In Vitro Anti-Biofilm Activity of Bacteriophage K (ATCC 19685-B1) and Daptomycin against Staphylococci

Abstract

The purpose of the present study was to investigate anti-staphylococcal activity of daptomycin and bacteriophage K, alone or in combination, against biofilm-producers and non-producers S. aureus and S. epidermidis strains, under biofilm forming and cells’ proliferation conditions. Daptomycin and bacteriophage K (ATCC 19685B1), in different concentrations, were tested against 10 Staphylococcus aureus and 10 S. epidermidis, characterized by phenotypes and genotypes. The quantitative microtiter plate (crystal violet, CV), methylthiazoltetrazolium (MTT), and growth curve (GC) assays were performed. No statistically significant difference was found between species, whereas daptomycin alone performed better using medium and high concentrations of the drug and bacteriophage K was more active against strains with higher susceptibility, by CV and MTT assays. Best results were achieved using both agents combined in high concentrations. Bacteriophage K was effective within 3.8 and 2.4 h, depending on the concentration used, by the GC assay. Combination of daptomycin with bacteriophage K was more effective against staphylococci, depending on the concentrations used and strains’ susceptibility. Further studies are needed to evaluate if this approach might be a choice for prevention or therapy of biofilm-associated infections.

Moxifloxacin Liposomes: Effect of Liposome Preparation Method on Physicochemical Properties and Antimicrobial Activity against Staphylococcus epidermidis

“…Bacterial Growth rates were spectrophotometrically monitored [30,33] both in the presence and absence of different liposomal or drug solutions (MOX liposomes, empty liposomes, mixtures of free MOX, and empty liposomes or free MOX) at the MIC50 concentration of free MOX (0.15 µM). Briefly, overnight grown bacterial cells from a TSA agar plate were allowed to grow in fresh TSB broth (without glucose) to their early exponential phase.…”

“…The antibiofilm activity was evaluated at concentrations corresponding to the MIC of MOX, i.e., 0.3 µM, for all the formulations, according to previously reported methods [31][32][33]. Crystal violet (CV) staining and a validated MTT [3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide, a yellow tetrazole] cell viability assays were used to assess biofilm susceptibility to each free or liposomal MOX formulation.…”

Biofilms: Formation, Research Models, Potential Targets, and Methods for Prevention and Treatment

“…investigated the efficacy of daptomycin and bacteriophage K in killing S. aureus and S. epidermidis strains. [ 276 ] They noticed there were no dramatic disparities between species. However, daptomycin showed higher efficacy when using medium and high concentrations of the drug.…”

Daptomycin Liposomes Exhibit Enhanced Activity against Staphylococci Biofilms Compared to Free Drug

“…In one case, it has been reported that Dapto rapidly penetrates a Staphylococcus epidermidis biofilm [ 15 ]. It was also recently demonstrated in our laboratories that various Staphylococci strains showed lower MIC to Dapto, under biofilm-forming conditions, suggesting that Dapto is active in embedded cells [ 16 ]. Nevertheless, the development of some Dapto-insusceptible MRSA isolates has been reported [ 17 , 18 ], raising serious concerns and indicating the importance of developing novel strategies for antimicrobial therapeutics.…”

“…In this context, we investigate herein the development and optimization of liposomal Dapto and evaluate the antimicrobial activity of optimal Dapto-liposome types (compared to the free drug) against four Staphylococci strains. The strains were selected between 20 clinical isolates that were previously characterized and studied for their susceptibility towards Dapto; two strains were found to be less susceptible towards Dapto and two were more Dapto-susceptible; the three that were also methicillin-resistant were selected for use in the current study [ 16 ].…”