[Mutual Influence Between Microbial Community, Wastewater Characteristics, and Antibiotic Resistance Genes During Spiramycin Production Wastewater Treatment].

Wastewater from antibiotic production usually contains a huge amount of antibiotic resistance genes (ARG). Therefore, it is essential to study the dissemination and control of antibiotic resistance during the treatment of antibiotic production wastewater. The mutual influence between microbial community evolution, wastewater characteristics, and ARG was investigated using high-throughput sequencing and a variety of statistical analysis methods. Results showed that the influent characteristics had only a marginal influence on the microbial community of each treatment section. Methanogenic bacteria and sulfate-reducing bacteria were the dominant microbes in the anaerobic and anoxic tank. Chemical oxygen demand (COD), NO2--N, and PO43--P exhibited an intimate relationship with the microbial community, whereas biomass, NH4+-N, and COD showed a strong correlation with ARG and mobile genetic elements (MGE). In the sludge, more genera (including pathogenic bacteria) were significantly correlated with ARG and MGE than that in the wastewater, indicating that bacteria in the sludge had a greater chance of acquiring pathogenicity and resistance. Therefore, more attnetion should be given to waste sludge from the treatment plants of antibiotic production wastewater. This research could provide further understanding of antibiotic resistance dissemination and control during wastewater treatment, especially for antibiotic production wastewater.

[Fate of ARB and ARGs During Wastewater Treatment Process of Spiramycin Production].

Antibiotic resistant bacteria (ARB) and antibiotic resistance gene(ARG) pose great risk to both environment and human health. This study aimed to investigate the fate of macrolide resistant bacteria, six macrolide resistance genes ermB, ermF, ermX, mefA, ereA, mphB and three transfer elements ISCR1, intIl and Tn916/1545 during wastewater biological treatment processes of spiramycin production. Samples were collected from an antibiotic wastewater treatment station in different seasons. Results showed that the total heterotrophs and Enterococci were mostly removed during wastewater biological treatment, with the reduction of 1. 6-2. 1 logs for total heterotrophs and of 3. 7 logs for Enterococci, respectively. For 94 antibiotic resistant Enterococci individually isolated from four different treatment units including adjusting tank, anaerobic tank, anoxic tank, and aerobic tank, all of these strains showed resistance to spiramycin, azithromycin, erythromycin, and clarithromycin; moreover, the antibiotic resistance rates was not reduced in the effluent. Results of PCR and quantitative PCR showed that 80% of antibiotic resistant Enterococci were positive for PCR amplification of erAB, but negative for PCR amplification of other genes. Concentrations of ermB and ermF were peaked in the spring and autumn samples. Resistance genes of ermB, ermF, mefA, ereA, mphB and transfer element of Tn916/1545 were reduced to some degree during antibiotic production wastewater treatment, but concentrations of ermX, intIl, ISCRl in the effluent were higher than those in the influent. The abundance of mefA, ereA and Tn916/1545 were reduced during wastewater treatment process, and the better removal performance for mefA, ereA, Tn916/1545 occurred in spring than in autumn; however, the abundance of ermX, intI1 and ISCR1 were increased.