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

Pseudomonas aeruginosa is the most prevalent pathogen in nosocomial infections it produces metallo-beta-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. 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. 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. 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.