Effects of prolonged vancomycin administration on methicillin-resistant Staphylococcus aureus (MRSA) in a patient with recurrent bacteraemia

Abstract

Despite the lack of development of detectable resistance, MRSA exposed to vancomycin for prolonged periods may begin to develop vancomycin tolerance and decreased autolysis. In addition, suppression of agr function appears to end after vancomycin is stopped. Whether these changes are prerequisites for attenuated vancomycin efficacy and the development of glycopeptide resistance warrants further study. The development of vancomycin resistance may be more difficult under conditions where vancomycin serum concentrations are maintained >10 mg/L.

The relationship between trough concentration of vancomycin and effect on methicillin-resistant Staphylococcus aureus in critically ill patients

“…16 This finding also supports other reports that trough concentration of vancomycin should be maintained above 10 mg/l for treatment to be successful and to prevent the development of vancomycin resistance. 9 The doses of vancomycin given to the critically ill patients were determined and adjusted according to the patient's renal function, creatinine clearance and the vancomycin trough concentration achieved with the earlier dose. Based on our study findings, a vancomycin dose of 15 mg/kg/day would be sufficient to produce optimal trough concentrations to eradicate MRSA.…”

“…This dose was estimated to produce the corrected vancomycin trough concentration of 11.64±1.50 mg/l, which is between 10 and 15 mg/l as previously recommended. 9 Others also failed to demonstrate the benefits of recently recommended higher serum vancomycin trough concentrations >15 mg/l in achieving better clinical outcomes. 10,11,17 The current findings may justify the vancomycin trough concentration between 10 and 15 mg/l as an effective and safe target for MRSA infection in critically ill patients.…”

“…8 Vancomycin resistance may be less likely to develop when serum trough concentrations are maintained above 10 mg/l. 9 Serum vancomycin trough concentrations of 15 -20 mg/l have been recommended for severe MRSA infections such as bacteraemia, endocarditis, osteomyelitis, meningitis and hospital-acquired pneumonia. 6 However, a trough concentration >15 mg/l has not been clearly associated with favourable outcomes.…”

Reduced Vancomycin Susceptibility inStaphylococcus aureus, Including Vancomycin-Intermediate and Heterogeneous Vancomycin-Intermediate Strains: Resistance Mechanisms, Laboratory Detection, and Clinical Implications

“…In particular, these changes have included reduced agr function, reduced susceptibility to host antimicrobial peptides including platelet microbiocidal protein and hNP-1, and increased adhesion to fibrinogen, fibronectin, and endothelial cells (88,297,391). In a study by Xiong et al, although there was no formal assessment for hVISA, in a rabbit endocarditis model, there was a reduced efficacy of vancomycin in one persistent bacteremia isolate compared to the control (391).…”

Vancomycin: the need to suit serum concentrations in hemodialysis patients

“…According to Rose et al (2007), all agr groups develop intermediate resistance to vancomycin with subtherapeutic exposures. 23 The study by Sakoulas et al (2006) has shown that the exposure to subtherapeutic vancomycin concentrations is associated with the development of clinically hetero-GISA (glycopeptide intermediate-resistant S. aureus) isolates. These authors consider that the constant 25 Due to the increasing use of vancomycin, worrisome vancomycin-resistant strains of E. faecium and E. faecalis have emerged.…”