Jaffar A Al-Tawfiq1,2,3, Ali A Rabaan4, Justin V Saunar5, Ali M Bazzi5. 1. Infectious Disease Unit , Specialty Internal Medicine, Johns Hopkins Aramco Healthcare, 31311 Dhahran, Saudi Arabia. 2. Infectious Disease Division, Department of Medicine, Indiana University School of Medicine, 46202 Indianapolis, IN, USA. 3. Infectious Disease Division, Department of Medicine, Johns Hopkins University School of Medicine, 21093 Baltimore, MD, USA. 4. Molecular Diagnostic Laboratory, Johns Hopkins Aramco Healthcare, 31311 Dhahran, Saudi Arabia. 5. Microbiology Laboratory Johns Hopkins Aramco Healthcare, 31311 Dhahran, Saudi Arabia.
Abstract
BACKGROUND: The molecular epidemiology of resistance of carbapenem-resistant Enterobacteriaceae (CRE) and Pseudomonas aeruginosa are important in the study of multidrug-resistant bacteria. We evaluate the prevalence of the different mechanisms of CRE in a hospital in Saudi Arabia. METHODS: Carbapenem non-susceptible isolates of Enterobacteriaceae and Pseudomonas aeruginosa were tested by real-time PCR for the detection of genes responsible for beta-lactam resistance. RESULTS: There were a total of 200 isolates with carbapenem non-susceptibility and these were Klebsiella pneumoniae (n=96, 48%), Escherichia coli (n=51, 25.5%) and Pseudomonas aeruginosa (n=45, 22.5%). The detected carbapenemases were oxacillinase-48 (OXA-48) (n=83, 41.5%), New Delhi metallo-β-lactamase (NDM) (n=19, 2.5%) and both NDM and OXA-48 (n=5, 2.5%). The other carbapenemases were imipenemase (n=1, 0.5%), Verona integrin encoded metallo-β-lactamase (n=6, 3%) and Klebsiella pneumoniae carbapenemase (n=1, 0.5%), but none were detected in 86 isolates (43%). CONCLUSION: The most common carbapenemases were OXA-48 and a significant percentage had no detectable genes. These data will help in the selection of new antimicrobial therapies.
BACKGROUND: The molecular epidemiology of resistance of carbapenem-resistant Enterobacteriaceae (CRE) and Pseudomonas aeruginosa are important in the study of multidrug-resistant bacteria. We evaluate the prevalence of the different mechanisms of CRE in a hospital in Saudi Arabia. METHODS: Carbapenem non-susceptible isolates of Enterobacteriaceae and Pseudomonas aeruginosa were tested by real-time PCR for the detection of genes responsible for beta-lactam resistance. RESULTS: There were a total of 200 isolates with carbapenem non-susceptibility and these were Klebsiella pneumoniae (n=96, 48%), Escherichia coli (n=51, 25.5%) and Pseudomonas aeruginosa (n=45, 22.5%). The detected carbapenemases were oxacillinase-48 (OXA-48) (n=83, 41.5%), New Delhi metallo-β-lactamase (NDM) (n=19, 2.5%) and both NDM and OXA-48 (n=5, 2.5%). The other carbapenemases were imipenemase (n=1, 0.5%), Verona integrin encoded metallo-β-lactamase (n=6, 3%) and Klebsiella pneumoniae carbapenemase (n=1, 0.5%), but none were detected in 86 isolates (43%). CONCLUSION: The most common carbapenemases were OXA-48 and a significant percentage had no detectable genes. These data will help in the selection of new antimicrobial therapies.