To evaluate the degree of competitive exclusion against Salmonella gallinarum(S. gallinarum) of Salmonella enteritidis(S. enteritidis) infected chickens, fifty-six, 4-week old Hyline layer suspected of S. enteritidis infection were challenged with S. gallinarum. All chickens were tested for S. enteritidis isolation using cloacal swabs and serum plate agglutination test using S. enteritidis Ag. before challenge and classified into four groups(SE isolated, SE nonisolated, SE seropositive and SE seronegative). None of the SE isolated and the SE seropositive groups died after challenge and the average weight gains were 245.5g and 254.6g, respectively. But in the SE nonisolated and the SE seronegative groups, mortality was 18.2% and 20.6% and the average weight gains were 150.1g and 111.2g. The incidence of reisolation of S. gallinarum of the SE isolated and the SE seropositive groups were 41.7% and 47.6% from liver, 33.3% and 47.6% from spleen and 8.3% and 14.3% from cecum, respectively, and the SE nonisolated and the SE seronegative group were 63.6% and 64.7% from liver, 84.1% and 88.2% from spleen and 47.7% and 52.9% from cecum. The serological response of the SE isolated and the SE seropositive groups hardly changed from 75.0 and 81.8% before challenge to 75.0 and 85.7% after. But, the other two groups were found to be significantly higher after challenge and increased from 0 and 18.2% to 100%. Consequently, S. enteritidis preinfected chickens were found to be significant different in terms of mortality, weight gain, reisolation of S. gallinarum and serological response compared to noninfected chickens. Moreover, our study shows that S. enteritidis infected chickens appear strong competitive exclusion against the colonization of S. gallinarum.
Animals ; Chickens ; Disease Outbreaks/veterinary ; Korea/epidemiology ; Oviposition ; Poultry Diseases/*microbiology ; Salmonella/*classification/*isolation & purification ; Salmonella Infections, Animal/*microbiology ; Salmonella enteritidis/*classification/*isolation & purification ; Serotyping ; Weight Gain

Salmonella enterica has been one of the most widespread foodborne pathogens in Korea. Between 1998 and 2007, a total of 9,472 Salmonella isolates were identified from foodborne and waterborne illness patients. During that time, Korea was transitioning into a developed country in industry as well as in its hygiene system. Although the isolation number of total Salmonella including serovar Typhi has decreased since 1999, the isolation of rare Salmonella serovars has emerged. Three most prevalent serovars during 1998-2007 were S. enterica Typhi, S. enterica Enteritidis, and S. enterica Typhimurium. There were remarkable outbreaks caused by rare serovars such as S. enterica Othmarschen, S. enterica London and S. enterica Paratyphi A, and overseas traveler-associated infections caused by S. enterica Weltevreden and S. enterica Anatum. Salmonella serovars from overseas travelers made a diverse Salmonella serovar pool in Korea. This study is the first review of the status of the human Salmonella infection trend in a developing country during 1998-2007. Newly emerging rare Salmonella serovars should be traced and investigated to control new type pathogens in the developed world.
Food Microbiology ; Humans ; Republic of Korea ; Salmonella/classification/genetics/*isolation & purification ; Salmonella Infections/epidemiology/etiology/*microbiology ; Serotyping ; Water Microbiology

OBJECTIVETo study the epidemiological characteristics and antibiotic resistance of Salmonella enterica serovar Pomona (S. Pomona).

METHODSAntimicrobial susceptible testing (AST) and pulsed field gel electrophoresis (PFGE) methods were used to analyze on S. Pomona strains that were isolated from diarrhea cases through the diarrhea network monitoring program, environment and food samples in Shanghai as well as from reptiles in Guangxi Zhuang Autonomous Region.

RESULTS4 553 clinic Salmonella (S.) strains were isolated from the Shanghai network laboratories from 2005 to 2012. The top 10 serotypes would include 20 serotypes all belonged to A-F groups, while S. Pomona was next to S. Wandsworth, according to the non- A-F groups. Young children seemed to be susceptible to S. Pomona, and might cause bloody stools and super-infection. The top 10 serotypes from 1 805 foodborne Salmonella strains were significantly more extensive than those from the human S. Pomona strains, followed by those rare serotypes which were mostly isolated from turtle, sea-shellfish and reptiles. Antibiotic resistance of S. Pomona strains from other sources were significantly more severe than those from human samples, and belonged to A and B clones by means of PFGE. Clone A strains were non-epidemic strains which showed multi-drug resistance (MDR) to antimicrobials. Clone B was the main epidemic-causing strain that not resistant to drugs, which consisting B- I from young-age-groups and B-II were from the seniors. B-I strains were homologous to those from shellfish, tortoises and lizards, while B-II strains only showing homology to those from shellfish. One S. Pomona strain-MDR, isolated from human was homologous to 8 antimicrobials.

