Beta-Lactamase Repressor BlaI Modulates Staphylococcus aureus Cathelicidin Antimicrobial Peptide Resistance and Virulence.
Pence. Morgan A MA; Haste. Nina M NM; Meharena. Hiruy S HS; Olson. Joshua J; Gallo. Richard L RL; Nizet. Victor V; Kristian. Sascha A SA
Key Findings
- BlaI, known for controlling beta‑lactamase, also protects S. aureus from LL‑37 killing
- Removing or inhibiting BlaI (using sub‑inhibitory 6‑aminopenicillanic acid) sensitizes the bacteria to LL‑37
- BlaI contributes to bacterial virulence in human blood and mouse infection models
Practical Outcomes
- For biohackers, the research suggests that pairing LL‑37 with agents that inhibit BlaI (like low‑dose 6‑APA) could theoretically enhance antimicrobial effects against Staph infections. However, this is an early‑stage finding in lab and animal studies, so it isn’t yet a ready‑to‑use protocol for humans.
Summary
The study found that a bacterial protein called BlaI helps Staph aureus resist the natural antimicrobial peptide LL‑37, and that blocking BlaI with a low dose of a penicillin‑related compound makes the bacteria more vulnerable to LL‑37. This shows a possible way to boost the peptide’s killing power, but the work is still in bacteria and animal models, not in people.
Abstract
BlaI is a repressor of BlaZ, the beta-lactamase responsible for penicillin resistance in Staphylococcus aureus. Through screening a transposon library in S. aureus Newman for susceptibility to cathelicidin antimicrobial peptide, we discovered BlaI as a novel cathelicidin resistance factor. Additionally, through integrational mutagenesis in S. aureus Newman and MRSA Sanger 252 strains, we confirmed the role of BlaI in resistance to human and murine cathelidicin and showed that it contributes to virulence in human whole blood and murine infection models. We further demonstrated that BlaI could be a target for innate immune-based antimicrobial therapies; by removing BlaI through subinhibitory concentrations of 6-aminopenicillanic acid, we were able to sensitize S. aureus to LL-37 killing.
Study Information
pubmed
2015
2015-08-25T00:00:00.000Z
10.1371/journal.pone.0136605
27
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