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Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
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Resistance to β-lactams in enterococci
Paula Gagetti1, Laura Bonofiglio2, Gabriela García Gabarrot3
1Grupo STREP de la Sociedad Argentina de Bacteriología, Micología y Parasitología Clínicas (SADEBAC), División de la Asociación Argentina de Microbiología, Argentina; Servicio Antimicrobianos, Departamento de Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI), ANLIS "Dr Carlos G. Malbrán", Ciudad Autónoma de Buenos Aires, Argentina.
Revista Argentina De Microbiologia
|September 24, 2018
Summary
High-level ampicillin resistance in Enterococcus faecium is a growing concern, primarily caused by alterations in the PBP5 protein. This resistance spreads through bacterial clonal expansion and horizontal gene transfer.
Area of Science:
- Microbiology
- Antimicrobial Resistance
- Molecular Biology
Background:
- Enterococci exhibit intrinsic resistance to antimicrobials and readily acquire new resistance mechanisms.
- Beta-lactam antibiotics are crucial for treating enterococcal infections, making resistance a significant clinical challenge.
- Ampicillin resistance is infrequent in Enterococcus faecalis but prevalent in hospital-associated Enterococcus faecium.
Purpose of the Study:
- To investigate the primary mechanisms driving high-level ampicillin resistance in Enterococcus faecium.
- To understand the genetic basis and dissemination routes of ampicillin resistance in this pathogen.
Main Methods:
- Analysis of PBP5 protein production and genetic polymorphisms in ampicillin-resistant Enterococcus faecium isolates.
- Investigation of clonal spread and horizontal gene transfer as dissemination mechanisms.
Main Results:
- High-level ampicillin resistance in Enterococcus faecium is predominantly linked to enhanced production of PBP5 and/or mutations in its beta subunit.
- Both the clonal spread of strains with mutated pbp5 genes and horizontal gene transfer contribute to the dissemination of this resistance.
Conclusions:
- Alterations in PBP5 are the key drivers of high-level ampicillin resistance in Enterococcus faecium.
- Understanding these mechanisms and dissemination routes is vital for combating antimicrobial resistance in clinical settings.
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