Abstract
Antibiotic resistance is an essential issue mostly in the intensive care units (ICUs). The Goal of this study was to investigate the widespread of multidrug resistance (MDR) gram-negative bacterial pathogens isolated from ICUs at King Khalid University Hospital (KKUH), Riyadh, KSA, and their ability to produce ESBL and MBL enzymes. All organisms were isolated from different ICUs at (KKUH) between June to December 2016. Identification and antimicrobial susceptibility were committed according to the laboratory policy. The bacterial Isolates flagged as ESBL or MBL by Vitek 2 were confirmed using E-test method recommended by CLSI. 70 isolates from different body sites comprising 25 (35.7 %) were P. aeruginosa, 23 (32.9 %) were K. pneumoniae, 16 (22.9%) were E. coli, and 6 (8.6 %) were A. baumannii. Among the 23 isolates K. pneumonia and 16 of E. coli, 19 (82.6%) and 16 (100%) were detected as ESBL (+) by double-disk diffusion method according to guidelines of CLSI. On the contrary, ESBL was not detected in any isolates of P. aeruginosa or in A. baumannii. All P. aeruginosa and A. baumannii isolates were carbapenem resistant. MBL was found in all P. aeruginosa, A. baumannii and 4 (17.4 %) of K. pneumonia where E. coli strains did not appear any MBL action. The essential resistance mechanisms in the evaluated strains were ESBL and MBL. Molecular testing is recommended to confirm the phenotypic results and to detect the resistant genes.