Staying one step ahead in the arms race against antibiotic resistant pathogenic bacteria is an ongoing challenge to the ingenuity of medicinal chemists. Multidrug-resistance has become a menacing threat to the antibiotic armoury used by clinicians to treat nosocomial and community-acquired bacterial infections. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most notorious of such hospital-acquired pathogens. Until recently, the glycopeptide antibiotic vancomycin (Van) was available as a last resort, to effectively treat patients suffering from life-threatening MRSA and multidrug resistant (MDR) infections. However, the emergence of vancomycin resistance in Enterococcus spp. and subsequently, albeit rarely, of vancomycin resistant (Van^R) S. aureus (VRSA), has threatened the usefulness of vancomycin. The more frequent occurrence of strains showing intermediate resistance to vancomycin: heterogeneous vancomycin intermediate S. aureus (h-VISA) (Howden et al, 2010) gives particular cause for concern. Despite this bleak picture, innovative lab scientists are constantly coming up with new ideas. Two recent publications, from independent research groups, report the effectiveness of conjugates of vancomycin with cell-penetrating peptides (CPPs) in combating strains of Van^R MRSA as well as h-VISA and Van^R enterococci (VRE), and give grounds for optimism.

Fluorescence microscopy images showing penetration of vancomycin-transportan 10 conjugate in mouse brain.

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Contributed by Susan J. Tzotzos

Susan Tzotzos works for the Vienna-based biotech company Apeptico Forschung & Entwicklung GmbH, where she designs therapeutic peptides, oversees their synthesis and follows up their application in clinical trials. Susan also manages various research collaborations with university departments carrying out projects investigating the mode of action of Apeptico’s therapeutic peptides.