Distribution of insertion sequences associated with Tn1546 and clonal diversity of vancomycin-resistant enterococci isolated from patients in Tehran, Iran
,
Abstract
Background and objectives: Infection with vancomycin-resistant enterococci (VRE) has caused a therapeutic problem. VanA and VanB resistant types are the predominant phenotypes among vancomycin resistant enetrococci. Transposon 1546 (Tn1546) harboring the vanA gene cluster, plays an important role in the horizontal transfer of vanA gene. In this study, we examined the phenotypic and genotypic diversity of a number of clinical VRE.
Materials and Methods: Twenty-four clinical VRE isolated from two university hospitals in Tehran were examined based on their antimicrobial susceptibility, Tn1546 related element organization and pulsed-field gel electrophoresis (PFGE) patterns. Integration of well-studied insertion sequence elements IS1216V, IS1542 and IS1251 was examined by PCR mapping and sequencing.
Results: From 24 isolates, 15 isolates with VanA phenotype and 9 isolates with VanB phenotype were identified which both groups interestingly possessed the vanA gene. According to PCR mapping, our isolates were assigned to 6 main groups. In 14 (58.3%) isolates, IS1216V was inserted in vanX-vanY region and/or in truncated left-hand of Tn1546-like elements. In 11 (45.8%) isolates, both IS1216V and IS1542 were inserted in vanX-vanY and orf2-vanR regions, respectively and none of them harbored IS1251. Interestingly, PFGE of the isolates showed a high degree of diversity.
Conclusion: PCR mapping revealed that VanA elements in our isolates were highly heterogeneous. Overall, we found no correlation between transposon type and PFGE pattern. Genetic diversity of VRE provides practical information for epidemiological studies and our data showed horizontal transfer of VRE in this region.
Mendez-Alvarez S, Perez-Hernaadez X, Claveria-Mar- tin F. Glycopeptide resistance in Enterococci. Internatl. Microbiol. 2000; 3: 71-80.
Oh JY, An S, Jin JS, Lee YC, Cho DT, Lee JC. Pheno- typic and genotypic differences of the vancomycin-re- sistant Enterococcus faecium isolates from humans and poultry in Korea. J. Microbiol. 2007; 45: 466-472.
Simjee S, White DG, McDermott PF, Wagner DD, Zervos MJ, Donabedian SM, et al. Characterization of Tn1546 in vancomycin-resistant enterococcus faecium isolated from canine urinary tract infections: evidence of gene exchange between human and animal entero- cocci. J. Clin. Microbiol. 2002; 40: 4659-4665.
Biavasco F, Foglia G, Paoletti GZ, Magi G, Guagli- anone E, Sundsfjord A, et al. VanA-type enterococci from humans, animals, and food: species distribution, population structure, Tn1546 typing and location, and virulence determinants. Appl. Environ. Microbiol. 2007;73: 3307-3319.
Henrique PM, Palazzo ICV, Zanella RC, Darini ALC.Molecular characterization of Enterococci harboring genotype and phenotype incongruence related to glyco- peptide resistance isolated ib Brazilian hospitals. Mem. Inst. Oswaldo. Cruz. 2008; 103: 301-305.
Gu L, Cao B, Liu Y, Guo P, Song S, Li R, et al. A new Tn1546 type of VanB phenotype-vanA genotype vancomycin-resistant Enterococcus faecium isolates in mainland China. Diagn. Microbiol. Infect. Dis. 2009;63: 70-75.
Dahl KH, Simonsen GS, Olsvik Ø, Sundffjord A. Het- erogeneity in the vanB gene cluster of genomically di- verse clinical strains of vancomycin-resistant Enterococci. Antimicrob. Agents Chemother. 1999; 43: 1105-1110.
Guardabassi L, Dalsgaard A. Occurrence, structure, and mobility of Tn1546-like element in environmental iso- lates of vancomycin-resistant Enterococci. Appl. Envi- ron. Microbiol. 2004; 70: 984-990.
Naas T, Fortineau N, Snanoudj R, Spicq C, Durrbach A, Nordmann P. First nosocomial outbreak of vancomycin- resistant enterococcus faecium expressing a vanD-like phenotype associated with a vanA genotype. J. Clin. Mi- crobiol. 2005; 43: 3642-3649.
Camargo ILBC, Del Peloso PF, Da Costa Leite CF, Goldman GH, Darini ALC. Identification of an unusual VanA element in glycopeptides-resistant Enterococ- cus faecium in Brazil following international transfer of a bone marrow transplant patient. Can. J. Microbiol.2004; 50: 767-770.
