Chromosomal DNA restriction endonuclease digestion patterns of beta-lactamase-producing Enterococcus faecalis isolates collected from a single hospital over a 7-year period.
Twenty-three beta-lactamase (beta-lac)-producing, highly gentamicin-resistant Enterococcus faecalis isolates collected over a 7-year period from the same hospital were examined by pulsed-field gel electrophoresis of SmaI-digested genomic DNA. The beta-lac+ isolates appeared to form a single clonal group, which had been previously designated the mid-Atlantic pattern. Eleven variations of the mid-Atlantic clone, differing by one to six bands, were identified; some of the changes were likely due to plasmid bands. However, a number of isolates had indistinguishable patterns, including some recovered over a 4-year period. There was a surprising lack of movement of the beta-lac determinant to other strains, although this trait was transferable in vitro by conjugation. We conclude that a single clone (the mid-Atlantic clone) of beta-lac+ E. faecalis has remained endemic in this hospital for at least 7 years. The reason(s) for the apparent lack of spread to other strains of E. faecalis is unknown.
Seetulsingh
P S
PS
Department of Internal Medicine, University of Texas Medical School, Houston 77030, USA.
Tomayko
J F
JF
Coudron
P E
PE
Markowitz
S M
SM
Skinner
C
C
Singh
K V
KV
Murray
B E
BE
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004262:DNA Restriction Enzymes; D004352:Drug Resistance, Microbial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D013293:Enterococcus faecalis / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D005839:Gentamicins / Q000494:pharmacology; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D006761:Hospitals; D010957:Plasmids / Q000235:genetics; D012150:Polymorphism, Restriction Fragment Length; D013048:Specimen Handling; D001618:beta-Lactamases / Q000096:biosynthesis*
D000900:Anti-Bacterial Agents; D005839:Gentamicins; D004262:DNA Restriction Enzymes; D001618:beta-Lactamases