Potential of bacteriophages as disinfectants to control of Staphylococcus aureus biofilms

Abstract

Background Staphylococcus aureus is the causative agent of chronic mastitis, and can form a biofilm that is difficult to completely remove once formed. Disinfectants are effective against S. aureus, but their activity is easily affected by environmental factors and they are corrosive to equipment and chemically toxic to livestock and humans. Therefore, we investigated the potential utility of a bacteriophage as a narrow-spectrum disinfectant against biofilms formed by S. aureus. In this study, we isolated and characterized bacteriophage vB_SauM_SDQ (abbreviated to SDQ) to determine its efficacy in removing S. aureus biofilms. Results SDQ belongs to the family Myoviridae and consists of a hexagonal head, long neck, and short tail. This phage can sterilize a 109 CFU/mL culture of S. aureus in 12 h and multiply itself 1000-fold in that time. Biofilms formed on polystyrene, milk, and mammary-gland tissue were significantly reduced after SDQ treatment. Fluorescence microscopy and scanning electron microscopy showed that SDQ destroyed the biofilm structure. Moreover, the titer of SDQ remained relatively high after the lysis of the bacteria and the removal of the biofilm, exerting a continuous bacteriostatic effect. SDQ also retained its full activity under conditions that mimic common environments, i.e., in the presence of nonionic detergents, tap water, or organic materials. A nonionic detergent (Triton X-100) enhanced the removal of biofilm by SDQ. Conclusions Our results suggest that SDQ, a specific lytic S. aureus phage, can be used to control biofilm infections. SDQ maintains its full activity in the presence of nonionic detergents, tap water, metal chelators, and organic materials, and can be used in combination with detergents. We propose this phage as a narrow-spectrum disinfectant against S. aureus, to augment or supplement the use of broad-spectrum disinfectants in the prevention and control of the mastitis and dairy industry contamination caused by S. aureus.

Bacteriophage Treatment before Chemical Disinfection Can Enhance Removal of Plastic-Surface-Associated Pseudomonas aeruginosa

“…Zhang and Hu looked at the interactions of phage and sodium hypochlorite on the formation and removal of P. aeruginosa wet biofilms and reported synergistic effects in biofilm lysis ( 49 ). Another study found that adding Triton X-100 (a nonionic detergent) could enhance biofilm removal by an S. aureus phage, although it reached the same level of removal as that of phage alone after 48 h, as determined by OD measurements ( 48 ). However, the current study reports this interaction on wet biofilms thoroughly over a range of concentrations (difference of 9 orders of magnitude in MOIs), showing that significantly lower phage concentrations can be used in combination with a chemical disinfectant to achieve the same inactivation as that with higher phage concentrations alone.…”

“…In contrast, less attention has been given to the interplay of phages and chemical disinfectants for use in combination treatments. Previous research has looked at simultaneous treatment with phage and disinfectants, with varying success ( 45 – 48 ), likely due to the confounding of the two treatments by the inactivation of the phages by the disinfectants. Also, most studies have shortcomings in the thoroughness of testing of a range of concentrations and a small dynamic quantification range since they determine removal by crystal violet staining or optical density (OD) measurement ( 46 – 49 ), which limits the amount of inactivation that can be seen.…”

Bacterial Biofilm Destruction: A Focused Review On The Recent Use of Phage-Based Strategies With Other Antibiofilm Agents

“… 55 Numerous mono phages have been applied to significantly inhibit or decrease to minimum levels of viable bacteria cells in biofilms and in liquid cultures with no considerable toxicity to mammalian cells. Notable among them are biofilms formed by E. faecalis , 56 S. aureus 57 and E. coli , 58 all belonging to the ESKAPEE group. As revealed in these studies, anti-biofilm effects of lytic mono phages are concentration-dependent.…”

Prospects of bacteriophage collections in disinfectant applications

“…These preparations are active against various strains of Escherichia coli, Listeria monocytogenes, Salmonella spp., and Shigella spp. Some other preparations are being tested or under development [14][15][16]. Bacteriophages are viruses that selectively attack bacterial cells.…”