title: Alterations in MurM, a cell wall muropeptide branching enzyme, increase high-level penicillin and cephalosporin resistance in Streptococcus pneumoniae.
abstract: We report that alteration in MurM, an enzyme involved in the biosynthesis of branched-stem cell wall muropeptides, is required for maximal expression of penicillin and cefotaxime resistance in the pneumococcus. Hungarian isolate 3191 (penicillin MIC, 16 microg/ml; cefotaxime MIC, 4 microg/ml) was a source of donor DNA in transformation experiments. Penicillin-binding protein DNA was insufficient to transform recipient strain R6 to full resistance. Further transformation with altered murM DNA was required for full expression of donor penicillin and cefotaxime resistance.
authors.affiliation: Pneumococcal Diseases Research Unit, Department of Clinical Microbiology and Infectious Diseases, South African Institute for Medical Research, Johannesburg, South Africa. anthonys@mail.saimr.wits.ac.za
authors.forename: A M
authors.initials: AM
authors.lastname: Smith
authors.forename: K P
authors.initials: KP
authors.lastname: Klugman
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D018550:Cephalosporin Resistance / Q000235:genetics; D002511:Cephalosporins / Q000494:pharmacology; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010403:Penicillin Resistance / Q000235:genetics; D010406:Penicillins / Q000494:pharmacology; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D002511:Cephalosporins; D017931:DNA Primers; D004269:DNA, Bacterial; D010406:Penicillins; C408066:MurM protein, Streptococcus pneumoniae; D010453:Peptide Synthases