Cell-penetrating peptide and antibiotic combination therapy: a potential alternative to combat drug resistance in methicillin-resistant Staphylococcus aureus

Abstract

The diverse pattern of resistance by methicillin-resistant Staphylococcus aureus (MRSA) is the major obstacle in the treatment of its infections. The key reason of resistance is the poor membrane permeability of drug molecules. Over the last decade, cell-penetrating peptides (CPPs) have emerged as efficient drug delivery vehicles and have been exploited to improve the intracellular delivery of numerous therapeutic molecules in preclinical studies. Therefore, to overcome the drug resistance, we have investigated for the first time the effects of two CPPs (P3 and P8) in combination with four antibiotics (viz. oxacillin, erythromycin, norfloxacin, and vancomycin) against MRSA strains. We found that both CPPs internalized into the MRSA efficiently at very low concentration (<10 μM) which was non-toxic to bacteria as well as mammalian cells and showed no significant hemolytic activity. However, the combinations of CPPs (≤10 μM) and antibiotics showed high toxicity against MRSA as compared to antibiotics alone. The significant finding is that P3 and P8 could lower the MICs against oxacillin, norfloxacin, and vancomycin to susceptible levels (generally <1 μg/mL) for almost all five clinical isolates. Further, the bacterial cell death was confirmed by scanning electron microscopy as well as propidium iodide uptake assay. Simultaneously, time-kill kinetics revealed the increased uptake of antibiotics. In summary, CPPs assist to restore the effectiveness of antibiotics at much lower concentration, eliminate the antibiotic toxicity, and represent the CPP-antibiotic combination therapy as a potential novel weapon to combat MRSA infections.

Prediction of Cell-Penetrating Potential of Modified Peptides Containing Natural and Chemically Modified Residues

“…In the era of drug resistance, where pathogen membrane provides a significant barrier, intracellular delivery of antibiotics/drugs by the virtue of CPP, proved to be a vital step in combating drug resistance to some extent (Sparr et al, 2013 ). CPP based conjugates (Ganguly et al, 2008 ; Jain et al, 2015 ) and combination therapy has been explored against several resistant pathogens (Randhawa et al, 2016 ). They have been proved effective against intracellular pathogens too (Gomarasca et al, 2017 ).…”

Nematode Peptides with Host-Directed Anti-inflammatory Activity Rescue Caenorhabditis elegans from a Burkholderia pseudomallei Infection

“…We suggest that these peptides may be effective if used in combination with antibiotics in the eradication phase of melioidosis treatment at a point when the infected host immune response is strong enough to eliminate the non-replicating bacteria. Recently, Randhawa et al (2016) have elegantly demonstrated the potential of a cell-penetrating peptide in combination with antibiotic therapy to combat bacterial infection. The cell-penetrating ability and low toxicity of NLP-31 and Y43C5A.3 reported in this study proposes a similar combination of antibiotics and AMPs for melioidosis treatment.…”

Efflux pump inhibitory activity of flavonoids isolated from Alpinia calcarata against methicillin-resistant Staphylococcus aureus

“…Kaempferol at concentration 31.25 µg/mL was used along with EtBr to check accumulation. Finally, cells were mounted on poly-L-lysine coated slides with antifade reagent (Invitrogen, Molecular Probes) as described by Randhawa et al (2016). Then coverslip was sealed with the nail-paint and thereafter slide with cell suspension was kept inverted and focused from the bottom and took the pictures at appropriate magnification.…”