title: Penicillin-resistant viridans streptococci have obtained altered penicillin-binding protein genes from penicillin-resistant strains of Streptococcus pneumoniae.
abstract: Penicillin-resistant strains of Streptococcus pneumoniae possess altered forms of penicillin-binding proteins (PBPs) with decreased affinity for penicillin. The PBP2B genes of these strains have a mosaic structure, consisting of regions that are very similar to those in penicillin-sensitive strains, alternating with regions that are highly diverged. Penicillin-resistant strains of viridans groups streptococci (e.g., S. sanguis and S. oralis) that produce altered PBPs have also been reported. The PBP2B genes of two penicillin-resistant clinical isolates of S. sanguis were identical in sequence to the mosaic class B PBP2B genes found in penicillin-resistant serotype 23 strains of S. pneumoniae. Emergence of penicillin resistance appears to have occurred by the horizontal transfer of an altered PBP2B gene from penicillin-resistant S. pneumoniae into S. sanguis. The PBP2B genes of three penicillin-resistant S. oralis strains were similar to the mosaic class B PBP2B gene of penicillin-resistant strains of S. pneumoniae but possessed an additional block of diverged sequence. Penicillin resistance in S. oralis has also probably arisen by horizontal transfer of this variant form of the class B mosaic PBP2B gene from a penicillin-resistant strain of S. pneumoniae.
authors.affiliation: Microbial Genetics Group, School of Biological Sciences, Sussex University, Falmer, Brighton, United Kingdom.
authors.forename: C G
authors.initials: CG
authors.lastname: Dowson
authors.forename: A
authors.initials: A
authors.lastname: Hutchison
authors.forename: N
authors.initials: N
authors.lastname: Woodford
authors.forename: A P
authors.initials: AP
authors.lastname: Johnson
authors.forename: R C
authors.initials: RC
authors.lastname: George
authors.forename: B G
authors.initials: BG
authors.lastname: Spratt
mesh_terms: D000595:Amino Acid Sequence; D019881:Aminoacyltransferases; D001426:Bacterial Proteins; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D005798:Genes, Bacterial; D006004:Glycogen Debranching Enzyme System / Q000235:genetics; D006602:Hexosyltransferases; D008969:Molecular Sequence Data; D009030:Mosaicism; D002267:Muramoylpentapeptide Carboxypeptidase / Q000235:genetics*; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D010403:Penicillin Resistance / Q000235:genetics*; D046915:Penicillin-Binding Proteins; D010406:Penicillins / Q000378:metabolism; D010458:Peptidyl Transferases; D016133:Polymerase Chain Reaction; D013045:Species Specificity; D013291:Streptococcus / Q000235:genetics*; D013296:Streptococcus pneumoniae / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D006004:Glycogen Debranching Enzyme System; D015345:Oligonucleotide Probes; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D019881:Aminoacyltransferases; C478701:penicillin-binding protein 2b, Streptococcus; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; C020569:4 alpha-glucanotransferase; D002267:Muramoylpentapeptide Carboxypeptidase