Antimicrobial susceptibility and distribution of extended-spectrum β-lactamases, AmpC β-lactamases and carbapenemases among Proteus, Providencia and Morganella isolated from global hospitalised patients with intra-abdominal and urinary tract infections: Results of the Study for Monitoring Antimicrobial Resistance Trends (SMART), 2008-2011

Objectives: The increasing trend of p-lactam resistance among Enterobacteriaceae is a worldwide problem. This study investigated isolates of the tribe Proteeae (Proteus, Providencia and Morganella) causing intra-abdominal and urinary tract infections from the worldwide Study for Monitoring Antimicrobial Resistance Trends (SMART) collected from 2008-2011. Methods: Antimicrobial susceptibility testing was performed on isolates with an ertapenem minimum inhibitory concentration >0.5 mg/L or those phenotypically producing extended-spectrum p-lactamases (ESBLs). ESBLs, AmpC beta-lactamases and carbapenemases were detected by multiplex PCR. Results: A total of 142 isolates, including Proteus mirabilis (n = 121), Proteus vulgaris (n =3), Providencia stuartii (n= 5), Providencia rettgeri (n = 6) and Morganella morganii (n= 7), were analysed. Proteus mirabilis was generally susceptible to ertapenem (similar to 90%) compared with imipenem (<= 25%). The most common ESBLs were CTX-M types (n = 64), followed by TEM (n =27) and SHV (n = 7). CTX-M-1, CTX-M-2 and CT-XM-15 were the dominant CTX-M-type ESBLs in P. mirabilis isolates. CMY (n = 14), which included CMY-2 (n = 6), was the most common AmpC beta-lactamase, followed by DHA (n = 6) and FOX (n = 4). NDM (n = 7), which included NDM-1 (n=4), was the most common carbapenemase, followed by KPC (n=2). Isolates from hospital-associated infections had more complicated beta-lactamase combinations than isolates from community-acquired infections. Conclusion: The global emergence and spread of beta-lactamase-producing Proteeae isolates are major issues in tackling antimicrobial resistance. Continuous monitoring of antimicrobial resistance trends and developing further resistance surveillance are necessary. (C) 2020 The Authors. Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.