CONCLUSIONS. Pomona was a quite common serotype among those rare serotypes, which showed higher pathogenicity to infants while genetic evolution might take place when comparing them with the strains isolated from the clinics in 2005. Surveillance programs should be intensified along with the early warnings systems on infections which were from seafood and reptiles.

China ; epidemiology ; Drug Resistance, Multiple, Bacterial ; Humans ; Molecular Epidemiology ; Salmonella Infections ; epidemiology ; microbiology ; Salmonella enterica ; classification ; isolation & purification ; Serogroup

OBJECTIVETo analyze the molecular types of Salmonella paratyphi A strains isolated in the recent years, and to construct the standard S. paratyphi A databank in the laboratory surveillance network PulseNet China.

METHODSS. paratyphi A isolates from 4 provinces were analyzed with the standard pulsed-field gel electrophoresis (PFGE) protocol used in PulseNet and their patterns compared. The databank was constructed with BioNumerics.

RESULTSEleven PFGE patterns were obtained, in which 3 predominant patterns were identifies with a similarity coefficient of 96.3%. The strains of these patterns, accounted for 86.5% of the analyzed strains, appeared in different provinces and years.

CONCLUSIONThe databank of S. paratyphi A was constructed and could be used in laboratory surveillance of S. paratyphi A in PulseNet China. From the analyses on molecular typing of the isolates, data suggested that the predominant strains might cause the epidemics in different regions.

China ; Electrophoresis, Gel, Pulsed-Field ; Salmonella paratyphi A ; classification ; genetics ; isolation & purification

Epidemiologic studies were conducted on 31 cases of Salmonella group E infection detected in 2000 through a laboratory-based pathogen surveillance in Gangwon Province, Korea. Data were collected on the environmental exposures and the patients' foods, including the brand (s) of milk consumed before the onset of diarrhea. The patients' medical records were also reviewed. All of the patients were infants under 10 months of age except one 7-year old child. Surprisingly, all of the infants were fed with infant formulas from Company A, although two infants were fed with infant formulas from both Company A and Company B. Antimicrobial susceptibility test and pulsed-field gel electrophoresis (PFGE) were performed in 25 out of 31 isolates from the patients and in 1 isolate from an opened packet of infant formula collected from the home of an infected infant. All of the 26 isolates were Salmonella enterica serovar London. They showed a single PFGE pattern, and all of the isolates were susceptible to the 18 antibiotics tested. The causative agent of the salmonella outbreaks in the Gangwon Province and its surrounding areas was Salmonella London, and the highly likely source of the infection was infant formula from Company A.
Child ; DNA, Bacterial/analysis ; *Disease Outbreaks ; Female ; *Food Contamination ; Human ; Infant ; *Infant Formula ; Infant, Newborn ; Korea/epidemiology ; Male ; Salmonella Infections/*epidemiology/*transmission ; Salmonella enterica/classification/genetics/*isolation & purification

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

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

OBJECTIVETo determine the contamination condition of Salmonella in broiler breeding and slaughter processing in China and to investigate the distribution of antimicrobial resistance profiles.

METHODSFive large-scale broiler holdings and fourteen slaughterhouses were chosen to detect Salmonella in Henan, Jiangsu, Sichuan and Shandong provinces in 2010. A total of 835 anal swabs and 744 chicken carcasses were sampled to compare the difference of Salmonella contamination rate.Salmonella isolates were identified by serotyping according to Kauffmann-White scheme.The antimicrobial susceptibilities of Salmonella isolates were determined by broth microdilution method and sixteen antimicrobial agents were chosen and examined.

