Search

Staphylococcus aureus is amongst the most virulent pathogens, causing chronic and life-threatening human infections. Methicillin-resistant S. aureus (MRSA) are multidrug-resistant strains, and the ability of forming a biofilm reduces their sensitivity to antibiotics. Thus, the alternative compounds inhibiting both resistant strains and biofilm formation are in high demand. In our study, the strain FJKB0103 was isolated from the rhizosphere of Garcinia mangostana, showing strong anti-MRSA activity. We performed molecular phylogenic analysis, analyzed average nucleotide identity (ANI), in silico DNA-DNA hybridization (isDDH), and biochemical characteristics to identify strain FJKB0103 as Pseudomonas protegens. Herein, the genome of strain FJKB0103 was sequenced and subjected to antiSMASH platform, mutational, and functional analyses. The FJKB0103 draft genome was 6,776,967 bp with a 63.4% G + C content, and 16 potential secondary compound biosynthetic clusters in P. protegens FJKB0103 were predicted. The deletion mutant and complementary analysis suggested that DAPG was the anti-MRSA compound. Further tests showed that MRSA strains were sensitive to DAPG, and the lysis of bacterial cells was observed at a high concentration of DAPG. Additionally, DAPG inhibited the biofilm formation of MRSA at subinhibitory concentration. These results suggested that DAPG might be a good alternative treatment to control infections caused by MRSA.

Vibrio parahaemolyticus causes aquatic vibriosis. Its biofilm protects it from antibiotics; therefore, a new different method is needed to control V. parahaemolyticus for food safety. Phage therapy represents an alternative strategy to control biofilms. In this study, the lytic Vibrio phage vB_VpaP_FE11 (FE11) was isolated from the sewers of Guangzhou Huangsha Aquatic Market. Electron microscopy analysis revealed that FE11 has a typical podovirus morphology. Its optimal stability temperature and pH range were found to be 20–50 °C and 5–10 °C, respectively. It was completely inactivated following ultraviolet irradiation for 20 min. Its latent period is 10 min and burst size is 37 plaque forming units/cell. Its double-stranded DNA genome is 43,397 bp long, with a G + C content of 49.24% and 50 predicted protein-coding genes. As a lytic phage, FE11 not only prevented the formation of biofilms but also could destroy the formed biofilms effectively. Overall, phage vB_VpaP_FE11 is a potential biological control agent against V. parahaemolyticus and the biofilm it produces.