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Intrahospital spread of a single gentamicin-resistant, beta-lactamase-producing strain of Enterococcus faecalis in
B E Murray1, H A Lopardo, E A Rubeglio
1Center for Infectious Diseases, University of Texas Medical School, Houston 77030.
Insights
A single strain of beta-lactamase-producing (Bla+) Enterococcus faecalis was identified in an Argentinian hospital over 17 months. Despite different plasmids, the bacteria shared chromosomal DNA, indicating a common source for this resistant pathogen.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Beta-lactamase (Bla+) Enterococcus faecalis poses a significant challenge in healthcare settings.
- Understanding the epidemiology of Bla+ E. faecalis is crucial for infection control.
Purpose of the Study:
- To investigate the genetic relatedness of beta-lactamase-producing Enterococcus faecalis isolates from an Argentinian pediatric hospital.
- To determine the origin and transmission patterns of Bla+ E. faecalis in a clinical environment.
Main Methods:
- Pulsed-field gel electrophoresis (PFGE) was used to analyze chromosomal DNA restriction patterns.
- Plasmid DNA profiles were compared between isolates.
- Hybridization studies were performed using a staphylococcal Bla gene probe.
Main Results:
- Six Bla+ E. faecalis isolates recovered over 17 months exhibited identical or near-identical chromosomal restriction patterns.
- Plasmid DNA patterns varied among the isolates.
- All isolates successfully transferred the Bla gene via conjugation.
- The isolates hybridized to a staphylococcal Bla gene probe, similar to US isolates.
Conclusions:
- A single strain of Bla+ E. faecalis was likely responsible for infections over the study period.
- The presence of a single strain, despite plasmid variability and conjugation, suggests a common source or successful clonal expansion.
- The findings highlight the importance of molecular typing for tracking the spread of antibiotic-resistant bacteria in hospitals.
Abstract:
Six beta-lactamase-producing (Bla+) isolates of Enterococcus faecalis recovered over a 17-month period from an Argentinian pediatric hospital were found to have identical or almost identical chromosomal restriction patterns by pulsed-field gel electrophoresis, although the plasmid patterns were different. These isolates, like Bla+ enterococci in the United States, hybridized to a staphylococcal Bla gene probe. The presence of a single strain was somewhat surprising, since all isolates transferred Bla by conjugation.