Clinical and molecular epidemiology of vancomycin-resistant Enterococcus faecium during its emergence in a city in southern Texas.
During a 19-month period from April 1993 to October 1994, 41 isolates of vancomycin-resistant Enterococcus faecium (VREF) were detected in seven different hospitals in a city in southern Texas. A case-control study to determine the risk factors for acquisition was done in the hospital in which the majority of isolates were detected. Pulsed-field gel electrophoresis (PFGE) of whole-cell DNA was used to determine strain identity. Thirty-five (85%) of the 41 VREF isolates were of the vanB phenotype. Of these, 32 (91%) of 35 were the same strain by PFGE typing. The same vanB strain was documented in five different hospitals in the city. In contrast, 4 (67%) of 6 of the vanA phenotype VREF isolates were distinct strains by PFGE typing. Significant risk factors for colonization or infection with VREF were prior exposure to antibiotics (P = .04), the previous use of third-generation cephalosporins (P = .03), and the previous use of parenteral vancomycin (P = .002). Infection-control and antibiotic-utilization measures were implemented to control cross-transmission and selection of VREF isolates. During the emergence of VREF in our city, clonal dissemination of a single strain of vanB VREF among six hospitals was documented. Limited cross-transmission of vanA phenotype VREF isolates occurred, but most vanA VREF isolates were distinct strains selected in individual hospital environments.
Moreno
F
F
Department of Medicine, University of Texas Health Science Center at San Antonio 78284-7881, USA.
Grota
P
P
Crisp
C
C
Magnon
K
K
Melcher
G P
GP
Jorgensen
J H
JH
Patterson
J E
JE
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016022:Case-Control Studies; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D016984:Enterococcus faecium / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D017720:Molecular Epidemiology; D010641:Phenotype; D012307:Risk Factors; D013781:Texas / Q000453:epidemiology; D014640:Vancomycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D014640:Vancomycin