Identification of Genes Encoding Aminoglycoside Modifying Enzymes among Clinical Isolates of Proteus species at a Tertiary Care Hospital in Dhaka, Bangladesh.

Proteus is considered as one of the major opportunistic pathogens liable for nosocomial infections and acquired several resistances to a wide range of antimicrobials such as aminoglycosides. The most common mechanism of aminoglycoside resistance is the inactivation of drugs by modifying enzymes. So, this cross-sectional study was undertaken to investigate the occurrence of aminoglycoside resistance and identify aminoglycoside modifying enzyme (AME) genes among clinical isolates of aminoglycoside resistant Proteus spp. A total of 40 Proteusmirabilis and Proteus vulgaris were isolated in the Department of Microbiology of Dhaka Medical College, Dhaka, Bangladesh from July 2018 to June 2019 of 500 wound swab & pus, urine and blood samples. Disk diffusion test was performed by modified Kirby Bauer method. Minimum inhibitory concentration (MIC) of amikacin was determined by agar dilution method. PCR was used to detect aac(3)-Ia, aac(6')-Ib, ant(4')-IIa, ant(2'')-Ia a and aph(3'')-Ib AMEs genes among aminoglycoside resistant Proteus spp. Sequencing of aac(6')-Ib gene was performed to identify aac(6')-Ib-cr variant. Thirty-two (80%) aminoglycoside resistant isolates were detected during disk-diffusion technique. The marked increase in MIC was observed between 256 - ≥2048μg/ml to amikacin. The most prevalent AME-genes were aac(6')-Ib (37.5%), ant(2'')-Iaa (21.86) followed by ant(4')-IIa(12.5%), aph(3'')-Ib (12.5%) andaac(3)-Ia (9.38%). The most frequent combination was aac(6')-Ib + aac(3)-Ia+ant(2'')-Iaa and aac(6')-Ib + ant(4')-IIa + aph(3'')-Ib(2 strains) followed by aac(6')-Ib + aac(3)-Ia(1 strain). Sequencing of aac(6')-Ib gene in this study did not harbor aac(6')-Ib-cr variant gene. The results of this study provide insight into the presence of high AME-genes among Proteus spp. in Bangladesh.