Q-173. Microbial Characterization of Biofilms in Drains and Bioaerosols in Hospital Rooms

C. Duchaine, Y. Gilbert, M. Veillette;
Ctr. de Recherche de l'Hôpital Laval, Québec, QC, CANADA.

Background: Nosocomial infections in hospitals pose a major health concern, both for patients and hospital employees. Those having their immune system impaired are especially concerned since they can be infected by opportunistic microorganisms. Some ways have been proposed to describe the transmission of those infections, such as contact-spread being the principal route and airborne microorganisms. Very few studies emphasized on the sources of those airborne microorganisms in hospital rooms. Sink drains are known to be colonized by many bacteria and thus could be a potential source for pathogen or opportunistic microorganisms. The principal objectives of this project was 1) to characterize the biodiversity of biofilms in sink drains and 2) to verify if the bacteria observed in the drains were found in air. Methods: Ten hospital rooms were visited during the experiment; a sample of drain biofilm was collected using a polyester swab and vortexed in a saline buffer. Serial dilutions were plated on TSA (Tryptic Soy Agar) and Blood Agar for isolation and bacterial DNA was extracted from the residual swab suspension for 16s rDNA DGGE analysis. Air was sampled using 6-stage Andersen impactors on TSA and Blood Agar and with MD8 Sartorius gel filters. Bacterial DNA was extracted from gel filters. Isolated bacteria were identified by 16s rDNA sequencing. Biodiversity was analyzed by 16s rDNA DGGE analysis using DNA extracts. DGGE bands were re-amplified and sequenced for bacterial identification. Results: Stenotrophomonas maltophilia, Chryseobacterium sp., Sphingomonas paucimobilis and Enterobacter sp. were isolated and found in DGGE profiles for most biofilm samples, while Bosea sp. was only observed by DGGE in some of the samples. All those bacteria were also observed in air samples, both as isolates and/or DGGE bands, suggesting that biofilm in sink drains could be a source of bioaerosols. Conclusion: We demonstrated that sink drains were mostly colonized by opportunistic microorganisms and that those bacteria were sporadically found in air samples, suggesting that this environment constitute a source for transmission of nosocomial infections.