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This study identified norovirus in children presenting with acute gastroenteritis and determined the capsid genotypes of the circulating norovirus strains in multiple regions in Thailand during October 2004 to December 2006 and March 2008 to August 2010. A total of 7,420 stool samples were collected from both cases (3621) and controls (3799). The stool samples were screened by two real-time RT-PCR assays to detect genogroup I and genogroup II noroviruses. Norovirus-positive samples were identified in 516 cases (14.3%) and 181 controls (4.8%) with more than half of norovirus positive samples from 7–24 months old children. Positive samples were sequenced and genotyped for the capsid gene. GII.4 was the genotype observed most frequently (56.4%) followed by GII.3 (28.2%). Five peaks of infection were observed, with predominant capsid genotypes that alternated during the surveillance periods between GII.4 and GII.3. Analyses of positive samples showed variation in genotype from each region as well as from different study periods. This emphasizes the importance of multi-site studies to investigate norovirus epidemiology. Additionally, the observed regional and temporal variations suggest that a systematic nation-wide surveillance effort in Thailand is needed to track the continually changing norovirus epidemiology. J. Med. Virol. 87:664–674, 2015. © 2015 Wiley Periodicals, Inc.

The objective of this study was to characterize extended-spectrum cephalosporinase (ESC)-producing isolates of Salmonella enterica serovar Choleraesuis recovered from patients in Thailand and Denmark. Twenty-four blood culture isolates from 22 patients were included in the study, of which 23 isolates were recovered from 21 Thai patients during 2003, 2007, or 2008 and one isolate was recovered from a Danish traveler to Thailand. ESC production was confirmed in 13 out of the 24 isolates by MIC testing. Microarray and plasmid profiling (replicon typing and restriction fragment length polymorphism [RFLP]) were used to characterize the genetic mechanisms of antimicrobial resistance in the 13 ESC-producing isolates. Pulsed-field gel electrophoresis (PFGE) and MIC testing were used to compare the clonality between the 13 ESC-producing isolates and the 11 non-ESC-producing isolates. Based on susceptibility patterns, the ESC-producing isolates were more closely related than non-ESC-producing isolates. Microarray, PCR, plasmid profiling, and replicon typing revealed that the 13 ESC-producing isolates harbored either bla CMY-2 containing incA/C or bla CTX-M-14 containing incFIIA , incFrepB , and an unknown replicon located on plasmids ranging in size from 75 to 200 kb. The RFLP and replicon typing clustered the isolates into four distinct groups. PFGE revealed 16 unique patterns and five clusters; each cluster contained two or three of the 24 isolates. The isolate from the Danish patient was indistinguishable from two Thai clinical isolates by PFGE. This study revealed the emergence of the bla CTX-M-14 gene among several clones of Salmonella serovar Choleraesuis. Numerous plasmids were identified containing up to two different ESC genes and four distinct replicons. A “travel-associated” spread was confirmed. Overall, a high degree of clonal diversity between isolates resistant and susceptible to cephalosporins was observed. The findings represent a serious threat to public health for the Thai people and tourists.

This study identified norovirus in children presenting with acute gastroenteritis and determined the capsid genotypes of the circulating norovirus strains in multiple regions in Thailand during October 2004 to December 2006 and March 2008 to August 2010. A total of 7,420 stool samples were collected from both cases (3621) and controls (3799). The stool samples were screened by two real-time RT-PCR assays to detect genogroup I and genogroup II noroviruses. Norovirus-positive samples were identified in 516 cases (14.3%) and 181 controls (4.8%) with more than half of norovirus positive samples from 7-24 months old children. Positive samples were sequenced and genotyped for the capsid gene. GII.4 was the genotype observed most frequently (56.4%) followed by GII.3 (28.2%). Five peaks of infection were observed, with predominant capsid genotypes that alternated during the surveillance periods between GII.4 and GII.3. Analyses of positive samples showed variation in genotype from each region as well as from different study periods. This emphasizes the importance of multi-site studies to investigate norovirus epidemiology. Additionally, the observed regional and temporal variations suggest that a systematic nation-wide surveillance effort in Thailand is needed to track the continually changing norovirus epidemiology.

Methicillin resistant Staphylococcus aureus (MRSA) have emerged among livestock in several countries. In this study, we describe the results of a screening performed in pigs and raw pork samples in Thailand. Ten pork samples and 15 nasal swabs from pigs were collected from 2 markets and 1 pig farm in the Samuth Songkhram province in Thailand. MRSA were isolated using selective isolation procedures and confirmed by mecA PCR. The MRSA were characterized by antimicrobial susceptibility testing, pulsed field gel electrophoresis (PFGE), spa typing, SCCmec typing, and MLST. Resistance and virulence markers were screened using a microarray. Five of the pork samples and six pig nasal swabs were positive for MRSA. All 11 isolates belonged to spa type t337 but showed diversity in antimicrobial resistance patterns and PFGE profiles. Additionally, the isolates were sequence-typed; ST9, ST2136, ST2278 belonging to the clonal complex; CC9. All isolates harbored SCCmec IX and were resistant to 7 out of 14 tested antimicrobials; additional resistances to all antimicrobials tested were found in some of the pork and pig isolates and 1 pork isolate was resistant to 13 antimicrobials tested. Microarray analysis identified blaZ, aac-aphD, vga(A), tetM, and a tet efflux marker, in all strains and additionally ermB and aadD, cat and fex(A) in the pork isolates. None of the isolates were found PVL-positive, but enterotoxins were identified in all isolates. To our knowledge, only a few descriptions of MRSA in livestock and food products in Thailand have been observed but this is the first observation of MRSA CC9 associated with SCCmec IX in pork. This study indicates a likely widespread distribution of MRSA in pig and pork in Thailand and further investigation on the prevalence and importance of livestock associated MRSA in Thailand is needed.