The Escalating Challenge of Vancomycin Resistance in Staphylococcus aureus

Abstract

The glycopeptide antibiotic vancomycin is considered indispensable for the treatment of multidrug-resistant Staphylococcus aureus infections, and so the acquisition by these organisms of transmissible glycopeptide resistance elements from enterococci had been anticipated with apprehension. It was therefore a considerable surprise when vancomycin-intermediate S. aureus (VISA) clinical isolates were reported in 1997, with a novel, borderline-resistance phenotype acquired without genetic exchange. Clinical vancomycin-resistant S. aureus (VRSA) were not reported until 2002, expressing high level, transmissible resistance by virtue of vanA resistance determinants within enterococcal transposable elements residing on staphylococcal plasmids. This review will provide an update on the frustratingly variable characteristics of the VISA phenotype, focus on the progress made in understanding the molecular basis of the VISA resistance mechanism from the viewpoint of genetic regulation and cell wall stress response, and summarize the information currently available on VRSA. Finally, alternatives to vancomycin that are already available or nearing approval will be briefly reviewed, with attention to their limitations and potential for resistance development.

Viridicatumtoxin B, a new anti-MRSA agent from Penicillium sp. FR11

“…the last-resort antibiotic, vancomycin [2]. Therefore, it is increasingly important and necessary to find new classes of antimicrobials.…”

“…In the course of our screening for new anti-MRSA agents from microbial resources, a new tetracycline-type antibiotic named viridicatumtoxin B (1) along with the known compound viridicatumtoxin (2) were isolated from liquid fermentation cultures of Penicillium sp. FR11 (Fig.…”

Verticillin G, a New Antibacterial Compound from Bionectra byssicola

“…Methicillinresistant S. aureus (MRSA) is known as a major nosocomial pathogen which has also developed resistance to many other antibiotics. Moreover, MRSA has been reported to acquire resistance to the last-resort antibiotic, vancomycin [2]. These facts suggest that S. aureus would fully acquire resistance to vancomycin in the near future.…”

Synthesis of some novel Carbazole derivatives and evaluation of their antimicrobial activity

“…Frequently, it is recommended to use new antibacterial agents with enhanced broad-spectrum potency. Therefore, recent efforts have been directed toward exploring novel antibacterial agents (1)(2)(3)(4). Apart from this, the incidence of fungal infections in the immunocompromised population has significantly increased over the past two decades.…”