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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
Published on: May 8, 2013
A novel Staphylococcus phage, vB_Sau-RP15, and its application in contaminated milk
Napakhwan Imklin1, Phiraphat Chaengphaniad1, Eugenijus Šimoliūnas2
1Department of Biotechnology, Faculty of Engineering and Industrial Technology, Silpakorn University, Sanamchandra Palace Campus, Nakhon Pathom 73000, Thailand.
Abstract:
The vB_Sau-RP15 phage, selected for its potential use as a phage treatment in milk, was isolated from raw milk using Staphylococcusaureus NP01 as the host. The host range test revealed that the phage was able to lyse 12 strains of Staph. aureus from raw milk. This phage was stable at 4-37°C and pH 6-9 for at least 1 h. The adsorption rate was ~78% within the first 3 min. A low frequency of phage-insensitive mutant induction (4.6 × 10-6) was observed. Genomic analyses revealed that the vB_Sau-RP15 represented a novel species in the genus Silviavirus. Even though no virulence or antibiotic resistance genes were detected, the phage genome carried lysogenic-associated genes. Phage treatments (108 PFU per ml) in pasteurized milk contaminated with low (104 CFU per ml) and high (107 CFU per ml) concentrations of Staph. aureus confirmed the proficiency of the phage in the diminishing of the number of bacterial cells at 4°C and ambient temperature. A Staphylococcus phage, vB_Sau-RP15, could be a promising agent for controlling Staph. aureus contamination in milk.
Insights
A novel bacteriophage, vB_Sau-RP15, effectively reduces Staphylococcus aureus in milk. This phage shows stability and a low mutation rate, making it a promising agent for controlling bacterial contamination in dairy products.
Area of Science:
- Microbiology
- Food Science
- Bacteriophage Therapy
Background:
- Staphylococcus aureus poses a significant contamination risk in milk and dairy products.
- Phage therapy offers a targeted approach to combat bacterial infections and spoilage.
- Controlling S. aureus in milk is crucial for food safety and quality.
Purpose of the Study:
- To isolate and characterize a bacteriophage with potential for treating Staphylococcus aureus contamination in milk.
- To evaluate the efficacy and safety of the isolated phage for application in dairy products.
Main Methods:
- Isolation of bacteriophage vB_Sau-RP15 from raw milk using Staphylococcus aureus NP01 as the host.
- Host range testing against 12 S. aureus strains from raw milk.
- Stability assays (temperature, pH), adsorption rate determination, and phage-insensitive mutant frequency analysis.
- Genomic analysis to determine phage classification and identify relevant genes.
- In vitro efficacy testing in pasteurized milk spiked with S. aureus at different concentrations.
Main Results:
- Phage vB_Sau-RP15 demonstrated lytic activity against 12 S. aureus strains.
- The phage exhibited stability at temperatures from 4-37°C and pH 6-9.
- A low frequency of phage-insensitive mutant induction (4.6 × 10-6) was observed.
- Genomic analysis classified vB_Sau-RP15 as a novel species in the genus Silviavirus, lacking virulence genes but possessing lysogenic-associated genes.
- Phage treatment significantly reduced S. aureus populations in contaminated pasteurized milk at both 4°C and ambient temperature.
Conclusions:
- Bacteriophage vB_Sau-RP15 is a promising candidate for controlling Staphylococcus aureus contamination in milk.
- Its stability, host range, and efficacy in reducing bacterial load support its potential application in the dairy industry.
- Further research into the lysogenic-associated genes is warranted, but the absence of virulence genes is favorable for its use as a biocontrol agent.
