Multi-biomarkers approach to determine the toxicological impacts of sulfamethoxazole antibiotic on freshwater fish Cyprinus carpio.

Antibiotics are increasingly detected in the aquatic environment and are raising severe concerns for human and ecological health. Sulfamethoxazole being a widely recommended antibiotic in both human and veterinary medicine is consequently found in the aquatic environment. The current research was aimed to investigate the potential bioaccumulation and sub-lethal toxicity in terms of oxidative stress and histopathology of targeted antibiotic sulfamethoxazole in Cyprinus carpio at environmentally relevant concentrations over a prolonged period. Fish were exposed for 28 days to environmentally realistic concentrations (25-200 µg/L) of sulfamethoxazole. HPLC analysis revealed an inverse relationship between dosages applied and bioaccumulation in fish muscle tissues. The highest concentrations of sulfamethoxazole in the muscle tissues exposed to 25, 50, 100 and 200 µg/L were 124, 202,104.5, and 123.2 ng/g, respectively at different sampling times. Moreover, exposure to sulfamethoxazole enabled ROS (Reactive oxygen species) production in both brain and gill tissues of fish, where the increase in ROS formation was dose and time dependent. Furthermore, histopathological analysis of gills and liver revealed various alterations including pycnotic nuclei, bile stagnation, vacuolization in the liver, and partial and complete fusion of lamella and blood congestion in gills, respectively. Organ pathological index also revealed that the intensity of tissue damage increased as sulfamethoxazole dosage was increased. Quantitative evaluation of gills morphometric parameters divulged that severity of histopathological changes increased with time for all the exposed groups at the end of exposure time (28th day) indicating physio-metabolic turmoil caused by molecular and biochemical action of sulfamethoxazole. In conclusion, the assessment of bioaccumulative potential, measurement of ROS, and histopathology of Cyprinus carpio appeared to be a useful biomarker to evaluate the toxic impacts of antibiotics on the health of fish.

Removal of levofloxacin from aqueous solution by green synthesized magnetite (Fe3O4) nanoparticles using Moringa olifera: Kinetics and reaction mechanism analysis.

Levofloxacin antibiotic is frequently being detected in the environment and regarded as an emerging contaminant. The present study was focused on the green synthesis of magnetite (Fe3O4 - gINPs) nanoparticles from Moringa olifera and its efficiency for removal of levofloxacin from aqueous solution. The adsorbent magnetite nanoparticles (Fe3O4) were prepared by green synthesis using Moringa olifera and coprecipitation method. Characterizations analyses of both chemically and green synthesized nanoparticles were performed by SEM, XRD, and FTIR. The average crystallite size of gINPs was 14.34 nm and chemically synthesized was 18.93 nm. The performance of the synthesized product was evaluated by adsorption capacity and removal efficiency. The parameters considered included adsorbent (gINPs) dosage, initial concentration of adsorbate, pH, contact time, and temperature. The obtained data were fitted to kinetic and isotherm models to determine the mechanism. Adsorption batch experiments were conducted to determine the reaction mechanism by studying kinetics while fitting isotherm models for samples analyzed using HPLC at 280 nm. Results showed that 86.15% removal efficiency of 4 mg L-1 levofloxacin was achieved by 100 mg L-1 gINPs in 24 h contact time when all other parameters (pH 7, temperature 25 °C) were kept constant. The maximum adsorption capacity achieved at equilibrium was 22.47 mg/g. Further, it was identified as a pseudo-second-order model with R2 = 0.965 for adsorption kinetics while isotherm data better fitted to the Freundlich model compared to Langmuir isotherm with R2 = 0.994. The potential pathway determined for levofloxacin removal was chemisorption with minor diffusion, multilayer, spontaneous and exothermic processes on the gINPs (Fe3O4). Reusability experiments were conducted in four cycles and removal efficiency varied from 85.35% to 80.47%, indicating very high potential of the adsorbent for re-use.

Occurrence and quantification of prevalent antibiotics in wastewater samples from Rawalpindi and Islamabad, Pakistan.

