Antimicrobial resistance of gram-negative bacteria: A six-year longitudinal study in a hospital in Saudi Arabia

Introduction: Increasing prevalence of antimicrobial resistance is a major concern especially in light of lack of new antimicrobial agents. Here, we present antibiotic resistance pattern of gram-negative bacteria (GNB) over six years (2013-2018) in a hospital in Saudi Arabia. Materials and Methods: The study included a report of the cumulative antibiogram of GNB. Interpretation of the antibacterial susceptibility tests was based on the Clinical and Laboratory Standards Institute guidelines and VITEK (R) 2 system. Results: There was a total of 32,890 GNB isolates and the most common were: Escherichia coli (69.8%), Klebsiella pneumoniae (17.2%) and Pseudomonas aeruginosa (12.8%). Antimicrobial susceptibility of P. aeruginosa and E. coli did not change overtime, however, susceptibility to ceftazidime decreased from 92% to 85% in P. aeuroginosa. Yearly antimicrobial susceptibility did not change significantly overtime for K. pneumoniae. ESBL isolates among K. peumoniae and E. coli was about 26% and 20%, respectively (p = 0.0068). For ESBL E. coli, the least effective antibiotics were ciprofloxacin (26%) and trimethoprim-sulfamethoxazole (34%). For ESBL K. pneumoniae, gentamicin, ciprofloxacin, trimethoprim-sulfamethoxazole, and nitrofurantoin had poor activity. For K. pneumoniae, both ciprofloxacin (90%) and trimethoprim-sulfamethoxazole (86%) had better coverage than for E. coli. K. pneumoniae showed less susceptibility to nitrofurantoin than E. coli (20% vs. 92%). Conclusion: Antibiotic resistance among P. aeruginosa and E. coli did not change overtime (2013-2018) and the rate of ESBL-producing E. coli and K. pneumoniae was high. Thus, continued surveillance is needed. (C) 2020 The Author(s). Published by Elsevier Ltd on behalf of King Saud Bin Abdulaziz University for Health Sciences.