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 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 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 analyses the genetic diversity and relationship of Salmonella typhi strains isolated from different years and districts in Guizhou province.

METHODSRibotyping with 16s rDNA probe was used to describe the diversity of the 209 strains which were isolated in 26 counties of Guizhou province, from 1959 to 1999. The antibiotics resistance was also studied.

RESULTSTwenty-six ribotypes were found in all 209 strains, with two dominant types. The strains isolated from local typhoid epidemics belonged to the unique Ribotypes. The major ribotypes of the resistant strains were RT7 and RT1.

CONCLUSIONThe Salmonella typhi isolates from Guizhou diverged obviously. The abundant clones and multi-resistance of the strains might serve the major reasons of the high morbidity of typhoid in Guizhou.

Blotting, Southern ; China ; DNA, Bacterial ; genetics ; DNA, Ribosomal ; genetics ; Phylogeny ; RNA, Ribosomal, 16S ; genetics ; Ribotyping ; Salmonella typhi ; classification ; genetics ; isolation & purification

OBJECTIVETo study the epidemiological characteristics and molecular phenotypes of Salmonella by pulsed-field gel electrophoresis (PFGE) in Beijing from 2008 to 2009.

METHODSA total of one hundred thirty-seven isolates recovered from the WHO Global Salmonella Surveillance system and entero clinic surveillance system were identified by biochemical tests and serotyping. The related epidemiological informations were also analyzed. The isolates were further typed by PFGE.

RESULTSThe prevalence of Salmonella from 2008 to 2009 showed obvious seasonal character. High incidence occurred from June to September, and 64.1% (84/131) isolates were recovered in this period. Patients of 18 - 40 year-old were 46.1% (58/128) and 80 patients were male and 40 patients were female with the ratio of 1.57:1. These 137 Salmonella isolates belonged to 20 serotypes, including Enteritidis (46.7%, 64/137) and Typhimurium (17.5%, 24/137) as the dominant serotype. In total, 71 PFGE profiles were identified. Four PFGE patterns of S. Enteritidis isolates (JEGX01.CN0001, JEGX01.CN0003, JEGX01.CN0002, JEGX01.CN0019) and S. Typhimurium pattern of JPXX01.CN0001 were dominant patterns.

CONCLUSIONThe prevalence of Salmonella from 2008 to 2009 showed distribution characteristics of sex, age and seasons. The numerous PFGE patterns of Salmonella showed diversity of these isolates and different clones existed in Beijing.

Adolescent ; Adult ; Bacterial Typing Techniques ; China ; epidemiology ; DNA, Bacterial ; isolation & purification ; Electrophoresis, Gel, Pulsed-Field ; Female ; Food Microbiology ; Humans ; Male ; Molecular Typing ; Salmonella ; classification ; genetics ; isolation & purification ; Salmonella Infections ; epidemiology ; microbiology ; Serotyping ; Young Adult

Controlling Salmonella in integrated broiler operation is complicated because there are numerous potential sources of Salmonella contamination, including chicks, feed, rodents, wild poultry operations, and the processing plant. The objective of this study was to investigate the distribution of Salmonella through all phases of two integrated broiler operations and to determine the key areas related to the control of all known sources of infection. Two different Salmonella serotypes were observed at integrated broiler chicken company A. S. enteritidis, the predominant company A isolate, was consistently found in the breeder farm, hatcheries, broiler farms, and chicken slaughterhouse. At company B, a total of six different serotypes, S. heidelberg, S. senftenberg, S. enteritidis, S. blockley, S. gallinarum, and S. virchow, were detected. Although S. heidelberg was not found in the broiler farms, it was consistently found in the breeder farm, hatcheries, and chicken slaughterhouse. In addition, S. enteritidis was found in the hatcheries, broiler farm, and chicken slaughterhouse. In order to obtain the genetic clonality, 22 S. enteritidis isolates were digested with XbaI and analyzed by pulsed-field gel electrohporesis (PFGE). A difference in the PFGE pattern was found to be related to the origin of the integrated broiler operation. These data support the critical need to control Salmonella in breeder farms and hatcheries, and demonstrate important points related to the control of infection in large-scale poultry operations of Korea.
Animal Husbandry ; Animals ; *Chickens ; DNA, Bacterial/chemistry/genetics ; Electrophoresis, Gel, Pulsed-Field/veterinary ; Female ; Food Microbiology ; Korea/epidemiology ; Poultry Diseases/epidemiology/*microbiology/transmission ; Salmonella/classification/genetics/*isolation & purification ; Salmonella Infections, Animal/epidemiology/*microbiology/transmission

OBJECTIVETo analyze molecular and evolution characteristics of Salmonella Paratyphi A isolates from 2000 to 2008, China.

