Abstract
The aminoglycosides are widely used for the therapeutic management of infections caused by gram-negative bacteria, including the
strains. However, the resistance to the members of the aminoglycoside family, such as amikacin, gentamicin, and tobramycin, is increasingly being common among the clinical isolates.
This study aimed to investigate the presence of 16SrRNA methylases and aminoglycoside modifying enzymes (AMEs) genes among aminoglycoside resistant
isolates and to study the genetic diversity of the clinical population of
in local hospitals.
The 143
clinical strains were analyzed for antimicrobial susceptibility, genetic screening for enzymes conferring aminoglycosides resistance followed by the multilocus sequence typing.
The 133/143 (93%) isolates were non-susceptible to at least one of the tested aminoglycosides, including amikacin, gentamicin, and tobramycin. The MIC distribution has shown that 87.486.7% strains were resistant to amikacin and gentamicin, respectively. The
6,
B,
1, and
1 were found in 74.1%, 59.4%, 16.1%, and 11.2% isolates, respectively, whereas the
A was found in 28% of the strains having a higher MIC value (MIC; ≥256µg/mL). The MLST data have shown that the ST589 and ST2 were the most common STs and corresponded to 51 (35.7%) and 38 (26.6%) isolates, respectively, and few of the isolates corresponding to these STs were found to harbor the
A gene with a variable genotypic profile for AMEs.
The study has reported the incidence of various enzymes conferring aminoglycoside resistance among the
clones for the first time from Pakistan. The findings suggest the possibility of transmission of aminoglycoside resistance determinants through the lateral gene transfer as well as clonal dissemination.