OBJECTIVES:

To evaluate and compare, in vitro, the antimicrobial action of surface disinfectants on fungi and bacteria, using the rubbing method.

MATERIALS AND METHODS:

The surfaces of two tables were disinfected with 70% alcohol, under friction, divided into 64 parts, and contaminated with a standardized microbial suspension of fungi and bacteria with turbidity corresponding to number 6 on the McFarland scale. The disinfectants tested were: 70% alcohol (A70), 0.2% peracetic acid (PA), 7% chlorine dioxide (CD), and 5.2% benzalkonium chloride with 3.5% polyhexamethylene biguanide (BCPB) which were rubbed for 10 s in contaminated areas. The samples were collected before (positive control) and after disinfection in triplicate, plated in culture mediums, and incubated for 48 h at 37 ºC).

RESULTS:

Microbial growth was observed by the presence of colony-forming units (CFU) on the agar. Candida albicans was the most resistant microorganism to the selected products, except for AP, which showed activity against all tested microorganisms. BCPB was the only disinfectant that did not reduce CFU formation.

CONCLUSION:

PA had the best antimicrobial effect, so it is the safest option for high-level disinfection. A70 and CD are indicated for intermediate disinfection. CBPB did not reduce the formation of CFUs, therefore it is not indicated for disinfection protocols.