Related Experiment Videos
Emergence of methicillin-resistant clones from cephamycin-resistant Staphylococcus aureus
1Central Research Division, Takeda Chemical Industries, Ltd., Osaka, Japan.
Abstract:
Staphylococcus aureus strains specifically resistant to cephamycin antibiotics have been found among recent clinical isolates. These strains formed penicillin-binding protein (PBP) 2' and became phenotypically resistant to methicillin after induction with cefoxitin. Other cephamycin-type antibiotics also induced methicillin-resistance, whereas non-cephamycin-type cephalosporins such as cefmenoxime and ceftizoxime did not do so. The clones that constitutively synthesized PBP 2' arose from the cephamycin-resistant strains at a frequency of 10(-5). They were indistinguishable from clinically isolated methicillin-resistant S. aureus (MRSA). Cephamycin-resistant S. aureus may be a source for emerging MRSA.
Insights
New cephamycin-resistant Staphylococcus aureus strains can develop methicillin resistance by producing penicillin-binding protein (PBP) 2'. These resistant strains may be a source for emerging methicillin-resistant S. aureus (MRSA).
Area of Science:
- Microbiology
- Infectious Diseases
- Antibiotic Resistance
Background:
- Emerging antibiotic resistance in Staphylococcus aureus poses a significant public health threat.
- Cephamycin antibiotics are a class of beta-lactam antibiotics used to treat bacterial infections.
- Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of hospital-acquired infections.
Purpose of the Study:
- To investigate the emergence of cephamycin resistance in Staphylococcus aureus.
- To understand the mechanism by which cephamycin-resistant strains develop methicillin resistance.
- To assess the potential of cephamycin-resistant strains as a source for MRSA.
Main Methods:
- Isolation and characterization of clinical Staphylococcus aureus strains.
- Induction of methicillin resistance using various cephalosporin antibiotics.
- Detection and analysis of penicillin-binding protein (PBP) 2' synthesis.
- Genetic analysis of resistant clones.
Main Results:
- Identified Staphylococcus aureus strains resistant to cephamycin antibiotics.
- Observed that these strains produced penicillin-binding protein (PBP) 2' upon induction with cefoxitin and other cephamycin-type antibiotics.
- Demonstrated that non-cephamycin cephalosporins did not induce methicillin resistance.
- Found that constitutive PBP 2' synthesis occurred at a frequency of 10(-5) in cephamycin-resistant strains, yielding clones indistinguishable from clinical MRSA.
Conclusions:
- Cephamycin-resistant Staphylococcus aureus strains can acquire methicillin resistance through the induction of PBP 2'.
- These strains represent a potential reservoir for the emergence of MRSA.
- Understanding this mechanism is crucial for developing strategies to combat antibiotic resistance.