Evidence for clonal spread of a single strain of beta-lactamase-producing Enterococcus (Streptococcus) faecalis to six hospitals in five states
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B E Murray1, K V Singh, S M Markowitz
1Center for Infectious Diseases, University of Texas Medical School, Houston 77030.
Abstract:
Beta-lactamase-producing (Bla+) enterococci have been reported in three state and two countries. Pulsed-field gel electrophoresis was used to compare 14 Bla+ Enterococcus (Streptococcus) faecalis isolated from hospitalized patients in seven states and three continents. The restriction endonuclease digestion patterns of isolates from Connecticut, Massachusetts, Lebanon, and Argentina were all markedly different, indicating that these were different strains. However, isolates from Delaware, Texas, Pennsylvania (Philadelphia and Pittsburgh), Florida, and Virginia were similar, indicating that these isolates were derivatives of a single strain. This conclusion was supported by hybridization using individual fragments as probes. Spread of Bla+ enterococci within the hospital setting was also demonstrated. These findings illustrate the value of pulsed-field gel electrophoresis for epidemiologic analyses and support the importance of identifying and containing organisms with new resistance properties in an effort to decrease their transmission to and from, as well as within, hospitals.
Insights
Beta-lactamase-producing (Bla+) enterococci strains spread within hospitals. Pulsed-field gel electrophoresis identified distinct strains and a single dominant strain, highlighting the need for containment strategies.
Area of Science:
- Microbiology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Beta-lactamase-producing (Bla+) enterococci are emerging pathogens.
- Previous reports indicated their presence across multiple states and countries.
Purpose of the Study:
- To investigate the genetic relatedness of Bla+ Enterococcus faecalis isolates.
- To understand the transmission dynamics of these resistant enterococci within healthcare settings.
Main Methods:
- Pulsed-field gel electrophoresis (PFGE) was employed to analyze DNA from 14 Bla+ E. faecalis isolates.
- Restriction endonuclease digestion patterns were compared.
- Hybridization studies using DNA fragments as probes were conducted.
Main Results:
- Isolates from Connecticut, Massachusetts, Lebanon, and Argentina exhibited distinct PFGE patterns, indicating different strains.
- Isolates from Delaware, Texas, Pennsylvania, Florida, and Virginia showed similar patterns, suggesting a common strain origin.
- Evidence of Bla+ enterococci spread within the hospital environment was observed.
Conclusions:
- PFGE is a valuable tool for analyzing the epidemiology of bacterial infections.
- Effective identification and containment of organisms with novel resistance mechanisms are crucial to limit transmission.
- Hospital-acquired infections with resistant enterococci require vigilant surveillance and control measures.