Release of emerging pollutants including antibiotics to the environment is a serious concern for environmentalist as well as policy makers. To explore the presence and real situation analysis, a study was conducted focusing on detection and quantification of selected antibiotics in wastewater channels of Rawalpindi/Islamabad, Pakistan along with development of a simple High-Performance Liquid Chromatography (HPLC) based method. The samples were collected in triplicates from all the main wastewater streams of the study area with potential presence of antibiotics in the wastewater coming from the surrounding industries, hospitals, drug formulation units and residential localities. Optimized method for detection and quantification was established and validated through spiked as well as real samples. The highest concentration was of Ciprofloxacin 332.154 µg mL-1 followed by Ofloxacin > Ampicillin > Levofloxacin > Sulfamethoxazole. The results showed the presence of antibiotics due to indiscriminate use that could lead to presence of resistant strains and thus ultimately causing the spread of antibiotic resistance.

Molecular investigation of antibiotic resistant bacterial strains isolated from wastewater streams in Pakistan.

Antibiotic resistance is a global public health issue and it is even more daunting in developing countries. The main objective of present study was to investigate molecular responses of antibiotic-resistant bacteria. The 48 bacterial strains, which were previously isolated and identified were subjected to disc diffusion and MIC (minimum inhibitory concentration) determination, followed by investigating the production of the three beta-lactamases (ESBLs (Extended-spectrum Beta-lactamases), MBLs (Metallo Beta-lactamases), AmpCs) and exploring prevalence of the two antibiotic-resistant genes (ARGs); blaTEM and qnrS. Higher MIC values were observed for penicillin(s) than that for fluoroquinolones (ampicillin > amoxicillin > ofloxacin > ciprofloxacin > levofloxacin). Resistance rates were high (58-89%) for all of the tested beta-lactams. Among the tested strains, 5 were ESBL producers (4 Aeromonas spp. and 1 Escherichia sp.), 2 were MBL producers (1 Stenotrophomonas sp. and 1 Citrobacter sp.) and 3 were AmpC producers (2 Pseudomonas spp. and 1 Morganella sp.). The ARGs qnrS2 and blaTEM were detected in Aeromonas spp. and Escherichia sp. The results highlighted the role of Aeromonas as a vector. The study reports bacteria of multidrug resistance nature in the wastewater environment of Pakistan, which harbor ARGs of clinical relevance and could present a public health concern.

Phytotoxicity of different antibiotics to rice and stress alleviation upon application of organic amendments.

Extensive use of antibiotic results in significant antibiotics pollution in the environment. Main objective of this study was to gain insight into potential impacts of antibiotics on plant physiological growth and nutritional composition, and stress alleviation through application of different organic amendments. Effects of five antibiotics (ciprofloxacin, levofloxacin, ofloxacin, amoxicillin and ampicillin) were observed in the presence of three organic amendments (rice husk, farmyard manure and poultry litter) with rice (Oryza sativa L.) as a model plant. Organic amendments were mixed with soil (@ 5 g kg-1) and after three weeks, antibiotics were applied (@10 mg kg-1) and plants were allowed to grow for four months. After which plants were harvested and physical growth parameters (root/shoot length, biomass) and nutritional composition (grain protein content, carbohydrates, phosphorous and iron) were monitored. It was observed that germination rate, seedling root/shoot length, seedling biomass and vigor index were negatively impacted. The application of organic amendments alleviated antibiotic stress on seedling dry biomass, length and vigor index by 1.8-, 3.1- and 2.5-folds, respectively as compared to the antibiotic controls. Concentrations of phosphorous, iron, carbohydrates and proteins were decreased by 5.3-, 1.3-, 1.4- and 1.6-folds upon application of antibiotics. Rice husk was the most effective treatment in case of physical growth parameters and alleviating antibiotics' induced genotoxicity. Whereas, poultry litter had the highest positive effect on nutritional composition of plants. In general, the application of organic amendments alleviated the phytotoxicity as well as genotoxicity in plants under antibiotics stress.