Research Article Resistance Determinants and Their Association with Different Transposons in the Antibiotic-Resistant Streptococcus pneumoniae Izabela Korona-Glowniak, Radoslaw Siwiec, and Anna Malm Department of Pharmaceutical Microbiology, Medical University of Lublin, Chodzki 1, 20-093 Lublin, Poland Correspondence should be addressed to Izabela Korona-Glowniak; iza.glowniak@umlub.pl Received 22 December 2014; Revised 16 March 2015; Accepted 16 March 2015 Academic Editor: Henny C. van der Mei Copyright © 2015 Izabela Korona-Glowniak et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Multiple resistance of Streptococcus pneumoniae is generally associated with their unique recombination-mediated genetic plasticity and possessing the mobile genetic elements. he aim of our study was to detect antibiotic resistance determinants and conjugative transposons in 138 antibiotic-resistant pneumococcal strains isolated from nasopharynx of healthy young children from Lublin, Poland. hese strains resistant to tetracycline and/or to chloramphenicol/erythromycin/clindamycin were tested by PCR using the speciic genes as markers. he presence of Tn916 family transposons, carrying tet(M) and int/xisTn916, was observed in all of the tested strains. Tn916 was detected in 16 strains resistant only to tetracycline. Tn6002 and Tn3872-related element were found among 99 erm(B)-carrying strains (83.8% and 3.0%, resp.). Eight strains harbouring mef (E) and erm(B) genes were detected, suggesting the presence of Tn2010 and Tn2017 transposons. Among 101 chloramphenicol-resistant strains, two variants of Tn5252-related transposon were distinguished depending on the presence of int/xis5252 genes speciic for cat gene-containing Tn5252 (75.2% of strains) or  Sp23FST81 gene, speciic for cat-containing ICESp23FST81 element (24.8% of strains). In 6 strains Tn916-like and Tn5252- like elements formed a Tn5253-like structure. Besides clonal dissemination of resistant strains of pneumococci in the population, horizontal transfer of conjugative transposons is an important factor of the high prevalence of antibiotic resistance. 1. Introduction Antimicrobial resistance among Streptococcus pneumoniae has spread worldwide and it causes higher risk of treat- ment failure in pneumococcal infections. S. pneumoniae is an important human pathogen associated with respiratory tract infections, bacteriemia, and meningitis. Primarily as a commensal, the pneumococcus colonizes the nasopharynx of 10–20% of healthy adults and 40–77% of healthy children [1]. Nasopharyngeal carriage in healthy children is a major factor in the horizontal transmission of pneumococcal strains, espe- cially between children attending day care centers (DCCs) or to other family members, and may be also the source of infection in other individuals. Moreover, pneumococcal nasopharyngeal isolates relect the strains currently circulat- ing in the community [1, 2]. Multiple resistance of pneumococci especially resistance to macrolides and tetracyclines as well as to chloramphenicol is generally associated with their unique recombination- mediated genetic plasticity and possessing the mobile genetic elements [3, 4]. Two major mechanisms of macrolide resis- tance in S. pneumoniae are noted. he irst one is target site modiication by a ribosome methylase, encoded by erm(B) gene and related to high-level resistance to macrolide, lin- cosamides, and streptogramin B (MLS B phenotype). Erm(B) resistance can be expressed by pneumococci either constitu- tively (cMLS B phenotype) or inducibly (iMLS B phenotype) [5]. he majority of macrolide-resistant S. pneumoniae strains are also resistant to tetracycline. his association is due to the insertion of erm(B) into conjugative and composite transposons of the Tn916 family that harbours tet(M) gene, encoding ribosome protection proteins. Members of this Hindawi Publishing Corporation BioMed Research International Volume 2015, Article ID 836496, 6 pages http://dx.doi.org/10.1155/2015/836496