1. Synthesis of tetrazole compounds as a novel type of potential antimicrobial agents and their synergistic effects with clinical drugs and interactions with calf thymus DNA
Ling-Ling Dai, Hui-Zhen Zhang, Sangaraiah Nagarajan, Syed Rasheed§ and Cheng-He Zhou*. Med. Chem. Commun.,2015,6,147–154
Fluconazole is one of the most important triazole-based compounds recommended as the first-line antifungal drug by the World Health Organization (WHO). It has been preva-lently employed to treat fungal infection byCandida albicans, Cryptococcus neoformans, Dermatitis blastomycosis, etc.due to its potent activity, excellent safety profile, and favorable pharmacokinetic characteristics. The triazole ring of Fluconazole could efficiently coordinate with the iron(II)ion of heme to inhibit the biosynthesis of ergosterol and thus inhibits the growth of fungi. However, the emergence of fluconazole-resistantCandida albicansisolates, increasingly serious drug resistance, narrow antifungal spectrum, and low activity against invasive mycoses have attracted great efforts towards modifying the side chain of Fluconazole or exploiting its new analogues. In our previous work, it has been demonstrated that the tertiary amine type of Fluconazole analogues displayed large potentiality as a new type of antimicrobial agents in which the tertiary alcohol moiety in Fluconazole was replaced by a tertiary amine fragment that may exert the same function with the active site residue H310 as the tertiary alcohol moiety in Fluconazole. However, to the best of our knowledge, so far the combination of a tetrazole ring with a tertiary amine fragment has not been reported.
2. Characterization of an exopolysaccharide from probiontEnterobacter faecalisMSI12 and its effect on the disruption of Candida albicansbiofilm
G. Seghal Kiran, S. Priyadharshini, K. Anitha, Elumalai Gnanamani and Joseph Selvin*. RSC Adv.,2015,5,71573–71585
A possible mechanism of destabilizing the EPS of biofilms includes breaking the bonds that connect polysaccharide residues in the EPS. This could be an effective means of dispersing biofilms and making the subjacent bacteria more susceptible to treatment by antibiotics. Enterococci are known for secretion of bacteriocins and therefore the EPS of E. faecalis MSI12 was expected to be synergized with antimi-crobial secretions. This study revealed that biofilm disruption/control using a probiont could deliver a synergistic approach as the probiotic strain can colonize in the host to prevent the formation of Candida biofilms. The EPS from Enterococcussp. MSI12 showed significant reduction of treated Candida biofilm. The antibiofilm potential of EPS was very stronger than the standard antifungal drug flonazole. The strainC. Albicans MTCC227 used in this study is resistant toflonazole. Previ-ously it was reported that even 3000mgml of fluconazole was not effective in inhibiting the growth ofC. albicansMTCC 227.36 The EPS produced by the probiotic E. faecalisMSI12 showed 100% disruption of C. albicansbiolm when compared with the drug flucanazole (80%). The literature shows that fluconazole is still used as drug in patients with candidemia or suspected invasive candidiasis. Fluconazole has excellentin vitro activity against C. albicans. Fluconazole can also be effective against non-albicans Candida species, including Candida parapsilosis, Candida tropicalisandCandida glabrata, although higher doses may be required. Usage of fluconazole has side effects and may cause gastrointestinal tract disorders like nausea, abdominal discomfort, vomiting, diar-rhea. The exopolysaccharides released by the biofilm of E. faecalis act as an effective antifungal as well as biofilm inhibi-tory agent. This study is the first report onE. Faecalisprobiotics from a marine environment as effective antifungal/anti biofilm agent.