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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.

SUBMITTER: Smith AM

PROVIDER: S-EPMC90664 | biostudies-literature | 2001 Aug

REPOSITORIES: biostudies-literature

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Alterations in MurM, a cell wall muropeptide branching enzyme, increase high-level penicillin and cephalosporin resistance in Streptococcus pneumoniae.

Smith A M AM Klugman K P KP

Antimicrobial agents and chemotherapy 20010801 8

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 ...[more]

PMID: 11451707

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Inhibition of the expression of penicillin resistance in Streptococcus pneumoniae by inactivation of cell wall muropeptide branching genes.

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Project description:The increasing rate of penicillin resistance in S. pneumoniae in the early 1970s has resulted in therapeutic challenges and has prompted the need for alternative therapy in the management of pneumococcal infections. The development of penicillin resistance has been documented to be as a result of altered penicillin binding protein which alters the binding capacity of the drug to the organism. We used microarrays to investigate other genes which may be involved in the development of penicillin resistance in S. pneumoniae and identified classes of genes on the surface of the organism which may contribute to resistance. Strains of S. pneumoniae with varying initial susceptibility to penicillin were selected. These strains were grown to the logarithmic phase before being exposed to subinhibitory concentration of penicillin. RNA was extracted before and after penicillin stress and hybridized on Affymetrix microarrays and represented as either Untreated (before penicillin stress) or treated (after penicillin stress). This was carried out for 3 representative strains; S676, I81, and R98. S, I, and R abbreviates Sensitive, Intermediate and resistant to Penicillin.

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| S-EPMC7580930 | biostudies-literature

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