Antimicrobial susceptibility and metallo-β-lactamase production among Pseudomonas aeruginosa isolated from Makkah Hospitals

Objectives: pseudomonas aeruginosa is the most prevalent pathogen in nosocomial infections— it produces metallo-β-lactamases (mbls) that reduce antibiotic effectiveness. this study aimed to determine the frequency, antimicrobial-susceptibility patterns, and mbl types of p. aeruginosa infections in clinical specimens obtained from patients in makkah hospitals. methodology: clinical isolates (478) were collected during a 6-month period, from september 2009 (ramadan 1430 ah), from various clinical wards of al-noor specialist, hera general, and king abdul-aziz hospitals. all isolates were subjected to routine microbiological investigations and automated antibiotic-susceptibility testing. mbl production was assessed using double-disk synergy test by comparing the zone of inhibition given by disks containing imipenem with and without ethylene diaminetetraacetic acid (edta) and mbl types distinguished by polymerase chain reaction. results: most p. aeruginosa strains (31%) were isolated from intensive care units (icus) and male medical wards (15.9%). p. aeruginosa mostly caused respiratory tract (52%), wound (26%), and urinary tract (12%) infections. p. aeruginosa was most susceptible to imipenem (65.9%), amikacin (62.7%), meropenem (58.7%), and piperacillin/tazobactam (57.2 %). mbl-producing p. aeruginosa were identified in 76 (15.9%) isolates. the rate of mbls types were 21% and 18.4% for imp and vim, respectively. conclusions: these results can be used as guidelines for treatment of bacterial infections in saudi arabia. multidrug-resistant and mbl-producing p. aeruginosa is a serious public health concern, which must be tackled.