IDENTIFICATION AND CHARACTERIZATION OF METALLO--LACTAMASES PRODUCING PSEUDOMONAS AERUGINOSA CLINICAL ISOLATES IN AL-AZHER UNIVERSITY HOSPITAL, ASSIUT

Abstract

Purpose: Study aimed to determine the frequency of nosocomial infections caused by P. aeruginosa and its distribution among different intensive care units (ICUs), to determine the antibiotic resistance pattern, and to determine the prevalence of Metallo-b-lactamase (MbL) among isolates by phenotypic methods. Methods: A total of 74 P. aeruginosa isolates were identified from different clinical specimens in AL-Azher University Hospital. The antimicrobial susceptibility was tested by disk diffusion (Kirby-Bauer) method and phenotypic screening for MbLs was performed using Combined Disk Test (CDT) and double-disk synergy test (DDST). Results: The frequency of P. aeruginosa isolates from clinical specimens was 18% (74/412). The highest sensitivity was to imipenem 38 isolates (51.3%). The antibiotic sensitivity was in descending manner to meropenem (48.6%) > levofloxacin (28.4%) > ciprofloxacin and ceftazidime (21.6%), while the highest resistance rates were to carbenicillin 70 isolates (94.6%) then gentamicin (70.3%). Out of 74 P. aeruginosa isolates, 51/74 (69%) strains were multidrug resistant (MDR), based on the CDT results 26/74 (35.1%) isolates and by DDST 23/74 (31.1%) isolates were confirmed to be MbLs producers. Conclusion: There is a growing risk for isolation of MDR P. aeruginosa among the MBL-producer isolates suggests the need for continuous assessment of antimicrobial susceptibility and surveillance of antibiotic prescription. In addition, infection control measures are needed to prevent further dissemination of these organisms.