@article{ajmr2017523,
author={{Tawfick, Mahmoud M. and El-Borhamy, Mervat I.},
title={PCR-RFLP-Based Detection of Mutations in the Chromosomal Fluoroquinolone Targets <i>g</i><i>yr</i><i>A</i> and <i>p</i><i>ar</i><i>C</i> Genes of <i>Acinetobacter </i><i>b</i><i>aumanii</i> Clinical Isolates from a Tertiary Hospital in Cairo, Egypt},
journal={American Journal of Microbiological Research},
volume={5},
number={2},
pages={37--43},
year={2017},
url={http://pubs.sciepub.com/ajmr/5/2/3},
issn={2328-4137},
abstract={<b>Background and Aim:</b> <i>Acinetobacter baumannii</i>?is one of the most antimicrobial resistant nosocomial pathogens encountered clinically worldwide. The emergence of fluoroquinolone resistance among <i>A. baumannii</i> isolates is currently of concern. This study aimed to investigate the antimicrobial susceptibility patterns among 49 clinical isolates of <i>A baumannii</i> collected from a tertiary care hospital in Egypt. These isolates were analysed for the mechanism of fluoroquinolone resistance based on the presence of mutations in the quinolone resistance-determining regions (QRDRs) of the chromosomal quinolone resistance determinants <i>gyrA</i> and <i>parC</i> genes. <b>Methods:</b> <i>A. baumannii</i> isolates were identified using conventional biochemical testing, VITEK 2 automated system and polymerase chain reaction (PCR) assay targeting the intrinsic <i>bla</i><SUB>OXA-51-like </SUB>gene of <i>A. baumannii</i> species. Antimicrobial susceptibility to different antimicrobial agents was tested using agar disk diffusion method and the minimum inhibitory concentration (MIC) of ciprofloxacin was determined using E-test (bioM¨¦rieux, France) on Mueller-Hinton agar medium following the Clinical and Laboratory Standards Institute guidelines. The QRDRs of the <i>gyrA</i> and <i>parC</i> genes in <i>A. baumannii</i> isolates were amplified by PCR using specific primers. Mutations in theses QRDRs were detected by <i>Hinf</i>I restriction fragment length polymorphism (RFLP) of PCR products and sequencing. <b>Results: </b>The <i>bla</i><SUB>OXA-51-like</SUB> gene was detected in all isolates confirming identification as <i>A. baumannii</i>. Antimicrobial susceptibility study showed that all isolates (100 %) were MDR. They were 100 % resistant to the tested fluoroquinolones, ciprofloxacin and levofloxacin. The MIC of ciprofloxacin ranged from 4 to ¡Ý 32 ¦Ìg/mL. All <i>A. baumannii</i> isolates (100 %) were found to harbour <i>gyrA </i>and<i> parC</i> genes. <i>Hinf</i>I restriction analysis showed a detectable mutation in QRDRs at position Ser-83 of <i>gyrA</i> gene and Ser-80 of <i>parC</i> gene. There was single mutation in either <i>gyrA</i> or <i>parC</i> in 11 isolates showed ciprofloxacin MIC of &lt; 32 ¦Ìg/mL, while 38 isolates with MIC of ¡Ý 32 ¦Ìg/mL had double mutations in QRDRs of both genes. <b>Conclusions:</b> Resistance of <i>A. baumannii </i>isolates to fluoroquinolones in Egypt is alarming as all MDR <i>A. baumannii </i>isolates in the current study were mostly highly resistant to ciprofloxacin with MIC ¡Ý 32 ¦Ìg/mL, limiting the remaining therapeutic options and a public health policy on appropriate prescribing and thus the rational use of antimicrobial agents is required. Double mutation with substitutions at positions Ser-83 and Ser-80 of <i>gyrA</i> and <i>parC</i> genes, respectively, could lead to high©\level ciprofloxacin resistant phenotype than a single mutation in one of them. Further extensive studies including a larger number of isolates from different geographic areas in Egypt and investigating other fluoroquinolone resistance mechanisms are warranted.},
doi={10.12691/ajmr-5-2-3}
publisher={Science and Education Publishing}
}