METHODSUsing pulsed-field gel electrophoresis (PFGE) method with SpeI restriction enzyme, and multilocus sequence typing (MLST) method based on housekeeping genes (aroC, thrA, hisD, purE, sucA, dnaN, hemD, adk, and purA), the genomic variations of 118 Salmonella Paratyphi A isolates from 10 regions during 2000 to 2008 were analyzed.

RESULTSUsing PFGE method, 118 Salmonella Paratyphi A isolates were clustered into 32 PFGE patterns, and 5 patterns were predominant (5 isolates or above). However, only 2 MLST types were identified for all isolates with MLST method. Among all Salmonella Paratyphi A isolates, the sequences of housekeeping genes were highly conservative and showed a high degree of cloning.

CONCLUSIONFor Chinese epidemic Salmonella Paratyphi A isolates during 2000 - 2008, MLST method showed low discrimination power and the MLST method should not be applied to outbreak and epidemiological surveillance of Salmonella Paratyphi A. Currently, nationwide paratyphoid fever epidemics is caused by highly clonal isolates in China. As the time changes, these isolates also accumulate sporadic mutations.

Bacterial Typing Techniques ; China ; DNA, Bacterial ; genetics ; Electrophoresis, Gel, Pulsed-Field ; methods ; Humans ; Multilocus Sequence Typing ; Paratyphoid Fever ; epidemiology ; microbiology ; Salmonella paratyphi A ; classification ; genetics ; isolation & purification ; Sequence Analysis, DNA ; Serotyping

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents ; pharmacology ; Ceftriaxone ; pharmacology ; Child, Preschool ; Drug Resistance, Microbial ; Hospitals, Public ; Humans ; Infant ; Microbial Sensitivity Tests ; Middle Aged ; Salmonella ; classification ; drug effects ; isolation & purification ; Salmonella Infections ; drug therapy ; microbiology ; Singapore ; beta-Lactamases ; genetics ; isolation & purification

This study was conducted to analyze the prevalence and quantitative loads of Salmonella spp. on pig farms in Chiang Mai, Lamphun, Thailand to assess loading levels before slaughtering. The serotype diversity, antimicrobial-resistance pattern and pulse-field type of Salmonella spp. were also characterized to assess the dynamic propagation of the pathogen. The Salmonella-positive prevalence was 246/805 (30.56%), and the quantitative loads varied from 1.48~4.04 Log10MPN/g, with a mean +/- standard deviation of 2.11 +/- 0.57. AMP/S/TE (ampicillin/streptomycin/tetracycline) was the highest frequency antimicrobial resistance pattern found in this study. In addition, Salmonella Rissen was the primary serotype in this region. PFGE results indicated the occurrence of infection by cross contamination among pig farms. Our study showed that pork is easily contaminated with this pathogen. Farm control programs must be based on strict biosecurity and hygienic measures, which could further reduce the contamination pressure at slaughterhouses or retail shops.
Abattoirs ; Animals ; Anti-Bacterial Agents/*pharmacology ; Bacterial Load/veterinary ; Colony Count, Microbial/veterinary ; Drug Resistance, Multiple, Bacterial/*drug effects ; Electrophoresis, Gel, Pulsed-Field/veterinary ; Feces/microbiology ; Female ; Male ; Prevalence ; Salmonella/classification/*drug effects/*genetics/isolation & purification ; Salmonella Infections, Animal/*epidemiology/microbiology/transmission ; Serotyping/veterinary ; Swine ; Swine Diseases/*epidemiology/microbiology/transmission ; Thailand/epidemiology