title: Tn5253 family integrative and conjugative elements carrying mef(I) and catQ determinants in Streptococcus pneumoniae and Streptococcus pyogenes.
abstract: The linkage between the macrolide efflux gene mef(I) and the chloramphenicol inactivation gene catQ was first described in Streptococcus pneumoniae (strain Spn529), where the two genes are located in a module designated IQ element. Subsequently, two different defective IQ elements were detected in Streptococcus pyogenes (strains Spy029 and Spy005). The genetic elements carrying the three IQ elements were characterized, and all were found to be Tn5253 family integrative and conjugative elements (ICEs). The ICE from S. pneumoniae (ICESpn529IQ) was sequenced, whereas the ICEs from S. pyogenes (ICESpy029IQ and ICESpy005IQ, the first Tn5253-like ICEs reported in this species) were characterized by PCR mapping, partial sequencing, and restriction analysis. ICESpn529IQ and ICESpy029IQ were found to share the intSp 23FST81 integrase gene and an identical Tn916 fragment, whereas ICESpy005IQ has int5252 and lacks Tn916. All three ICEs were found to lack the linearized pC194 plasmid that is usually associated with Tn5253-like ICEs, and all displayed a single copy of a toxin-antitoxin operon that is typically contained in the direct repeats flanking the excisable pC194 region when this region is present. Two different insertion sites of the IQ elements were detected, one in ICESpn529IQ and ICESpy029IQ, and another in ICESpy005IQ. The chromosomal integration of the three ICEs was site specific, depending on the integrase (intSp 23FST81 or int5252). Only ICESpy005IQ was excised in circular form and transferred by conjugation. By transformation, mef(I) and catQ were cotransferred at a high frequency from S. pyogenes Spy005 and at very low frequencies from S. pneumoniae Spn529 and S. pyogenes Spy029.
authors: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy.
authors: Marina
authors: M
authors: Mingoia
authors: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy.
authors: Eleonora
authors: E
authors: Morici
authors: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy.
authors: Gianluca
authors: G
authors: Morroni
authors: Unit of Microbiology, Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy.
authors: Eleonora
authors: E
authors: Giovanetti
authors: Department of Infectious, Parasitic, and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors: Maria
authors: M
authors: Del Grosso
authors: Department of Infectious, Parasitic, and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
authors: Annalisa
authors: A
authors: Pantosti
authors: Unit of Microbiology, Department of Biomedical Sciences and Public Health, Polytechnic University of Marche Medical School, Ancona, Italy pe.varaldo@univpm.it.
authors: Pietro E
authors: PE
authors: Varaldo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D013297:Streptococcus pyogenes / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins