Reservoirs of antibiotic-resistant bacteria are of great importance for the risk of a « naive » new patient to be contaminated when hospitalized in the room of a previously colonized or infected patient by an extended- spectrum betalactamase-producing bacteria. This risk may be considered near to 2 for this naive new patient in comparison to the risk encountered when hospitalized in a room previously occupied by a non-infected patient. This is particularly hazardous in case of gram negative carbapenemase-producing bacteria (CPB) which are an increasing public health threat at the international level. Thus, the daily cleaning and the final one with terminal disinfection are of critical importance to avoid the persistence of a CPB strain-reservoir in this room.
With the aim to target this cleaning, the Montpellier’s team performed a study on the surface-contamination in rooms of 32 isolated patients because CPB carriers or infected. This contamination was studied by swabbing 24hours after the room had been cleaned. 2,677 samples were collected and cultured. After identification of the bacterial strains using a Maldi-Tof system, in all 238 points of contamination with CPB were detected, involving the following bacteria: Klebsiella pneumoniae (100), Acinetobacter baumannii (59) and Enterobacter cloacae (57). Room-contamination rates ranged from 0% to 31%, unrelated to CPB species, to the infectious status of the patient (carrier or infected) or to the type of ward. Surfaces with the highest contamination rates belonged to the « furnitures » near the patient (30%) and « water point » (26%) categories. The diffusion seems only linked to the bacterial strain and not the species. On the 91 sampled surfaces, 49 were not contaminated; on the otherhand the most contaminated surfaces at the « water-points » were sink-drains, toilets and shower-walls which are at high-risk for a future transmission.
Cleaning needs to be done very carefully and, for the rooms with water point of use filters (POUF), the possibility of a retrograde contamination, especially from the sink-drain which is a quasi-constant reservoir of this kind of AB resistant gram-negative bacteria should not be disregarded. These surfaces should therefore come first in the list of room-cleaning priorities. This siphon drains the liquids after washing the patient and nursing cares; it must be considered as regularly feeded with CPBs. This sink drain is now recognized as a very hazardous reservoir ; even a lot of attempts for finding a technical solution, the success is, until now, not present with the exception of very expensive devices. Thus, the POUFs must be managed carefully in order to avoid retrograde contamination.