Abstract

GENETIC ELEMENTS RESPONSIBLE FOR EXTREME DRUG RESISTANCE (XDR) IN KLEBSIELLA PNUMONIAE VAR PNUMONIAE ISOLATED FROM CLINICAL SAMPLES OF IRAQI PATIENTS

Rawa Abdul Redha Aziz* and Sawsan Sajid Al-Jubori

Abstract

Twenty four isolates primarily diagnosed as Klebsiella pneumoniae were isolated from different samples from patients submitted to Baghdad hospitals\Iraq. Bacterial diagnosis was performed using complementary Vitek system. A house keeping gene(primers were designed for the 16s and 23s rRNA region) was used for genotypic diagnosis with amplified size 639bp.The results of antimicrobial susceptibility testing (disc diffusion method) revealed that most isolates displayed extremely high drug resistance (XDR) patterns. The highest resistance percentage was towards Ampicillin (95.83%) followed by Ceftazidime (87.50%) compared with other used antibiotic groups. Results also reveal that 16\24 (66.67%) isolates were resistant to Colistin sulphate, while only 2\24 (8.33%) isolates were resistant to Tigecycline. The MIC test for polymyxin B revealed that 22/24 (91.67%) isolates were resistant to ˃32μg/ml of this antibiotics. The results of modified Hodge test and rapid ESβLs production test revealed positivity of 100%(24/24) and 58.33% (14/24), respectively. About genotypic screening test for antibiotic resistance genes, the results revealed that the highest percentage were towards aminoglycoside modifying enzyme group type aac(6)-Ib followed by aac(3)-I (100% and 75%, respectively) as compared with other genes in the same group. For efflux pump gene about 88% of the isolates were harbored mexX gene and only 29% harbored mexY. Also 16.67% of the isolates harbor the metalo β-lactamase gene blaIMP-1 while none of the isolates were positive to blaVIM gene. The ESBLs genes bla SHV, bla AMP-C, and bla CMY revealed 58.33%, zero%, and 33.33% among K. pneumonia local isolates tested in this study. The highest percentage was towards rmtF (66.67%) followed by rmtB (54.17%) as compared with other gene in the methylation group. Some of the isolates encode the quinolones resistance genes ParC2 and GyrA (54.17% and 75%, respectively). For oxacillinace genes (OXA58, OXA51, OXA24, and OXA23), only OXA 23 was detected (8.33%) among K. pneumonia isolates. As a conclusion, most isolates harbor more than one resistant mechanisms which might considered a sign for emergency pan drug resistant not only XDR pattern.

Keywords: XDR Klebsiella pneumonia, ESBLs, Hodege test, Different resistance mechanism.