Prevalence of Extended-Spectrum Beta-Lactamase and Carbapenemase Genes in Clinical Isolates of Escherichia coli in Myanmar: Dominance of bla and Emergence of bla.

The increasing trend of Escherichia coli producing extended-spectrum beta-lactamases (ESBLs) and carbapenemases is a global public health concern. In this study, prevalence and molecular characteristics of E. coli harboring ESBL and carbapenemase genes were investigated for 426 isolates derived from various clinical specimens in a teaching hospital in Yangon, Myanmar, for the 1-year period beginning January 2016. A total of 157 isolates (36.9%) were ESBL producers and harbored CTX-M-1 group genes (146 isolates; bla, bla) or CTX-M-9 group genes (11 isolates; bla, bla). Carbapenem resistance was detected in 35 isolates (8.2%), among which 26 isolates had carbapenemase genes encoding NDM-1 (2 isolates), NDM-4 (6 isolates), NDM-5 (14 isolates), NDM-7 (3 isolates), and OXA-181 (2 isolates). bla was identified in phylogenetic groups A, B1, and D isolates belonging to various genotypes (ST101, ST354, ST405, ST410, ST1196) associated with bla, bla, bla, bla, bla, bla, qnrB, qnrS, or aac6'-Ib-cr. While two isolates with bla belonged to phylogenetic group A-ST410, one isolate had also bla, as well as bla and bla, and the other harbored bla and aac6'-Ib-cr, showing different resistance patterns. Phylogenetic group B2 isolates examined were classified into mostly ST131 and had solely bla or bla, harboring more virulence factors than other phylogenetic groups. The present study revealed high prevalence of ESBL genes represented by bla and dominance of bla among NDM genes, disseminating to various E. coli clones. Notably, carbapenemase gene encoding OXA-181 was first identified in Myanmar, suggesting its spread together with NDM genes.