title: Evidence for tetracycline resistance determinant tet(M) allele replacement in a Streptococcus pneumoniae population of limited geographical origin.
abstract: A collection of 185 Streptococcus pneumoniae isolates was tested for their susceptibility to antipneumococcal drugs, with a focus on the distribution of tetracycline resistance determinants tet(M) and tet(O). Resistance patterns were compared with established correlates of multidrug resistance, and tetracycline-resistant isolates were tested for clonality and allelic variation within tet(M). Resistance to tetracyclines, penicillins and macrolides were all strongly related to multidrug resistance. Over one-quarter of the strains were tetracycline resistant, all via the tet(M)-mediated mechanism. Restriction fragment length polymorphism analysis revealed a high degree of allelic variation within tet(M) and gave evidence of a clonal and horizontal spread of selected alleles. A tet(M) variant that emerged with the onset of epidemic multidrug-resistant strains was replacing old alleles in the population.
authors.affiliation: Department of Clinical Microbiology and Immunology, Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-736 Warszawa, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Dzierzanowska-Fangrat
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Semczuk
authors.forename: Paulina
authors.initials: P
authors.lastname: Górska
authors.forename: Stefania
authors.initials: S
authors.lastname: Giedrys-Kalemba
authors.forename: Maria
authors.initials: M
authors.lastname: Kochman
authors.forename: Alfred
authors.initials: A
authors.lastname: Samet
authors.forename: Stefan
authors.initials: S
authors.lastname: Tyski
authors.forename: Danuta
authors.initials: D
authors.lastname: Dzierzanowska
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Trzciński
mesh_terms: D000483:Alleles; D005798:Genes, Bacterial; D006801:Humans; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000382:microbiology; D011044:Poland; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D013753:Tetracycline Resistance / Q000235:genetics*