Novel and Future Treatment Strategies for Biofilm-Associated Infections

Biofilm formation by pathogenic bacteria is a matter of considerable concern in healthcare as it is a leading cause of emerging multidrug resistance in microbes. Microbial biofilms are often found on the surfaces of biomaterials such as contact lenses and medical devices including implants and urinary catheters. Several bacteria like Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp., together termed as ESKAPE pathogens, are responsible for nosocomial infections that result in increased morbidity and mortality. This imposes a significant financial burden on the healthcare system. Available antimicrobial therapeutics are rendered ineffective due to compact and complex biofilm architecture which is composed of mainly extracellular polymeric substances (EPS). This leads to persistent infections untreatable by conventional therapy. Thus, there is a high demand for novel strategies for inhibition as well as disruption of biofilms to control biofilm-associated infections. In this chapter, we provide an elaborate account of complementary and alternative therapeutic strategies for biofilm control that include isolation of quorum-sensing inhibitors, metal chelators, and biofilm efflux pump inhibitors from medicinal plants. Further, dispersion of a preformed biofilm can be achieved by ultrasonic disruption, enzyme-mediated degradation of EPS, acidic electrolyzed water-assisted disruption, and bacteriophage-assisted biofilm disruption. Another attractive approach includes modification of the surface of medical devices by antibiofilm nanoscale biomaterials. Gold, silver, iron oxide, and bimetallic nanoparticles either individually or multifunctionalized with polymeric substances or drugs have also been fabricated to control biofilm formation by the interruption of quorum sensing, cell-to-cell communication, and multidrug efflux pumps. Similarly, antibiofilm nanostructures may also induce oxidative stress by generating reactive oxygen species which can play an important role in biofilm inhibition. Additionally, the future scope of integrating therapeutics, employing drugs, targeting ligands, and nanomedicine is discussed as promising strategies for better biofilm control compared to conventional treatments.