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Canadian Journal of Infectious Diseases and Medical Microbiology
Volume 2019, Article ID 6054694, 9 pages
Research Article

Phenotypic Characterization and Antibiotic Resistance Patterns of Extended-Spectrum β-Lactamase- and AmpC β-Lactamase-Producing Gram-Negative Bacteria in a Referral Hospital, Saudi Arabia

1Department of Basic Medical Science (Microbiology Unit), College of Medicine, University of Bisha, Bisha, Saudi Arabia
2Department of Pediatrics, College of Medicine, University of Bisha, Bisha, Saudi Arabia
3Department of Family Medicine, College of Medicine, University of Bisha, Bisha, Saudi Arabia
4Department of Medical Microbiology, Faculty of Medical Laboratory Sciences, University of Khartoum, Khartoum, Sudan

Correspondence should be addressed to Mutasim E. Ibrahim; moc.liamtoh@78idahmisatum

Received 5 February 2019; Revised 25 May 2019; Accepted 16 June 2019; Published 26 June 2019

Academic Editor: Kapil Chousalkar

Copyright © 2019 Mutasim E. Ibrahim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. Emergence of pathogenic bacteria carrying β-lactamase-resistant determinants has become a major health problem in the hospital setting. The study aimed to determine antibiotic-resistant patterns and frequency of extended-spectrum β-lactamase- (ESBL-) producing Gram-negative bacteria (GNB) and AmpC β-lactamase-producing GNB. Methodology. A prospective cross-sectional study was conducted during a period from September 2017 to August 2018 at King Abdullah Hospital, Bisha Province, Saudi Arabia. GNB (n = 311) were recovered from patients’ clinical specimens including sputum, urine, wound pus, blood, tracheal aspirates and high vaginal swabs, umbilical discharge, eye discharge, and cerebrospinal fluids. Isolates were identified by the Phoenix identification system. Antimicrobial susceptibility was tested by the Kirby–Bauer disk procedure. Phenotypic characterization of ESBLs and AmpC β-lactamases was performed utilizing the double-disk synergy test and inhibitor-based method, respectively. Associations with outcome measures were determined by simple descriptive statistics and a chi-square test. Results. Out of 311 GNB isolates, the frequency of ESBL and AmpC β-lactamase producers was 84 (27%) and 101 (32.5%), respectively. Klebsiella pneumoniae and Escherichia coli were common ESBL producers. AmpC β-lactamases predominate among Acinetobacter spp. and Pseudomonas aeruginosa. Coproduction of ESBLs and AmpC β-lactamases was found in 36 (11.6%) isolates, with very close relative frequencies among K. pneumoniae, Acinetobacter spp., and P. aeruginosa. β-Lactamase producers were predominantly found in the surgical department (56.5%) and ICUs (44.2%). ESBL producers revealed high resistance for cefuroxime (96.4%), cefotaxime (92.9%), and trimethoprim/sulfamethoxazole (90.5%). The resistance rates were significantly higher among ESBL producers than nonproducers for cephalosporins (), amoxicillin/clavulanate (), piperacillin/tazobactam (), nitrofurantoin (), aztreonam (), ciprofloxacin (), and trimethoprim/sulfamethoxazole (). Significantly higher () resistance rates were observed among AmpC β-lactamase producers than nonproducers for all tested antibiotics. Conclusions. This finding showed a high prevalence of ESBL- and AmpC β-lactamase-producing GNB in our hospital. Quality control practice and routine detection of β-lactamase producers before deciding on antibiotic therapy are advocated.