Thanaa R. Abdulrahman, Bushra J. Hmoood Jabbar S. Hassan, Riyam F. Salih, Salma N. Malik
الملخص الانجليزي
Background: Quinolone resistance Escherichia coli have been dramatically increased in last years. This
resistance occurs either by chromosomal, or plasmid-mediated. The plasmid-mediated Quinolone
resistance (qnr) gene which encompasses five different groups including qnrA, qnrB, qnrC, qnrD, and
qnrS has been shown to aid resistance to fluoroquinolones. Objective: To estimate the occurrence of qnr
among Diarrheagenic E coli strains isolated from patients with acute diarrhea. Methods: This study
included 43 E. coli clinical isolates recovered from 304 fresh stool specimens which were collected from
patients presenting with acute diarrhea. Stool samples were plated onto MacConkey agar for 24 hr at
37ºC. The susceptibility and resistance to Ciprofloxacin and Nalidixic acid for all bacterial isolates were
identified by standard procedures such as disk diffusion test and minimum inhibitory concentration.
DNA was extracted from plasmids using commercial kits and then, the molecular diagnosis was
performed with Multi-Plex polymerase chain reaction (PCR) technique using specific primers for qnr
genes. Results: Culture result revealed that E. coli was isolated from 43(14.1%) of 304 stool samples.
Among these, 12 isolates were resistant to both nalidixic acid and ciprofloxacin. There were 18 qnr genes
among these isolates. The qnrA gene was the most common (8/18, 44.4%) followed by qnrB (6/18, 33.3%),
whereas qnrS gene represented only 4/18 (22.2%) of the total gens. Conclusion: there is an increase in
the occurrence of quinolone resistance among Diarrheagenic E. coli which harbored multiple plasmids
profile. The most common gene for quinolone resistance in current study was qnrA gene.
جبار سلمان حسان | Jabbar Salman Hassan | 774