عنوان المقالة:Screening of Ambler class C and extended-spectrum β-lactamases in multi-drug resistant Pseudomonas aeruginosa and selected species of Enterobacteriaceae Screening of Ambler class C and extended-spectrum β-lactamases in multi-drug resistant Pseudomonas aeruginosa and selected species of Enterobacteriaceae
SHAYMAA H. AL-KUBAISY1 ; RAWAA A. HUSSEIN2 ; MUSHTAK T.S. AL-OUQAILI3
الملخص الانجليزي
Background and objective: As a major clinical concern worldwide, the occurrence of extended spectrum
β-lactamases (ESBLs) has been increasingly reported in Pseudomonas aeruginosa. The goal of the study for the
detection the occurrence of β-lactamase bla-OXA specifically, the OXA II gene and III in study isolates and its
role in the resistance pattern.
Patients and Methods: One-hundred of clinical specimens were obtained from different clinical sites.
Antibiotic susceptibility testing was performed for the study isolates of Pseudomonas aeruginosa according to
the recommendations laid down by CLSI. ESBLs confirmatory test had been done by double-disc synergy test.
Bacterial DNA extraction was achieved using automated DNA extraction unit, SaMag, Italy. RT-PCR was used
for amplification of β-lactamase (blaOXA) genes and detected using agarose gel electrophoresis.
Results: Out of 100 clinical specimens, 75 (75%) were culture-positive. Of these, 35 (46.7%) isolates were
diagnosed as P. aeruginosa, 23 (30.7%) E. coli isolates and 17 (22.6%) K. pneumonia. Based on the
confirmatory test for the extended-spectrum β-lactamase production, 40 (53.33%) isolates were considered
to produce ESBLs, including 22 (55%) P. aeruginosa, 8 (20%) K. pneumoniae, and 10 (25%) E. coli isolates. RTPCR was then used to detect the presence of the OXAII and III genes in the K. pneumoniae, E. coli, and P.
aeruginosa clinical isolates. Five (14.28%) isolates of P. aeruginosa were producing OXAII while three (8.57 %)
of them produced OXAIII. Two(8.69%) isolates from E. coli for OXAII and III gene and 2(11.76%) isolates
from K. pneumonia were positive for the presence of OXAII while Five (29.4%) of them produced OXAIII.
Conclusion: PCR is so helpful for the identification of specific β-lactamase genes. Also, the study suggested
that a significant presence of blaOXA-II and blaOXA-III genes among study isolates were detected and the
highlighting for the need for suitable infection control strategies to effectively treat patients and prevent the
further distribution of these resistant organisms.
الأستاذ الدكتور مشتاق طالب صالح الندا | Dr. Mushtak T. S. Al-Neda | 8275