Mycoplasma synoviae (MS) is a contagious pathogen that poses a significant threat to the poultry industry. Detection plays an important role in the prevention and control of MS, particularly in differentiating between wild-type MS and live attenuated vaccine strains for vaccination selection and culling of animals with wild-type only. The live attenuated ts+ vaccine strain MS-H is recognized as the most effective and widely used vaccine. In this study, we have developed a method called double enzyme-activated differentiation probes PCR (DEA-probes PCR) for the differentiation of MS-H vaccine strain from wild-type strain by targeting the single nucleotide polymorphism (SNP) of the 367th nucleotide in the Obg gene sequence. We developed 2 modified probes with the ribonucleotide insert. When the probe perfectly complements with the target, the ribonuclease H2 (RNase H2) will cleave the ribonucleotide, resulting in the generation of fluorescent signal. With a detection limit of 5.8 copies/µL, the DEA-probes PCR method demonstrates 100% specificity in distinguishing wild-type MS from MS-H strains in 1 h. The method demonstrated great performance in real application of 100 superior palate cleft swab samples from chickens in poultry farms. Twenty-eight samples were detected as MS positive, consistent with the results of the Chinese industry standard method. Additionally, our method was able to distinguish 19 wild-type MS strains from 9 MS-H vaccine strains. The DEA-probes PCR method is rapid, specific and sensitive for SNP detection, overcoming the misidentification in MS detection and differentiation. It can be also applied to the differentiation of infected from vaccinated animals (DIVA) for other pathogens.
Overuse of sulfonamides in aquaculture and agriculture leads to residual drugs that cause serious pollution of the environment. However, the residues of sulfonamides in the environment are not unique, and the existing microbial degradation technology has a relatively low degradation rate of sulfonamides. Therefore, in this study, a Pseudomonas stutzeri strain (DLY-21) with the ability to degrade four common SAs was screened and isolated from aerobic compost. Under optimal conditions, the DLY-21 strain degraded four sulfonamides simultaneously within 48 h, and the degradation rates were all over 90%, with the average degradation rates of SAs being sulfoxide (SDM) ≈ sulfachloropyridazine (SCP) > sulfa quinoxaline (SQ) > sulfadiazine (SQ). In addition, the main compounds of the strain DLY-21-degrading SAs were identified by LC-MS analysis. On this basis, four detailed reaction pathways for SA degradation were deduced. This is the first report of the use of a P. stutzeri strain to degrade four sulfonamide antibiotics (SQ, SDM, SCP, and SM1), which can improve the removal efficiency of sulfonamide antibiotic pollutants and thus ameliorate environmental pollution. The results showed that DLY-21 had a good degradation effect on four SAs (SQ, SDM, SCP, and SM1).
In this study, a pilot-scale integrated process was developed, which combined the integrated biological contact oxidation technology (AO) and the improved constructed wetland technology. The results showed significant removal efficiency for both conventional and trace organic pollutants. The average removal efficiencies for COD, NH4+-N, and TP were 78.52, 85.95, and 49.47%, respectively. For trace organic pollutants, triclocarban, triclosan, and sulfadiazine, the removal efficiencies reached 60.14, 57.42, and 84.29%, respectively. The AO stage played a crucial role in removing trace organic pollutants, achieving removal efficiencies of 37.28, 43.44, and 83.82% for triclocarban, triclosan, and sulfadiazine, respectively. Subsequent treatment using improved constructed wetland technology with coal slag + gravel fillers demonstrated the highest removal efficiency, with average efficiencies of 68.66, 63.38, and 81.32% for triclocarban, triclosan, and sulfadiazine, respectively. Correlation analysis revealed positive correlations between temperature, precipitation, and the removal efficiency of COD, NH4+-N, and TP, while negative correlations were observed with the removal efficiency of triclocarban, triclosan, and sulfadiazine. Furthermore, the influent concentrations of triclocarban and triclosan were significantly negatively correlated with the removal efficiency of COD and TP. The presence of triclocarban and triclosan potentially reduced the microbial diversity and hindered sludge sedimentation performance.
