also suggests that the processes of cracking eggs may be a source of cross-contamination within the kitchen.

Rapid Detection of Salmonella Enterica Serovar Enteritidis from Eggs and Chicken Meat by Real‐Time Recombinase Polymerase Amplification in Comparison with the Two‐Step Real‐Time PCR

AbstractSalmonella is the most common cause of foodborne outbreaks throughout the world and Salmonella enterica serovar Enteritidis is one of the major causes of salmonellosis. We describe a rapid, sensitive and inexpensive method for the detection of S. Enteritidis from eggs and chicken meat using the real‐time recombinase polymerase amplification (Real‐time RPA) and compared this assay with the two‐step real‐time polymerase chain reaction (PCR) (Real‐time PCR). The detection sensitivity of the RPA and PCR assays was identical in pure culture, however, the reaction time was as short as 10 min compared with 40 min for the PCR assay. In food application, the detection sensitivity of the RPA assay was 10 cfu/g from eggs and 100 cfu/g from chicken samples without additional DNA purification steps before the amplification – therefore, the sensitivity of the RPA assay was 100 times greater from eggs and 10 times greater from chicken than the PCR assay.Practical ApplicationsNumerous epidemiological investigations attributed the source of sporadic Salmonella outbreaks as poultry and poultry‐by‐products including eggs. This is the first study in which a real‐time RPA was developed to detect the Salmonella Enteritidis specifically. The whole procedure is fairly simple and does not require specific equipment, making it potentially applicable in the monitoring and detection of S. Enteritidis in eggs and poultry products.

A case study on Salmonella enterica serovar Typhimurium at a dairy farm associated with massive sparrow death.

Background Salmonella enterica Typhimurium (S. Typhimurium) is the most common cause of bovine salmonellosis in Japan and where it is also cause of salmonellosis in wild birds. In 2008, a postpartum cow at a dairy farm developed diarrhea caused by S. Typhimurium. The herd was extensively surveilled for Salmonella sp. and we characterized bacterial isolates from this and other cows to determine the source of infection.ResultsEight isolates of S. Typhimurium from cattle were identified as phage type DT40 and showed a 100 % similarity by pulsed-field gel electrophoresis and the same or similar multiple-locus variable-number tandem-repeat analysis profiles as those of S. Typhimurium isolated from dead sparrows (Passer montanus) collected at Asahikawa in 2006. S. Typhimurium DT40 was considered to be a major cause of high sparrow mortality in Hokkaido in 2005–2006 and 2008–2009, suggesting that DT40 maintained in sparrows was transmitted to cattle.Conclusions S. Typhimurium DT40 may be transmitted from sparrows to dairy cattle.

Survival of Salmonella enterica Serovar Infantis on and within Stored Table Eggs

Contaminated table eggs are considered a primary source of foodborne salmonellosis globally. Recently, a single clone of Salmonella enterica serovar Infantis emerged in Israel and became the predominant serovar isolated in poultry. This clone is currently the most prevalent strain in poultry and is the leading cause of salmonellosis in humans. Because little is known regarding the potential transmission of this strain from contaminated eggs to humans, the objective of this study was to evaluate the ability of Salmonella Infantis to survive on the eggshell or within the egg during cold storage or at room temperature. Salmonella cells (5.7 log CFU per egg) were inoculated on the surface of 120 intact eggs or injected into the egg yolk (3.7 log CFU per egg) of another 120 eggs. Half of the eggs were stored at 5.5 ± 0.3°C and half at room temperature (25.5 ± 0.1°C) for up to 10 weeks. At both temperatures, the number of Salmonella cells on the shell declined by 2 log up to 4 weeks and remained constant thereafter. Yolk-inoculated Salmonella counts at cold storage declined by 1 log up to 4 weeks and remained constant, while room-temperature storage supported the growth of the pathogen to a level of 8 log CFU/ml of total egg content, as early as 4 weeks postinoculation. Examination of egg content following surface inoculation revealed the presence of Salmonella in a portion of the eggs at both temperatures up to 10 weeks, suggesting that this strain can also penetrate through the shell and survive within the egg. These findings imply that Salmonella enterica serovar Infantis is capable of survival both on the exterior and interior of table eggs and even multiply inside the egg at room temperature. Our findings support the need for prompt refrigeration to prevent Salmonella multiplication during storage of eggs at room temperature.

