Recurrent Challenges for Clinicians: Emergence of Methicillin-resistant Staphylococcus aureus, Vancomycin Resistance, and Current Treatment Options

Abstract

Gram-positive pathogens mainly, Staphylococcus aureus, Enterococcus and coagulase-negative Staphylococcus, are developing increasing resistance to glycopeptides that pose a problem in treating infections caused by these pathogens. Vancomycin is the treatment of choice in treating methicillin-resistant S. aureus (MRSA). Community-acquired MRSA is associated with infections in patients without recent history of hospital admission and without the classical risk factors for MRSA carriage (including healthcare personnel). MRSA poses new threats and challenges beyond the hospital with the emergence of community-acquired MRSA. Indiscriminate use of vancomycin leads to the emergence and spread of vancomycin resistance in multidrug resistant strains is of growing concern in the recent years. Minimum Inhibitory concentration (MIC) remains an important determinant in choosing the right antibiotics. Infections caused by MRSA strains with vancomycin MIC > 4 μg/mL leads to the vancomycin treatment failure. The Clinical Laboratory Standards Institute had also lowered the cut-off susceptibility and resistance breakpoints for vancomycin. Despite the availability of newer antimicrobial agents (Linezolid, Daptomycin, Tigecycline) for drug-resistant Gram-positive pathogens, clinicians and patients still need options for treatment of MRSA infection. There is a need to reduce the global burden of infections caused by Gram-positive pathogens and its resistant strains (mainly MRSA). Continuous efforts should be made to prevent the spread and the emergence of glycopeptide resistance by early detection of the resistant strains and using the proper infection control measures in the hospital setting.

Complications from the use of intrawound vancomycin in lumbar spinal surgery: a systematic review

“…While the development of vancomycin-resistant S. aureus has not been published in the spinal surgery literature, vancomycin-resistant S. aureus development has been found to be a concern when the MIC of vancomycin is below 4 mg/ml. 24 However, previously published studies have demonstrated that vancomycin can reach high concentrations well beyond the MIC needed to treat gram-positive organisms without systemic effects.…”

Can Nasal Methicillin-Resistant Staphylococcus aureus Screening Be Used to Avoid Empiric Vancomycin Use in Intra-Abdominal Infection?

“…However, vancomycin is not a benign therapy and the incidence of vancomycin-induced nephrotoxicity varies from 5%-35%. Most importantly, vancomycin-resistant strains of bacteria are increasing [5][6][7] and the excessive use of antimicrobial agents has worsened the susceptibility to vancomycin [8].…”

Cellular Pharmacokinetics and Intracellular Activity of the Novel Peptide Deformylase Inhibitor GSK1322322 against Staphylococcus aureus Laboratory and Clinical Strains with Various Resistance Phenotypes: Studies with Human THP-1 Monocytes and J774 Murine Macrophages

“…he spread of multidrug-resistant Staphylococcus aureus strains in hospitalized patients and other individuals without health care-related risk factors raises alarming concerns in various countries and clinical settings due to the increasing likelihood of treatment failures and ensuing morbidity and mortality (1)(2)(3). In addition, the ability of S. aureus to sojourn and thrive intracellularly, well described in in vitro and in vivo models (4-7) and also documented in human infections, is considered to play a critical role in their persistent and recurrent character (8)(9)(10).…”