Antimicrobial activities of the crude ethanolic extracts of five plants were screened against multidrug resistant (MDR) strains of Escherichia coli, Klebsiella pneumoniae and Candida albicans. ATCC strains of Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, Streptococcus bovis, Pseudimonas aeruginosa, Salmonella typhimurium, Escherichia coli, Klebsiella pneumoniae and Candida albicans were also tested. The strains that showed resistance against the maximum number of antibiotics tested were selected for an antibacterial assay. The MDR strains were sensitive to the antimicrobial activity of Acacia nilotica, Syzygium aromaticum and Cinnamum zeylanicum, whereas they exhibited strong resistance to the extracts of Terminalia arjuna and Eucalyptus globulus. Community-acquired infections showed higher sensitivity than the nosocomial infections against these extracts. The most potent antimicrobial plant was A. nilotica (MIC range 9.75-313µg/ml), whereas other crude plant extracts studied in this report were found to exhibit higher MIC values than A. nilotica against community acquired as well as nosocomial infection. This study concludes that A. nilotica, C. zeylanicum and S. aromaticum can be used against multidrug resistant microbes causing nosocomial and community acquired infections.

Since 1944, we have come a long way using aminoglycosides as antibiotics. Bacteria also have got them selected with hardier resistance mechanisms. Aminoglycosides are aminocyclitols that kill bacteria by inhibiting protein synthesis as they bind to the 16S rRNA and by disrupting the integrity of bacterial cell membrane. Aminoglycoside resistance mechanisms include: (a) the deactivation of aminoglycosides by N-acetylation, adenylylation or O-phosphorylation, (b) the reduction of the intracellular concentration of aminoglycosides by changes in outer membrane permeability, decreased inner membrane transport, active efflux, and drug trapping, (c) the alteration of the 30S ribosomal subunit target by mutation, and (d) methylation of the aminoglycoside binding site. There is an alarming increase in resistance outbreaks in hospital setting. Our review explores the molecular understanding of aminoglycoside action and resistance with an aim to minimize the spread of resistance.

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Candida sp. impelled opportunistic infection in immune-compromised patients ensuing from asymptomatic colonization to pathogenic forms. Moreover, slow spread of Candida species inducing refractory mucosal and invasive infections brings acute resistance to antifungal drugs. Hence, here we probed the effect of encapsulated preparation of cinnamaldehyde (CNMA) in multilamellar liposomes (ML) against Candida albicans. The efficacy of ML-CNMA against Candida biofilm was assessed by scanning electron microscopy, transmission electron microscopy, as well as light microscopy and its percent inhibition, was determined by XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] and crystal violet assay. ML-CNMA showed more fungicidal activity than free CNMA as well as multilamellar liposomal amphotericin B (ML-Amp B), which was further confirmed by spot test assay and Log-logistic dose–response analysis. Antifungal activity was driven by reactive oxygen species and cellular damage by sustained release of CNMA. Effect on hyphal formation during 48 h in presence/absence of ML-CNMA was observed under a microscope and further substantiated by RT-PCR by amplifying HWP1, the gene responsible for hyphal wall protein formation. Apoptotic programmed cell death was analyzed by FACS analysis which was further confirmed by cytochrome C release assay. This study elucidates the mechanistic insight of the enhanced antifungal activity of ML preparation of CNMA against Candida infections.

Background: The emerging trends of multidrug resistance among several groups of microorganisms against different classes of antibiotics led different researchers to develop efficient drugs from plant sources to counter multidrug resistant strains. This study investigated different solvent extracts of Prosopis spicigera (P. Spicigera), Zingiber officinale, and Trachyspermum ammi (T. ammi) to determine their efficacy against multidrug resistant microbes. Methodology: Successive extractions of these plants were performed using a Soxhlet apparatus, using solvents with increasing polarities. Preliminary phytochemical analysis was also performed .Minimum inhibitory concentration was determined by a two-fold serial dilution method followed by determination of minimum bactericidal/fungicidal concentration. Multidrug resistant (MDR) strains of Candida albicans, Candida krusei, Candida tropicalis, Candida glabrata, Escherichia coli and reference strains of Streptococcus mutans and Streptococcus bovis were used in the study. Results: The ethanolic fraction of P. spicigera (least minimum inhibitory concentration [MIC] -4.88 µg/ml) demonstrated a remarkable inhibition of the microorganisms while fractions obtained from those of Zingiber officinale (least MIC-78.125 µg/ml) exhibited little activity. The petroleum ether fraction of T. ammi (least MIC-625 µg/ml) showed best activity when compared to its other fractions. Qualitative analysis of the phytoconstituents was also performed. Conclusions: The potency shown by these extracts recommends their use against multidrug resistant microorganisms. This study also showed that P. spicigera could be a potential source of new antimicrobial agents.