The enumeration of bacteria and CRB in wastewater and sludge samples is shown in Supplementary Table S2. The colony-forming unit (CFU) of general heterotrophic bacteria, E. coli, and non-E. coli other bacteria enumerated in wastewater and sludge samples ranged from 1.4 × 10⁵ ± 3.2 × 10⁴ to 1.9 × 10⁶ ± 3.3 × 10⁵CFU/mL and 3.3 × 10⁴ ± 1.1 × 10⁴ to 1.4 × 10⁶ ± 1.9 × 10⁵CFU/g, respectively. On the other hand, carbapenem-resistant heterotrophic bacteria detected in wastewater and sludge samples were 1.0 × 10⁴ ± 3.8 × 10³ CFU/mL and 3.7 × 10⁴ ± 1.1 × 10⁴CFU/g, respectively. On mTEC agar, carbapenem-resistant other bacteria detected were less than 100 colonies in both wastewater and sludge samples. Since there were no carbapenem-resistant E. coli colonies (Supplementary Table S2), 17 carbapenem-resistant colonies that did not show the characteristic E. coli blue color, but grew on the mTEC agar, were isolated. These bacterial isolates were subsequently identified as P. otitidis (MR1–MR11, MR13–MR18) by 16S rRNA gene sequencing (Table 1). PFGE fingerprinting patterns showed that among the 17 P. otitidis, five isolates were identical to one of the isolates, that is MR3 to MR1, MR5, MR10 to MR4, MR13 to MR11, MR18 to MR16 (Supplementary Figure S1). These identical isolates of P. otitidis were not included in the following bla_POM analysis. MICs of these 17 P. otitidis isolates showed that isolates MR6, MR7, and MR8 showed resistance to meropenem at 8 mg/L. The remaining P. otitidis isolates have MIC of 16 mg/L. PCR and sequencing of bla_POM showed that 12 P. otitidis (MR1, MR2, MR4, MR6, MR7, MR8, MR9, MR11, MR14, MR15, MR16, and MR17) were found to possess a subclass B3 MBL named POM (P. otitidis MBL).