Related Experiment Video

Updated: Oct 5, 2026

Experimental Endocarditis Model of Methicillin Resistant Staphylococcus aureus (MRSA) in Rat
07:46

Experimental Endocarditis Model of Methicillin Resistant Staphylococcus aureus (MRSA) in Rat

Published on: June 4, 2012

[Investigation of infective endocarditis clinical isolates of methicillin resistant Staphylococcus aureus

Y Takayama1, K Yoshida, Y Yamaguchi

  • 1Dept. of Infectious Diseases, Kitasato Univ. School of Med.

Kansenshogaku Zasshi. the Journal of the Japanese Association for Infectious Diseases
|August 10, 2001
PubMed

Insights

This study tracked Methicillin-resistant Staphylococcus aureus (MRSA) strains in patients with infective endocarditis. The same MRSA strain was repeatedly isolated, showing reduced susceptibility over time.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Antimicrobial Resistance

Background:

  • Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of hospital-acquired and post-operative infections.
  • Infective endocarditis caused by MRSA can be challenging to treat, particularly when vancomycin (VCM) is not fully effective.

Observation:

  • MRSA strains were isolated from patients with infective endocarditis at three distinct time points.
  • These isolates were analyzed for minimum inhibitory concentration (MIC), fractional inhibitory concentration (FIC) index, Mu 3 agar, population analysis, and pulse field gel electrophoresis (PFGE).

Findings:

  • PFGE analysis revealed identical banding patterns across all three MRSA isolates, indicating the selection of a single, persistent MRSA strain.
  • Population analysis demonstrated a characteristic pattern associated with Mu 3 and Mu 50, suggesting the development of reduced susceptibility.

Implications:

  • The findings highlight the potential for a single MRSA strain to persist and develop reduced susceptibility during treatment for infective endocarditis.
  • Understanding the genetic stability and susceptibility patterns of MRSA is crucial for effective treatment strategies and infection control.
  • Further research into the mechanisms of reduced susceptibility in persistent MRSA strains is warranted.

Related Concept Videos

Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Automated Microbial Diagnostics01:24

Automated Microbial Diagnostics

Automated diagnostic analyzers have transformed clinical microbiology by providing rapid and reliable methods for pathogen identification and antibiotic susceptibility testing. Among these systems, the Vitek 2 is widely used because it automates the traditionally labor-intensive processes of microbial identification (ID) and antibiotic susceptibility testing (AST), delivering standardized and timely results that are essential for effective patient care.Microbial Identification with ID CardsThe...
Staphylococcal Skin Infections01:29

Staphylococcal Skin Infections

Staphylococcus aureus is a Gram-positive coccus that resides harmlessly on the skin and mucous membranes of healthy individuals. When the skin barrier is breached, it can shift from a commensal to an opportunistic pathogen. This transition is facilitated by surface adhesins, such as clumping factor B and S. aureus surface protein G (SasG), which bind to structural proteins, including loricrin and cytokeratin, in the damaged epidermis. Protein A, another key factor, binds the Fc region of...