DETECTION AND MOLECULAR CHARACTERIZATION OF ENTEROAGGREGATIVE ESCHERICHIA COLI FROM DIARRHEAL PATIENTS IN TERTIARY HOSPITALS, SOUTHERN THAILAND.

Enteroaggregative Escherichia coli (EAEC) is a member of diarrheagenic E. coli, which plays an important role in human infections in developing countries. Investigations of EAEC in diarrheal patients at Hat-Yai and Pattani Hospitals, southern Thailand identified 5 EAEC strains, which were classified into serogroups, O44 and O127a. All 5 EAEC contained the global transcriptional regulator gene, aggR, and possessed fimbrial subunit genes, aggA and aafA, and EAEC-related toxin genes, astA and pet. PCR-based phylogenetic group assay revealed that the EAEC belonged to groups B1 and D. Low levels of clump formation were observed for all EAEC strains. Scanning electron microscopy showed an absence of fimbrial structure. DNA profiles generated by BOX- and ERIC2-PCR exhibited correspondingly identical patterns among all 5 EAEC strains, suggesting that they evolved from the same bacterial clone. Thus, there exists a low but still significant prevalence of EAEC-related diarrheal illnesses in the southern region of Thailand.

ENTEROTOXIGENIC ESCHERICHIA COLI O169:HUT FROM A DIARRHEAL PATIENT: PHYLOGENETIC GROUP AND ANTIMICROBIAL SUSCEPTIBILITY.

Enterotoxigenic Escherichia coli (ETEC) is one of the most common pathogenic E. coli pathotypes causing diarrhea in children worldwide. Its enterotoxins, LT and ST, including colonization factors mainly are responsible for human pathogenesis. From 239 rectal swabs of diarrheal patients at Hat Yai and Pattani Hospitals during August 2013 and May 2014, five isolates from only a single E. coli sample demonstrated the possession of estA1, encoding porcine heat-stable enterotoxin (STp). These isolates all belonged to serotype 0169:H Untypeable (HUT) and carried astA, encoding enteroaggregative heat-stable enterotoxin 1. A PCR-based phylogenetic group investigation classified them as members of the virulent E. coli phylogenetic group D. The isolates were resistant to cephalothin, penicillin G, streptomycin, tetracycline and vancomycin. Confirmation of their clonality was conducted by enterobacterial repetitive intergenic consensus sequence PCR typing, which revealed that these ETEC were derived from the same clone. This is the first report of ETEC O169:HUT in southern Thailand.

Under-Reporting Cases and Deaths from Melioidosis: A Retrospective Finding in Songkhla and Phatthalung Province of Southern Thailand, 2014-2020.

Melioidosis, caused by Burkholderia pseudomallei, is a notifiable disease associated with a high mortality rate in Thailand. The disease is highly endemic in northeast Thailand, while its prevalence in other parts of the country is poorly documented. This study aimed at improving the surveillance system for melioidosis in southern Thailand, where the disease was believed to be underreported. Two adjacent southern provinces, Songkhla and Phatthalung, were selected as the model provinces to study melioidosis. There were 473 individuals diagnosed with culture-confirmed melioidosis by clinical microbiology laboratories at four tertiary care hospitals in both provinces from January 2014 to December 2020. The median age was 54 years (IQR 41.5-64), 284 (60%) of the patients were adults ≥50 years of age, and 337 (71.2%) were male. We retrospectively analyzed 455 patients treated at either Songklanarind Hospital, Hatyai Hospital, Songkhla Provincial Hospital, or Phatthalung Provincial Hospital, of whom 181 (39.8%) patients died. The median duration from admission to death was five days (IQR 2-17). Of the 455 patients, 272 (57.5%) had at least one clinical risk factor, and 188 (39.8%) had diabetes. Two major clinical manifestations, bacteremia and pneumonia, occurred in 274 (58.1%) and 166 (35.2%) patients, respectively. In most cases, 298 (75%) out of 395 local patients were associated with rainfall. Over the seven years of the study, the average annual incidence was 2.87 cases per 100,000 population (95% CI, 2.10 to 3.64). This study has confirmed that these two provinces of southern Thailand are endemic to melioidosis; even though the incidence rate is much lower than that of the Northeast, the mortality rate is comparably high.