In vitro porphyrin-based photodynamic therapy against mono and polyculture of multidrug-resistant bacteria isolated from integumentary infections in animals.

Multidrug-resistant (MDR) organisms have been frequently isolated from integumentary lesions of animals, and these lesions are usually infected by more than one pathogen. This study evaluated an in vitro antimicrobial photodynamic therapy (aPDT) using two water-soluble tetra-cationic porphyrins (3-H2TMeP and 4-H2TMeP) against mono and polyculture of MDR bacteria isolated from dogs, cats, and horses. Ten isolates of MDR bacteria (two of each species: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus pseudointermedius) were used to evaluate aPDT against the monoculture using a non-cytotoxic concentration of 3-H2TMeP and 4-H2TMeP porphyrins (40 µM), with 30 min of light irradiation in Gram-positive and 90 min for Gram-negative bacteria. The aPDT using the 4-H2TMeP porphyrin was also tested against five different polycultures (Coagulase positive Staphylococcus (CPS) and Pseudomonas sp.; E. coli and Proteus sp.; Pseudomonas sp. and Proteus sp.; CPS and E. coli; and CPS and Proteus sp.) for 90 min. The efficacy of both treatments was evaluated by plating the solution exposed to light or kept in the dark and counting the colonies forming units after 24 h of incubation at 37 °C. Atomic force microscope analysis was used to map bacteria morphological changes and extract adhesion force parameters from the bacteria membranes. Only the 4-H2TMeP porphyrin had antibacterial activity against MDR bacteria in monoculture, especially S. pseudointermedius and P. aeruginosa. In polyculture, the 4-H2TMeP porphyrin reduced bacterial concentrations (p < 0.05) in the associations of E. coli and S. pseudointermedius, P. aeruginosa and S. pseudointermedius, and P. aeruginosa and P. mirabilis. These results showed that aPDT using 4-H2TMeP is a good option for future associations of aPDT and other therapies or in vivo research.

Water Quality Assessment of the Pardo River Basin, Brazil: A Multivariate Approach Using Limnological Parameters, Metal Concentrations and Indicator Bacteria.

Located in the southeast of Brazil, the Pardo River Basin has a large population and an economy focused on agriculture, with a strong predominance of the sugarcane agro-industry. The purpose of the study was to assess the water quality of the Pardo River Basin under a multivariate approach using limnological parameters, metal concentrations, and indicator bacteria. Nine sampling campaigns were performed during both the dry and rainy seasons. Element concentrations were determined by inductively coupled plasma spectrometry (ICP-MS, Perkin Elmer Elan 6000). A battery of test to determine limnological parameters was performed (in situ). Total coliforms and Escherichia coli were detected and quantified using Defined Substrate Technology Colilert® and multiple tube dilutions. Principal component analysis and hierarchical cluster analysis were used as multivariate exploratory analysis. In general, the results suggest the influence of rain, possible sewage discharges into the watercourse, and the input of organic matter in some sampling points in both seasons, besides the absence of riparian vegetation in much of the Pardo River. The likely influence of industrial activities that do not have great prominence in the region was supported by temporal/spatial assessment of Cr and V. The water quality monitoring of Pardo River is an important tool for environmental management, and its continuity is indicated to obtain a consistent series of systematic data and thereby support concretely the actions of planning and controlling the use of water from the Pardo River and soil around them.

Health risks of environmental exposure to metals and herbicides in the Pardo River, Brazil.

Mixture of metals and herbicides in rivers may pose relevant risks for the health of surrounding communities. Humans may be exposed to river pollution through intake of contaminated water and fish, as well as irrigated agricultural products. The aim of this study was to assess the human health risks of environmental exposure to metals and herbicides through water and fish intake in the Pardo River. Metals (Al, As, Be, Cd, Cr, Cu, Pb, Mn, Hg, Ni, Tl, Sn, V, and Zn) were analyzed in river water and in edible fish. Herbicides (ametryn, atrazine, diuron, hexazinone, simazine, and tebuthiuron) were analyzed in river water. Seasonal variances were also studied. Aluminum, Cd, Cu, Mn, Pb, and Zn levels in river water were higher than the USEPA benchmarks. Non-carcinogenic risks due to pollutants mixture exposure were above the limit, and carcinogenic risks of As exposure were >10-6 in the sampling points during the rainy season. Metal levels in fish were lower than the Brazilian legislation and do not pose a threat to public health. Herbicides were detected in four sampling points, with atrazine concentrations (range 0.16-0.32 µg/L) below the Brazilian standard (2.0 µg/L), but above the European Union standard (0.1 µg/L). Considering the water supply needs of cities located in the Pardo River Basin and the persistence of metals and herbicides, the present study indicated that there was a seasonal influence on non-carcinogenic and carcinogenic risks to human health, especially in the rainy season. Studies for water treatment plants implantation should consider the risks of exposure to persistent substances, in order to protect the population.

Integrating three tools for the environmental assessment of the Pardo River, Brazil.

There is a growing need for strategic assessment of environmental conditions in river basins around the world. In spite of the considerable water resources, Brazil has been suffering from water quality decrease in recent years. Pardo River runs through Minas Gerais and São Paulo, two of the most economically important states in Brazil, and is being currently promoted as a future drinking water source. This study aimed at integrating three different tools to conduct a hydromorphological assessment focused on the spatial complexity, connectivity, and dynamism of the Pardo River, Brazil. Twelve sampling stretches were evaluated in four sampling campaigns, in dry and rainy seasons. In each stretch, permanent preservation areas (PPAs), hydromorphological integrity by rapid assessment protocol (RAP), and physicochemical parameters were qualified. The kappa coefficient was used to assess statistical agreement among monitoring tools. The PPA analysis showed that in all stretches, the vegetation was modified. RAP results revealed environmental deterioration in stretches located near human activities and less variability of substrates available for aquatic fauna and sediment deposition as well. Low values for dissolved oxygen in the river mouth were noted in the rainy season. Electrical conductivity was higher in stretches near sugarcane crops. The poor agreement (k<0.35) between the RAP and physicochemical parameters indicates that the tools generate different and complementary information, while they are not replaceable. Potential changes of the hydromorphological characteristics and variations in physicochemical indicators must be related to extensive PPA modification.