The effect of the sulfonamide class of antibiotics, namely, trimethoprim and sulfamethoxazole (TMP–SMX) on growth and metabolism of a bacterial consortium isolated from an anaerobic digester of a sewage treatment plant, was investigated. The bacterial consortium was exposed to various concentrations of TMP–SMX. The results indicated that there was no effect of TMP and SMX on the bacterial consortium in terms of bacterial growth and carbon and nitrate removal even at the highest concentration tested at 250 mg/L. The carbon removal was more than 90%, and the nitrate removal was more than 87% in all culture conditions. A pure culture was isolated and identified as Leuconostoc mesenteroides from the consortium, which was able to use TMP and SMX as the sole source of carbon for growth. This pure culture has the sul1 gene to show resistance to these antibiotics. This research could be used in the anaerobic digestion process to degrade various classes of sulfonamide antibiotics before the treated sludge is discharged into the environment to reduce the concentration of TMP and SMX.

On August 29, 2021, Hurricane Ida made landfall as a category 4 hurricane, bringing a torrent of wind, rain, and storm surge to Southeast Louisiana. This hurricane brought several feet of sediment into the residential areas of southeast Louisiana affecting homes and businesses. The sediment contains industrial waste and sewage sludge. A study was conducted to find the presence of antibiotic-resistant bacteria (ARB) in the sediments. The results of this study show the presence of human polyomavirus BK in the sediments indicating the presence of human feces. The sediment also showed high levels of antibiotics such as tetracycline and sulfonamide. Presence of many multidrug resistant bacteria were found in the sediments along with the presence of various antibiotic resistance genes (ARGs) such as sul1 and sul2 for sulfonamide resistant and tetA gene for resistant to tetracycline. The heavy metal analysis revealed an elevated presence of heavy metal contamination.