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Updated: Jun 26, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)
Published on: February 9, 2011
Treatment of methicillin-resistant Staphylococcus aureus in neonatal mice: lysostaphin versus vancomycin
Frank X Placencia1, Lingkun Kong, Leonard E Weisman
1Department of Pediatrics, Texas Children's Hospital, Houston, Texas 77030, USA.
Abstract:
S. aureus is a significant cause of late-onset sepsis in neonates. Increasing antibiotic resistance, however, requires additional treatment options. Lysostaphin, an endopeptidase, has that potential. The objective of this study is to compare lysostaphin versus vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) in a neonatal mouse model. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against MRSA strain USA300 were determined using standard methods. To determine pharmacokinetics, neonatal pups received either vancomycin or lysostaphin intraperitoneal and serum samples were obtained. To evaluate efficacy, pups were infected s.c. and littermates randomized to receive either saline, vancomycin, or lysostaphin intraperitoneal. Pups were observed for survival and growth. Quantitative blood cultures were obtained 24 h after infection. The MIC/MBC for vancomycin and lysostaphin were 0.71/1.19 microg/mL and <0.008/0.015 microg/mL, respectively. Mean lysostaphin concentrations ranged from 2.34 to 8.92 microg/mL. Mean vancomycin concentrations ranged from 1.72 to 11.2 microg/mL. Lysostaphin improved survival compared with placebo (p < 0.00001) and vancomycin (p < 0.03). There was no significant difference in growth among the groups. All treatment regimens resulted in less bacteremia compared with placebo (p < 0.0001). Lysostaphin appears to be more effective than vancomycin in treating MRSA in a neonatal model.
Insights
Lysostaphin shows greater effectiveness than vancomycin in treating methicillin-resistant Staphylococcus aureus (MRSA) sepsis in newborn mice. This novel treatment offers a promising alternative for neonatal infections caused by antibiotic-resistant bacteria.
Area of Science:
- Neonatal Medicine
- Infectious Diseases
- Pharmacology
Background:
- Staphylococcus aureus causes significant late-onset sepsis in neonates.
- Rising antibiotic resistance necessitates novel treatment strategies.
- Lysostaphin, an endopeptidase, presents potential as an alternative therapeutic agent.
Purpose of the Study:
- To compare the efficacy of lysostaphin against vancomycin in treating methicillin-resistant Staphylococcus aureus (MRSA) infections in a neonatal mouse model.
- To evaluate survival rates, growth, and bacteremia levels in response to different treatment regimens.
Main Methods:
- Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for lysostaphin and vancomycin against MRSA USA300.
- Pharmacokinetic profiles were assessed in neonatal pups receiving either drug.
- Efficacy was evaluated by infecting pups and treating them with saline, vancomycin, or lysostaphin, followed by survival and blood culture analysis.
Main Results:
- Lysostaphin demonstrated significantly lower MIC/MBC values compared to vancomycin.
- Lysostaphin treatment resulted in improved survival rates compared to both placebo and vancomycin.
- Both treatments reduced bacteremia compared to placebo, with no significant difference in pup growth.
Conclusions:
- Lysostaphin is more effective than vancomycin in treating MRSA infections in a neonatal mouse model.
- Lysostaphin represents a promising therapeutic option for neonatal sepsis caused by resistant S. aureus strains.
- Further research into lysostaphin's clinical application for neonatal infections is warranted.
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