A sustained endemic outbreak of vancomycin-resistant Enterococcus faecium: A 30-month surveillance study.
BACKGROUND
The assessment of risk factors for the nosocomial acquisition of colonization and infection by vancomycin-resistant Enterococcus faecium (VREfm) is often problematic due to scarce data on antibiotic use. A 30-month prospective cohort study was conducted to characterize VREfm strains isolated during an outbreak and endemic period, identifying the risk factors, antibiotic consumption, and prevalence of virulence determinants.


METHODS
The study was conducted in a tertiary care hospital. A representative number (171 patients) of isolates that were classified as resistant to high-level vancomycin (minimum inhibitory concentration (MIC) ≥ 256 μg/ml) were investigated.


RESULTS
Among 171 colonized patients, 22 (12.9%) developed VRE infection. All VREfm isolates harboured vanA genes. Genes codifying virulence factors such as enterococcal surface protein (esp), aggregation substance 1 (asa1), and gelatinase (gelE) were detected in the VREfm studied. All patients infected with VRE had previously been colonized and became infected on average 14 days after colonization. Only previous use of aminoglycosides was a risk factor independently associated with VRE infection; however, glycopeptide consumption in defined daily doses (DDD) per 1000 patient-days was associated with the presence of this microorganism. The monthly colonization pressure ranged from 0.004% to 1.32% during the 30-month study period.


CONCLUSIONS
We found a high incidence of VRE in a tertiary care hospital, independently associated with the prior use of aminoglycosides and the administration of glycopeptides.
From the Laboratory of Microbiology, Institute of Biomedical Sciences, Federal University of Uberlândia , Uberlândia MG , Brazil.
Paola A
PA
Campos
Deivid W F
DW
Batistão
Paulo P
PP
Gontijo-Filho
Rosineide M
RM
Ribas
D000368:Aged; D000617:Aminoglycosides / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics; D019729:Carbon-Oxygen Ligases / Q000235:genetics; D015331:Cohort Studies; D004196:Disease Outbreaks; D019353:Endemic Diseases; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D062665:Epidemiological Monitoring; D005260:Female; D006020:Glycopeptides / Q000627:therapeutic use; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D015994:Incidence; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D062606:Tertiary Care Centers; D065507:Vancomycin-Resistant Enterococci / Q000302:isolation & purification*; D037521:Virulence Factors / Q000235:genetics
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D006020:Glycopeptides; C071437:VanA ligase, Bacteria; D037521:Virulence Factors; D019729:Carbon-Oxygen Ligases
Outbreaks; colonization pressure; vancomycin-resistant enterococci