[en] Highlights: • Toxicity of five SAs to duckweed after prolonged exposure times was determined. • Shift in the order of toxicity of the SAs was observed in the prolonged test. • After irradiation concentration and toxicity of all the SAs decreased within time • Potentially produced photodegradation products less toxic than native forms • SAs toxicity in the prolonged exposure might be explained by different mode of action. Sulphonamides (SAs) are one of the most commonly used veterinary drugs and therefore their residues are regularly found in the environment. So far scientific attention has mostly been paid to the evaluation of their acute ecotoxicological effects with data on long-term effects for non-target organisms still largely missing. Therefore, the main aim of this study was to evaluate the potential toxicities of five sulphonamides to duckweed (Lemna minor) after prolonged exposure time (14 days). To elucidate whether their phytotoxic effects result from potential photodegradation products, the toxicity of standard solutions of selected sulphonamides was also investigated in a standard 7-day test but after irradiation (by keeping them under the test conditions) for the selected time (after 7 and 14 days). The ecotoxicological tests were accompanied by chemical analyses to be able to link the observed effects to the concentrations and nature of the exposed compounds. The results showed a shift in the toxicity of SAs: a strong decrease in toxicity for the two most toxic sulphonamides (sulphamethoxazole and sulphadimethoxine) and a slight increase in toxicity for three other SAs (sulphadimidine, sulphathiazole, sulphamerazine) in the prolonged test. However, a decrease in the toxicity and concentration of all the SAs was observed when stock solutions were irradiated prior to the toxicity experiment, which suggests that the observed effects towards L. minor of five SAs in the prolonged test cannot be directly associated with the degradation of these compounds under the test conditions but with their different mode of toxic action towards these organisms.

[en] To evaluate direct drug susceptibility testing on MGIT 960 system for detection of multidrug resistant tuberculosis from smear positive pulmonary specimens. Study Design: Cross-sectional analytical study. Place and Duration of Study: Microbiology Department, Armed Forces Institute of Pathology, Rawalpindi, from July 2016 to September 2017. Methodology: Smear positive specimens were pretreated according to guidelines and then tested on MGIT 960 TB system for direct drug susceptibility testing (DST) of isoniazid and rifampin. Samples were also processed by gold standard indirect method, which comprises culture and then DST from positive growth by MGIT 960 TB system. Results: Out of 108 specimens, 95 (88%) DST results were reportable. Out of 95 reportable specimens, 17 isolates were resistant to both isoniazid (INH) and rifampin (RIF) by direct DST. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for INH were 92%, 93%, 82%, 97% and 92.6%, respectively; and 95%, 96%, 86.3%, 98.6% and 95.7%, respectively for RIF. Average time to report DST by indirect method was 23.6 ±3.9 days, while it was 11.4 +-2.7 days for the direct method. Conclusion: Direct susceptibility testing on MGIT 960 system showed very good agreement when compared with indirect method. Time saving is crucial factor in initiation of early effective therapy, especially in drug resistant cases. Further studies on large scale are required for more accurate evaluation of this method. (author)

[en] A spectrophotometric method is proposed for determining sulfonamides in pure form and in pharmaceutical preparations , based on the charge transfer (CT) complex formation between phenosefranine as an acceptor and sulphonamides as as donors in acetate buffer (pH3). The factors affecting the formation of CT-complex were studied ,linear calibration graphs were obtained in the concentration range 1.07-16.70ug/ml at 25C. The minimum detection limit is in the range 0.428-0.573 ug/ml. The same complexes have been studied in aqueous media for conductometric mesurement The method could be successfully adopted for pharmaceutical preparations.The molar conductivity coefficients were found to increase with increasing temprature (25-35C)in all systems studied .The stoichiometry of the sulfonamides phenosefranine complexes were found to be 1:1 in both techniquecs. (author)

[en] UV-irradiation (254 nm, 10 or 20 J/cm²) of p-aminobenzoic acid (PABA) and p-aminosalicylic acid (NaPAS) potentiated their antimuta-genicity towards N-methyl-N'-nitro-N-nitrosoguanide metagenesis in Salmonella typhimurium. Their inhibitory action towards the formation of mutagen N-methyl-N-mitrosourea from the nitrosation mixture of N-methylurea and nitrite was also increased by UV-irradiation. In contrast, UV-irradiated PABA exhibited no inhibitory effects towards the mutagenicity of sodium azide or 3-azidoglycerol. Neither PABA nor NaPAS not their UV-irradiation products were themselves mutagenic in the Ames assay. 13 refs.; 5 tabs

[en] Sulfadiazine is an antibiotic used in animals and humans, this molecule is being released increasingly into the aquatic environment, which is why the depletion of this molecule in rainbow trout (Oncorhynchus mykkis) was studied using radiometric techniques with ¹⁴C, for which a specific activity of 3.5171 MBq mg^-1 was used, during 14 days in semi-static conditions. The study found accumulation in trout on day four 5.10 × 10^-4 mg g^-1 after the exposure phase, and 1.0 × 10^-4 mg g^-1 after the purification phase, indicates that the concentration used puts human health at risk because exceed the maximum residual limits. (author)

