<abstract xmlns="http://www.w3.org/1999/xhtml">

<bold>Introduction</bold>: In the last 40 years, Acinetobacter baumannii has been among the bacteria known to acquire multiple mechanisms of antibiotic resistance and, as a result, it is now one of the pathogens involved in healthcare-associated infections with multidrug resistant strains. Our study aimed to assess the production of carbapenemases in carbapenem-resistant A. baumannii by means of phenotypic methods and polymerase chain reaction technique (PCR), as well as to appraise the performances of carbapenemase detection by phenotypic tests compared to the PCR approach.
<bold>Materials and Methods</bold>: We used phenotypic methods (E-test MBL, CIM, MHT, Rosco® Kit/OXA/MBL, OXA-23 K-SeT® assay) to investigate the production of carbapenemases in 43 carbapenem-resistant A. baumannii isolates, and PCR to screen for the genes blaOXA-23, blaOXA-24, blaOXA-58, blaOXA-51, blaVIM, blaIMP and blaNDM.
<bold>Results</bold>: The carbapenem inactivation method (CIM) at 2 hours, CIM at 4h, OXA-23 K-SeT® assay, Rosco® Kit/OXA, and modified Hodge test (MHT) identified 26%, 63%, 65%, 81%, and 42% carbapenemase-producing isolates, respectively. The phenotypic E-test MBL detected metallo-β-lactamase (MBL) production in 79% of strains. PCR revealed blaOXA-51 in all the isolates, blaOXA-23 in 35/43 (81%), blaOXA-24 in 28/43 (65%), blaVIM in 7/43 (3%) and blaOXA-58, blaIMP, blaNDM were not detected.
<bold>Conclusion</bold>: Because phenotypic tests do not highlight all the carbapenemase-producing strains, their results must be interpreted with caution relative to their level of performance, and negative results should be confirmed by means of PCR.
</abstract>

Introduction: In the last 40 years, Acinetobacter baumannii has been among the bacteria known to acquire multiple mechanisms of antibiotic resistance and, as a result, it is now one of the pathogens involved in healthcare-associated infections with multidrug resistant strains. Our study aimed to assess the production of carbapenemases in carbapenem-resistant A. baumannii by means of phenotypic methods and polymerase chain reaction technique (PCR), as well as to appraise the performances of carbapenemase detection by phenotypic tests compared to the PCR approach.
Materials and Methods: We used phenotypic methods (E-test MBL, CIM, MHT, Rosco® Kit/OXA/MBL, OXA-23 K-SeT® assay) to investigate the production of carbapenemases in 43 carbapenem-resistant A. baumannii isolates, and PCR to screen for the genes blaOXA-23, blaOXA-24, blaOXA-58, blaOXA-51, blaVIM, blaIMP and blaNDM.
Results: The carbapenem inactivation method (CIM) at 2 hours, CIM at 4h, OXA-23 K-SeT® assay, Rosco® Kit/OXA, and modified Hodge test (MHT) identified 26%, 63%, 65%, 81%, and 42% carbapenemase-producing isolates, respectively. The phenotypic E-test MBL detected metallo-β-lactamase (MBL) production in 79% of strains. PCR revealed blaOXA-51 in all the isolates, blaOXA-23 in 35/43 (81%), blaOXA-24 in 28/43 (65%), blaVIM in 7/43 (3%) and blaOXA-58, blaIMP, blaNDM were not detected.
Conclusion: Because phenotypic tests do not highlight all the carbapenemase-producing strains, their results must be interpreted with caution relative to their level of performance, and negative results should be confirmed by means of PCR.

Phenotypic Carbapenemase Production and <italic>bla</italic>OXA detecting by PCR in <italic>Acinetobacter baumannii</italic> isolates from a Hospital of Infectious Diseases from North-East Romania

Department of Preventive Medicine and Interdisciplinarity

“Grigore T. Popa” University of Medicine and Pharmacy Iași

Revista Romana de Medicina de Laborator

This work is licensed under the Creative Commons Attribution 4.0 International License.

Phenotypic Carbapenemase Production and  detecting by PCR in  isolates from a Hospital of Infectious Diseases from North-East Romania

Introduction: In the last 40 years, Acinetobacter baumannii has been among the bacteria known to acquire multiple mechanisms of antibiotic resistance and, as a...

Phenotypic Carbapenemase Production and bla_OXA detecting by PCR in Acinetobacter baumannii isolates from a Hospital of Infectious Diseases from North-East Romania

Published Online: Oct 20, 2022

Page range: 453 - 465

Received: Apr 19, 2022

Accepted: Jul 12, 2022

DOI: https://doi.org/10.2478/rrlm-2022-0033

Keywords
Acinetobacter baumannii, genotyping, carbapenemase production, OXA-23, OXA-24

© 2022 Elena-Roxana Buzilă et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Phenotypic Carbapenemase Production and blaOXA detecting by PCR in Acinetobacter baumannii isolates from a Hospital of Infectious Diseases from North-East Romania

Published Online: Oct 20, 2022

Page range: 453 - 465

Received: Apr 19, 2022

Accepted: Jul 12, 2022

DOI: https://doi.org/10.2478/rrlm-2022-0033

KeywordsAcinetobacter baumannii, genotyping, carbapenemase production, OXA-23, OXA-24

© 2022 Elena-Roxana Buzilă et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Phenotypic Carbapenemase Production and bla_OXA detecting by PCR in Acinetobacter baumannii isolates from a Hospital of Infectious Diseases from North-East Romania

Keywords
Acinetobacter baumannii, genotyping, carbapenemase production, OXA-23, OXA-24