Insights on carbapenem-resistant Acinetobacter baumannii : phenotypic characterization of relevant isolates

Donadu Matthew Gavino and Zanetti Stefania and Nagy Ádám László and Barrak Ibrahim and Gajdács Márió: Insights on carbapenem-resistant Acinetobacter baumannii : phenotypic characterization of relevant isolates. In: Acta biologica Szegediensis, (65) 1. pp. 85-92. (2021)

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Acinetobacter baumannii (A. baumannii) is an important nosocomial pathogen, which may be a causative agent in a wide-range of human pathologies. Carbapenems are usually considered the last safe and effective choice of drugs for the treatment of Gram-negative infections. The emergence of carbapenem-resistant A. baumannii (CRAB) is a critical public health issue as they leave clinicians with limited therapeutic options. In this study, phenotypic methods were used to characterize sixty-two (n = 62) A. baumannii isolates, which were included based on their suspected non-susceptibility to meropenem. Minimum inhibitory concentrations (MICs) of meropenem, levofloxacin, gentamicin, sulfamethoxazole/trimethoprim, tigecycline were determined using E-tests, while colistin MICs were determined using broth microdilution. The isolates were subjected to the modified Hodge test (MHT), the modified carbapenem-inactivation method (mCIM) and the imipenem/EDTA combined disk test (CDT). Efflux pump overexpression was studied using agar plates containing phenylalanine-arginine β-naphthylamide (PAβN). Assessment of biofilm-formation was carried out using the crystal violet tube-adherence method. 64.5% of the strains showed meropenem MICs in the resistant range (>8 mg/L), resistance rates were similarly high to the other tested antibiotics. The MHT and mCIM assay were positive in 79.0% and 67.7% of cases, respectively; the presence of an MBL was suggested for 29.0% of isolates. Efflux-pump overexpression was seen in 12.9% of isolates. 54.8% of the isolates were characterized as strong biofilm-producers. Microbiology laboratories have an important role in differentiating the distinct mechanisms by which these pathogens develop the CRAB phenotype, as plasmid-borne carbapenemases are significant from the standpoint of public health microbiology.

Item Type: Article
Journal or Publication Title: Acta biologica Szegediensis
Date: 2021
Volume: 65
Number: 1
ISSN: 1588-4082
Page Range: pp. 85-92
Language: English
Publisher: University of Szeged
Place of Publication: Szeged
Related URLs:
DOI: 10.14232/abs.2021.1.85-92
Uncontrolled Keywords: Biokémia, Mikrobiológia
Additional Information: Bibliogr.: p. 89-92. ; összefoglalás angol nyelven
Subjects: 01. Natural sciences
01. Natural sciences > 01.06. Biological sciences
Date Deposited: 2022. May. 12. 09:45
Last Modified: 2022. May. 12. 09:45

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