Characterization of the environment of patients colonized with carbapenemase-producing organisms: role of air and surfaces in the dissemination of key resistance genes.

BACKGROUND

Hospital-associated infections caused by carbapenemase-producing organisms (CPOs) pose a significant health concern. Healthcare settings implement measures to control the spread of CPOs and prevent outbreaks, but the role of air in disseminating carbapenemase genes remains unclear. This study assessed three carbapenemase-associated genes (bla, bla and bla) in the environment of CPO-colonized patients.

METHODS

A prospective observational study was conducted in four hospitals in Quebec, Canada in the rooms of CPO-colonized patients. Air was collected actively inside the rooms of CPO-colonized patients, and floor and no-touch surfaces were sampled using pre-moistened swabs and sponges; the findings were compared with those from control rooms (i.e. rooms hosting non-CPO-colonized patients) located on the same floor. Additional floor samples were collected in adjacent hallways to estimate potential dissemination within the settings. The presence and abundance of carbapenemase-producing genes (bla, bla and bla) were evaluated using quantitative polymerase chain reaction.

RESULTS

Carbapenemase-encoding genes were detected frequently in CPO-colonized patient environments, notably on floors (97% of detection frequency), door frames (52%), and no-touch surfaces (42%). Conversely, only one air sample tested positive for bla. These genes were also detected in hallways adjacent to the rooms of CPO-colonized patients (92%), control rooms (100%), and hallways adjacent to the rooms of non-CPO-colonized patients (78%), with abundance decreasing with distance from CPO-colonized rooms.

CONCLUSION

These findings suggest that carbapenem resistance can spread within healthcare settings, and air may play a role in gene dissemination. Additional measures should be considered to limit resistance gene transfer, particularly via floors and air.