BACKGROUND: Antibiotic resistance is problematic in Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii, and is often associated with serious infections. Carbapenems are often one of the few remaining therapeutic options, so it is important to monitor carbapenem activity against these pathogens and to identify resistance mechanisms. METHODS: Carbapenem susceptibilities were determined for 14 359 Enterobacteriaceae, 3614 P. aeruginosa and 994 A. baumannii from the USA (2007-09). Klebsiella pneumoniae with doripenem MICs ≥2 mg/L (n = 88), and P. aeruginosa (n = 452), A. baumannii (n = 349) and other enterics (n = 13) with doripenem MICs ≥4 mg/L were screened for carbapenem resistance mechanisms. RESULTS: Doripenem/meropenem and imipenem susceptibilities for Enterobacteriaceae were >99% and 89%, respectively. Doripenem susceptibility (2007-09) for P. aeruginosa was 87.4%-84.1%; comparable to meropenem and higher than imipenem. For A. baumannii, doripenem susceptibility (2007-09) was 63%-58.2%; lower than imipenem and meropenem. Resistant K. pneumoniae had KPC and lacked porins OmpK35/OmpK36. In 2009, 3.4% of all K. pneumoniae possessed KPC. Five other enterics and one P. aeruginosa possessed KPC. Resistance mechanisms in P. aeruginosa were loss of porin OprD (90%), efflux (55%) and elevated AmpC activity (25%). Acquired carbapenemases OXA-23/-24 were present in 48% of resistant A. baumannii. VIM metallo-β-lactamases were present in three P. aeruginosa and one A. baumannii isolates. CONCLUSIONS: Doripenem and meropenem were more active than imipenem against Enterobacteriaceae and P. aeruginosa from the USA. Carbapenem resistance mechanisms included serine carbapenemases, elevated AmpC activity, efflux and porin deficiencies occurring mostly in P. aeruginosa. Metallo-β-lactamases were found in <0.1% of isolates.
BACKGROUND: Antibiotic resistance is problematic in Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii, and is often associated with serious infections. Carbapenems are often one of the few remaining therapeutic options, so it is important to monitor carbapenem activity against these pathogens and to identify resistance mechanisms. METHODS:Carbapenem susceptibilities were determined for 14 359 Enterobacteriaceae, 3614 P. aeruginosa and 994 A. baumannii from the USA (2007-09). Klebsiella pneumoniae with doripenem MICs ≥2 mg/L (n = 88), and P. aeruginosa (n = 452), A. baumannii (n = 349) and other enterics (n = 13) with doripenem MICs ≥4 mg/L were screened for carbapenem resistance mechanisms. RESULTS:Doripenem/meropenem and imipenem susceptibilities for Enterobacteriaceae were >99% and 89%, respectively. Doripenem susceptibility (2007-09) for P. aeruginosa was 87.4%-84.1%; comparable to meropenem and higher than imipenem. For A. baumannii, doripenem susceptibility (2007-09) was 63%-58.2%; lower than imipenem and meropenem. Resistant K. pneumoniae had KPC and lacked porins OmpK35/OmpK36. In 2009, 3.4% of all K. pneumoniae possessed KPC. Five other enterics and one P. aeruginosa possessed KPC. Resistance mechanisms in P. aeruginosa were loss of porin OprD (90%), efflux (55%) and elevated AmpC activity (25%). Acquired carbapenemases OXA-23/-24 were present in 48% of resistant A. baumannii. VIM metallo-β-lactamases were present in three P. aeruginosa and one A. baumannii isolates. CONCLUSIONS:Doripenem and meropenem were more active than imipenem against Enterobacteriaceae and P. aeruginosa from the USA. Carbapenem resistance mechanisms included serine carbapenemases, elevated AmpC activity, efflux and porin deficiencies occurring mostly in P. aeruginosa. Metallo-β-lactamases were found in <0.1% of isolates.
Authors: Fred C Tenover; Rafael Canton; JoAnn Kop; Ryan Chan; Jamie Ryan; Fred Weir; Patricia Ruiz-Garbajosa; Vincent LaBombardi; David H Persing Journal: J Clin Microbiol Date: 2013-09-04 Impact factor: 5.948
Authors: Yiying Cai; Tze-Peng Lim; Jocelyn Teo; Suranthran Sasikala; Winnie Lee; Yanjun Hong; Eric Chun Yong Chan; Thean Yen Tan; Thuan-Tong Tan; Tse Hsien Koh; Li Yang Hsu; Andrea L Kwa Journal: Antimicrob Agents Chemother Date: 2016-08-22 Impact factor: 5.191
Authors: Yiying Cai; Tze-Peng Lim; Jocelyn Qi-Min Teo; Suranthran Sasikala; Eric Chun Yong Chan; Yan Jun Hong; Winnie Lee; Thean Yen Tan; Thuan Tong Tan; Tse Hsien Koh; Li Yang Hsu; Andrea L Kwa Journal: Antimicrob Agents Chemother Date: 2016-12-27 Impact factor: 5.191
Authors: Clyde A Smith; Hilary Frase; Marta Toth; Malika Kumarasiri; Kwame Wiafe; Jared Munoz; Shahriar Mobashery; Sergei B Vakulenko Journal: J Am Chem Soc Date: 2012-11-16 Impact factor: 15.419
Authors: Krisztina M Papp-Wallace; Baui Senkfor; Julian Gatta; Weirui Chai; Magdalena A Taracila; Veerabahu Shanmugasundaram; Seungil Han; Richard P Zaniewski; Brian M Lacey; Andrew P Tomaras; Marion J Skalweit; Michael E Harris; Louis B Rice; John D Buynak; Robert A Bonomo Journal: Antimicrob Agents Chemother Date: 2012-08-20 Impact factor: 5.191