Related Experiment Video
Updated: Mar 18, 2026
Development and Assessment of Intracellular Infection Models for Staphylococcus aureus
Published on: January 17, 2025
SLPW: A Virulent Bacteriophage Targeting Methicillin-Resistant Staphylococcus aureus In vitro and In vivo
Zhaofei Wang1, Panpan Zheng1, Wenhui Ji1
1Shanghai Key Laboratory of Veterinary Biotechnology, Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, School of Agriculture and Biology, Shanghai Jiao Tong University Shanghai, China.
Abstract:
Staphylococcus aureus (S. aureus) is a Gram-positive pathogen causing a variety of infections in humans and animals. Extensive use of antibiotics has led to the emergence of methicillin-resistant S. aureus (MRSA). As an alternative antibacterial agent against drug-resistant S. aureus, a lytic phage, designated SLPW, was isolated from fecal sewage in a pig farm. The SLPW was morphologically classified under Podoviridae and contains a double-stranded DNA genome. The genome of SLPW was 17,861 bp (29.35% G+C) containing 20 open reading frames and lacked regions encoding lysogeny-related integrase gene and cI repressor gene. Phage SLPW showed a broad host range and high efficiency of plating against various types of S. aureus. One-step growth curve showed a short latency period (10 min) and a long lytic period (120 min). Phage SLPW remained stable under a wide range of temperatures or pH and was almost unaffected in chloroform or ultraviolet light. Further, it efficiently lysed MRSA strains in vitro and in vivo. Intraperitoneal phage administration at 1 h post-infection cured the mice and reduced the bacterial expression of inflammatory cytokines in mice. Specifically, the phage SLPW displayed a wide antibacterial spectrum. It was therapeutically effective against intra-abdominal infection in mice harboring different multilocus sequence typing (MLST) types of S. aureus strains. Therefore, phage SLPW is a potential therapeutic agent against MRSA infections.
Insights
A novel lytic phage, SLPW, effectively targets drug-resistant Staphylococcus aureus (S. aureus), including methicillin-resistant S. aureus (MRSA). This phage demonstrates therapeutic potential against MRSA infections in preclinical models.
Area of Science:
- Microbiology
- Virology
- Infectious Diseases
Background:
- Staphylococcus aureus (S. aureus) is a significant Gram-positive pathogen.
- Antibiotic resistance, particularly methicillin-resistant S. aureus (MRSA), poses a major global health threat.
- Novel therapeutic strategies are urgently needed to combat drug-resistant bacterial infections.
Purpose of the Study:
- To isolate and characterize a lytic bacteriophage with activity against drug-resistant S. aureus.
- To evaluate the therapeutic efficacy of the isolated phage against MRSA infections in vitro and in vivo.
- To assess the stability and host range of the candidate phage.
Main Methods:
- Isolation and characterization of a lytic phage (SLPW) from pig farm sewage.
- Genomic analysis of the phage SLPW, including genome size and open reading frames.
- Assessment of phage host range, efficiency of plating, and one-step growth kinetics.
- Evaluation of phage stability under various environmental conditions (pH, temperature, chloroform, UV light).
- In vitro and in vivo efficacy studies against MRSA strains, including mouse infection models.
Main Results:
- Phage SLPW, belonging to the Podoviridae family, possesses a double-stranded DNA genome (17,861 bp).
- SLPW exhibited a broad host range against S. aureus, with a short latency (10 min) and lytic (120 min) period.
- The phage demonstrated stability across a range of temperatures and pH, and resistance to chloroform and UV light.
- SLPW efficiently lysed MRSA strains in vitro and significantly reduced bacterial burden and inflammatory cytokines in vivo.
- Intraperitoneal administration of SLPW successfully treated intra-abdominal MRSA infections in mice.
Conclusions:
- Phage SLPW is a robust lytic bacteriophage with significant antibacterial activity against diverse S. aureus strains, including MRSA.
- Its stability, broad host range, and demonstrated efficacy in preclinical models highlight its potential as a therapeutic agent.
- Phage SLPW offers a promising alternative strategy for combating challenging MRSA infections.
Related Concept Videos
01:30Lytic Cycle of Bacteriophages
01:31Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
01:28Gene Regulation in Microbial Communities: Quorum Sensing