Molecular mechanisms of antimicrobial resistance and phylogenetic relationships of Salmonella enterica isolates from febrile patients in Yangon, Myanmar

Abstract

Background Enteric fever is common in southeast Asia. However, there is little information on the circulating Salmonella enterica strains causing enteric fever in Myanmar. Methods We performed antimicrobial susceptibility testing and whole genome sequencing on S. enterica bloodstream isolates from febrile patients aged ≥12 y attending two hospitals in Yangon, Myanmar, from 5 October 2015 through 4 October 2016. We identified the serovar of S. enterica, determined antimicrobial susceptibility and the molecular mechanisms of resistance. We analysed phylogenetic relationships among Myanmar S. enterica isolates and those with isolates from neighbouring countries. Results Of 73 S. enterica isolated, 39 (53%) were serovar Typhi and 34 (47%) were Paratyphi A. All isolates were susceptible to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole but resistant to ciprofloxacin. We identified mutations in chromosomal genes gyrA, gyrB and parC as responsible for fluoroquinolone resistance. All S. enterica Typhi isolates were of 4.3.1 subclade (formerly known as H58) and formed two closely related genotypic clusters; both clusters were most closely related to isolates from India from 2012. All S. enterica Paratyphi A were lineage C, clade C4 and were closely related. Conclusion Our study describes currently circulating S. enterica serovars in Myanmar, the genetic basis of their antimicrobial resistance and provides a genotypic framework for epidemiologic study.

A prospective study of bloodstream infections among febrile adolescents and adults attending Yangon General Hospital, Yangon, Myanmar

“…Phylogenetic analysis was performed as previously described [28]. Recombinant regions were filtered from the core genome SNP alignment and a maximum likelihood phylogenetic tree generated using Gubbins [29].…”

“…We have submitted sequence data for S. enterica Typhi and Paratyphi A isolates to GenBank under BioProject PRJNA493305 [28] and E. coli, K. pneumoniae, and S. agalactiae to BioProject PRJNA624724. Accession numbers and metadata for E. coli, K. pneumoniae, and S. agalactiae are provided in supporting information (S1-S3 Appendices).…”

“…We have recently reported the AST pattern of S. enterica isolates [28]. Among gram-positive bloodstream isolates, no S. aureus were methicillin-resistant (MRSA).…”

Sequential Helicobacter pylori eradication therapy in Myanmar; a randomized clinical trial of efficacy and tolerability

“…The study hospital serves a relatively disadvantaged population in Yangon and it is notable that less than 10% of this cohort had a per capita monthly income of >US$100. Poverty is one of the reasons that very few people in Myanmar are ever tested or treated for H. pylori , with symptoms often simply managed with acid suppression, an approach which may be potentially problematic in a country where gastrointestinal infections are common …”

“…Poverty is one of the reasons that very few people in Myanmar are ever tested or treated for H. pylori, with symptoms often simply managed with acid suppression, an approach which may be potentially problematic in a country where gastrointestinal infections are common. 28,29 The fact then that the much cheaper sequential therapy was as effective and as well tolerated as the standard first-line concomitant therapy has enormous potential implications for management of H. pylori in Myanmar. The utility of sequential therapy has been examined extensively in other countries.…”