Silver Inhibits the Biofilm Formation of Pseudomonas aeruginosa

Abstract

Biofilm is the assemblage of microbial cells that are irreversibly\rassociated with biotic and abiotic surfaces and is usually enclosed in the self\rsecreted extracellular polymeric substances (EPS). The presence of EPS in\rbiofilm makes the microbial population resistance against antibiotics and other\rdrugs. Biofilms are considered as a serious challenge to pharmaceutical\rindustries because most of the microbial diseases are now associated with\rbiofilm. In this context, we have addressed the biofilm potentialities of Pseudomonas\raeruginosa, which has\rbeen found to be associated with several deadly diseases including septicemia,\rurinary tract infections, and gastrointestinal infections, and wherein biofilm\rplays a crucial role in pathogenesis. Since silver had been used globally for a long time for treating a wide range of\rillnesses from burn wounds, typhoid, and anthrax to bacterial conjunctivitis in\rnewborns, but its antibiofilm activity is still unknown. Thus, in this current\rstudy, we have tried to examine the antibiofilm potentiality of silver\ragainst the biofilm of Pseudomonas\raeruginosa. Our result showed that\rsilver exhibited considerable antimicrobial property against Pseudomonas\raeruginosa where the minimum inhibitory concentration (MIC) was found at 25\rμg/ml. Biofilm inhibition by silver against Pseudomonas aeruginosa was\rthen evaluated by crystal violet (CV) staining, estimation of total biofilm\rprotein and microscopy based microbial adherence test using the sub MIC doses\rof silver. The results showed that all the tested sub MIC doses of silver\rexhibited considerable antibiofilm activity against P. aeruginosa, wherein\rthe maximum biofilm attenuation was showed by a silver concentration of 20 μg/ml. We also observed that all these sub MIC doses of silver neither interfere\rwith the growth cycle of the bacteria nor affect the cell viability but only\rattenuates biofilm formation property of the bacteria. The current study\rdeciphers a new axis in biofilm biology where a metal like silver can inhibit\rthe formation of biofilm markedly. Thus, the knowledge gathered in this study\rmay help the pharmaceutical sector to design combinatorial drug where silver\rcould be an important partner to reduce the load of pathogenesity caused by\rbiofilm.