Parenteral administration of attenuated Salmonella Typhimurium ΔznuABC is protective against salmonellosis in piglets

A major cause of salmonellosis in humans is the contamination of pork products. Infection in pigs can be controlled using bio-security programs, but they are not sufficient in countries where a high level of infection is recorded. In this context, the use of vaccines can represent a valid supplementary method of control. Recently, we have demonstrated that an attenuated strain of Salmonella enterica serovar Typhimurium (Salmonella Typhimurium ΔznuABC) is protective against systemic and enteric salmonellosis in mouse and pig infection models, candidating this strain as an oral attenuated vaccine. In this study, we compared the efficacy of this attenuated Salmonella Typhimurium strain when administered orally or parenterally. Furthermore, in order to reproduce a pseudo-natural infection model, vaccinated pigs were allocated in the same pen with animals shedding virulent Salmonella Typhimurium. Animals were monitored weekly after vaccination and contact with infected piglets. Diarrhea and ataxia were recorded and Salmonella shedding was tested individually through bacterial culture. After four weeks of cohousing, piglets were euthanized, after which lymph nodes reactivity and gross lesions of the gut sections were scored at necropsy. Organs were submitted to microbiological and histological analyses.The data reported herein show that parenterally vaccinated animals do not shed the attenuated strain, and at the same time the absence of symptoms and decrease in virulent strain shedding in feces from day 6 after challenge demonstrated protection against infection induced by virulent Salmonella Typhimurium. In conclusion, our findings suggest that this is an alternative route of Salmonella Typhimurium ΔznuABC administration, without ignoring the advantages associated with oral vaccination.

Complete Genome Sequence of a Multidrug-Resistant Salmonella enterica Serovar Typhimurium var. 5− Strain Isolated from Chicken Breast

Salmonella enterica subsp. enterica serovar Typhimurium is a leading cause of salmonellosis. Here, we report a closed genome sequence, including sequences of 3 plasmids, of Salmonella serovar Typhimurium var. 5− CFSAN001921 (National Antimicrobial Resistance Monitoring System [NARMS] strain ID N30688), which was isolated from chicken breast meat and shows resistance to 10 different antimicrobials. Whole-genome and plasmid sequence analyses of this isolate will help enhance our understanding of this pathogenic multidrug-resistant serovar.

Evaluation of Virulence and Antimicrobial Resistance inSalmonella entericaSerovar Enteritidis Isolates from Humans and Chicken- and Egg-Associated Sources

Salmonella enterica serovar Enteritidis is a leading cause of salmonellosis throughout the world and is most commonly associated with the consumption of contaminated poultry and egg products. Salmonella Enteritidis has enhanced ability to colonize and persist in extraintestinal sites within chickens. In this study, 54 Salmonella Enteritidis isolates from human patients (n=28), retail chicken (n=9), broiler farms (n=9), and egg production facilities (n=8) were characterized by antimicrobial susceptibility testing, plasmid analysis, genetic relatedness using XbaI and AvrII pulsed-field gel electrophoresis (PFGE), and the presence of putative virulence genes. Nine isolates were evaluated for their abilities to invade and survive in intestinal epithelial and macrophage cell lines. Overall, 56% (n=30) of isolates were resistant to at least one antimicrobial agent tested, yet no isolates showed resistance to more than three antimicrobials. All isolates carried a common ∼55-kb plasmid, with some strains containing additional plasmids ranging from 3 to 50 kb. PFGE analysis revealed five XbaI and AvrII clusters. There were significant overlaps in the PFGE patterns of the isolates from human, chicken, and egg houses. All isolates tested PCR positive for iacP, purR, ttrB, spi4H, rmbA, sopE, invA, sopB, spvB, pagC, msgA, spaN, orgA, tolC, and sifA, and negative for iss, virB4, and sipB. Of the isolates selected for virulence testing, those containing the iron acquisition genes, iutA, sitA, and iucA, and ∼50-kb plasmids demonstrated among the highest levels of macrophage and epithelial cell invasion, which may indicate their importance in pathogenesis.

