Figure 1
Carbapenem-resistant bacterial species from river sediment cultured on CHROMagar Acinetobacter. Red – Acinetobacter spp., Pseudomonas sp., and Stenotrophomonas sp. (similar to Acinetobacter but of different morphology). Blue – Enterobacterales
Figure 2
Recommended protocol for the detection and characterisation of CRB from the environment
Table 1
Minimum inhibitory concentrations (MIC) of imipenem, meropenem, and ertapenem according to EUCAST (48) and CLSI (49) criteria for clinically relevant CRE, CRA, and carbapenem-resistant P. aeruginosa
Figure 3
Mechanisms of carbapenem resistance in environmental isolates (drawing created with bioRender). 1) overexpression of the efflux pump; 2) reduced porin activity; 3) carbapenemase-catalysed reactions (carbapenem hydrolysis)
Table 2
Literature reports of CRB presence in different environmental samples
| Species | Sample type | Reference |
|---|---|---|
| A. baumannii, Enterobacterales | Hospital environment (sheets, bed rail, bedside table, keyboard, devices, ventilator tube, air sample, air conditioner, sheets and infusion pump) | (88,89,90, 92, 93) |
| K. pneumoniae, A. baumannii, P. aeruginosa | Hospital sewage | (44, 95, 96) |
| K. pneumoniae, A. baumannii, P. aeruginosa | Urban sewage | (96, 97) |
| K. pneumoniae, A. baumannii, Pseudomonas sp. | River water and sediment | (30, 32, 104, 126) |
| Klebsiella spp., Acinetobacter spp., Pseudomonas spp. E. coli | Sea water and sediment | (109, 110) |
| E. asburiae | Lake water | (108) |
| A. baumannii | Soil | (111) |
| K. pneumoniae, A. baumannii, E. cloacae | Hospital WWTP | (98, 102) |
| K. pneumoniae, A. baumannii, E. coli | Urban WWTP | (43, 100) |
| A. baumannii, E. coli | Companion animals | (113, 115) |
| K. pneumoniae | Domestic animals | (118) |
| K. pneumoniae, A. baumannii, E. coli | Ready-to-eat vegetables | (121, 122) |
Figure 4
Possible transmission routes and reservoirs of CRB in the natural environment (drawing created with bioRender). 1) discharge of untreated hospital and urban sewage; 2) hospital and urban sewage that goes through WWTP but is released as partially treated effluent; 3) transmission of CRB through animals and ready-to eat-vegetables