Rectal Surveillance Culture of Vancomycin-Resistant Enterococci in Hospitalized Patients at Hematology-Oncology Unit / 감염과화학요법

BACKGROUND: Vancomycin-resistant enterococci (VRE) have emerged as important pathogens among hospitalized patients. We evaluated the prevalence of rectal VRE colonization at hematology-oncology unit and the correlation between VRE colonization and infection. MATERIALS & METHODS: All VRE isolates were obtained from rectal swabs and clinical samples of the patients hospitalized over 14-month period at hematology-oncology unit in St. Mary's Hospital. The agar screening test was performed by using 6 microgram/ml of vancomycin in brain heart infusion agar with 106 CFU inoculum. During this period, the environmental surveillance culture was performed in 4 hospital rooms. Species identification of VRE was done by Microscan and MICs to vancomycin. Identification and genotyping of VRE pattern were confirmed by multiplex PCR. RESULTS: Rectal colonization rate was 50.9% (230 among 452 patients). The most common isolate was E. faecium (72.4%) followed by E. faecalis (24.1%), and all had vanA genotype. Four VREs (three E. faecium and one E. faecalis) were isolated from 2 hospital rooms. During this period, 33 clinical VRE strains from 32 patients were isolated (infected or colonized). Twenty nine (90.6%) of these clinical isolates came from VRE carriers. CONCLUSION: This study showed a high rectal colonization rate of VRE in patients hospitalized at the hematology-oncology unit in St. Mary's Hospital. The colonization rate of VRE in the rectum was higher among the patients who had clinical infection by VRE. Therefore, the strategies for prevention and control of VRE infection should be deveoloped and monitored.

Rectal Surveillance Culture of Vancomycin-Resistant Enterococci in Hospitalized Patients at Hematology-Oncology Unit / 감염과화학요법

BACKGROUND: Vancomycin-resistant enterococci (VRE) have emerged as important pathogens among hospitalized patients. We evaluated the prevalence of rectal VRE colonization at hematology-oncology unit and the correlation between VRE colonization and infection. MATERIALS & METHODS: All VRE isolates were obtained from rectal swabs and clinical samples of the patients hospitalized over 14-month period at hematology-oncology unit in St. Mary's Hospital. The agar screening test was performed by using 6 microgram/ml of vancomycin in brain heart infusion agar with 106 CFU inoculum. During this period, the environmental surveillance culture was performed in 4 hospital rooms. Species identification of VRE was done by Microscan and MICs to vancomycin. Identification and genotyping of VRE pattern were confirmed by multiplex PCR. RESULTS: Rectal colonization rate was 50.9% (230 among 452 patients). The most common isolate was E. faecium (72.4%) followed by E. faecalis (24.1%), and all had vanA genotype. Four VREs (three E. faecium and one E. faecalis) were isolated from 2 hospital rooms. During this period, 33 clinical VRE strains from 32 patients were isolated (infected or colonized). Twenty nine (90.6%) of these clinical isolates came from VRE carriers. CONCLUSION: This study showed a high rectal colonization rate of VRE in patients hospitalized at the hematology-oncology unit in St. Mary's Hospital. The colonization rate of VRE in the rectum was higher among the patients who had clinical infection by VRE. Therefore, the strategies for prevention and control of VRE infection should be deveoloped and monitored.

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 / 감염

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.