Isolation, Characterization, and Comparison of Efficiencies of Bacteriophages to Reduce Planktonic and Biofilm-Associated Staphylococcus aureus

Abstract

Introduction In the present era, wherein occurrence of antimicrobial resistance compounded with biofilms in disease conditions has rendered present antibiotic therapy ineffective, the need for alternative strategies to treat bacterial infections has brought bacteriophages to the forefront. The antimicrobial activity of phages is often determined by a viable cell reduction assay which focuses only on planktonic forms. The physiology of an organism in biofilm differs from those that are planktonic; hence, there is a need to evaluate the activity of phages both on planktonic forms, as well as on biofilms, to select candidate therapeutic phages. Methods Bacteriophages for Staphylococcus aureus were isolated from environmental samples and characterized based on growth kinetics and DNA fingerprint patterns. Activity of isolated phages on planktonic forms was determined by viable count reduction assay. Phage ability to prevent biofilm formation and ability to disperse formed biofilms were performed in 96-well microtiter plates and biofilm estimated by crystal violet assay. Results Four bacteriophages designated, that is, P3, PD1, PE1, and PE2, were isolated and characterized. Planktonic cells of S. aureus were found to be sensitive to phages PD1, PE1, and PE2. Phages PD1 and PE2 were efficient in preventing biofilm formation and phages PD1, PE1, and P3 were efficient in dispersing formed biofilms. Conclusion The ability of some phages to disperse biofilms effectively, while unable to show the same efficiency on planktonic cells, indicates that viable count reduction assay alone may not be a sufficient tool to imply bactericidal activity of bacteriophages, especially while trying to eradicate biofilms.

Understanding bacterial biofilms: From definition to treatment strategies

“…Novel phage F 15 produces a polysaccharide depolymerase that hydrolyzes the EPS of a single species of single-species Pseudomonas putida and inhibits biofilm formation (Cornelissen et al, 2011). Rai et al (2020) used CV staining to determine the biofilm content. They found that phage PD1 and PE2 could effectively prevent the formation of S. aureus biofilms, while PD1, PE1, and P3 could disperse mature biofilms.…”

“…Novel phage Φ 15 produces a polysaccharide depolymerase that hydrolyzes the EPS of a single species of single-species Pseudomonas putida and inhibits biofilm formation ( Cornelissen et al., 2011 ). Rai et al. (2020) used CV staining to determine the biofilm content.…”

Comparison of Antibiofilm Activity of Pseudomonas aeruginosa Phages on Isolates from Wounds of Diabetic and Non-Diabetic Patients

“…However, reports of phages have shown promising results in vitro but failed to deliver the same in vivo. This difference is because phage efficacy is often tested only on planktonic cells, but in vivo, organisms form biofilms that provide better survival [ 13 , 14 ]. The ability of P. aeruginosa to form biofilms correlates with its ability to impair the healing of diabetic wounds [ 15 ].…”

New Research Areas in Clinical Microbiology

“…Three 1 2 3 have some diagnostic care component and the subject of the other three is the laboratory diagnosis of COVID-19. 4 5 6 Since JHAS-NU began in 2016, there have been 2 publications on biofilms, 7 8 3 publications on the microbiome, 9 10 11 2 publications on nanotechnology, 12 13 and 1 publication on probiotics. 14…”