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

Abstract 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 CTX-M-15 (70.1%), bla TEM-OSBL (48.5%), bla SHV-OSBL (27.9%), and bla CTX-M-14 (10.7%). AmpC resistance genes were identified in 9.7% of the isolates, dominated by bla CMY-2 (5.7%) . Carbapenem resistance genes were detected in 45.3% of the isolates. In K . pneumoniae , bla OXA-48 dominated (40.6%), followed by bla NDM-1 (23.7%) and bla OXA-232 (4.5%). In E . coli , the most frequent genes were bla NDM-5 (9.6%), bla OXA-181 (5.5%), bla OXA-244 (3.7%), and bla NDM-1 (3.7%). bla KPC-2 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.