Antibiotic resistance in Pseudomonas aeruginosa and alternative therapeutic options.

Pseudomonas aeruginosa is a leading cause of nosocomial infections and is responsible for ∼10% of all hospital-acquired infections worldwide. It continues to pose a therapeutic challenge because of the high rate of morbidity and mortality associated with it and the possibility of development of drug resistance during therapy. Standard antibiotic regimes against P. aeruginosa are increasingly becoming ineffective due to the rise in drug resistance. With the scope for developing new antibiotics being limited, alternative treatment options are gaining more and more attention. A number of recent studies reported complementary and alternative treatment options to combat P. aeruginosa infections. Quorum sensing inhibitors, phages, probiotics, anti-microbial peptides, vaccine antigens and antimicrobial nanoparticles have the potential to act against drug resistant strains. Unfortunately, most studies considering alternative treatment options are still confined in the pre-clinical stages, although some of these findings have tremendous potential to be turned into valuable therapeutics. This review is intended to raise awareness of several novel approaches that can be considered further for combating drug resistant P. aeruginosa infections.

Chemical modifications of cinchona alkaloids lead to enhanced inhibition of human butyrylcholinesterase.

Butyrylcholinesterase (BChE) inhibitors were identified from a collection containing cinchonine, cinchonidine and synthetic derivatives, and further characterized using cytotoxicity and molecular docking studies. The most active ones were: (10 triple bond)-10,11-dibromo-10,11-dihydrocinchonidine (11), a competitive inhibitor with Ki = 3.45 +/- 0.39 microM, and IC50 BChE = 9.83 +/- 0.30 microM/human (h)BChE = 34.47 +/- 4.63 and O-(trimethylsilyl)cinchonine (15), a mixed inhibitor with Kiuc = 1.73 +/- 0.46 microM and Kic = 0.85 +/- 0.26 microM, and IC50 BChE = 0.56 +/- 0.14 microM/hBChE = 0.24 +/- 0.04. In cytotoxicity experiments, > or = 80% of the cells remained viable when exposed to concentrations of up to 80 microM of both inhibitors in four different cell lines, including neurons. Due to the bulkier trimethylsilyl side group of 15, it covered the active site of hBChE better than 11 with an OH-group while not being able to fit into the active site gorge of hAChE, thus explaining the selectivity of 15 towards hBChE.