Molecular characterization of multidrug-resistant Gram-negative pathogens in three tertiary hospitals in Cairo, Egypt.

High rates of antimicrobial resistance (AMR) among Gram-negative pathogens (GNP) have been reported in Egypt. Antimicrobial surveillance and identifying the genetic basis of AMR provide important information to optimize patient care. In this study, we aimed to identify the beta-lactam resistance phenotypes and genotypes of multidrug-resistant (MDR) non-repetitive GNP from 3 tertiary hospitals in Egypt. WZe studied 495 non-repetitive MDR Gram-negative isolates from patients with complicated intra-abdominal infections (cIAI), complicated urinary tract infection (cUTI), and lower respiratory tract infection (LRTI), collected as part of the "Study for Monitoring Antimicrobial Resistance Trends" (SMART) conducted in 3 tertiary hospitals in Cairo, Egypt, from 2015 to 2016. Identification and susceptibility testing of GNP to antimicrobials were tested in each hospital laboratory and confirmed in a reference laboratory (International Health Management Associates (IHMA), Inc., Schaumburg, IL, USA). Molecular identification of extended-spectrum beta-lactamases (ESΒLs), AmpC, and carbapenem resistance genes was conducted in IHMA. Among the 495 MDR isolates, Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) were the most common (52.7% and 44.2%). K. pneumoniae was most susceptible to colistin, amikacin, ertapenem, and imipenem (92.7%, 72.7%, 69.3%, and 64%, respectively). E. coli was most susceptible to colistin (100%), amikacin (94.1%), imipenem (90.4%), and ertapenem (83.6%). ESBL was detected in 96.2% and ESBL genotypes included bla (70.1%), bla (48.5%), bla (27.9%), and bla (10.7%). AmpC resistance genes were identified in 9.7% of the isolates, dominated by bla (5.7%). Carbapenem resistance genes were detected in 45.3% of the isolates. In K. pneumoniae, bla dominated (40.6%), followed by bla (23.7%) and bla (4.5%). In E. coli, the most frequent genes were bla (9.6%), bla (5.5%), bla (3.7%), and bla (3.7%). bla was identified in 0.4% of isolates. Notably, 32.3% of isolates carried more than one resistance gene. Our findings emphasize the continued need for molecular surveillance of MDR pathogens, implementation of strict infection control measures, and antimicrobial stewardship policies in our hospitals.