Novel Peptides Targeting the β-Clamp Rapidly Kill Planktonic and Biofilm Staphylococcus epidermidis Both in vitro and in vivo

Abstract

Antimicrobial resistance is an increasing threat to global health and challenges the way we treat infections. Peptides containing the PCNA interacting motif APIM (APIM-peptides) were recently shown to bind to the bacterial PCNA homolog, the beta (β)-clamp, and to have both antibacterial and anti-mutagenic activities. In this study we explore the antibacterial effects of these peptides on Staphylococcus epidermidis, a bacterial species commonly found in prosthetic joint infections (PJI). Drug-resistant bacterial isolates from PJIs often lead to difficult-to-treat chronic infections. We show that APIM-peptides have a rapid bactericidal effect which when used at sublethal levels also increase the efficacy of gentamicin. In addition, APIM-peptides reduce development and eliminate already existing S. epidermidis biofilm. To study the potential use of APIM-peptides to prevent PJI, we used an in vivo bone graft model in rats where APIM-peptide, gentamicin, or a combination of the two was added to cement. The bone grafts containing cement with the combination was more effective than cement containing only gentamicin, which is the current standard of care. In summary, these results suggest that APIM-peptides can be a promising new drug candidate for anti-infective implant materials to use in the fight against resistant bacteria and chronic PJI.

Broad-Spectrum Antibacterial Peptide Kills Extracellular and Intracellular Bacteria Without Affecting Epithelialization

“…Therefore, MICs for betatide are much lower than doses that affect mammalian cells. APIM-peptides kill bacteria rapidly, i.e., 1× MIC leads to 97% killing within 5 min (Raeder et al, 2021); thus, the short serum half-life of 15-30 min in humans found for the similar anticancer APIMpeptide ATX-101 (Lemech et al, 2021) may therefore be sufficient for good antibacterial in vivo activity. Short serum half-life may rather be an advantage as this lowers the chances of developing immunogenicity and affecting the normal microbiota if given intravenously and/or topically.…”

“…Long-time exposure to sub-MIC levels of antibiotics are known to increase TLS and induce resistance development (Kreuzer, 2013;Raeder et al, 2021). To directly examine the resistance development against betatide, we exposed E. coli and S. aureus (both MDR and reference strain) to sub-MIC and 1×-2× MIC levels of betatide through serial passage and measured MIC over 20-30 days.…”

“…This antibacterial property was mainly due to their ability to bind to the bacterial β-clamp via their APIM sequence, thereby inhibiting bacterial DNA replication and TLS. This killed the bacteria or, at sublethal concentrations, reduced their ability to develop resistance against other antibiotics if used in combination treatments (Nedal et al, 2020;Raeder et al, 2021). The APIM-peptide variant ATX-101, which is under development as an anticancer drug, was shown to have a favorable toxicity profile in a recent Phase I study (Lemech et al, 2021).…”

Activation of multiple stress responses in Staphylococcus aureus substantially lowers the minimal inhibitory concentration when combining two novel antibiotic drug candidates

“…The lead antibacterial APIM-peptide, BTP-001 (β-clamp targeting peptide-001), is rapidly bactericidal in several bacterial species, including the ESKAPE pathogens, at doses that do not affect epithelization ( Nepal et al, 2021 ). Biofilm studies demonstrated that BTP-001 eradicates existing biofilms and prevents biofilm formation in Staphylococcus epidermidis , and that it showed promise for use in bone cement to prevent prosthetic joint infection ( Raeder et al, 2021 ). In addition, a recent study showed a strong additive effect of BTP-001 combined with a brominated pyrrolopyrimidine called JK-274 in Staphylococcus aureus ( Olsen et al, 2022 ).…”

Expression of Anti-Lipopolysaccharide Factor Isoform 3 in Chlamydomonas reinhardtii Showing High Antimicrobial Activity

“…AMPs are peptides consisting of 5-300 amino acids and are widely distributed in various organisms [6][7][8][9]. In general, AMPs own a broad-spectrum antimicrobial activity [10,11], anti-cancer cell activity [12,13], and antiviral activity [14]. As one of the known AMPs, anti-lipopolysaccharide factors (ALFs) were firstly identified from the hemocytes of Limulus polyphemus [15].…”