title: Diversity of putative Tn5253-like elements in Streptococcus pneumoniae.
abstract: Pneumococcal resistance to tetracycline, chloramphenicol, erythromycin and clindamycin is often attributed to carriage of conjugative transposons of the Tn916 family. The less well studied conjugative transposon Tn5253 is a composite transposon consisting of a Tn916-like element inserted within the unrelated Tn5252 element, which has also been associated with chloramphenicol and tetracycline resistance. Here, carriage of the Tn5252 integrase (int(5252)), Tn5252-encoded umuC and umuD homologues and Tn916 integrase (int(916)) was examined among 55 clinical isolates of Streptococcus pneumoniae resistant to one or more of the above mentioned antibiotics. Tn5253-associated genes were common among the antibiotic-resistant S. pneumoniae examined, including members of international clones, although the spectrum of genes and resistances carried was diverse. Analysis of five isolates demonstrated insertion of a Tn5253-related element at the same chromosomal locus but sequence and restriction site diversity. This study shows for the first time a high degree of variability of Tn5253-related elements within clinical isolates of pneumococci. The fact that these elements are prevalent among internationally recognised pandemic clones warrants a more intensive investigation.
authors.affiliation: School of Health and Biosciences, University of East London, London, UK. S.Henderson-Begg@uel.ac.uk
authors.forename: S K
authors.initials: SK
authors.lastname: Henderson-Begg
authors.forename: A P
authors.initials: AP
authors.lastname: Roberts
authors.forename: L M C
authors.initials: LM
authors.lastname: Hall
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics*; D024881:Drug Resistance, Bacterial; D023061:Gene Order; D005798:Genes, Bacterial; D019426:Integrases / Q000235:genetics; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D019426:Integrases