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Comparative in vitro activity of carbapenems against clinical isolates of Acinetobacter baumannii
Author(s) -
Douraghi M.,
Ghalavand Z.,
Nateghi Rostami M.,
Zeraati H.,
Aliramezani A.,
Rahbar M.,
Mohammadzadeh M.,
Ghourchian S.,
Boroumand M.A.,
Abdollahi A.
Publication year - 2016
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13178
Subject(s) - doripenem , meropenem , imipenem , acinetobacter baumannii , carbapenem , microbiology and biotechnology , medicine , acinetobacter , ertapenem , antibiotics , biology , pseudomonas aeruginosa , antibiotic resistance , bacteria , genetics
Aims The aim of this multi‐hospital study was to assess the in vitro activity of doripenem and its comparators, imipenem and meropenem, using the new CLSI breakpoints against a large population of a frequently isolated nosocomial pathogen, Acinetobacter baumannii . Methods and Results During a 2‐year period, four referral or tertiary hospitals submitted 400 isolates of Ac. baumannii for susceptibility testing using imipenem, meropenem and doripenem via disc diffusion and E ‐test methods. A subset of 390 isolates was resistant to all three tested carbapenems. Doripenem and meropenem ( MIC 50 , 32 μ g ml −1 ) had comparable activity, albeit doripenem's activity was greater than imipenem ( MIC 50 , >32 μ g ml −1 ). A significantly higher proportion of the isolates were inhibited by doripenem than by imipenem at MIC values of 12, 16, 24 and 32 μ g ml −1 ( P < 0·05). The cumulative percentage of imipenem MIC s was lower compared to its comparators. The comparison of resistance rate to imipenem and meropenem based on old and new breakpoints showed <1% difference. The overall agreement between the two susceptibility testing methods was ≥95%. Conclusion Doripenem has a slightly greater in vitro activity than imipenem in terms of zone breakpoints and MIC values, but its activity is comparable to meropenem. Significance and Impact of the Study Doripenem should be considered as a therapeutic option for monotherapy or combination therapy, particularly when the therapeutic options are limited.