Bactericidal Activity and Synergy Studies of Peptide AP-CECT7121 Against Multi-resistant Bacteria Isolated from Human and Animal Soft Tissue Infections

Abstract

AP-CECT7121 is an antimicrobial peptide, produced by Enterococcus faecalis CECT7121, with bactericidal activity against Gram-positive bacteria. The aim of this study was to evaluate the bactericidal activity of AP-CECT7121, alone and with gentamicin, against multi-resistant bacteria isolated from human and animals with soft tissue infections. During the period 2014-2015, bacterial strains producing human and animal soft tissue infections were studied. Samples from patients attended at a general hospital and cattle from four dairies in the Province of Buenos Aires (Argentina) were included. Twenty-two methicillin-resistant Staphylococcus aureus (11, human blood samples; 11, cow milk) and five vancomycin-resistant Ent. faecium strains isolated from four mastitic dairy cows were tested. AP-CECT7121 (12 mg/L) potency was assessed by time-kill curves alone or with sub-inhibitory concentrations of gentamicin. All staphylococcal strains were susceptible to gentamicin; enterococci did not show high-level gentamicin resistance. Colony counts were carried out at 0, 2, 4, 8, and 24 h of incubation. AP-CECT7121 showed bactericidal activity against all the enterococcal strains. In addition, AP-CECT7121 had a bactericidal effect on most staphylococci (16/22). Early AP-CECT7121/gentamicin synergy (4-8 h) for all staphylococci was detected. At 24 h, synergy (19/22) and indifference (3/22) were observed. Synergy with gentamicin was detected for staphylococci. AP-CECT7121 constitutes an attractive candidate for its use as a natural therapeutic tool for the treatment of infections produced by multi-resistant Staph. aureus and vancomycin-resistant Ent. faecium isolated from humans and animals.

Impact on Public Health of the Spread of High-Level Resistance to Gentamicin and Vancomycin in Enterococci

“…The use of Gram-positive bacteriocins alone or in combination with antibiotics was proposed as a novel strategy to develop in human and veterinary medicines in order to help conventional antimicrobials against many multi-drug resistant pathogens. These combinations allow decreasing the MIC for achieving a bactericidal effect and, also, reduce undesirable side-effects of antibiotics (Lebel et al, 2013; Naghmouchi et al, 2013; Delpech et al, 2017). Randomized controlled trials are needed for obtaining scientific evidence about the usefulness of these novel compounds against pathogenic enterococci.…”

Challenge in the Discovery of New Drugs: Antimicrobial Peptides against WHO-List of Critical and High-Priority Bacteria

“…Delpech et al [ 104 ] evaluated the peptide AP-CECT7121 alone and combined with gentamicin against five clinical isolates of VRE, ampicillin, and tetracycline. The five (DF02–043, DF04–056, DF02–065, DF03–072, and DF03–078)-resistant strains were isolated from mastitic cows.…”

Draft Genome Sequence of Enterococcus faecalis Strain CECT7121, a Corn Silage Isolate with Antibacterial Activity against Gram-Positive Pathogens

“…Enterococcus faecalis CECT7121 (formerly MR99) is a probiotic strain isolated from Argentinean corn silage that has bactericidal activity against Gram-positive bacteria (1, 2). E.…”

“…E. faecalis CECT7121 was grown in brain heart infusion broth (Laboratorios Britania, Buenos Aires, Argentina) at 35 ± 2°C for 18 h (2), and genomic DNA isolation was performed as described by Brown et al (3).…”