The sample of municipal sewage was obtained from the influx of wastewater-related plant in Luzhou City (Sichuan Province, China) in March 2019. The sewage was 1:10 diluted and an aliquot (10 μL) was streaked onto a CHROM Agar Orientation (CHROMAgar, Paris, France) agar plate containing 2 mg/L meropenem (Solarbio, China) and then incubated at 37 °C overnight. Bacterial species identification was carried out by the Vitek2 system (BioMérieux, France), 16srRNA sequencing and matrix-assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry. The minimal inhibitory concentrations (MICs) of 15 antimicrobial agents (Solarbio, China) including meropenem, imipenem, cefepime, cefotaxime, ceftazidime, piperacillin-tazobactam, amoxicillin-clavulanic acid, gentamicin, amikacin, aztreonam, erythromycin, chloramphenicol, sulfadiazine, colistin and ciprofloxacin were determined by broth microdilution method according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI 2013, M100-S23). Escherichia coli strain ATCC 25,922 was used as quality control. Polymerase chain reaction (PCR) amplification and DNA sequencing were performed to identify the key carbapenemase-encoding genes (blaNDM and blaKPC) as previously reference.7 (link)