The proline-rich antimicrobial peptide B7-005: low bacterial resistance, safe for human cells and effective in zebrafish embryo bacteraemia model.

Proline-rich antimicrobial peptides (PrAMPs) have gained attention due to their antimicrobial properties and low cytotoxicity. B7-005, a small optimized PrAMP, exhibits a broader spectrum of activity than native PrAMPs, due to an antimicrobial mechanism based on inhibiting prokaryotic protein synthesis and destabilizing bacterial membranes. However, the toxicity and the efficacy of B7-005 remain poorly understood, so and microbiology and toxicology experiments were used to assess its suitability as an anti-infective agent.

Paenilamicins are context-specific translocation inhibitors of protein synthesis.

The paenilamicins are a group of hybrid nonribosomal peptide-polyketide compounds produced by the honey bee pathogen Paenibacillus larvae that display activity against Gram-positive pathogens, such as Staphylococcus aureus. While paenilamicins have been shown to inhibit protein synthesis, their mechanism of action has remained unclear. Here we determine structures of paenilamicin PamB2-stalled ribosomes, revealing a unique binding site on the small 30S subunit located between the A- and P-site transfer RNAs (tRNAs).

Serological responses to target Streptococcus pyogenes vaccine antigens in patients with proven invasive beta-haemolytic streptococcal infections.

Background: Rising incidence of invasive beta-haemolytic streptococcal (iBHS) infections has prompted consideration of vaccination as a preventative strategy for at-risk populations. The benefits of a vaccine targeting Lancefield group A (Streptococcus pyogenes; Strep A) would increase if cross-species immunity against Lancefield groups C/G (Streptococcus dysgalactiae subspecies equisimilis; SDSE) and B (Streptococcus agalactiae; GBS) was demonstrated.

Methods: A prospective, observational study of adult patients with iBHS infections due to Strep A, SDSE or GBS.

Serological Responses to Vaccine Candidate Antigens Suggests That Is the Predominant Cause of Lower Limb Cellulitis.

Background: A future (Strep A) vaccine will ideally prevent a significant burden of lower limb cellulitis; however, natural immune responses to proposed vaccine antigens following an episode of cellulitis remain uncharacterized.

Methods: We enrolled 63 patients with cellulitis and 26 with invasive beta hemolytic streptococci infection, using a multiplexed assay to measure immunoglobulin G against Strep A vaccine candidate antigens, including: streptolysin O (SLO), deoxyribonuclease B (DNB), group A carbohydrate (GAC), C5a peptidase (ScpA), cell envelope proteinase (SpyCEP), and adhesion and division protein (SpyAD). Responses in the invasive cohort were used to predict the infecting etiology in the cellulitis cohort.