Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida.

The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure period of 2 days; and mortality, weight loss, enzymatic activities (cholinesterase, lactate dehydrogenase and alkaline phosphatase) and histopathological effects after an exposure period of 14 days. Carbendazim was found to be highly toxic to E. fetida (LC50=2mg/kg d.w.), significantly reducing earthworm weight and showing an avoidance response at soil concentrations that are close to those predicted in rice-fields and in surrounding ecosystems. The insecticide dimethoate showed a moderate acute toxicity (LC50=28mg/kg d.w.), whereas the rest of tested pesticides showed low toxicity potential (LC50 values above 100mg/kg d.w.). For these pesticides, however, weight loss was identified as a sensitive endpoint, with NOEC values approximately 2 times or lower than the calculated LC10 values. The investigated effects on the enzymatic activities of E. fetida and the observed histopathological alterations (longitudinal and circular muscle lesions, edematous tissues, endothelial degeneration and necrosis) proved to be sensitive biomarkers to monitor pesticide contamination and are proposed as alternative measures to evaluate pesticide risks on agro-ecosystems.

Prevalence and Characterization of Beta-Lactam and Carbapenem-Resistant Bacteria Isolated from Organic Fresh Produce Retailed in Eastern Spain.

Fresh fruits and vegetables are potential reservoirs for antimicrobial resistance determinants, but few studies have focused specifically on organic vegetables. The present study aimed to determine the presence of third-generation cephalosporin (3GC)- and carbapenem-resistant Gram-negative bacteria on fresh organic vegetables produced in the city of Valencia (Spain). Main expanded spectrum beta-lactamase (ESBL)- and carbapenemase-encoding genes were also detected in the isolates. One hundred and fifteen samples were analyzed using selective media supplemented with cefotaxime and meropenem. Resistance assays for twelve relevant antibiotics in medical use were performed using a disc diffusion test. A total of 161 isolates were tested. Overall, 33.5% presented multidrug resistance and 16.8% were resistant to all ß-lactam antibiotics tested. Imipenem resistance was observed in 18% of isolates, and low resistance levels were found to ceftazidime and meropenem. Opportunistic pathogens such as Acinetobacter baumannii, Enterobacter spp., Raoultella sp., and Stenotrophomonas maltophilia were detected, all presenting high rates of resistance. PCR assays revealed blaVIM to be the most frequently isolated ESBL-encoding gene, followed by blaTEM and blaOXA-48. These results confirm the potential of fresh vegetables to act as reservoirs for 3GC- and carbapenem-producing ARB. Further studies must be carried out to determine the impact of raw organic food on the spread of AMRs into the community.

Distal osteotomy of the first metatarsal bone for the correction of hallux valgus: comparison of the sagittal stability of two percutaneous techniques-a cadaveric study.

BACKGROUND: Distal first metatarsal osteotomy is used to correct mild or moderate hallux valgus (HV). We designed a cadaveric study to compare the resistance to axial load between two percutaneous distal first metatarsal osteotomies: Bösch osteotomy and percutaneous chevron. The first aim of this study was to develop a systematic technique for measuring the sagittal displacement on lateral foot X-rays. Our second objective was to measure the resistance to axial load for both of these osteotomies. METHODS: Ten pairs of freshly frozen cadaveric feet were randomly assigned to one of the two techniques investigated. Pre- and post-operative lateral X-rays were obtained. After surgery, the feet were placed under progressive axial loads up to 60 kg. Metaphyseo-diaphyseal angle (MDA) and the distance between bone fragments were measured, and the differences between the two techniques were statistically assessed. RESULTS: The MDA decreased in both surgical techniques. The mean plantar tilt was -6.90 degrees (SD = 10.251) for chevron osteotomy and -5.34 degrees (SD = 16.621) for Bösch osteotomy. There was no significant difference between the techniques (p = 0.41). Regarding the distance between the bone fragments, the Bösch osteotomy produced more plantar displacement than the chevron osteotomy, which was statistically significant for the 10 and 20 kg loads (p = 0.031 and 0.04, respectively). At loads ≥ 30 kg, the bone fragment distance did not differ significantly between the techniques (p = 0.114). CONCLUSIONS: Although the chevron technique confers higher stability regarding fragment displacement during axial loading, both techniques increase the plantar angulation of the metatarsal head. LEVEL OF EVIDENCE: Cadaveric study.

