Aims: Salmonella is one of the most common foodborne illnesses worldwide. Poultry meat and products are the main sources of human infection. Therefore, the main objective of the current study was to assess the genetic virulence of biofilm-forming Salmonella isolated from chicken sausage and nuggets. Methodology and results: Isolation of Salmonella was carried out using XLD agar; suspected colonies were identified biochemically and then serotyped using the Kauffman-White scheme for detection of somatic (O) and flagellar (H) antigens. Congo red (CR) medium was used for the assessment of biofilm formation of the isolated strains. The invasion gene (invA), the heat-labile Salmonella enterotoxin gene (stn), plasmid-encoded fimbriae (pefA) genes, the protein effectors sopB, sopD and biofilm genes in six Salmonella isolates were investigated using mPCR, following QIAamp® DNA Mini Kit instructions and 1.5% agarose gel electrophoreses. Salmonella was detected in 12%, 8% and 4% of the examined frozen packaged raw chicken sausage, frozen packaged raw chicken nuggets and ready-to-eat sausage. The isolated strains were S. Typhimurium, S. Enteritidis, S. Essen and S. Montevideo. Moreover, mPCR indicated the presence of biofilm gene (csgD gene), stn, sopB and sopD virulence genes in all isolated strains (100%); however, pefA gene failed to be detected. Conclusion, significance and impact of study The current findings showed that every Salmonella isolate examined was capable of creating biofilm at room temperature. As a result, these isolates are more likely to persist on abiotic surfaces, which raises the danger of cross-contamination and foodborne outbreaks.
Salmonella Food Poisoning

OBJECTIVETo study the relationship between foodborne diseases (FBD) and contamination of Salmonella spp. in catering foods, quantitative microbiological risk assessment (QMRA) of Salmonella spp. was used to evaluate the food material or the ready to eat food.

METHODSThe contamination data of Salmonella spp. in 10 896 food samples of 9 categories of food which were collected by National Food Contamination and Food Borne Disease Surveillance Net, combining with diet consumption data from National Food Nutrition Survey in 2002, were analyzed by the microbiological risk assessment model developed by WHO/FAO or FDA/FSIS of US to predict probability of FBD.

RESULTSThe results of MRA showed that the probability of salmonellosis by consuming ready to eat meat in summer and autumn was 0.20, much higher than the other foods. Although the contamination level in raw poultry was higher than meat, the probability of salmonellosis by raw poultry (9.11 x 10(-6)) was lower than meat (3.14 x 10(-5)) because of the low consumption volume.

CONCLUSIONProbability of FBD was significantly correlated with the volume of food consumption, the status of economy and bacteria contamination level. The level of FBD in summer season was higher than in winter and spring because of ambient temperature.

Food Contamination ; Food Microbiology ; Humans ; Risk Assessment ; Salmonella ; isolation & purification ; Salmonella Food Poisoning ; prevention & control

OBJECTIVES: A field investigation was done to identify the level of epidemic and to evaluate the infection route of Salmonellosis occurred in a baby's first birthday banquet in Jeju Island. METHODS: Among participants in the banquet given on a baby's first birthday, persons showing gastrointestinal symptoms were conducted by the structured questionnaire and stool culture. The symptomless persons were also surveyed by self-responded structured questionnaire. The causal relationship between food items and gastrointestinal symptoms was proved by odds ratio and Wilcoxon rank-sum test. RESULTS: Salmonella london was identified in the stools of 12 subjects among 20 participants showing gastrointestinal symptoms, as well as in the boiled pork hock. CONCLUSIONS: This outbreak event is thought to happen after participants took the boiled pork hock that contaminated with S almonella london during the storage process.
Humans ; Odds Ratio ; Salmonella ; Salmonella Food Poisoning ; Salmonella Infections* ; Tarsus, Animal ; Surveys and Questionnaires

This study was designed to define the epidemiology of a food-borne outbreak caused by Salmonella enteritidis that affected only one squadron of a military battalion located in the vicinity of the city of Edirne in Turkey. The outbreak was analyzed by a standard surveillance form of the Centers for Disease Control and Prevention. The relationship between the eaten foods and cases was analyzed by Fisher's exact chi-square test, and odds ratios were calculated by a case-control study. The outbreak affected 60 of 168 soldiers in the squadron, 16 of whom were hospitalized. S.enteritidis was cultured in stools from 13 of the hospitalized soldiers and from 3 soldiers who had prepared the food. All strains were completely susceptible to antibiotics; their plasmid profiles were also identical. The highest attack rate detected was 55.7% in an omelet eaten 24 hours before (p < 0.001). Furthermore, it was the riskiest food according to the case-control study (OR=7.88; 95% CI=3.68-16.89). The food samples were unobtainable because they had been discarded. All of the hospitalized cases recovered, and none of the control cultures of stools yielded the pathogen after three weeks. In conclusion, although our results didn't indicate the exact source of the outbreak microbiologically, the omelet was considered to be the source based on the epidemiological proofs.
*Disease Outbreaks ; Eggs/microbiology ; Human ; Salmonella Food Poisoning/*epidemiology/etiology ; Salmonella enteritidis/*isolation & purification ; Turkey/epidemiology