RESULTSIn total, Salmonella isolates were recovered in 56 (6.7%) specimens among 835 collected anal swabs and 122 (16.4%) specimens among 744 broiler carcasses. Positive rate of Salmonella in broiler carcasses was higher than anal swabs (χ(2) = 36.94, P < 0.05). The dominant Salmonella serovars isolated from broiler anal swabs were S.enterica serovar Indiana and S.enterica serovar Enteritidis, accounting for 58.9% (33/56) and 32.1% (18/56) respectively. The prevalent serovars in broiler carcasses were also the two serovars and occupied 29.8% (37/124), 32.2% (40/124) respectively. Nearly 95.0% (171/180) Salmonella isolates were resistant to at least one antimicrobial, 78.3% (141/180) Salmonella strains were multi-drug resistant isolates and 20 (11.1%) Salmonella isolates were resistant to 14 antimicrobials.

CONCLUSIONOur findings indicated that Salmonella contamination was common and serious in commercial broiler production and processing course in China. Salmonella contamination rate in broiler slaughter processing performance was higher than broiler flocks. Additionally, antibiotic resistance of Salmonella was in serious situation.

Animals ; Chickens ; microbiology ; China ; Drug Resistance, Multiple, Bacterial ; Food Contamination ; Meat-Packing Industry ; Salmonella ; classification ; drug effects ; isolation & purification ; Serotyping

OBJECTIVETo develop a protocol for the rapid detection of Salmonellae.

METHODSA mono-antibody-based direct-ELISA and PCR methods for the detection of Salmonella were developed previously. This study assessed the accuracy of both direct-ELISA and PCR methods for the rapid detection of Salmonella and set up a new detection protocol.

RESULTSThe sensitivity of the PCR method was higher than that of direct-ELISA method. In the 2002 spring physical examination for employees, 1 546 human fecal samples were examined by the combination of direct-ELISA and PCR method. Compared with the results of national standard method, the sensitivity and specificity of direct ELISA was 100% and 97.14%, respectively, while those of PCR method reached both 100%. It also indicated that combination use of two methods could give positive report within 40 hrs, and also achieve high sensitivity and specificity.

CONCLUSIONSBased on the results obtained, a protocol for the rapid detection of Salmonella was developed. The first step is to us direct-ELISA method to screen the large number of samples, and then use PCR method to validate the ELISA positive samples, and the final step is, if needed, is to use the national standard method to determine the serotypes of Salmonellae.

Enzyme-Linked Immunosorbent Assay ; methods ; Feces ; microbiology ; Humans ; Polymerase Chain Reaction ; methods ; Salmonella ; classification ; genetics ; isolation & purification ; Serotyping

OBJECTIVETo understand pathogen patterns of enteric infectious diseases and its impact on this pattern due to aggregation of a great deal of foreign visitors during Beijing Olympic Games.

METHODSThe diarrheal patient's rectal swabs and stool specimens were collected from Olympic stadium and hospitals of four districts, including Dongcheng, Xicheng, Haidian and Chaoyang. Enteric multiple pathogens were detected from the total 45 specimens. The culture method was used for the enteric bacteria, ELISA and RT-PCR for the enteric viruses. Molecular typing of Salmonella Enteritidis isolation was completed by PFGE.

RESULTSIt was found that 26 out of 45 cases were positive with 57.8 percent for pathogen detection, and 24 were identified as enteric pathogenic bacteria, including Vibrio parahaemolyticus, Salmonella, diarrheagenic Escherichia coli and Campylobacter jejuni, two as norovirus. There were mixed infections of two pathogenic bacteria for three cases. Ten kinds of pathogens were detected from foreign cases, while five kinds from Chinese cases. A total of 5 PFGE patterns were identified in 10 Salmonella Enteritidis isolates from national and foreign diarrheal cases, which were concentrative in some extent.

CONCLUSIONVibrio parahaemolyticus, Salmonella, diarrheagenic Escherichia coli and Campylobacter jejuni were found to be the primary bacterial pathogens during the Olympic Games. Enteric virus infection existed in summer diarrhea.

Adult ; Bacterial Typing Techniques ; Campylobacter jejuni ; classification ; isolation & purification ; China ; Diarrhea ; epidemiology ; etiology ; microbiology ; virology ; Enterobacteriaceae ; classification ; isolation & purification ; Enterovirus ; isolation & purification ; Escherichia coli Infections ; microbiology ; Female ; Humans ; Male ; Salmonella ; classification ; isolation & purification ; Shigella ; classification ; isolation & purification ; Sports ; Vibrio parahaemolyticus ; classification ; isolation & purification