Evaluation of the different diffusion capacity from a contaminated zone to adjacent areas, of two epidemic strains of K. pneumoniae OXA48 carbepenemase

Abstract

Introduction: Some disinfectants as detergent solutions, used in rooms with patients in isolation
precautions, can seed to the patiens` environment multi-resistant bacteria better than chlorinate
products. This fact can be evaluated through new methods of surfaces disinfection. Methods: 1)
“Immediate effect”: Four disinfectants were compared using a glass germ-carrier and Klebsiella
pneumoniae with carbepenemase OXA-48 (2 strains: ST 11 and ST405). Disinfectants were applied with
microfiber cloths (unused or re-used 20-30 times). Log10 reductions were calculated for colony forming
units (CFU) obtained after 15 min of disinfectant application. 2) Also was assessed whether these
microfiber cloths (unused or reused 20-30 times), could “transfer microorganisms” to adjacent areas.
Results: Sodium hypochlorite, chlorine dioxide or the mixture alcohol + quaternary ammonium
compounds (QUACs) produced complete destruction of all used microorganisms. Moreover diffusion of
microorganisms to around area was none o very little. Nevertheless, the diluted quaternary ammonium
permitted K pneumoniae-OXA48 diffusion to adjacent areas, through the re-used microfiber cloth. With
unused microfiber, the results improve, but did not eliminate this diffusion to around area. Conclusion:
Two types of tests should be performed before advising surface disinfectant of hospital rooms of
patients on contact precautions: 1) direct effect and 2) evaluation of the possibility of transfer of
microorganisms by the used or unused microfiber. In our case, chlorine dioxide, hypochlorite or
alcohol + QUACs must be preferred to QUACs, in rooms´ disinfection of patients with K. pneumoniae
OXA48.