Disease Outbreaks ; Epidemics ; Foodborne Diseases ; Humans ; Salmonella Food Poisoning ; Salmonella enteritidis

OBJECTIVES: A salmonellosis outbreak occurred within a community of Gyeongju residents who ingested catered food from a wedding in June 2009. We aimed to epidemiologically investigate the probable vehicle of the infection. METHODS: We conducted a retrospective cohort study on 34 local residents who ingested the wedding food. RESULTS: Among the 34 residents, 31 (91.2%) reported symptoms of infection after eating the food. Among all of the wedding foods, pan-fried foods were highly associated with the diarrheal attack rate. On bacteriological examination, Salmonella species were detected in the pan-fried foods among the leftover foods and in 17 of the 31 stool specimens from the cases. There were five different types of pan-fried foods, but the onset of symptoms was independent of the ingredients used. We found that the pan-fried food was prepared at a food store in Seoul and that eggs were a common ingredient. CONCLUSIONS: The major cause of the salmonellosis in this population was presumed to be the pan-fried food prepared with contaminated eggs. These food items might have been partially undercooked because of their irregular shape, which allowed the Salmonella species to survive and multiply before ingestion.
Cohort Studies ; *Disease Outbreaks ; Eggs/microbiology ; Feces/microbiology ; *Food Microbiology ; Fruit/microbiology ; Humans ; Republic of Korea/epidemiology ; Retrospective Studies ; Salmonella/*isolation & purification ; Salmonella Food Poisoning/*epidemiology ; Time Factors

INTRODUCTIONNon-typhoidal Salmonellae are important causes of bacterial food-borne infection, especially in institutional settings. An outbreak of gastrointestinal infection occurred in a military camp in January 2007, and an epidemiological outbreak investigation was conducted.

MATERIALS AND METHODSA survey was conducted on soldiers in the camp on their clinical symptoms, and recent meals consumed. After determining the affected meal, a subsequent survey was conducted on those who had eaten the meal. A case-control study was then performed to determine the outbreak's likely food source. Laboratory tests were also conducted to determine the bacteriological cause.

RESULTSOf the 94 responders, 55 (58.5%) met our case definition of gastrointestinal illness. The dinner on 9 January was the most likely affected meal, with the onset of symptoms occurring within 6 to 36 hours. The mashed potato was the most likely food source with an attack rate of 80.7% for those who consumed it versus 32.7% for those who did not (P <0.01). From the multivariate analysis, the mashed potato remained the only food item independently and significantly associated with infection, with a relative risk of infection 9.49 times those who did not consume it (95% CI, 2.73-32.97). Salmonella group E was cultured from 4 individuals. Although no specific contamination was identified, the mashed potato was stored for more than 5 hours before the last serving.

CONCLUSIONRisk during preparation of large quantities of food should be identified a priori, and measures taken to reduce them, to prevent outbreaks.

Case-Control Studies ; Disease Outbreaks ; Food Microbiology ; Gastroenteritis ; etiology ; Military Medicine ; Salmonella ; isolation & purification ; Salmonella Food Poisoning ; etiology ; Singapore ; Solanum tuberosum

OBJECTIVETo investigate the application of pulsed-field gel electrophoresis (PFGE) in food-borne outbreak.

METHODSPathogens were isolated and further characteristics identified by traditional methods. The strains isolated were carried out with molecular typing with using PFGE. PFGE was performed by Laboratory Directions for molecular subtyping of Salmonella by PFGE (CDC, USA) and the results of PFGE were analyzed by BioNumerics soft.

RESULTSTotally 14 Salmonella serotype Muenchen strains were isolated from 19 patients, 3 of 9 suspicious foods were positive for S. muenchen and 7 strains were isolated from 18 cooks. The biochemistry characterization and antimicrobial susceptibility of all the strains isolated were the same. 23 S. muenchen isolates were all shown indistinguishable by PFGE.

