Related Experiment Video

Updated: May 31, 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

Endocarditis caused by methicillin-susceptible Staphylococcus aureus with reduced susceptibility to vancomycin: a

Beatriz Perazzi1, Natalia Bello, Marta Mollerach

  • 1Clinical Bacteriology Laboratory, Department of Clinical Biochemistry, Hospital de Clinicas, Faculty of Pharmacy & Biochemistry, University of Buenos Aires, Córdoba 2351, Capital Federal, City of Buenos Aires, Argentina. hugodandrea@ciudad.com.ar.

Journal of Medical Case Reports
|July 8, 2011
PubMed
Abstract

Insights

Vancomycin treatment failed for infective endocarditis caused by methicillin-susceptible Staphylococcus aureus. This strain had subpopulations with reduced vancomycin susceptibility, highlighting the need for susceptibility testing.

Area of Science:

  • Infectious Diseases
  • Microbiology
  • Clinical Medicine

Background:

  • Staphylococcus aureus is a leading cause of infective endocarditis.
  • Heteroresistance to vancomycin has been reported in methicillin-resistant strains.
  • This case highlights vancomycin treatment failure in methicillin-susceptible S. aureus endocarditis.

Purpose of the Study:

  • To report the first case in Argentina of vancomycin treatment failure in endocarditis.
  • To describe a case of methicillin-susceptible S. aureus with vancomycin-reduced susceptibility subpopulations.
  • To emphasize the clinical significance of vancomycin susceptibility testing.

Main Methods:

  • Case report of a 66-year-old male with infective endocarditis.
  • Initial treatment with cephalothin and gentamicin, switched to vancomycin due to adverse reactions.
  • Treatment ultimately successful with vancomycin, gentamicin, and rifampin combination therapy.

Main Results:

  • The patient presented with infective endocarditis and septic emboli.
  • Methicillin-susceptible S. aureus with reduced vancomycin susceptibility was identified.
  • Vancomycin monotherapy failed, necessitating combination therapy for resolution.

Conclusions:

  • Vancomycin treatment failure can occur with methicillin-susceptible S. aureus harboring vancomycin-reduced susceptibility subpopulations.
  • This case underscores the importance of screening for reduced vancomycin susceptibility.
  • Minimum inhibitory concentration (MIC) testing for vancomycin is crucial for guiding S. aureus endocarditis treatment.

More Related Videos

Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)12:18

Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)

Published on: February 9, 2011

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...
Endocarditis I: Introduction01:25

Endocarditis I: Introduction

Introduction:Endocarditis is the infection of the endocardium, the inner lining of the heart and its valves. When the heart muscle is involved, the condition is termed myocarditis, while an infection of the outer lining is called pericarditis. Infective endocarditis (IE) primarily affects the endocardium, where pathogens adhere to the valves or lining, forming vegetation that can lead to severe complications. Infective endocarditis occurs when microorganisms, usually bacteria from other body...
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...
Endocarditis III: Medical Management01:18

Endocarditis III: Medical Management

Infective endocarditis management involves a multifaceted approach encompassing infection prevention, lifestyle modifications, pharmacological therapy, and surgical management.Infection Prevention:Hand Hygiene: Thorough handwashing is crucial to prevent the spread of infection. Hand hygiene should be performed regularly, especially before and after using the restroom.Oral Hygiene: Good oral hygiene is essential. It includes brushing teeth immediately after waking up and before bed, flossing...
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...
Endocarditis II: Clinical Features of Infective Endocarditis01:25

Endocarditis II: Clinical Features of Infective Endocarditis

Endocarditis can present various clinical features depending on the causative organism and the patient's underlying health conditions. Initially, the clinical features of infective endocarditis develop gradually, presenting with nonspecific symptoms that can be easily mistaken for other illnesses.General SymptomsEarly symptoms of infective endocarditis are fever, chills, weakness, malaise, fatigue, and weight loss. These symptoms reflect the systemic nature of the infection and the body's...