Samadi, Nasrin, Abadian, Neda, Ahmadkhaniha, Reza, Amini, Farzaneh, Dalili, Dina, Rastkari, Noushin, Safaripour, Eliyeh, and Mohseni, Farzaneh Aziz
Folia microbiologica, 2012 Nov., v. 57, no. 6, p. 501-508.
Subjects
liquid chromatography, oxacillin, antibiotic resistance, bioassays, surface tension, biosurfactants, bioactive properties, MS, tandem mass spectrometry, synergism, chemical structure, Pseudomonas aeruginosa, Staphylococcus aureus, rhamnose, polluted soils, minimum inhibitory concentration, micelles, and methicillin
Abstract
The aim of present work was to study chemical structures and biological activities of rhamnolipid biosurfactants produced by Pseudomonas aeruginosa MN1 isolated from oil-contaminated soil. The results of liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed that total rhamnolipids (RLs) contained 16 rhamnolipid homologues. Di-lipid RLs containing C10-C10 moieties were by far the most predominant congeners among mono-rhamnose (53.29 %) and di-rhamnose (23.52 %) homologues. Mono-rhamnolipids form 68.35 % of the total congeners in the RLs. Two major fractions were revealed in the thin layer chromatogram of produced RLs which were then purified by column chromatography. The retardation factors (R f) of the two rhamnolipid purple spots were 0.71 for RL1 and 0.46 for RL2. LC-MS/MS analysis proved that RL1 was composed of mono-RLs and RL2 consisted of di-RLs. RL1 was more surface-active with the critical micelle concentration (CMC) value of 15 mg/L and the surface tension of 25 mN/m at CMC. The results of biological assay showed that RL1 is a more potent antibacterial agent than RL2. All methicillin-resistant Staphylococcus aureus (MRSA) strains were inhibited by RLs that were independent of their antibiotic susceptibility patterns. RLs remarkably enhanced the activity of oxacillin against MRSA strains and lowered the minimum inhibitory concentrations of oxacillin to the range of 3.12–6.25 μg/mL.
Journal of essential oil-bearing plants, 2011 Jan. 1, v. 14, no. 6, p. 684-692.
Subjects
oxacillin, bacterial infections, bacteria, synergism, essential oils, drug resistance, antibacterial properties, Staphylococcus aureus, minimum inhibitory concentration, and methicillin
Abstract
In this study the essential oil of Thymus kotschyanus Boiss. & Hohen, which is endemic of Iran, was investigated for its antibacterial activity and its combined effects with oxacillin or methicillin against several clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations of oxacillin, methicillin and essential oil against MRSA strains were determined by the micro-dilution method. Synergy testing of each antibiotic and essential oil against MRSA was performed by the checkerboard technique. The results indicated that T. kotschyanus essential oil had synergistic effect with oxacillin or methicillin against MRSA strains. The best synergistic effect obtained against MRSA5 and S. aureus ATCC 33591 which resulted in 32 times decrease in MIC values of oxacillin and methicillin. The synergistic activity showed that this non-antibiotic agent manifests a broad spectrum of activity against MRSA bacteria which might open a new therapeutic approach to combat drug-resistance in bacterial infections.
Original Article, Microbial contamination, MDVs, ADXs, Hospitals, and hormones, hormone substitutes, and hormone antagonists
Abstract
There is possibility of microbial contamination of any single-dose vials (SDVs), multiple-dose vials (MDVs) and admixtures (ADXs) during the preparation and injection to the patients that could be resulted in bloodstream infection. The goal of this study was to investigate the microbial contamination of MDVs and SDVs after multiple use and ADXs prepared by nursing staff in the treatment room versus those prepared by the hospital pharmacist in the clean room. The sterility of 43 opened MDVs and SDVs, 92 prepared ADXs in treatment room and 17 prepared ADXs in clean room were studied by membrane filtration method. Only one of 92 ADXs prepared in treatment room was contaminated with Bacillus subtilis (%1.1) and none of the ADXs prepared in clean room, MDVs and SDVs had microbial contamination. Although good sanitization practices and training of nurses could reduce the risk of microbial contamination in traditional units, using clean room for preparation of parenteral products could be the best strategy.
Journal of Essential Oil Bearing Plants; January 2011, Vol. 14 Issue: 6 p684-692, 9p
Abstract
AbstractIn this study the essential oil of Thymus kotschyanusBoiss. & Hohen, which is endemic of Iran, was investigated for its antibacterial activity and its combined effects with oxacillin or methicillin against several clinical isolates of methicillin-resistant Staphylococcus aureus(MRSA). The minimum inhibitory concentrations of oxacillin, methicillin and essential oil against MRSA strains were determined by the micro-dilution method. Synergy testing of each antibiotic and essential oil against MRSA was performed by the checkerboard technique. The results indicated that T. kotschyanusessential oil had synergistic effect with oxacillin or methicillin against MRSA strains. The best synergistic effect obtained against MRSA5 and S. aureusATCC 33591 which resulted in 32 times decrease in MIC values of oxacillin and methicillin. The synergistic activity showed that this non-antibiotic agent manifests a broad spectrum of activity against MRSA bacteria which might open a new therapeutic approach to combat drug-resistance in bacterial infections.