title: Potential of sequential treatment with minocycline and S. aureus specific phage lysin in eradication of MRSA biofilms: an in vitro study.
abstract: Lysins are novel class of anti-infectives which are derived from bacteriophage. In the present study, the potential of previously characterised phage borne endolysin MR-10 in eradicating methicillin-resistant Staphylococcus aureus (MRSA) biofilm was evaluated. Scanning electron microscopic examination showed that both ica-positive and ica-negative MRSA formed equally potent mature biofilm. Different approaches were employed to eradicate the young as well as older biofilm formed by both types of MRSA strains. Our results showed a significant decrease (p < 0.01) in biofilm count on sequentially treating the MRSA biofilm with minocycline (4 μg/ml) for 3 h followed by treatment with endolysin MR-10. Since endolysin can act effectively irrespective of the metabolic status of the cells hence, they are capable of killing the rapidly growing cells (log phase cells) as well as non-dividing (stationary phase) cells. As a result they are effective in eradicating the younger and older biofilm. On staining the ica-positive MRSA biofilm with wheat germ agglutinin (WGA)-Alexa Flour 350, reduction in poly-intercellular adhesion (PIA) content was observed in comparison to control biofilm. In addition, a significant decrease (p < 0.01) in extracellular DNA (eDNA) content of ica-negative MRSA biofilm was also observed. Further, Live/Dead Baclight™ staining also showed presence of higher population of dead cells after treatment with minocycline and endolysin MR-10. Hence, our results showed that using minocycline sequentially with endolysin, MR-10 can effectively eradicate both young as well as older biofilm formed by ica-positive and ica-negative MRSA.
authors.affiliation: Department of Microbiology, Panjab University, Chandigarh, 160014, India.
authors.forename: Shivani
authors.initials: S
authors.lastname: Chopra
authors.forename: Kusum
authors.initials: K
authors.lastname: Harjai
authors.forename: Sanjay
authors.initials: S
authors.lastname: Chhibber
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001435:Bacteriophages / Q000737:chemistry; D018441:Biofilms / Q000187:drug effects; D010450:Endopeptidases / Q000494:pharmacology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology; D008911:Minocycline / Q000494:pharmacology*
chemical_list: D018829:Adhesins, Bacterial; D000900:Anti-Bacterial Agents; D010450:Endopeptidases; C001143:endolysin; D008911:Minocycline