Disinfection efficacy of ozone on ESKAPE bacteria biofilms: Potential use in difficult-to-access medical devices.

BACKGROUND

Medical devices can be reservoirs of multidrug-resistant bacteria that may be involved in the acquisition of infections since bacteria with the ability to form biofilms that are difficult to eradicate, mainly in mechanical ventilators. The aim of this work was to evaluate the efficacy of O against biofilms of bacteria ESKAPE group through disinfection studies.

METHODS

The formation of biofilms of ESKAPE group bacteria was induced in vitro. O was injected at different exposure times at a constant dose of 600 mg/h. The recovery of surviving bacteria after O treatment was assessed by bacterial counts and biofilm disruption was analyzed. Finally, the viability and integrity of biofilms after O treatment was determined by confocal laser scanning microscopy (CLSM).

RESULTS

O showed bactericidal activity on biofilms from 12 min/7.68 ppm for A. baumannii and C. freundii. P. aeruginosa, K. pneumoniae and S. aureus were killed after 15 min/9.60 ppm. Correlation analyses showed inversely proportional relationships between the variables "disruption versus O". CLSM revealed that death was time-dependent of biofilms upon O exposure. Orthogonal plane analysis showed that bacteria located in the outer region of the biofilms were the ones that initially suffered damage from O exposure.

CONCLUSIONS

Our findings suggest that this method could be an alternative for the disinfection in mechanical ventilators colonized by bacteria biofilm forming.