Dataset Information

Promoter Identification and Transcription Analysis of Penicillin-Binding Protein Genes in Streptococcus pneumoniae R6.

ABSTRACT: Penicillin-binding proteins (PBPs) are membrane-associated enzymes, which are involved in the last two steps of peptidoglycan biosynthesis, and some of them are key players in cell division. Furthermore, they are targets of ?-lactams, the most widely used antibiotics. Nevertheless, very little is known about the expression and regulation of PBP genes. Using transcriptional mapping, we now determined the promoter regions of PBP genes from the laboratory strain Streptococcus pneumoniae R6 and examined the expression profile of these six promoters. The extended -10 region is highly conserved and complies with a ?(A)-type promoter consensus sequence. In contrast, the -35 region is poorly conserved, indicating the possibility for differential PBP regulation. All PBP promoters were constitutively expressed and highly active during the exponential and early stationary growth phase. However, the individual expression of PBP promoters varied approximately fourfold, with pbp1a being the highest and pbp3 the lowest. Furthermore, the deletion of one nucleotide in the spacer region of the PBP3 promoter reduced pbp3 expression ?10-fold. The addition of cefotaxime above the minimal inhibitory concentration (MIC) did not affect PBP expression in the penicillin-sensitive R6 strain. No evidence for regulation of S. pneumoniae PBP genes was obtained.

SUBMITTER: Peters K

PROVIDER: S-EPMC5036317 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature

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Promoter Identification and Transcription Analysis of Penicillin-Binding Protein Genes in Streptococcus pneumoniae R6.

Peters Katharina K Pipo Julia J Schweizer Inga I Hakenbeck Regine R Denapaite Dalia D

Microbial drug resistance (Larchmont, N.Y.) 20160713 6

Penicillin-binding proteins (PBPs) are membrane-associated enzymes, which are involved in the last two steps of peptidoglycan biosynthesis, and some of them are key players in cell division. Furthermore, they are targets of β-lactams, the most widely used antibiotics. Nevertheless, very little is known about the expression and regulation of PBP genes. Using transcriptional mapping, we now determined the promoter regions of PBP genes from the laboratory strain Streptococcus pneumoniae R6 and exam ...[more]

PMID: 27409661

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Project description:Unlabelled?-Lactam antibiotics are the drugs of choice to treat pneumococcal infections. The spread of ?-lactam-resistant pneumococci is a major concern in choosing an effective therapy for patients. Systematically tracking ?-lactam resistance could benefit disease surveillance. Here we developed a classification system in which a pneumococcal isolate is assigned to a "PBP type" based on sequence signatures in the transpeptidase domains (TPDs) of the three critical penicillin-binding proteins (PBPs), PBP1a, PBP2b, and PBP2x. We identified 307 unique PBP types from 2,528 invasive pneumococcal isolates, which had known MICs to six ?-lactams based on broth microdilution. We found that increased ?-lactam MICs strongly correlated with PBP types containing divergent TPD sequences. The PBP type explained 94 to 99% of variation in MICs both before and after accounting for genomic backgrounds defined by multilocus sequence typing, indicating that genomic backgrounds made little independent contribution to ?-lactam MICs at the population level. We further developed and evaluated predictive models of MICs based on PBP type. Compared to microdilution MICs, MICs predicted by PBP type showed essential agreement (MICs agree within 1 dilution) of >98%, category agreement (interpretive results agree) of >94%, a major discrepancy (sensitive isolate predicted as resistant) rate of <3%, and a very major discrepancy (resistant isolate predicted as sensitive) rate of <2% for all six ?-lactams. Thus, the PBP transpeptidase signatures are robust indicators of MICs to different ?-lactam antibiotics in clinical pneumococcal isolates and serve as an accurate alternative to phenotypic susceptibility testing.ImportanceThe human pathogen Streptococcus pneumoniae is a leading cause of morbidity and mortality worldwide. ?-Lactam antibiotics such as penicillin and ceftriaxone are the drugs of choice to treat pneumococcal infections. Some pneumococcal strains have developed ?-lactam resistance through altering their penicillin-binding proteins (PBPs) and have become a major concern in choosing effective patient therapy. To systematically track and predict ?-lactam resistance, we obtained the sequence signatures of PBPs from a large collection of clinical pneumococcal isolates using whole-genome sequencing data and found that these "PBP types" were predictive of resistance levels. Our findings can benefit the current era of strain surveillance when whole-genome sequencing data often lacks detailed resistance information. Using PBP positions that we found are always substituted within highly resistant strains may lead to further refinements. Sequence-based predictions are accurate and may lead to the ability to extract critical resistance information from nonculturable clinical specimens.

Dataset Information

Promoter Identification and Transcription Analysis of Penicillin-Binding Protein Genes in Streptococcus pneumoniae R6.

Publications

Promoter Identification and Transcription Analysis of Penicillin-Binding Protein Genes in Streptococcus pneumoniae R6.

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