Multiresistant-MRSA tricuspid valve infective endocarditis with ancient osteomyelitis locus

Area of Science:

• Infectious Diseases
• Clinical Microbiology
• Cardiology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) infections with reduced susceptibility to glycopeptides are infrequent.
• The case involves a 50-year-old patient without a history of intravenous drug use.

Observation:

• The patient presented with tricuspid valve infective endocarditis (IE) caused by MRSA strains resistant to vancomycin and linezolid.
• The MRSA isolate exhibited identical resistance profiles to strains isolated four years prior, linked to recurrent osteomyelitis.
• Previous treatments including teicoplanin-cotrimoxazole and linezolid with vancomycin-rifampicin-cotrimoxazole were ineffective.

Findings:

• Successful treatment of MRSA IE was achieved with quinupristin/dalfopristin after 28 days of therapy.
• This represents the first reported instance of successful quinupristin/dalfopristin treatment for resistant-MRSA IE of the tricuspid valve complicated by pulmonary septic infarction.

Implications:

• This case expands treatment options for glycopeptide-resistant MRSA IE, particularly in non-intravenous drug users.
• The findings underscore the importance of considering alternative antibiotics like quinupristin/dalfopristin for highly resistant MRSA strains.
• Further research into the management of complex, resistant MRSA infections is warranted.