Antibiotic resistance and biofilm tolerance: a combined threat in the treatment of chronic infections.

Since the introduction of antibiotics into human medicine in the 1940's, antibiotic resistance has emerged at an alarming rate and is now a major threat to public health. This problem is amplified by pathogenic bacteria existing most commonly in biofilm form, creating additional bacterial tolerance to antimicrobial agents. Biofilm is now considered to be a primary cause of chronic infection, and antibiotic-resistant bacteria are prevalent in biofilm form. In particular, chronic non-healing wounds commonly harbour complex polymicrobial, pathogenic biofilm that is tolerant to systemic and topical antimicrobial therapy. Antibiotic stewardship programmes have emerged globally to improve antibiotic prescribing practices, and to curb the emergence and spread of bacterial resistance. In this regard, new antimicrobial strategies must be considered, one of which is to use antibiofilm/antimicrobial combinations to disrupt biofilm, thereby facilitating effectiveness of antimicrobial agents, and reducing the opportunity for antibiotic resistance gene transfer within biofilm. This strategy is being considered in several clinical conditions, one of which is chronic non-healing wounds, where antibiotics are used excessively and often indiscriminately. A combination antibiofilm/antimicrobial wound dressing has been shown to facilitate healing in previously biofilm-impaired non-healing wounds. This approach must be considered as part of antibiotic stewardship programmes to reduce the usage and implications of antibiotic therapy, and improve outcomes associated with chronic infections.