Assessing the Contamination of the External Surfaces of Reused Calen® System Tubes

Abstract

Objective: To determine the presence of contamination on the external surface of reused Calen® System tubes before (TA) and after (TB) the action of four disinfectants: 0.12% chlorhexidine, 2% glutaraldehyde, 70 % alcohol and 1% sodium hypochlorite. Material and Methods: Microbiological collection of 20 tubes from dental clinics was performed with the aid of sterile swabs moistened in saline and rubbed for one minute on their surfaces and inserted in tubes containing 4 ml BHI and incubated under microaerophilic conditions (37°C for 24h) for further Mc Farland (F0.5 to F10) and Gram staining analyses. For disinfection (TB), cotton wicks with 1 ml of disinfectant or distilled water (control) was rubbed for 30 seconds, and after drying by evaporation, new samples were collected from the surfaces, which were submitted to the same incubation and Gram staining process for the analyses of slides. Results: Prevalence of F4 and F5 in the same proportion in TA and F1 in TB. Gram + cocci were present in 100% of TA and TB, and prevalence of Gram + cocci, Gram + and – bacilli, spores, Gram - cocci and vibrios in descending order. Conclusion: All external surfaces of reused Calen® System tubes were contaminated before and after disinfection. In descending order, the disinfectant that provided a greater reduction in the Mc Farland scale and thus a greater reduction in the number of microorganisms was 1% sodium hypochlorite, followed by 2% glutaraldehyde, 0.12% chlorhexidine, 70% alcohol and distilled water (control).