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Generic and specific adaptative response of S. pneumoniae to challenge with three distinct antimicrobial peptides

ABSTRACT: To investigate the response of S. pneumoniae to three distinct antimicrobial peptides (AMPs), i.e. bacitracin, nisin and LL-37, transcriptome analysis of challenged bacteria was performed. Only a limited number of genes was found to be up- or down-regulated in all cases. Several of these common highly induced genes were chosen for further analysis, i.e. SP0385-0387, SP0912-0913, SP0785-0787, SP1714-1715 and the blp cluster. Deletion of these genes in combination with MIC determinations showed that several putative transporters, i.e. SP0785-0787 and SP0912-0913, were indeed involved in resistance to lincomycin, LL-37 and to bacitracin, nisin, lincomycin, respectively. Mutation of blp-bacteriocin production and its immunity genes resulted in an increased of sensitivity to LL-37. Interestingly, a putative ABC transporter (SP1715) protected against bacitracin and Hoechst 33342, but confered sensitivity to LL-37. A GntR-like regulator, SP1714, was identified as a negative regulator of itself and two of the putative transporters. In conclusion, we show that resistance to three different AMPs in S. pneumoniae is mediated by several putative ABC transporters, some of which have not been associated with antimicrobial resistance in this organism before. In addition, a GntR-like regulator was identified, which regulates two of these transporters. Our findings extend the undertstanding of defense mechanisms of this important human pathogen against antimicrobial compounds and points toward novel proteins, i.e. putative ABC transporters, which can be used as targets for the development of new antimicrobials.

ORGANISM(S): Streptococcus pneumoniae D39 Streptococcus pneumoniae

PROVIDER: GSE16491 | GEO | 2010/01/08

SECONDARY ACCESSION(S): PRJNA116009

REPOSITORIES: GEO

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