[en] Sorption of sulfonamides on biochars is poorly understood, thus sulfamethoxazole (SMX) sorption on biochars produced at 300–600 °C was determined as a function of pH and SMX concentration, as well as the inorganic fractions in the biochars. Neutral SMX molecules (SMX⁰) were dominant for sorption at pH 1.0–6.0. Above pH 7.0, although biochars surfaces were negatively-charged, anionic SMX species sorption increased with pH and is regulated via charge-assisted H-bonds. SMX⁰ sorption at pH 5.0 was nonlinear and adsorption-dominant for all the biochars via hydrophobic interaction, π–π electron donor–acceptor interaction and pore-filling. The removal of inorganic fraction reduced SMX sorption by low-temperature biochars (e.g., 300 °C), but enhanced the sorption by high-temperature biochars (e.g., 600 °C) due to the temperature-dependent inorganic fractions in the biochars. These observations are useful for producing designer biochars as engineered sorbents to reduce the bioavailability of antibiotics and/or predict the fate of sulfonamides in biochar-amended soils. -- Highlights: •Sulfamethoxazole (SMX) sorption on biochars at pH 5.0 was adsorption-dominant. •Removal of inorganic fractions in low-temperature biochars reduced SMX sorption. •Removal of inorganic fractions in high-temperature biochars enhanced SMX sorption. •Anionic SMX was adsorbed on negatively charged biochar via charge-assisted H-bond. -- Solution pH and biochar property control the sorption amount and mechanisms of antibiotic sulfamethoxazole

[en] Self-decomposition and removal of antibiotics by ionic treatment was evaluated in this study. Seven sulfonamide classes (SA) and seven tetracycline classes (TA) of antibiotic were selected for this purpose. According to this study, self-decomposition of SAs and TAs was slow, and a considerable amount of antibiotics still remained after 15 days. Ionic treatment was effective for removal of SAs and TAs, but organic interference was observed. When dissolved organic (DOC) was present in raw water, the removal performance of antibiotics generally deteriorated due to competition with organics. SAs and TAs, which were present in ionic form at neutral pH, were removed through ion exchange. Their removal efficiencies were closely related to their chemical structure. Antibiotics with stronger electronegativity were easier to remove by ionic treatment. Equilibrium equations for removal of SAs and TAs by ionic treatment were also presented

[en] A total of (400) clinical and environmental samples were collected during the period from Sep/2018 to Jan/2019 from different hospitals in Hilla city. The isolates were identified and based on microscopic features and standard biochemical tests. The results showed there were (150) isolates of E.coli from clinical and the environmental samples. The clinical isolates (67 isolates) were collected from patients suffering from different infections such as UTI (30 isolates), gastroenteritis (diarrhea) (22 isolates), and wound infections (15 isolates). Also, the environmental isolates (83) were collected from the different site of hospitals environment include surgery room, hospital floors, the hospital cafeteria, the corridors of the hospital, and from workers dress and stool. All 150 E.coli isolates were primarily screened for colistin resistance, The following antibiotics were used for susceptibility testing to the resistance isolates for colistin (17 isolates): Aminoglycosides (Amikacin, Gentamicin, kanamycin ), Sulfonamide (Trimethoprim), Nitrofurans (Nitrofurantoin), Fluoroquinolons (Ciprofloxacin, Norfloxacin), Cefeme (Cephalothin, Ceftriaxone, Ceftazidime), Macrolides (Erythromycin), carbapenems (Imipenem, meropenem), beta-Lactams (Amoxicillin, Carbenicillin ), Tetracyclin, Chloramphenicol. our result show that E. coli the most causative agent of UTI infection especially in women. there is a high resistance to cefems and beta- lactam antibiotic (100%) among these isolates which play as a cell wall inhibitors. And moderate resistance to ciprofloxacin (52.9%), Chloramphenicol and Norfloxacin (29.14%), and weak resistance to Gentamycin. (paper)

[en] A very sensitive catalytic spectrophotometric method for the determination of copper (II) in concentration as low as 0.01 ng/ml has been described. This method is based on the oxidation of iso nicotinic acid hydrazide by hydrogen peroxide in ammoniacal medium, catalysed by copper (II). various metal interferences have been studied and are reported in this study. Structure of the oxidation product is not known. (author)

[en] We investigated the effect of solution pH and soil structure on transport of sulfonamide antibiotics (sulfamethoxazole, sulfadimethoxine and sulfamethazine) in combination with batch sorption tests and column experiments. Sorption isotherms properly conformed to Freundlich model, and sorption potential of the antibiotics is as follows; sulfadimethoxine > sulfamethoxazole > sulfamethazine. Decreasing pH values led to increased sorption potential of the antibiotics on soil material in pH range of 4.0–8.0. This likely resulted from abundance of neutral and positive-charged sulfonamides species at low pH, which electrostatically bind to sorption sites on soil surface. Due to destruction of macropore channels, lower hydraulic conductivities of mobile zone were estimated in the disturbed soil columns than in the undisturbed soil columns, and eventually led to lower mobility of the antibiotics in disturbed column. The results suggest that knowledge of soil structure and solution condition is required to predict fate and distribution of sulfonamide antibiotics in environmental matrix. - Highlights: • Sorption potential of sulfamethoxazole, sulfadimethoxine and sulfamethazine depends on pH. • Transport of the sulfonamide antibiotics is also pH-dependent in soil system. • Preferential flow in the undisturbed soil columns induces faster transport of the sulfonamide antibiotics. - Sorption potential and transport of sulfamethoxazole, sulfadimethoxine and sulfamethazine in agricultural soils depend on pH and soil structure.