First Report of bla(CTX-M-28) in Enterobacteriaceae Isolates in the United Arab Emirates

BACKGROUND: The CTX-M family of extended-spectrum beta lactamase (ESBL) enzymes is comprised of over 60 bla(CTX-M) gene variants with the predominance of bla(CTX-M-15) in many regions. In this report, we present the first description of bla(CTX-M-28) in the United Arab Emirates. METHODS: Forty-five non-duplicate ESBL producing isolates identified in a secondary care facility in the United Arab Emirates from June to July 2016 were studied. Gene sequencing was performed and DNA sequences were annotated using the BLAST program to identify the gene subtypes. RESULTS: The majority of the ESBL positive isolates were E. coli (n/N = 39/45; 86.6%) followed by K. pneumoniae (n = 5) and K. oxytoca (n = 1). All isolates harboured bla(CTX-M) and bla(TEM) genes, 18 had bla(SHV), and 2 were bla(VIM) positive. Thirty-seven isolates (82.2%) were positive for bla(CTX-M-28). Other bla(CTX-M) genes identified include bla(CTX-M-167) (n = 2; isolates #1 and 26) and one each for bla(CTX-M-38), bla(CTX-M-163), and bla(CTX-M-198). No bla(CTX-M-15) was identified. The predominant bla(TEM) subtype was bla(TEM-171) (n = 8) followed by one of each of bla(TEM-120), bla(TEM-163), and bla(TEM-206). The bla(SHV) subtypes were bla(SHV-148) and bla(SHV-187). CONCLUSION: The findings indicate the first description of bla(CTX-M-28) in a setting where bla(CTX-M-15) was previously predominant.