Identification of Protein Drug Targets of Biofilm Formation and Quorum Sensing in Multidrug Resistant Enterococcus faecalis.

Enterococcus faecalis (E. faecalis) is an opportunistic multidrug-resistant (MDR) pathogen found in the guts of humans and farmed animals. Due to the occurrence of (MDR) strain there is an urgent need to look for an alternative treatment approach. E. faecalis is a Gram-positive bacterium, which is among the most prevalent multidrug resistant hospital pathogens. Its ability to develop quorum sensing (QS) mediated biofilm formation further exacerbates the pathogenicity and triggers lifethreatening infections. Therefore, developing a suitable remedy for curing E. faecalis mediated enterococcal infections is an arduous task. Several putative virulence factors and proteins are involved in the development of biofilms in E. faecalis. Such proteins often play important roles in virulence, disease, and colonization by pathogens. The elucidation of the structure-function relationship of such protein drug targets and the interacting compounds could provide an attractive paradigm towards developing structure-based drugs against E. faecalis. This review provides a comprehensive overview of the current status, enigmas that warrant further studies, and the prospects toward alleviating the antibiotic resistance in E. faecalis. Specifically, the role of biofilm and quorum sensing (QS) in the emergence of MDR strains had been elaborated along with the importance of the protein drug targets involved in both the processes.

Maximizing EPS production from Pseudomonas aeruginosa and its application in Cr and Ni sequestration.

Heavy metal contamination of water bodies has been a cause of grave concern around the globe. Analysis of various industrial effluents has revealed a perilous level of Cr (VI) and Ni (II). Pseudomonas aeruginosa is an extracellular polymeric substances (EPSs) producing bacterium. EPS has a great potential in the sequestration of heavy metal ions. In the present study efforts have been made to understand the effect of time, pH, and temperature on production of EPS by P. aeruginosa (MTCC 1688). The extracted EPS has been applied for removal of Ni (II) and Cr (VI) ions from aqueous system. The results revealed that highest EPS yield (26 mg/50 mL) can be obtained after 96 h of incubation at pH 6 and 32 °C temperature in 50 mL of culture. Treatment of 10 mg/L Cr (VI) and Ni (II) with 30 mg/L EPS resulted in the removal of 26% and 9% of Cr (VI) and Ni (II), respectively. Fourier-transform infrared spectral analysis revealed the involvement of -OH, -NH, C-O, diketone, and ester functional groups of EPS in the attachment of Cr (VI) ion while involvement of amide and -C[bond, double bond]O groups in Ni (II) binding with EPS. Scaling-up the production of EPS using bioreactor may further help in developing an efficient process for treatment of water polluted with Cr and Ni.

Optimization of Extracellular Polymeric Substances production using Azotobacter beijreinckii and Bacillus subtilis and its application in chromium (VI) removal.

Extracellular Polymeric Substances (EPS) of microbial origin are complex biopolymers and vary greatly in their chemical composition. They have a great potential in chelation of metal ions. In this work, the effect of growth phase, temperature and pH on production of EPS by two bacteria Azotobacter beijreinckii and Bacillus subtilis have been studied. Extracted EPS was used to remove Cr(VI) from aqueous system. A. beijreinckii produced maximum EPS after 24h at pH 7 and temperature 30°C while B. subtilis produced maximum EPS after 96h at pH 7 and temperature 37°C. For an initial concentration of 10ppm, 26% and 48% Cr(VI) removal was recorded for EPS derived from A. beijreinckii and B. subtilis respectively. The presence of functional groups on EPS and their interaction with Cr(VI) was confirmed using Fourier-transform infrared (FTIR) spectra analysis. In both the bacteria, carboxyl and phosphate groups show involvement in metal binding.