Evaluation of Detection Methods for Wastewater Surveillance of Antimicrobial-Resistant Bacteria from Healthcare Facilities

Carbapenem resistance is an urgent public health threat. Wastewater surveillance could support antimicrobial resistance monitoring at long-term care facilities (LTCFs). Feasibility of wastewater sampling (via composite or passive sampler, and sewer biofilm swabs) for carbapenemase genes (blaKPC, blaVIM, blaOXA-48-like, blaNDM, and blaIMP) detected by qPCR or GeneXpert(R) Carba-R from a LTCF was assessed over 16 months and compared to clinical infections. blaKPC, blaOXA-48-like, and blaVIM were routinely detected in composite wastewater samples (6.4{+/-}0.8 log10 gene copy (GC)/ml (100% of 61 samples), 5.5{+/-}0.8 (98%), and 5.9{+/-}1.3 (34%), respectively), passive samples (8.2{+/-}0.5 log10 GC/g (31% of 55), 6.6{+/-}0.5 (96%), and 6.6{+/-}0.7 (31%)) and sewer biofilm (6.0{+/-}0.7 log10 GC/cm2 of pipe (100% of 17), 5.0{+/-}0.7 (100%), and 5.8{+/-}2.7 (24%)). Resistomes of wastewater and sewer biofilms differed, but both contained blaKPC, blaVIM, and blaIMP. Passive sampling may be a suitable alternative to composite sampling. Wastewater surveillance is a promising addition to carbapenemase monitoring.