Genetic Diversity of CMY Beta-Lactamase Genes in Clinical Isolates of Escherichia coli in Myanmar: Identification of Three Novel Types and Updated Phylogenetic Classification of blaCMY.

The dissemination of CMY-type enzymes, one of the plasmid-mediated AmpC beta-lactamases, among Enterobacteriaceae has become an important public health concern. In this study, genetic diversity of CMY beta-lactamase genes was investigated for 50 blaCMY-positive isolates detected from 426 clinical isolates of Escherichia coli in Yangon, Myanmar. CMY genes were differentiated into 9 types, with blaCMY-42 being predominant (22 isolates, 44%), followed by blaCMY-2, blaCMY-6, blaCMY-146, and included three novel types (CMY-156, CMY-158, CMY-159). Among E. coli harboring blaCMY, phylogenetic group D-sequence type (ST)405 and A-ST410 were the most common genotypes, and blaCTX-M-15 was detected in 72% (36/50) of isolates. blaCMY-42 was distributed to phylogenetic groups A, B1, and D E. coli with 11 STs, which included 10 isolates harboring carbapenemase genes (blaNDM-4, blaNDM-5, or blaNDM-7). Phylogenetic analysis of all the blaCMY genes reported to date, including the three novel types in the present study, revealed the presence of at least four distinct genetic groups, that is, CMY-1, CMY-2, CMY-70, and CMY-98 group, showing less than 91% nucleotide sequence identities among different groups. CMY-2 group beta-lactamase genes, which contained by far the largest number of CMY types (89.7%) with extensive diversity, were divided into two clusters (I and II). While eight CMY types identified in the present study were classified into CMY-2 group cluster I, novel type CMY-159 was assigned into CMY-98 group with a Citrobacter freundii strain in Thailand.

Re-emergence of melioidosis in Myanmar.

After the discovery of melioidosis and its causative organism, Burkholderia pseudomallei, in Burma (Myanmar) in 1912 and further reports in 1915 and 1917, no further reports of melioidosis emerged from the country in the international medical literature. The present study aimed to determine whether the occurrence of melioidosis among hospital patients with abscess in Yangon, Myanmar is sufficiently frequent to indicate further studies to determine its clinical and public health significance in the country. A clinical and bacteriological survey of patients with abscess at 21 hospitals in Yangon was carried out during 2004-2006. Pus specimens from three of 133 patients yielded bacteria with the morphological, cultural and biochemical characteristics of B. pseudomallei. The estimated melioidosis prevalence rate among patients with abscess in selected Yangon hospitals was approximately 2%. Further studies are indicated to assess the clinical and public health significance of melioidosis in Myanmar.