Antimicrobial effects of Medicines for Malaria Venture Pathogen Box compounds on strains of Neisseria gonorrhoeae.

Therapeutic options for Neisseria gonorrhoeae are limited due to emerging global resistance. New agents and treatment options to treat patients with susceptible and multi-extensively drug-resistant N. gonorrhoeae is a high priority. This study used an in vitro approach to explore the antimicrobial potential, as well as synergistic effects of Medicine for Malaria Venture (MMV) Pathogen Box compounds against ATCC and clinical N. gonorrhoeae strains. Microbroth dilution assay was used to determine pathogen-specific minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the Pathogen Box compounds against susceptible and resistant N. gonorrhoeae strains, with modification, by adding PrestoBlue HS Cell Viability Reagent. A checkerboard assay was used to determine synergy between the active compounds and in conjunction with ceftriaxone. Time-kill kinetics was performed to determine if the compounds were either bactericidal or bacteriostatic. The Pathogen Box compounds: MMV676501, MMV002817, MMV688327, MMV688508, MMV024937, MMV687798 (levofloxacin), MMV021013, and MMV688978 (auranofin) showed potent activity against resistant strains of N. gonorrhoeae at an MIC and MBC of ≤10 µM. Besides the eight compounds, MMV676388 and MMV272144 were active against susceptible N. gonorrhoeae strains, also at MIC and MBC of ≤10 µM. All the compounds were bactericidal and were either synergistic or additive with fractional inhibitory concentration index ranging between 0.40 and 1.8. The study identified novel Pathogen Box compounds with potent activity against N. gonorrhoeae strains and has the potential to be further investigated as primary or adjunctive therapy to treat gonococcal infections.

In-vitro Bactericidal Activity of a Novel Plant Source Plumeria pudica against Some Human and Fish Pathogenic Bacteria.

BACKGROUND: The only remedy for up surging problem of antibiotic resistance is the discovery of antibacterial agents of natural origin. OBJECTIVE: The present study was aimed at finding antibacterial potential of crude and solvent extracts of mature leaves of Plumeria pudica. METHODS: Antibacterial activity of three different solvent extracts were evaluated in four human and four fish pathogenic bacteria by measuring the zone of inhibition and determining Minimum Inhibitory Concentration and Minimum Bactericidal Concentration values. Standard antibiotics were used as positive control. Preliminary phytochemical screening of most effective extract i.e., ethyl acetate extract, Fourier Transform Infra Red analysis and GC-MS analysis of the Thin Layer Chromatographic (TLC) fraction of ethyl acetate extract were done meticulously. All experiments were done thrice and analyzed statistically. RESULTS: Crude leaf extracts and solvent extracts caused good inhibition of bacterial growth in all selected bacteria. Ethyl acetate extract showed highest inhibition zones in all tested strains with maximum inhibition (19.50±0.29 mm) in Escherichia coli (MTCC 739). MBC/MIC of the extracts indicated that all three solvent extracts were bactericidal. Preliminary phytochemical tests revealed the presence of tannins, steroids and alkaloids and FT-IR analysis revealed presence of many functional groups namely alcoholic, amide, amine salt and aldehyde groups. From the GC-MS analysis of TLC fraction of ethyl acetate extract, five different bioactive compounds e.g., 2,4-ditert -butylphenyl 5-hydroxypentanoate, Oxalic acid; allyl nonyl ester, 7,9-Ditert-butyl-1-oxaspiro(4,5)deca-6,9-diene- 2,8-dione, Dibutyl phthalate and 2,3,5,8-tetramethyl-decane were identified. CONCLUSION: Leaf extracts of P. pudica contain bioactive compounds that can be used as broad spectrum bactericidal agent.

Evaluation of In Vitro Bactericidal Activity of Disinfectants against Major Nosocomial Pathogens / 병원감염관리

BACKGROUND: Disinfectants play an important role in preventing nosocomial infection. But the misuse of disinfectants may lead to waste money and decrease the effectiveness of disinfectants by emergence of resistant-bacteria. We studied to evaluate the in vitro bactericidal activity of various disinfectants used in the hospital against major nosocomial pathogens. METHOD: Disinfectants studied were chlorhexidine (0.05%, 0.1 %, 02%, 0.5%, 1%), hibicol 0.5%, alkyl diaminoethyl glycine (0.01 %. 0.05%, 0.1%. 0.5%, 1%), benzalkonium chloride (0, 1%, 0.3%), hydrogen peroxide (1.5%,3%), isopropyl alcohol 70%, potadine iodine(7.5%, 10%), and gentian violet (0.01 %, 0.1%, 1%). Bactericidal activity of disinfectants was assessed against MRSA (methicillin-resistant S. aureus), P. aeruginosa, VRE (vancomycin-resistant enterococci), K. pneumoniae. CNS (coagulase-negative staphylococci) and C albicens. Those microorganisms were obtained from the patients with hospital-acquired infections, In vitro susceptibility was determined using a macrodilution method with various exposure times to several concentrations of disinfectants of 30sec, 1 min, 2 min, 5 min, 15 min and 30 min. RESULT: Microorganism studied were killed after exposure to hibicol 0,5%, isopropyl alcohol 70%, pcradme iodine (7.5%, 10%) within 30sec. 0.05% chlorhexidine needs exposure time above 5 min for bactericidal action. 0.01% alkyl diaminoethyl glycine needs exposure time above 15 min. 0.1% and 0.3% benzalkonium chloride needs exposure time above 1 min. MRSA and P. aeruginosa were killed within 30sec after exposure to gentian violet (GV), but against CNS, 0.01% GV needs exposure time for 15min and 0.1% and 1% GV needs exposure time for 2 min. C. albicans were killed above 1 min. K. pneumoniae was not killed at all. H202 was ineffective for all tested bacteria. CONCLUSION: The results of this study show most disinfectants used in our hospital demonstrated bactericidal activity against major nosocomial pathogens. In-house diluted, 3% H202 failed to demonstrate killing of any microorganisms tested. The appropriate selection of disinfectants regarding to concentration and exposure time was necessary to inhibit growth of major nosocomial pathogens.