Molecular Study of Quinolone Resistance in Klebsiella pneumoniae and Citrobacter freundii Isolates


A total of 97 burns swab collected from patients treated in burns unit of Al-Sader Hospital, Al-Najaf Province, during the period five months (1/6/2014 to 1/11/2014). Only 75/97(77.31%) were positive bacterial culture on MacConkey agar medium compared with 22/97(22.68%) specimens gave negative bacterial growth. The results of microscopic, morphology culture, biochemical test and Vitek-2 system revealed that 23/75(30.66%) isolates, were obtained as following 21/75(28%) Klebsiella pneumoniae ssp pneumoniae and 2/75(2.66%) Citrobacter freundii were recovered from 75 positive specimens obtained aseptically from admitted patients in the burn unit. Out of these, 15/23 (65.21%) were isolated from female patients and 8/23 (34.78 %) from male patients.Antimicrobial susceptibility were done using disk diffusion method and minimal inhibitory concentration (MIC) strip test. Results showed high degree resistance to most antibiotic under study and all tested isolates were at least resistant to three or more of antibiotic classes and then consider as multidrug resistant isolates (MDR) , At same time, ertapenem revealed maximum effectiveness against K. pneumoniae and C. freundii isolates with resistance rate reached to (28.57%) and (0%) respectively. While cloxacillin, oxacillin, and carbenicillin were offered less effective among antibiotic through resistance 100%. 14(66.66%) of K. pneumoniae isolates gave high level of resistance to nalidixic acid and ciprofloxacin with MIC ≥ 256 µg/ml and MIC ≥32 µg/ml respectively compared with 1(50%) in C. freundii isolates and these were considered as highly resistance. The PCR data showed that aac(6’)-Ib –cr gene high prevalence 15(71.42%) in K. pneumoniae isolates compared to 1(50%) in C. freundii no.2. Also qnr B gene was positive in 10(47.61%) K. pneumoniae, while only 1 (50%) of C. freundii isolates was harbored qnr B gene. While qnr, qnr C and qnr D genes did not detect in this study.