Korean J Infect Dis.  2002 Oct;34(5):276-284.

Colonization Rate, Risk Factor for Acquisition and Genetic Diversity of Vancomycin-Resistant Enterococci (VRE) Isolated from Rectal Culture of Patients in Intensvie Care Units from Ten Large Hospitals in Korea

• Cheong HJ
• Song JY
• Eom JS
• Kim WJ
• Choi SJ
• Choi JH
• Lee H
• Chung MH
• Lee KM
• Shin DH
• Sohn BR
• Choi JS
• Woo HJ
• Kwon JA
• Lee KW
• Choe KW
• Park SC

Abstract

BACKGROUND: VRE have become an emerging nosocomial pathogen in Korea, but there has not been nationwide study on the colonization of VRE among high risk groups of hospitalized patients. The purpose of this study was to determine the prevalence of rectal colonization of VRE among patients hospitalized in the intensive care unit (ICU), to study the risk factors for nosocomial acquisition of VRE among those patients, to define the genetic diversity of VRE strains in major hospitals in Korea.
METHODS
Between January the 20th and 30th of 2000, a point surveillance study was conducted in the ICU of the ten large hospitals, which were located nationwide. Surveillance rectal swab cultures for detecting VRE were obtained among 214 patients admitted to the ICU during the study period. To isolate VRE, rectal swab cultures were performed on Enterococcosel(R) agar that containing 6 microgram/mL of vancomycin. Minimal inhibitory concentrations (MICs) of vancomycin and teicoplanin were determined by agar dilution method. For the genotyping of VRE isolates, the detection of vanA, vanB, vanC1 and vanC2 gene by polymerase chain reaction was done. Pulsed-field gel electrophoreis (PFGE) was used for elucidating the genetic relatedness of VRE isolates. To identify the risk factors for rectal VRE colonization, patients harboring VRE were compared to patients who were not colonized with this organism.
RESULTS
The rectal colonization rate of VRE was variable from 9.7% to 51.9% according to hospital. 64 VRE strains which were isolated from 63 patients included 37 E. feacium. 26 E. gallinarum and 1 E. casseliflavus isolates. Therefore the colonization rate of clinically significant vanA type VRE was 17.3% (37/ 214). 37 E. feacium. 26 E. gallinarum and 1 E. casseliflavus isolates were presented as vanA, vanC1 and vanC2 genotypes, respectively. Risk factors for rectal VRE colonization included the presence of chronic illness, previous use of broad spectrum antibioitcs es-pecillay vancomycin, and prolonged stay in ICU. Various PFGE patterns are noted among vanA type VRE isolates, so individual acquisition of VRE during stay in the majority of ICUs were suggested. But there is some evidence of focal VRE spread within the ICU and between hospitals.
CONCLUSION
This study demonstrated the high rectal colonization rate (17.3%) of clinically significant vanA type VRE among patients admitted to the ICUs of ten large hospitals located nation-widely. This study suggested that practicing HICPAC guidelines, restricted vancomycin usage and periodic surveillance cultures in patients with high risk factors are important in preventing the emergence and spread of VRE infection among ICU patients.

Keyword

Vancomycin-Resistant Enterococci; Rectal colonization; Intensive Care Unit; Rectal Surveillance

MeSH Terms

Agar
Chronic Disease
Colon*
Genetic Variation*
Genotype
Humans
Intensive Care Units
Korea*
Polymerase Chain Reaction
Prevalence
Risk Factors*
Teicoplanin
Vancomycin
Agar
Teicoplanin
Vancomycin