Chronic and repeated exposure of environmental bacterial communities to anthropogenic antibiotics have recently driven some antibiotic-resistant bacteria to acquire catabolic functions, enabling them to use antibiotics as nutritive sources (antibiotrophy). Antibiotrophy might confer a selective advantage facilitating the implantation and dispersion of antibiotrophs in contaminated environments. A microcosm experiment was conducted to test this hypothesis in an agroecosystem context. The sulfonamide-degrading and resistant bacterium Microbacterium sp. C448 was inoculated in four different soil types with and without added sulfamethazine and/or swine manure. After 1 month of incubation, Microbacterium sp. (and its antibiotrophic gene sadA) was detected only in the sulfamethazine-treated soils, suggesting a low competitiveness of the strain without antibiotic selection pressure. In the absence of manure and despite the presence of Microbacterium sp. C448, only one of the four sulfamethazine-treated soils exhibited mineralization capacities, which were low (inferior to 5.5 ± 0.3%). By contrast, manure addition significantly enhanced sulfamethazine mineralization in all the soil types (at least double, comprised between 5.6 ± 0.7% and 19.5 ± 1.2%). These results, which confirm that the presence of functional genes does not necessarily ensure functionality, suggest that sulfamethazine does not necessarily confer a selective advantage on the degrading strain as a nutritional source. 16S rDNA sequencing analyses strongly suggest that sulfamethazine released trophic niches by biocidal action. Accordingly, manure-originating bacteria and/or Microbacterium sp. C448 could gain access to low-competition or competition-free ecological niches. However, simultaneous inputs of manure and of the strain could induce competition detrimental for Microbacterium sp. C448, forcing it to use sulfamethazine as a nutritional source. Altogether, these results suggest that the antibiotrophic strain studied can modulate its sulfamethazine-degrading function depending on microbial competition and resource accessibility, to become established in an agricultural soil. Most importantly, this work highlights an increased dispersal potential of antibiotrophs in antibiotic-polluted environments, as antibiotics can not only release existing trophic niches but also form new ones.

Sulfonamides are recommended as part of first-line therapy for most Nocardia infections, with trimethoprim-sulfamethoxazole (TMP-SMX) considered the drug of choice for susceptible isolates. However, in the case of central nervous system, disseminated disease, and other serious Nocardia infections, TMP-SMX should not be used as monotherapy. The preferred treatment for a patient unable to take TMP-SMX because of allergy or intolerance remains uncertain. Prior to the availability of TMP-SMX in 1973, other sulfonamides were mainstays of treatment. We describe a Nocardia infection successfully treated with sulfadiazine in a lung transplant recipient who could not tolerate TMP-SMX. A review of similar cases reported in the literature provides insight into the successful treatment of Nocardia infections with sulfonamide regimens not containing trimethoprim in transplant recipients and other immunocompromised hosts.

Drug-induced skin reactions are common, but only a small portion (10%) are attributed to a vasculitic mechanism. Small-vessel vasculitis (SVV) with leukocytoclastic histopathology is usually described in drug-induced vasculitis; however, given the shared histopathologic features between drug-induced vasculitis and other SVV, it is crucial to rule out infectious or other autoimmune etiologies underlying the clinical presentation. We hereby sought to present a case of sulfonamide-induced leukocytoclastic vasculitis, limited to the skin, in a patient with Ehlers-Danlos syndrome in order to emphasize the need for a broad diagnostic and clinical exclusion workup.

Diode lasers, especially 405 nm diode laser, as excitation sources offer new opportunities for laser-induced fluorescence (LIF) detection, but the lack of available derivatization reagents limits their widespread applications. Herein, a commercial fluorescent dye, 7-(diethylamino)coumarin-3-carboxylic acid (DEAC-C) was introduced as derivatization reagent and corresponding derivatization strategy for DEAC-C labeling sulfonamides was developed for 405 nm LIF detection. After systematic optimization, three sulfonamides including hydrochlorothiazide (HCTZ), chlorothiazide (CTZ) and chlortalidone (CTD) could be efficiently labeled by DEAC-C in the presence of cyanuric chloride and triethylamine (1.5%) in acetonitrile at 50 °C for 180 min. Based on the laboratory-built capillary electrophoresis-LIF system, a robust method was then proposed for the separation of DEAC-C labeled sulfonamides by micellar electrokinetic chromatography (MEKC) using the classic borax-SDS system. Under the optimized conditions, a baseline separation of three sulfonamides was achieved within 15 min, and the detection limits were determined to be 0.24, 0.29, and 0.23 nM for HCTZ, CTZ, and CTD, respectively. Furthermore, the developed MEKC-LIF method was validated using sulfonamide standards and spiked human urine sample and successfully applied for the analysis of three sulfonamides in complex pharmaceutical and physiological samples.