Monitoring photolysis and (solar photo)-Fenton of enrofloxacin by a methodology involving EEM-PARAFAC and bioassays: Role of pH and water matrix.

The degradation of enrofloxacin (ENR) by direct photolysis, Fenton and solar photo-Fenton processes has been studied in different water matrices, such as ultra-pure water (MQ), tap water (TW) and highly saline water (SW). Reactions have been conducted at initial pH 2.8 and 5.0. At pH = 2.8, HPLC analyses showed a fast removal of ENR by (solar photo)-Fenton treatments in all studied water matrices, whereas a 40% removal was observed after 120 min of photolysis. However, TOC measurements showed that only solar photo-Fenton was able to produce significant mineralization (80% after 120 min of treatment); differences between ENR removal and mineralization can be attributed to the release of important amounts of reaction by-products. Excitation-emission matrices (EEMs) combined with parallel factor analysis (PARAFAC) were employed to gain further insight into the nature of these by-products and their time-course profile, obtaining a 5-component model. EEM-PARAFAC results indicated that photolysis is not able to produce important changes in the fluoroquinolone structure, in sharp contrast with (solar photo)-Fenton, where decrease of the components associated with fluoroquinolone core was observed. Agar diffusion tests employing E. coli and S, aureus showed that the antibiotic activity decreased in parallel with the destruction of the fluoroquinolone core.

A mechanistic study on the potential of quinolinium salts as photocatalysts for the abatement of chlorinated pollutants.

Photocatalytic degradation of three highly chlorinated contaminants, namely 2,4,6-trichlorophenol (TCP), 2,4,6-trichloroanisole (TCA) and 5-chloro-2-(2,4-dichlorophenoxy)phenol (triclosan, TCS) has been investigated in the presence of N-methylquinolinium tetrafluoroborate (NMQ+), a photocatalyst able to act via Type I or Type II mechanism. Photodegradation of contaminants under aerobic conditions was achieved within hours; and it was accompanied by mineralization, as demonstrated by trapping of the evolved carbon dioxide as barium carbonate. Moreover, a high degree of detoxification, based on % inmobilization of daphnids (Daphnia magna bioassay), was reached after 70 h of irradiation. Quenching of the NMQ+ fluorescence by the pollutants was evidenced by a decrease in the emission intensity and lifetime. Detection of the reduced NMQ· by laser flash photolysis in the presence of the pollutants provided an unambigous evidence of the electron transfer process. Quenching of singlet oxygen by the contaminants showed the typical singlet oxygen quenching constants (105-106 M-1 s-1). Evaluation of the relative contribution of both pathways (Type I vs Type II) point to the photodegradation occurring via a Type I mechanism, being the contribution of Type II mechanism negligible at any concentration range.

Determination of trichothecenes, zearalenone and zearalenols in commercially available corn-based foods in Spain.

Among the main Spanish commercially available trademarks, we have selected a total of 25 samples of corn-based foods, which have the highest consume rate, to carry out the analysis of deoxynivalenol (DON), T-2 toxin, zearalenone (ZEA) and zearalenols (ZOL). The contents of mycotoxins were determined by gas chromatography with flame ionization detection, and those of ZEA were confirmed by HPLC with fluorescence detection. Of the 25 analyzed samples, the incidence of DON, ZEA and alfa-ZOL was 68, 44 and 24%, respectively; levels detected ranged from 29-195, 34-216, and 36-71 microg/kg, respectively. T-2 toxin was only detected in one sample (<50 microg/kg). Beta-ZOL was not present in excess of the detection limit in the investigated samples. The results suggest a risk for consumers of corn products and the need to monitor the final products before consumption. This is the first report in Spain on natural contamination with these mycotoxins in corn-based foods.