Carbapenem Susceptibility Testing Errors Using Three Automated Systems, Disk Diffusion, Etest, and Broth Microdilution and Carbapenem Resistance Genes in Isolates of Acinetobacter baumannii-calcoaceticus Complex
| Autor: | Ana Elizabeth Markelz, Kevin S. Akers, Katrin Mende, Tatjana P. Calvano, Xin Yu, Wendy C. Zera, Miriam L. Beckius, Duane R. Hospenthal, Clinton K. Murray |
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| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Acinetobacter baumannii
Author's Correction Carbapenem Imipenem Microbial Sensitivity Tests Meropenem beta-Lactamases Microbiology Bacterial Proteins Drug Resistance Bacterial medicine polycyclic compounds Humans Pharmacology (medical) Acinetobacter calcoaceticus Letter to the Editor Etest Pharmacology biology Broth microdilution Doripenem Acinetobacter biochemical phenomena metabolism and nutrition biology.organism_classification bacterial infections and mycoses Anti-Bacterial Agents Infectious Diseases Carbapenems Susceptibility bacteria Thienamycins medicine.drug Acinetobacter Infections |
| Popis: | The Acinetobacter baumannii-calcoaceticus complex (ABC) is associated with increasing carbapenem resistance, necessitating accurate resistance testing to maximize therapeutic options. We determined the accuracy of carbapenem antimicrobial susceptibility tests for ABC isolates and surveyed them for genetic determinants of carbapenem resistance. A total of 107 single-patient ABC isolates from blood and wound infections from 2006 to 2008 were evaluated. MICs of imipenem, meropenem, and doripenem determined by broth microdilution (BMD) were compared to results obtained by disk diffusion, Etest, and automated methods (the MicroScan, Phoenix, and Vitek 2 systems). Discordant results were categorized as very major errors (VME), major errors (ME), and minor errors (mE). DNA sequences encoding OXA beta-lactamase enzymes ( bla OXA-23-like , bla OXA-24-like , bla OXA-58-like , and bla OXA-51-like ) and metallo-β-lactamases (MBLs) (IMP, VIM, and SIM1) were identified by PCR, as was the KPC2 carbapenemase gene. Imipenem was more active than meropenem and doripenem. The percentage of susceptibility was 37.4% for imipenem, 35.5% for meropenem, and 3.7% for doripenem. Manual methods were more accurate than automated methods. bla OXA-23-like and bla OXA-24-like were the primary resistance genes found. bla OXA-58-like , MBLs, and KPC2 were not present. Both automated testing and manual testing for susceptibility to doripenem were very inaccurate, with VME rates ranging between 2.8 and 30.8%. International variability in carbapenem breakpoints and the absence of CLSI breakpoints for doripenem present a challenge in susceptibility testing. |
| Databáze: | OpenAIRE |
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