Park IJ, Lee WG, Shin JH, Lee KW, Woo GJ. VanB phenotype-vanA genotype Enterococcus faecium with heterogeneous expression of teicoplanin resistance. J. Clin. Microbiol. 2008; 46: 3091-3093.
Jung WK, Hong SK, Koo HC, Kwon NH, Park Y.H.Nucleotide sequence of IS1678, an insertion sequence in the vanA cluster of enterococci. Antimicrob. Agents Chemother. 2005; 49: 1666-1667.
Jensen LB, Ahrns P, Dons L, Jones RN, Hammerum AM, Aarestrup FM. Molecular analysis of Tn1546 in Enterococcus faecium isolated from animals and hu- mans. J. Clin. Microbiol. 1998; 36: 437-442.
Huh JY, Lee WG, Lee K, Shin WS, Yoo JH. Distribu- tion of insertion sequences associated with Tn1546-like elements among Enterococcus faecium isolates from pa- tients in Korea. J. Clin. Microbiol. 2004; 42: 1897-1902.
Donabedian S, Hershberger E, Thal LA, Chow JW, Clewell DB, Robinson-Dunn B, et al. PCR fragment length polymorphism analysis of vancomycin-resistant Enterococcus faecium. J. Clin. Microbiol. 2000; 38:2885-2888.
Novais C, Coque TM, Sousa JC, Baquero F, Peixe L, and The portuguese resistance study group. Local ge- netic patterns within a vancomycin-resistant enterococ- cus faecalis clone isolated in three hospitals in Portugal. Antimicrob. Agents Chemother. 2004; 48: 3613-3617.
Novais C, Sousa JC, Coque TM, Peixe L, and The por- tuguese resistance study group. Molecular character- ization of glycopeptide-resistant Eterococcus faecium isolates from Portuguese hospitals. Antimicrob. Agents Chemother. 2005; 49: 3073-3079.
Manero A, Blanch AR. Identification of Enterococcus spp. with a biochemical key. Appl. Environ. Microbiol.1999; 65: 4425-4430.
Clinical and Laboratory Standards Institute. Perfor- mance standards for antimicrobial susceptibility testing,16th informational supplement, M100-S16. Clinical and Laboratory Standards Institute, Wayne, Pa, USA. 2006.
McEllistrem MC, Stout JE, Harrison LH. Simplified protocol for Pulsed-Field Gel Electrophoresis analysis of Streptococcus pneumonia. J. Clin. Microbiol. 2000;38(1): 351-353.
Jung WK, Hong SK, Lim JY, Lim SK, Kwon NH, Kim JM, et al. Phenotypic and genetic characterization of vancomycin-resistant enterococci from hospitalized hu- mans and from poultry in Korea. FEMS Microbiol. Lett.2006; 260: 193-200.
Busani L, Grosso MD, Paladini C, Graziani C, Pantosti A, Biavasco F, et al. Antimicrobial susceptibility of van- comycin-susceptible and –resistant enterococci isolated in Italy from raw meat products, farm animals, and human infections. Int. J. Food Microbiol. 2004; 97: 17-22.
Ko KS, Baek JJ, Lee J, Oh WS, Peck KR, Lee NY, et al. Molecular characterization of vancomycin-resistant Enterococcus faecium isolates from Korea. J Clin Mi- crobiol. 2005; 43: 2303-2306.
Willems RJL., Top J, Braak NVD, Belkum AV, Mevius DJ, Hendriks G, et al. Molecular diversity and evolu- tionary relationships of Tn1546-like elements in entero- cocci from humans and animals. Antimicrob. Agents Chemother. 1999; 43: 483-491.
Woodford N, Adebiyi AA, Palepou MI, Cookson BD.Diversity of VanA glycopeptide resistance elements in enterococci from humans and nonhuman sources. Anti- microb. Agents Chemother. 1998; 42: 502-508.
Miele A, Bandera M, Goldstein BP. Use of primers se- lective for vancomycin resistance gene to determine van genotype in enterococci and to study gene organization in VanA isolates. Antimicrob. Agents Chemother. 1995;39: 1772-1778.
Yu H, Seol S, Cho D. Diversity of Tn1546-like elements in vancomycin-resistant enterococci isolated from hu- mans and poultry in Korea. J. Clin. Microbiol. 2003; 41:2641-2643.
| Files | ||
| Issue | Vol 2 No 1 (2010) | |
| Section | Articles | |
| Keywords | ||
| Vancomycin- resistant enterococci Tn1546 insertion sequences Iran | ||
| Rights and permissions | |
|
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