Detection of Salmonella in Chicken Meat by Insulated Isothermal PCR

Consumption of Salmonella-contaminated foods, such as poultry and fresh eggs, is known to be one of the main causes of salmonellosis. Conventional PCR methods, including real-time PCR for rapid detection of Salmonella, in general require skilled technicians and costly instruments. A recently developed novel convective PCR, insulated isothermal PCR (iiPCR), is carried out in polycarbonate capillary tubes. In this study, we designed TaqMan probes and PCR primers based on the yrfH gene encoding a heat shock protein for the iiPCR detection of Salmonella in chicken meat samples. The TaqMan probe was labeled with 6-carboxyfluorescein and 6-carboxytetramethylrhodamine at the 5' and 3' ends, respectively. The PCR amplicon was 133 bp. A typical run of this iiPCR assay was completed within 1 h. Specific PCR products were obtained for 148 strains representing 49 serotypes of Salmonella tested. Under the same conditions, false-positive results were not obtained for 98 non-Salmonella strains tested, including strains of Enterobacteriaceae closely related to Salmonella. For chicken meat samples, with a 5-h enrichment step Salmonella at as low as 10⁰ CFU/g of poultry meat could be detected. Because the amplification signals from the probes are detectable at 520 nm, identification of the PCR products by gel electrophoresis is not required. Compared with conventional PCR, the iiPCR system requires less expertise and provides an economical, reliable, and rapid tool for result interpretation. Detection results can be obtained within 8 h, including the enrichment and DNA extraction steps.

Dissemination of ClonalSalmonella entericaSerovar Typhimurium Isolates Causing Salmonellosis in Mauritius

Salmonella enterica serotype Typhimurium is one of the leading causes of salmonellosis in Mauritius, where it has also been associated with outbreaks of foodborne illness. However, little is known about its molecular epidemiology in the country. This study was therefore undertaken to investigate the clonality and source of Salmonella Typhimurium in Mauritius by studying human, food, and poultry isolates by pulsed-field gel electrophoresis (PFGE) and antibiotic minimum inhibitory concentration determination. Forty-nine isolates collected between 2008 and 2011 were analyzed, including 25 stool isolates from foodborne illness outbreaks and sporadic gastroenteritis cases, four blood isolates, one postmortem colon isolate, 14 food isolates, and five poultry isolates. All isolates were pansusceptible to the 16 antibiotics tested, except for two isolates that were resistant to sulfamethoxazole and trimethoprim. Overall characterization of the isolates by PFGE digested with XbaI and BlnI resulted in eight different patterns. The largest of the clusters in the composite dataset consisted of 20 isolates, including two raw chicken isolates, four poultry isolates, and nine human stool isolates from two outbreaks. A second cluster consisted of 18 isolates, of which 12 originated from human blood and stool samples from both sporadic and outbreak cases. Six food isolates were also found in this cluster, including isolates from raw and grilled chicken, marlin mousse, and cooked pork. One poultry isolate had a closely related PFGE pattern. The results indicate that one clone of Salmonella Typhimurium found in poultry has been causing outbreaks of foodborne illness in Mauritius and another clone that has caused many cases of gastrointestinal illness and bacteremia in humans could also be linked to poultry. Thus, poultry appears to be a major reservoir for Salmonella Typhimurium in Mauritius. Initiating on-farm control strategies and measures against future dissemination may substantially reduce the number of cases of salmonellosis in the country.

Development and evaluation of a novel nucleic acid sequence-based amplification method using one specific primer and one degenerate primer for simultaneous detection of Salmonella Enteritidis and Salmonella Typhimurium

Salmonella Enteritidis and Salmonella Typhimurium are the most widespread causes of salmonellosis and gastrointestinal diseases worldwide. Thus, their simple and sensitive detection is significantly important in biosafety and point-of-care diagnostics. In that regard, although present nucleic acid-based attempts are mainly focused on the detection methods encompassing all Salmonella enterica members in a single reaction, serotypes other than S. Enteritidis and S. Typhimurium are clinically and epidemiologically rare to humans. Therefore, regarding high ribosomal RNA (rRNA) copy numbers in a cell, isothermal nucleic acid sequence-based amplification (NASBA) technique was employed for simple, sensitive and simultaneous detection of the bacteria. However, due to high sequence homology among 16S rRNA genes and consequently, very few specific regions, we developed a novel NASBA method called “single specific primer-NASBA or SSP-NASBA” in which the specificity of the antisense primer is sufficient to perform a specific NASBA reaction. Accordingly, we designed highly specific NASBA antisense and degenerate sense primers for a segment of 16S rRNA variable region by universal sequence alignment to simultaneously detect S. Enteritidis and S. Typhimurium. Meanwhile, the approach was successfully evaluated for various Salmonella as well as closely related non-Salmonella serovars. Specific and simultaneous detection of both bacteria was achieved with the designed primer set in a single reaction environment with a detection limit of less than 10CFUsmL−1. The developed NASBA assay should facilitate the overall process and provide a simple, fast, specific and sensitive approach for molecular diagnostics of pathogens under various circumstances, e.g. outbreaks.

