Molecular Characterization of Vancomycin-resistant Enterococci from Clinical and Surveillance Specimens

BACKGROUND: Vancomycin-resistant enterococci(VRE) were first detected in Europe in 1986, and have been isolated from hospitalized patients worldwide. VanA resistance, characterized by high level resistance to vancomycin and teicoplanin, is the most prevalent in clinical enterococcal isolates. To target infection control, the molecular characteristics of clinical and intestinal enterococcal isolates recovered from hospitalized patients, was compared. Screening and structural analysis of enterococcal surface protein gene, esp, were also performed. METHOD: From January 2002 to May 2004, Thirty pairs of vanA-containing enterococci were collected from Ajou University Hospital(Ajou UH). Each of the pairs were intestinal and clinical isolates from the same patient. Fifteen vancomycin-susceptible enterococci(VSE) in clinical specimens and fifteen VRE isolated from chicken are also analyzed as a control. Multiplex PCR were performed to examine the presence of vanA, vanB, and vanC1/C2 genes. For structural analysis of Tn1546 PCR amplification of overlapping internal regions of Tn1546 was performed. To clarify insertion sequence(IS), genomic DNA of isolates were amplified with a combination of Tn1546-derived primer and IS primer. Pulsed-field gel electrophoresis(PFGE) of SmaI-digested genomic DNA was performed using CHEF-DRII device. The banding patterns were interpreted as described by Tenover et al. The presence of esp gene were determined by PCR for the N-terminal of esp gene. A and C repeat number variation of each esp gene also assessed by PCR. RESULT: Tn1546 pattern showed 4 types[I(prototype), II, III, IV]. All strains isolated from chicken represented type I. All clinical and intestinal VRE isolates belonged to type II, type III and type IV, which contained IS1542 and IS1216V. VRE isolates from the same patient were closely related in nineteen pairs. Five pairs of isolates were unrelated and represented different Tn1546 types in each pairs. Six pairs of isolates revealed identical Tn1546 type but were genetically unrelated in each pairs, suggesting horizontal spread of vanA gene. Twenty six of clinical VRE isolates(87%) and twenty five of intestianl VRE isolates(83%) harbored esp gene and ten of VSE(67%) also revealed the presence of esp gene. Only one chicken isolate(7%) harbored esp gene. CONCLUSION: Among nineteen pairs, the clinical and intestinal VRE isolates from same patients revealed genetically closely related and harbored identical Tn1546. They also agreed with the presence of esp gene. Therefore, patients colonized with VRE will continue to serve as a reservoir for the transmission of VRE. A regular VRE rectal surveillance program should be needed.

Author dc:creator

• 허, 지영

Contributors dc:contributor

• 이, 위교
• 대학원 의학과
• 103214

• VRE
• Tn1546
• vanA
• esp

Language dc:language

ko

Identifier

http://dcoll.ajou.ac.kr:9080/dcollection/jsp/common/DcLoOrgPer.jsp?sItemId=000000000382
000000000382

OAI identifier oai:identifier

oai:repository.ajou.ac.kr:201003/1492