CONCLUSIONPFGE should play a key role in identifying the outbreak-associated isolates and distinguishing them from unrelated sporadic isolates. It might also demonstrate that the genetic fingerprints of serotype Muenchen isolates derived from patients were indistinguishable from those derived from drinks. PFGE might provide precise information on bacterial food-borne pathogens, promptly identify the source of infection, and effectively prevent from spreading. It should be one of the early warning method on controlling outbreak of the food-borne disease.

China ; epidemiology ; Disease Outbreaks ; Electrophoresis, Gel, Pulsed-Field ; methods ; Humans ; Microbial Sensitivity Tests ; Salmonella Food Poisoning ; epidemiology ; microbiology ; Salmonella enterica ; classification ; isolation & purification ; Serotyping

OBJECTIVEDual detection of Salmonella and Shigella using modified molecular beacons and real-time PCR was developed. The established method was applied to rapid diagnosis of Salmonella and Shigella' food poisoning, and for routine monitoring programs.

METHODSTwo sets of primers were designed based on the core sequence of invA gene and ssaR gene published on GenBank to detect Salmonella, and ipaH gene were selected to detect Shigella. Three corresponding modified molecular beacons labeled with different fluorophors were designed. The molecular beacons and primer sets were tested against numerous strains from 55 different bacterial species. Then the two assays were combined to establish the dual real-time PCR assay, and were applied to the food poisoning diagnosis and surveillance.

RESULTSFor the modified molecular beacons-based dual real-time PCR assay, the sensitivity achieved was 69-93 fg/microl, 32-64 CFU/ml or 1-2 CFU/PCR reaction. There was no cross-reaction with other bacteria served as control. The dual real-time PCR assay was used to detect 134 Salmonella strains and 67 Shigella strains but no false signals were observed. 1100 food poisoning samples were tested with 569 Salmonella and 42 were Shigella identified by real time PCR. Among the positive samples, 551 were detected Salmonella and 41 were Shigella by traditional culture method. The overall test could be finished within 2 hours to one day starting from sample preparation.

CONCLUSIONThe modified molecular beacons-based dual real-time PCR assay was rapid, sensitive, and specific. It could be applied to the rapid diagnosis of Salmonella and Shigella' food poisoning.

DNA Primers ; Dysentery, Bacillary ; diagnosis ; Genes, Bacterial ; Humans ; Polymerase Chain Reaction ; methods ; Salmonella ; genetics ; Salmonella Food Poisoning ; diagnosis ; Sensitivity and Specificity ; Shigella ; genetics

OBJECTIVETo conduct an etiological molecular epidemiological survey and laboratory test on a foodborne disease epidemic outbreak to make clear of the cause and implement effective prevention and control on it.

METHODSOn May 12th 2012, 135 kindergarten children were sent to Xuzhou City People's Hospital and Children's Hospital with gastrointestinal infection disease. A total of 34 anus swab samples and 4 vomit samples were collected from the patients. Real-time PCR rapid detection, strains separation and cultivation, phage lysis experiments, ATB automated identification system were used to make etiological detection and identification. The genomic DNA of salmonella enteritidis were typed with the pulsed-field gel electrophoresis (PFGE), cluster analysis were carried out together with the patterns of local Salmonella infections.

RESULTSChildren in 20 classes were suffered from the gastrointestinal infection among the 21 classes. There were no significant aggregation of class distribution. Among the 135 patients, 76 were boys (56.3%) and 59 were girls (43.7%). The main symptoms were fever (above 38°C), diarrhea and bellyache. Through real-time PCR detection and strains separation, 19 salmonella enteritidis were isolated from 34 anus swab samples of suspected cases and the detection rate was 56%. There were no strains detected from vomit samples. All of the 19 salmonella enteritidis showed the same serological subtype, biochemical reaction, drug sensitivity and phage lysis pattern. The salmonella enteritidis had the identical PFGE pattern (100% similarity), and were different from the pattern of local sporadic infection cases.

CONCLUSIONIt was confirmed that this was an epidemic outbreak of foodborne disease caused by homologous salmonella enteritidis by epidemiological survey, clinical information, lab etiological test and molecular typing.

Bacteriophage Typing ; Child, Preschool ; China ; epidemiology ; Disease Outbreaks ; Electrophoresis, Gel, Pulsed-Field ; Female ; Humans ; Male ; Molecular Epidemiology ; Salmonella Food Poisoning ; epidemiology ; microbiology ; Salmonella enteritidis ; classification ; isolation & purification