Survival and growth of epidemically successful and nonsuccessful Salmonella enterica clones after freezing and dehydration.

The spread of epidemically successful nontyphoidal Salmonella clones has been suggested as the most important cause of salmonellosis in industrialized countries. Factors leading to the emergence of success clones are largely unknown, but their ability to survive and grow after physical stress may contribute. During epidemiological studies, a mathematical model was developed that allowed estimation of a factor (q) accounting for the relative ability of Salmonella serovars with different antimicrobial resistances to survive in the food chain and cause human disease. Based on this q-factor, 26 Salmonella isolates were characterized as successful or nonsuccessful. We studied the survival and growth of stationary- and exponential-phase cells of these isolates after freezing for up to 336 days in minced meat. We also investigated survival and growth after dehydration at 10°C and 82% relative humidity (RH) and 25°C and 49% RH for 112 days. Stationary-phase cells were reduced by less than 1 log unit during 1 year of freezing, and growth was initiated with an average lag phase of 1.7 h. Survival was lower in exponentialphase cells, but lag phases tended to be shorter. High humidity and low temperature were less harmful to Salmonella than were low humidity and high temperature. Tolerance to adverse conditions was highest for Salmonella Infantis and one Salmonella Typhimurium U292 isolate and lowest for Salmonella Derby and one Salmonella Typhimurium DT170 isolate. Dehydration, in contrast to freezing, was differently tolerated by the Salmonella strains in this study, but tolerance to freezing and dehydration does not appear to contribute to the emergence of successful Salmonella clones.

Comparison Of Prevalence And Antimicrobial Sensitivity Of Salmonella typhimurium In Apparently Healthy Cattle And Goat In Sango-Ota, Nigeria

Salmonella typhimurium has been extensively incriminated worldwide as common causes of Salmonellosis in humans, with food-animals serving as important reservoirs. This study was aimed at determining and comparing the prevalence of Salmonella typhimurium isolated from faeces of goats and cattle in Sango-Ota and also at determining the antimicrobial sensitivity of the isolated organisms. A total of 157 fresh faecal samples (50 from goat and 107 from cattle) were examined for the presence of Salmonella typhimurium using standard microbiological and biochemical methods. 22 (14%) of the total samples were positive for Salmonella typhimurium and 13 (8.28%) were positive for Salmonella spp. 19 (86.4%) of Salmonella typhimurium were isolated from cattle while 3 (13.6%) from goats while 12 (92.31%) of Salmonella spp were isolated from cattle while 1 (7.69%) from goats. Other organisms isolated were Citrobacter spp, Providencia spp, Pseudomonas spp, Proteus spp, Klebsiella spp, Yersinia spp, Morganella spp, Enterobacter spp, Escherichia coli and Serratia spp. Antibiotic susceptibility test revealed that majority of the isolates were susceptible to ofloxacin, ciprofloxacin, pefloxacin, gentamicin, and nalidixic acid. A majority of Salmonella typhimurium, Salmonella spp, and other bacterial isolates were susceptible to all fluoroquinolones used in this study. A majority of the isolates were resistant to amoxicillin, ampicillin, augmentin, cotrimoxazole, streptomycin, tetracycline, and all cephalosporins used in this study. Salmonella typhimurium was present in both cattle and goat faeces in Sango-Ota and therefore if food from these sources are not properly handled it could lead to spread of the organism and occurrence of food borne salmonellosis.

Prevalence of Campylobacter and Salmonella in raw chicken on retail sale in the republic of Ireland.

To assess the current risks to consumers from Campylobacter and Salmonella in raw chicken products sold in the Republic of Ireland, a retail survey was undertaken to define their prevalence. Samples (n = 510) were analyzed using protocols based on ISO 10272-1:2006 and ISO 6579:2002. Processor codes on pack labels showed that 67% of samples were produced in the Republic of Ireland and 25% in the United Kingdom. Salmonella was present in 5.1% of samples, but the eight serovars found caused less than 7% of human salmonellosis reported in the Republic of Ireland. The results suggest that on-farm controls to limit Salmonella infection of broilers have been successful and that in Ireland raw chicken is not a significant cause of salmonellosis in humans. The overall prevalence of Campylobacter spp. was 84.3%. Isolation by the ISO method found 52.7% of samples to be positive, but overgrowth by contaminants was frequently evident. Therefore, in addition to enrichment, an homogenized sample was plated directly onto modified charcoal cefoperazone deoxycholate agar, and this detected a further 31.6%. Speciation of isolates (n = 426) determined that 67% were Campylobacter jejuni and 32% were Campylobacter coli. These species are the most common cause of campylobacteriosis in man. The results indicate that there is a need for poultry producers to introduce interventions to minimize the exposure of consumers in the Republic of Ireland to Campylobacter spp., as has been successfully done for Salmonella.

