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1.
J Environ Manage ; 285: 112204, 2021 May 01.
Article in English | MEDLINE | ID: mdl-33618138

ABSTRACT

This work aimed to assess the elimination and inactivation of resistance-conferring plasmids (RCPs) present in suspension in secondary wastewater by solar photo-Fenton as these are important vectors for the dissemination of antimicrobial resistance. Experiments were performed in synthetic secondary wastewater (SWW) and municipal wastewater treatment plant effluent (MWWTPE). Solar photo-Fenton (50 mg L-1 of H2O2 and 30 mg L-1 of Fe2+) was carried out for 60 min at neutral pH by applying the intermittent iron addition strategy. The removal of RCPs was assessed by Real-Time Polymerase Chain Reaction (qPCR). The transformation of competent non-resistant E. coli was used to evaluate the inactivation of target RCPs harboring antibiotic resistance genes (ARGs) to ampicillin (pSB1A2) or kanamycin (pSB1K3) after treatment and controls. Solar photo-Fenton completely removed RCPs initially present in both matrixes (SWW and MWWTPE), showing enhanced performance compared to the dark Fenton process. Both RCPs were inactivated after 30 min of solar photo-Fenton treatment, while 60 min were necessary to achieve the same effect for the dark Fenton reaction under similar conditions. These results indicate the potential of solar photo-Fenton to improve wastewater quality and reduce the spread of antimicrobial resistance in the environment by hampering the discharge of cell-free RCPs present in suspension in MWWTP onto environmental waters.


Subject(s)
Wastewater , Water Pollutants, Chemical , Anti-Bacterial Agents , DNA , Drug Resistance, Bacterial/genetics , Escherichia coli/genetics , Hydrogen Peroxide , Oxidation-Reduction , Plasmids/genetics
2.
Ecotoxicol Environ Saf ; 143: 57-61, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28501730

ABSTRACT

Control of Culex quinquefasciatus using chemical insecticides may result in the selection of resistant mosquito strains. Thus, the use of plant-derived products has been studied as alternative for the mosquito control. Fatty acid methyl esters (FAMEs) obtained by transesterification of vegetable oils may result in compounds with larvicidal potential against C. quinquefasciatus. However, little is known about the morphological, physiological or biochemical effects that these FAMEs may have on mosquito larvae. The present study reports the effects of these FAMEs in mosquito larvae. The FAMEs were obtained by transesterification of canola, corn, sunflower, and soybean oils with acid catalysis and the determination of FAMEs composition was done by gas chromatography-mass spectrometry (GC-MS). Larvae of C. quinquefasciatus were exposed to different concentrations of the vegetable oils and FAMEs. Thereby, different FAMEs showed LC50 values ranging from 42.32 to 196.27mg/L against C. quinquefasciatus larvae. The methyl ester obtained from sunflower oil showed the lowest LC50. Histology of C. quinquefasciatus larvae exposed to LC50 of FAMEs was performed and changes in the midgut and fat body morphology were identified. Therefore, larval mortality and changes in the internal organs suggested that FAMEs might be a promising new class of larvicidalcompounds. Cytotoxicity of FAMEs compounds was assessed with the HeLa human cell line and no effect was observed.


Subject(s)
Culex/drug effects , Fatty Acids/pharmacology , Insecticides/pharmacology , Mosquito Control/methods , Plant Oils/pharmacology , Animals , Cell Survival/drug effects , Fatty Acids/chemistry , Fatty Acids/toxicity , Gas Chromatography-Mass Spectrometry , HeLa Cells , Humans , Insecticides/chemistry , Larva/drug effects , Lethal Dose 50 , Plant Oils/chemistry , Plant Oils/toxicity , Sunflower Oil
3.
Braz. j. microbiol ; 45(4): 1341-1347, Oct.-Dec. 2014. graf, tab
Article in English | LILACS | ID: lil-741285

ABSTRACT

Bacterial infections cause thousands of deaths in the world every year. In most cases, infections are more serious because the patient is already weakened, and often, the bacteria are already resistant to the antibiotics used. Counterparting this negative scenario, the interest in medicinal plants as an alternative to the synthetic antimicrobial drugs is blossoming worldwide. In the present work, we identified the volatile compounds of ethanol extracts of Melissa officinalis, Mentha sp., Ocimum basilicum, Plectranthus barbatus, and Rosmarinus officinalis by gas chromatography/mass spectrometry (GC/MS). Also was evaluated antimicrobial activity of ethanol extracts against 6 bacteria of clinical interest, and was tested the interaction of these extracts with a commercial antibiotic streptomycin. Phytol was a compound identified in all extracts by GC/MS, being majoritary component in Plectranthus barbatus and Rosmarinus officinalis. The Gram-positive bacteria were more sensitive to ethanol extracts, and Plectranthus barbatus and Rosmarinus officinalis were the most active extracts. Ethanol extracts exhibited a synergetic effect with streptomycin. These results encourage additional studies, in order to evaluate the possibilities of using ethanol extracts of Lamiaceae family as natural source for antibacterial activity.


Subject(s)
Humans , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Drug Synergism , Lamiaceae/chemistry , Plant Extracts/pharmacology , Streptomycin/pharmacology , Volatile Organic Compounds/pharmacology , Anti-Bacterial Agents/isolation & purification , Gas Chromatography-Mass Spectrometry , Microbial Sensitivity Tests , Plant Extracts/isolation & purification , Volatile Organic Compounds/isolation & purification
4.
Braz J Microbiol ; 45(4): 1341-7, 2014.
Article in English | MEDLINE | ID: mdl-25763039

ABSTRACT

Bacterial infections cause thousands of deaths in the world every year. In most cases, infections are more serious because the patient is already weakened, and often, the bacteria are already resistant to the antibiotics used. Counterparting this negative scenario, the interest in medicinal plants as an alternative to the synthetic antimicrobial drugs is blossoming worldwide. In the present work, we identified the volatile compounds of ethanol extracts of Melissa officinalis, Mentha sp., Ocimum basilicum, Plectranthus barbatus, and Rosmarinus officinalis by gas chromatography/mass spectrometry (GC/MS). Also was evaluated antimicrobial activity of ethanol extracts against 6 bacteria of clinical interest, and was tested the interaction of these extracts with a commercial antibiotic streptomycin. Phytol was a compound identified in all extracts by GC/MS, being majoritary component in Plectranthus barbatus and Rosmarinus officinalis. The Gram-positive bacteria were more sensitive to ethanol extracts, and Plectranthus barbatus and Rosmarinus officinalis were the most active extracts. Ethanol extracts exhibited a synergetic effect with streptomycin. These results encourage additional studies, in order to evaluate the possibilities of using ethanol extracts of Lamiaceae family as natural source for antibacterial activity.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Drug Synergism , Lamiaceae/chemistry , Plant Extracts/pharmacology , Streptomycin/pharmacology , Volatile Organic Compounds/pharmacology , Anti-Bacterial Agents/isolation & purification , Gas Chromatography-Mass Spectrometry , Humans , Microbial Sensitivity Tests , Plant Extracts/isolation & purification , Volatile Organic Compounds/isolation & purification
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