Investigation of Risk Factors for Vancomycin-Resistant Enterococci(VRE) Infection and Colonization / 대한임상병리학회지

BACKGROUND: The emergence of vancomycin-resistant enterococci(VRE) is increasingly serious problem throughout the world and is likely to increase in Korea. However, a few epidemiologic studies and risk factors of VRE infection have been reported in Korea. We investigated risk factors for VRE infection and colonization. METHODS: We analyzed 48 patients with VRE(24 infection, 24 fecal colonization) and 62 vancomycin-sensitive enterococci(VSE) in Ewha Womans university hospital from January 1997 to December 1998 and we performed case-control study to assess the risk factors for VRE. RESULTS: The incidence of VRE infection was 7.3% of all enterococcal isolates and the incidence of VRE colonization from surveillance cultures was increased 0.1% to 1.5% from 1997 to 1998. Compared with patients with VSE, patients with VRE had significantly longer hospital stays. They also had more frequent stays in intensive care unit(ICU) and oncology wards. They had more frequent invasive procedures such as central lines, urinary catheters, nasogastric tubes, ventilators and were more likely to have received vancomycin or teicoplanin or aztreonam or aminoglycosides or cephalosporins therapy(P<0.05). Compared with the patients infected with VRE, the patients colonized with VRE had significantly more frequent stays in the ICU(P <0.05). CONCLUSIONS: To prevent the VRE infection and colonization, appropriate antibiotic therapy according to the guidelines and cautious handling of medical devices may be necessary.

Investigation of Prevalence of Vancomycin-resistant Enterococci and Genotypes of Glycopeptide Resistance Using Polymerase Chain Reaction / 대한임상병리학회지

BACKGROUND: Enterococci are a leading cause of nosocomial infection and the emergence of resistant strain to various antibiotics including vancomycin is increasingly serious problems among enterococci. And the risk of spread of glycopeptide genes to other Gram-positive cocci makes the problems more serious. To evaluate the presence of vancomycin-resistant enterococci (VRE) in Ewha Womans University Hospital (EWUH), we screened hospitalized patients for fecal colonization and clinical isolates. METHODS: We screened VRE in 574 stool specimens requested for routine cultures and 91 perirectal swabs or stool specimens from patients who reside in intensive care unit and hemato-oncologic ward in Mookdong and Tongdaemoon EWUH from December 1996 through April 1997. And 295 enterococcal species isolated from various clinical specimens were also included. To detect VRE, specimens were cultured in BHI agar medium including 6 g/mL of vancomycin and to determine the antibiotic susceptibility pattern, broth microdilution test using VITEK GPS-IZ, disk diffusion test and standard agar dilution test were performed. Multiplex PCR was done to determine the genotypes of VRE. RESULTS: Nine enterococci (0.9%) were interpreted as VRE in standard agar dilution method. Two (0.3%) out of 665 were from stool speciemens for surveillence cuture and 7 (2.3%) out of 295 were from various clinical specimens for ordinary cultures including 5 E. casseliflavus, 2 E. gallinarum, 1 E. flavescens and 1 Enterococcus species. All isolates showed low-level resistance against vancomycin (8-16 g/mL) by standard agar dilution. But both disk diffusion method and VITEK system demonstrated difficulties in detecting low-level resistance. The genotypes of VRE were classified as van C-1 in 2 isolates and as van C-2 in 6 isolates except 1 isolates, which was unclassifiable in our study. CONCLUSIONS: Even though VRE with high- or medium-level resistance against glycopeptide was not detected in EWUH from this period of investigation, the possibility of presence of VRE is impanding because several teaching hospitals already reported the presence of VRE in clinical isolates and fecal colonization. So continuous surveillence and strict infection control measures must be implemented to detect and prevent transmission of VRE infection.