Single nucleotide polymorphisms that differentiate two subpopulations of Salmonella enteritidis within phage type

BackgroundSalmonella Enteritidis is currently the world's leading cause of salmonellosis, in part because of its ability to contaminate the internal contents of eggs. Previous analyses have shown that it is an exceptionally clonal serotype, which nonetheless generates considerable phenotypic heterogeneity. Due to its clonality, whole genome analysis is required to find genetic determinants that contribute to strain heterogeneity of Salmonella Enteritidis. Comparative whole genome mutational mapping of two PT13a strains that varied in the ability to contaminate eggs and to form biofilm was achieved using a high-density tiling platform with primers designed from a PT4 reference genome. Confirmatory Sanger sequencing was used on each putative SNP identified by mutational mapping to confirm its presence and location as compared to the reference sequence. High coverage pyrosequencing was used as a supporting technology to review results.ResultsA total of 250 confirmed SNPs were detected that differentiated the PT13a strains. From these 250 SNPS, 247 were in the chromosome and 3 were in the large virulence plasmid. SNPs ranged from single base pair substitutions to a deletion of 215 bp. A total of 15 SNPs (3 in egg-contaminating PT13a 21046 and 12 in biofilm forming PT13a 21027) altered coding sequences of 16 genes. Pyrosequencing of the two PT13a subpopulations detected 8.9% fewer SNPs than were detected by high-density tiling. Deletions and ribosomal gene differences were classes of SNPs not efficiently detected by pyrosequencing.ConclusionsThese results increase knowledge of evolutionary trends within Salmonella enterica that impact the safety of the food supply. Results may also facilitate designing 2nd generation vaccines, because gene targets were identified that differentiate subpopulations with variant phenotypes. High-throughput genome sequencing platforms should be assessed for the ability to detect classes of SNPs equivalently, because each platform has different advantages and limits of detection.

PREVALENCE OF INFECTIOUS DIARRHEA CAUSED BY SALMONELLA SPP. IN SLOVAKIA (SR)

Background: Salmonella infections are caused by non-typhoid salmonellas which are transmitted from animals to human with typical clinical symptoms including severe diarrhea with fever, etc. (Bálint et al., 2000). They are Salmonellas primarily adapted to animals causing zoonoses. Apart from other characteristics of pathogenicity and virulence factors common also for typhoid salmonellas they increasingly produce enterotoxin which is similar to enterotoxic E. coli. Together with cytotoxin of other invasive enteropathogens they cause inflammatory type of diarrhea. The source of infection include warm-blooded and cold-blooded vertebrates (Rovný et al., 1995). Material and methods: The diagnosis of salmonellosis is confirmed by the clinical picture testing stool, urine, hemocultivation, cultivation of pus or other liquid, obtained by puncturing. Results: During years 2000 - 2006 salmonellosis mostly occurred in Slovakia in months May - September with the highest incidence of 2886 cases (June 2000), 2819 (July 2001), 2449 (June 2002), 2265 (June 2003), 2086 (September 2004) and 1879 (September 2005). In October no occurence of salmonellosis was monitored during the whole period. The increase was recorded in months November - December (1675-1438, 2000; 1535-1552 in year 2001; 962-1118 in year 2002; 947-1213 in year 2003; 1126-1127 in year 2004; 1071-734 in year 2005). The most frequent causes of salmonellosis included infected households (28% of cases), public supply (25%) school meals (20%), catering (8%), hospitals (5%), social institutions (2%), import (2%), other (4%). Conclusion: Sustainability of good health is the main objective of the European Union and the organizations which through their activities are involved in processes to improve public health, disease prevention, and identifying sources of health hazards. Acknowledgements: This work was supported by the Agency of the Ministry of Education, Science, Research and Sport SR for EU Structural funds projects: ITMS 26220120023, ITMS 26220120041.