Document Type : New and original researches in the field of Microbiology.
Authors
1
Department of Medical Microbiology and Immunology, Faculty of Medicine, Helwan University, Ain Helwan, Cairo 11795, Egypt
2
Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University, Cairo 11562, Egypt; Basic Medical Sciences Department, Faculty of Medicine, Galala University, Suez, Egypt
3
Department of Biochemistry and Molecular Biology, Faculty of Medicine, Cairo University, Cairo 11562, Egypt
4
Department of Medical Microbiology and Immunology, Faculty of Medicine, Cairo University, Cairo 11562, Egypt
Abstract
Background: In Egypt, the prevalence of plasmid-mediated class C (AmpC) beta-lactamases (β-lactamases) in Acinetobacter species is on the rise, and its resistance to a wide range of β-lactam drugs makes it a hazardous condition. Objectives: The aim of this research was to assess the occurrence of AmpC among Acinetobacter clinical isolates by phenotypic confirmatory tests and to compare them with PCR as the gold standard method. Methodology: The current study incorporated 50 Acinetobacter clinical isolates. Detection of AmpC-producing Acinetobacter isolates was done by two phenotypic methods; AmpC disk test with Tris-EDTA and disk potentiation test (DPT) with aminophenyl boronic acid (APB) and then compared with genotypic detection of plasmid-mediated AmpC (pAmpC) gene(s) families by multiplex PCR as the gold reference technique. Results: According to the study's findings, the frequency of AmpC-producing isolates was 68.8% by AmpC disk test, 72.9% by DPT with APB test, and 79.2% by PCR. The sensitivity of AmpC disk test and DPT with APB test was 86.8% and 92.1% respectively and the specificity was 100% for both tests. The CIT family of AmpC genes was the most common type to be found in the study (33.3%). Conclusion: Phenotypic detection of AmpC was more sensitive by DPT with APB test than the AmpC disk test with Tris-EDTA. Phenotypic methods are influenced by false-negative results. Therefore, PCR remains the gold standard for detecting different forms of pAmpC gene families and determining their precise prevalence, enabling the taking of suitable actions to restrict the spread of resistant microorganisms.
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