title: Increasing antibiotic resistance among methicillin-resistant Staphylococcus aureus strains.
abstract: Vancomycin use has increased dramatically worldwide since the mid-1980s, largely as a result of empirical and directed therapy against burgeoning methicillin-resistant Staphylococcus aureus (MRSA) infections. With limited choices, clinicians have traditionally relied on vancomycin alone in the management of serious MRSA infections and have enjoyed a significant period free of vancomycin resistance in S. aureus. Even now, 5 decades after its introduction, vancomycin resistance among S. aureus strains, as currently defined microbiologically, remains rare. Yet it is becoming clear that vancomycin is losing potency against S. aureus, including MRSA. Serious infections due to MRSA defined as susceptible in the laboratory are not responding well to vancomycin. This is demonstrated by increased mortality seen in patients with MRSA infection and markedly attenuated vancomycin efficacy caused by vancomycin heteroresistance in S. aureus. Therefore, it appears that our definition of vancomycin susceptibility requires further scrutiny as applied to serious MRSA infections, such as bacteremia and pneumonia.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Westchester Medical Center and New York Medical College, Valhalla, New York, USA.
authors.forename: George
authors.initials: G
authors.lastname: Sakoulas
authors.forename: Robert C
authors.initials: RC
authors.lastname: Moellering
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D016106:Methicillin Resistance; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology* / Q000401:mortality; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D014640:Vancomycin / Q000494:pharmacology* / Q000627:therapeutic use; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin