Genomic analyses of two novel biofilm-degrading methicillin-resistant Staphylococcus aureus phages

Abstract

Background Methicillin-resistant Staphylococcus aureus (MRSA) biofilm producers represent an important etiological agent of many chronic human infections. Antibiotics and host immune responses are largely ineffective against bacteria within biofilms. Alternative actions and novel antimicrobials should be considered. In this context, the use of phages to destroy MRSA biofilms presents an innovative alternative mechanism. Results Twenty-five MRSA biofilm producers were used as substrates to isolate MRSA-specific phages. Despite the difficulties in obtaining an isolate of this phage, two phages (UPMK_1 and UPMK_2) were isolated. Both phages varied in their ability to produce halos around their plaques, host infectivity, one-step growth curves, and electron microscopy features. Furthermore, both phages demonstrated antagonistic infectivity on planktonic cultures. This was validated in an in vitro static biofilm assay (in microtiter-plates), followed by the visualization of the biofilm architecture in situ via confocal laser scanning microscopy before and after phage infection, and further supported by phages genome analysis. The UPMK_1 genome comprised 152,788 bp coding for 155 putative open reading frames (ORFs), and its genome characteristics were between the Myoviridae and Siphoviridae family, though the morphological features confined it more to the Siphoviridae family. The UPMK_2 has 40,955 bp with 62 putative ORFs; morphologically, it presented the features of the Podoviridae though its genome did not show similarity with any of the S. aureus in the Podoviridae family. Both phages possess lytic enzymes that were associated with a high ability to degrade biofilms as shown in the microtiter plate and CLSM analyses. Conclusions The present work addressed the possibility of using phages as potential biocontrol agents for biofilm-producing MRSA. Electronic supplementary material The online version of this article (10.1186/s12866-019-1484-9) contains supplementary material, which is available to authorized users.

Characterization of Salmonella Phage LPST153 That Effectively Targets Most Prevalent Salmonella Serovars

“…It was confirmed that each single phage LPST153 could produce one relatively large and clear plaque (diameter, 3.2 ± 0.2 mm) with a halo zone (diameter, 8.5 ± 0.4 mm) within 24 h. However, LPST89 created smaller plaques than LPST153 (0.5 to 1.0 mm in diameter) which remained approximately the same size after 24 h of incubation. It is believed that phenotype of halo zone is an indication of the ability to depolymerize exopolysaccharide and biofilm [ 50 ]. LPST153 with halo zone ( Figure 1 B) was chosen for further study.…”

The Protective Effect of Staphylococcus epidermidis Biofilm Matrix against Phage Predation

“…In contrast to temperate phages, strictly virulent phages do not integrate their nucleic acids into the host chromosome, so their use for therapeutic purposes has been described as harmless to humans and animals [ 26 , 27 ]. Indeed, successful results have already been observed for the treatment of Staphylococcus aureus biofilm-associated infections [ 28 , 29 ]. However, only few studies have addressed the efficacy of S. epidermidis phages against biofilms [ 30 ].…”

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

“…Recent studies on use of S. aureus phages have focused on the need for the ability of phages to disperse biofilms. [7][8][9][10][11][12][13][14] Studies that have looked at deciphering the reasons for phage therapy failure in experimental animals, wherein in vitro results were very promising and have suggested that absence of depolymerase may result in inability of phages to disrupt biofilms. 29 In the present study, planktonic cells of S. aureus were sensitive to phages PD1, PE1, and PE2.…”

“…The ability of phages and phage-derived proteins to remove S. aureus in clinical models has been lower compared with planktonic forms as tested in vitro. [8][9][10][11][12][13][14] More than 80% human infections caused by bacteria, infections are manifested by growth of the organism in biofilms. 15 The physiology of an organism in biofilm differs from those that are planktonic, 16 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.…”