Wastewater treatment plants hold a vast pool of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). The aim of this study is to analyze the ARB and ARGs in a pharmaceutical and chemical wastewater treatment plant using a metagenomic technique. The results of taxonomic annotation revealed that bacteria were the predominant domain. The most abundant phyla and genus was Proteobacteria and Hyphomicrobium, respectively. A total of 74 categories of ARGs were predicted using CARD with the most dominant types being sav 1866, dfrE, and mfd. Furthermore, a network analysis was conducted to investigate the co-occurrence patterns between ARGs and microbial taxa. ARGs were found to be highly connected to microbial taxa at the genus level. With respect to the antibiotic resistance mechanisms, antibiotic-specific efflux pumps appeared to be the most common mechanisms. Among these, resistance-nodulation-cell division (RND) was the major type. The most important functional pathway of this microbial community was metabolic correlation. Interestingly, there were many genes related to human diseases, among which bacterial infectious diseases were the main ones. On the one hand, these data further confirmed that pharmaceutical and chemical wastewater treatment plants are rich in ARB and ARGs. The accumulation of ARGs increases the potential environmental risks, and hence it is necessary to strengthen the active monitoring of ARB and ARGs in pharmaceutical and chemical wastewater treatment plants. On the other hand, research on ARB and ARGs offers important information for the selection of deep processing technology to effectively remove ARB and ARGs.
Keywords: antibiotic; antibiotic resistance genes(ARGs); antibiotic resistant bacteria(ARB); metagenomic technique; pharmaceutical and chemical wastewater treatment plants.