Antimicrobial surveillance and identifying the genetic basis of antimicrobial resistance provide important information to optimize patient care. The present study was analytical cross sectional study aimed to determine the prevalence of MDR, XDR, PDR and extended-spectrum ?-lactamases genes among Gram-negative bacteria isolated in Saudi Arabia. A total number of 386 non-duplicate Gram-negative isolate were collected. Identification and susceptibility testing were done using automation system (BD Phoenix™). The extracted DNA were subjected to multiplex polymerase chain reaction (PCR). The results showed that only 15 (3.9%) of isolates were fully susceptible, the overall prevalence of XDR, MDR, PDR was 129 (33.4%), 113 (29.3%) and 48(12.4%) respectively. High resistant rate was observed against the antibiotic agents of cephalosporins class 79.3% followed by the agents of penicillins class 69.4%. The most dominant resistant gene was bla SHV which detected in 106/386 (27.5%) isolates followed by bla CTX-M 90/386 (23.3%). Bla CTX-M showed significant relation with all used antibiotic except ampicillin/clavulanic acid, aztreonam, cefoxtin, and meropene. The isolates which showed frequent resistant genes were Klebsiella pneumoniae 90/124 (72.6%), A. baumanni 37/67 (55.2%), and P. mirabilis 24/44 (54.5%). These findings underscores the need for optimization of current therapies and prevention of the spread of these organisms.

Keywords: MDR, XDR, PDR, ESBLs, bla SHV, bla TEM, bla CTX-M