TITLE:
Silver Inhibits the Biofilm Formation of Pseudomonas aeruginosa
AUTHORS:
Bipin Kumar Sharma, Animesh Saha, Lovely Rahaman, Surajit Bhattacharjee, Prosun Tribedi
KEYWORDS:
Pseudomonas, Silver, Antimicrobial, Antibiofilm
JOURNAL NAME:
Advances in Microbiology,
Vol.5 No.10,
September
7,
2015
ABSTRACT: Biofilm is the assemblage of microbial cells that are irreversibly
associated with biotic and abiotic surfaces and is usually enclosed in the self
secreted extracellular polymeric substances (EPS). The presence of EPS in
biofilm makes the microbial population resistance against antibiotics and other
drugs. Biofilms are considered as a serious challenge to pharmaceutical
industries because most of the microbial diseases are now associated with
biofilm. In this context, we have addressed the biofilm potentialities of Pseudomonas
aeruginosa, which has
been found to be associated with several deadly diseases including septicemia,
urinary tract infections, and gastrointestinal infections, and wherein biofilm
plays a crucial role in pathogenesis. Since silver had been used globally for a long time for treating a wide range of
illnesses from burn wounds, typhoid, and anthrax to bacterial conjunctivitis in
newborns, but its antibiofilm activity is still unknown. Thus, in this current
study, we have tried to examine the antibiofilm potentiality of silver
against the biofilm of Pseudomonas
aeruginosa. Our result showed that
silver exhibited considerable antimicrobial property against Pseudomonas
aeruginosa where the minimum inhibitory concentration (MIC) was found at 25
μg/ml. Biofilm inhibition by silver against Pseudomonas aeruginosa was
then evaluated by crystal violet (CV) staining, estimation of total biofilm
protein and microscopy based microbial adherence test using the sub MIC doses
of silver. The results showed that all the tested sub MIC doses of silver
exhibited considerable antibiofilm activity against P. aeruginosa, wherein
the 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
with the growth cycle of the bacteria nor affect the cell viability but only
attenuates biofilm formation property of the bacteria. The current study
deciphers a new axis in biofilm biology where a metal like silver can inhibit
the formation of biofilm markedly. Thus, the knowledge gathered in this study
may help the pharmaceutical sector to design combinatorial drug where silver
could be an important partner to reduce the load of pathogenesity caused by
biofilm.