Antibiotic resistance trends were examined for Shigella species, nontyphoidal Salmonella species, enterotoxigenic Escherichia coli (ETEC), and Campylobacter species isolates from indigenous persons and travelers in Thailand for up to 15 years. Resistance to trimethoprim-sulfamethoxazole was found in ú90% of Shigella and 40% of ETEC and nontyphoidal Salmonella isolates. Resistance to nalidixic acid was found in 97% -100% of Shigella dysenteriae 1 strains isolated between 1992 and 1995. Ciprofloxacin resistance was detected in 1% of ETEC isolates in 1994 and 1995 and in one of 349 nontyphoidal Salmonella isolates in 1995. Ciprofloxacin resistance among Campylobacter species increased from zero before 1991 to 84% in 1995 (P õ .0001). Azithromycin resistance was found in 7% -15% of Campylobacter isolates in 1994 and 1995, as well as 15% of ETEC and 3% of Salmonella isolates in 1995. Enteric pathogens in Thailand have developed resistance to virtually all antibiotics routinely used in the treatment of diarrhea, as well as the newer fluoroquinolone and macrolide classes of drugs.

Antimicrobial resistance rates for shigella, campylobacter, nontyphoidal salmonella, and enterotoxigenic Escherichia coli were compared for Vietnam and Thailand from 1996 to 1999. Resistance to trimethoprim-sulfamethoxazole, ampicillin, chloramphenicol, and tetracycline was common. Quinolone resistance remains low in both countries, except among campylobacter and salmonella organisms in Thailand. Nalidixic acid resistance among salmonellae has more than doubled since 1995 (to 21%) in Thailand but is not yet documented in Vietnam. Resistance to quinolones correlated with resistance to azithromycin in both campylobacter and salmonella in Thailand. This report describes the first identification of this correlation and its epidemiologic importance among clinical isolates. These data illustrate the growing magnitude of antibiotic resistance and important differences between countries in Southeast Asia.

These data on the etiology of diarrhea and antibiotic resistance patterns in Cambodia will have significant effect on local public health policies and on local resource prioritization practices.

5For diarrheagenic Escherichia coli identification, five lactose-fermenting and up to five non-lactose-fermenting E. coli colonies isolated from each child were spotted on nylon membranes N+ (GE Healthcare, Buckinghamshire, UK). The

BackgroundArcobacter spp. are a common contaminant of food and water, and some species, primarily A. butzleri and A. cryaerophilus, have been isolated increasingly from human diarrheal stool samples. Here, we describe the first Arcobacter multilocus sequence typing (MLST) method for A. butzleri, A. cryaerophilus, A. skirrowii, A. cibarius and A. thereius.ResultsA sample set of 374 arcobacters, including 275 A. butzleri, 72 A. cryaerophilus, 15 A. skirrowii and 8 A. cibarius isolates from a wide variety of geographic locations and sources, was typed in this study. Additionally, this sample set contained four strains representing a new Arcobacter species, A. thereius. The seven loci used in the four-species Arcobacter MLST method are the same as those employed previously in C. jejuni, C. coli, C. helveticus and C. fetus (i.e. aspA, atpA(uncA), glnA, gltA, glyA, pgm and tkt). A large number of alleles were identified at each locus with the majority of isolates containing a unique sequence type. All Arcobacter isolates typed in this study contain two glyA genes, one linked to lysS (glyA1) and the other linked to ada (glyA2). glyA1 was incorporated into the Arcobacter MLST method while glyA2 was not because it did not increase substantially the level of discrimination.ConclusionNo association of MLST alleles or sequence types with host or geographical source was observed with this sample set. Nevertheless, the large number of identified alleles and sequence types indicate that this MLST method will prove useful in both Arcobacter strain discrimination and in epidemiological studies of sporadic Arcobacter-related gastroenteritis. A new Arcobacter MLST database was created http://pubmlst.org/arcobacter/; allele and ST data generated in this study were deposited in this database and are available online.

Worldwide, foodborne illness is often associated with consumption of meats and poultry products sold at retail markets. A cross-sectional retail food study was conducted in Bangkok, Thailand to assess the prevalence of bacterial pathogens on retail food samples. Raw chicken, beef, pork, and chicken eggs were purchased from fresh markets and supermarkets and tested for Salmonella spp., Campylobacter spp., Arcobacter spp., and Enterococcus spp. Suspect bacterial pathogens were isolated by differential culture and Salmonella species were serotyped. A total of 200 samples were collected from 50 markets between May and August 2003. Of the 200 samples tested, 121 (61%) were positive for at least one Salmonella spp. serogroup. A total of 175 Salmonella spp. were isolated. The most common serotype was Salmonella Anatum, followed by S. Corvallis and S. Derby. Campylobacter spp. were found in 31 (15.5%) of 200 samples. C. jejuni was isolated from 15% of fresh market chicken samples and 35% of supermarket chicken samples. Arcobacter spp. were isolated from 42 (21%) samples; fresh market chicken had significantly higher A. butzleri contamination than supermarket chicken. The presence of Enterococcus spp., an indication of fecal contamination, was detected in 188 (94%) samples, including 100% of the beef and pork sources. Few studies have examined retail food contamination in Thailand. In particular, the high prevalence of samples with Arcobacter spp. warrants further study to determine pathogenicity.

This study was conducted to investigate the presence of intestinal parasites among pre-school children (aged 3 months to 5 years) in Sangkhlaburi, a rural district in the west of Thailand along the Thai-Myanmar border. Stool specimens were collected from October 2001 through October 2002. A total of 472 pre-school children, 233 males and 239 females, 236 children with diarrhea and 236 asymptomatic children were recruited for the study. Each specimen was processed and examined by direct wet smear, modified acid fast stain, formalin-ethylacetate sedimentation concentration technique, and trichrome stain. In detecting Giardia lamblia and Cryptosporidium species ProSpecT Microplate assays (Alexon-Trend, Lenexa, KS) were performed. There were 107 individuals (22.7%), 41 diarrheal and 66 asymptomatic children, infected with intestinal parasites. The most frequent parasites identified in cases and controls were G. lamblia and Cryptosporidium spp. Eighteen specimens (3.8%) showed mixed parasite infections. Highest proportion of intestinal parasites occurred during the rainy season (June-October).

This study investigated fluoroquinolone, macrolide resistances and serotype distributions among Campylobacter jejuni and Campylobacter coli isolated from children in Bangkok and rural settings during 1991-2000. Phenotypic identification, serotyping, and susceptibility testing were performed by standard microbiological procedures. The predominant serotypes of C. jejuni were Lior 36, 2 and 4 and of C. coli were Lior 8, 29 and 55. Resistance to nalidixic acid increased significantly during 1991-2000 and the frequency of isolates resistant to both nalidixic acid and ciprofloxacin in Bangkok was significantly greater than in rural settings. In 1996-2000, a significant trend was observed in C. jejuni isolates resistant to ciprofloxacin from Bangkok but not for macrolide resistance from both settings. In summary, fluoroquinolone resistance among C. jejuni and C. coli isolates became widespread in both Bangkok and rural settings in Thailand in the 1990s while widespread resistance to macrolides was undetected.