Bacterial Resistance to Chemotherapy. I. Effect of Continuous Feeding of Chlortetracycline, Sulfaethoxypyridazine, Sulfaquinoxaline, and Chlortetracycline-Sulfaethoxypyridazine Combinations on the Development of Resistance by Salmonella Gallinarum in Chickens

Structural Elucidation of Sulfaquinoxaline Metabolism Products and Their Occurrence in Biological Samples Using High-Resolution Orbitrap Mass Spectrometry

“…Thus, the necessary collision energies are higher but virtually identical for all sulfonamides. 41 Similarly, N 4 -acetylated sulfonamide metabolites show a number of group-specific product ions which indicates an identical fragmentation pattern as compared to those of the compounds, i.e., at m/z 134 (92 + 42) and 198 (156 + 42), together with characteristic compound-specific product ions. 41 For instance, the m/z 145 could be chosen for confirmation of SQX and N 4 -acetylsulfaquinoxaline as compound-specific ion and m/z 134 as the corresponding N 4 -acetylated group-specific fragment.…”

“…By decades, SQX was the most important coccidiostatic drug, and its use promoted an impressive decline in the poultry production costs . However, the incorrect use of SQX, as other sulfonamides, can lead to serious problems as permanence of residues of the drug and their metabolism products in food or the spread of bacterial resistance. − For this reason, residues of sulfonamides have maximum residues limits (MRL) established in several countries. In Brazil, SQX is still commonly used to prevent and treat poultry, swine, and ovine coccidiosis .…”