Development of an orbital shaker-assisted fatty acid-based switchable solvent microextraction procedure for rapid and green extraction of amoxicillin from complex matrices: Central composite design.

In this study, a cheap, fast and simple orbital shaker-assisted fatty acid-based switchable solvent microextraction (OS-FASS-ME) procedure was developed for the extraction of amoxicillin (AMOX) in dairy products, pharmaceutical samples and wastewater prior to its spectrophotometric analysis. Fatty acid-based switchable solvents were investigated for extracting AMOX. The key factors of the OS-FASS-ME procedure were optimized using a central composite design. The linearity of OS-FASS-ME procedure was in the range 5-600 ng mL-1 with a correlation coefficient of 0.991. In five replicate experiments for 20 ng mL-1 of AMOX solution, the recovery and relative standard deviation were 95.8% and 2.2%, respectively. Limits of detection and quantification were found 1.5 ng mL-1 and 5 ng mL-1, respectively. The accuracy, precision, robustness and selectivity of the OS-FASS-ME procedure were investigated in detail under optimum conditions. The OS-FASS-ME procedure was applied to milk, cheese, wastewater, syrups and tablets. A comparison of the results obtained from the reference method and the OS-FASS-ME method showed that the OS-FASS-ME procedure can be successfully applied to complex matrices.

Ecotoxicology Evaluation of a Fenton-Type Process Catalyzed with Lamellar Structures Impregnated with Fe or Cu for the Removal of Amoxicillin and Glyphosate.

Antibiotics and pesticides, as well as various emerging contaminants that are present in surface waters, raise significant environmental concerns. Advanced oxidation processes, which are employed to eliminate these substances, have demonstrated remarkable effectiveness. However, during the degradation process, by-products that are not completely mineralized are generated, posing a substantial risk to aquatic ecosystem organisms; therefore, it is crucial to assess effluent ecotoxicity following treatment. This study aimed to assess the toxicity of effluents produced during the removal of amoxicillin and glyphosate with a Fenton-type process using a laminar structure catalyzed with iron (Fe) and copper (Cu). The evaluation included the use of Daphnia magna, Selenastrum capricornutum, and Lactuca sativa, and mutagenicity testing was performed using strains TA98 and TA100 of Salmonella typhimurium. Both treated and untreated effluents exhibited inhibitory effects on root growth in L. sativa, even at low concentrations ranging from 1% to 10% v/v. Similarly, negative impacts on the growth of algal cells of S. capricornutum were observed at concentrations as low as 0.025% v/v, particularly in cases involving amoxicillin-copper (Cu) and glyphosate with copper (Cu) and iron (Fe). Notably, in the case of D. magna, mortality was noticeable even at concentrations of 10% v/v. Additionally, the treatment of amoxicillin with double-layer hydroxides of Fe and Cu resulted in mutagenicity (IM ≥ 2.0), highlighting the necessity to treat the effluent further from the advanced oxidation process to reduce ecological risks.

Antimicrobial susceptibility of Clostridium perfringens isolated from piglets with or without diarrhea in Brazil

The minimum inhibitory concentration (MIC) was determined for 13 antibiotics against Clostridium perfringens isolated from Brazilian piglets. The collection of isolates was performed in June to October 2010. All isolates were susceptible to amoxicillin and ceftiofur, whereas most were resistant to tetracycline and lincomycin. Avilamycin and narasin were more effective against isolates from non-diarrheic than from diarrheic piglets. The other antimicrobials were less active in need of high concentrations to inhibit the growth of the C. perfringens type A. These results suggest the need for further studies evaluating molecular factors related to the antimicrobial resistance of C. perfringens.

Sensibilidad antibiótica y recomendaciones de tratamiento para Streptococcus pneumoniae / Antibiotic sensitivity and treatment recommendations for Streptococcus pneumoniae

El objetivo del presente trabajo fue conocer la sensibilidad antibiótica de Streptococcus pneumoniae a los antimicrobianos usados con más frecuencia en la práctica clínica y revisar las recomendaciones actuales de tratamiento de la enfermedad neumocócica. Durante el periodo octubre 2000 a septiembre 2002 se recogieron los datos demográficos, el diagnóstico clínico del paciente, el origen de la muestra y la sensibilidad antibiótica de todos los Streptococcus pneumoniae aislados en los laboratorios de microbiología del Servicio Navarro de Salud, que atienden a una población de 555.829 habitantes. Se obtuvieron 465 aislamientos de Streptococcus pneumoniae (166 de origen invasor). Los aislamientos procedentes de exudado ótico fueron los más resistentes y los de hemocultivo los más sensibles. El porcentaje de resistencia a penicilina fue del 43 por ciento, 6,1 por ciento para amoxicilina y 6,6 por ciento para cefotaxima. El 36,3 por ciento de los aislamientos fueron resistentes a eritromicina, de ellos un 85,45 por ciento exhibía un fenotipo MLSB y un 14,55 por ciento un fenotipo M. Se detectó multirresistencia en un 32,3 por ciento de los aislamientos. La resistencia de Streptococcus pneumoniae a betalactámicos, especialmente penicilina, amoxicilina y cefotaxima/ceftriaxona no impide su uso clínico en la mayoría de los aislamientos de Streptococcus pneumoniae de nuestra área, exceptuando los casos de meningitis neumocócica (AU)