Phenotypic and genotypic characterisation of clinically relevant bacteria isolated from dental waste and waste workers' hands, mucosas and coats

Abstract

Infectious wastes are potential sources of pathogenic micro-organisms, whichmay represent a risk to the professionals who manage them. In this study, weaimed to characterize the infectious bacteria present in dental waste and wasteworkers. The dental waste produced over 24 h was collected and waste workerswere sampled by swabbing. Isolate resistance profiles were characterized byVitekâand PCR and biofilm formation by Congo Red agar, string test andmicrotitre assay. To assess similarity between the waste and the workers’samples, a random amplified polymorphic DNA test was used. Twenty-eightbacteria were identified as clinically relevant. The most frequent gene wasblaTEMpresent in five Gram-negative micro-organisms, and one blaSHVinKlebsiella pneumoniae. All Pseudomonas aeruginosa were positive to extracellularpolymeric substances formation, except one isolated from a worker. Klebsiellapneumoniae had negative results for the string test. Pseudomonas aeruginosashowed better adherence at 25°C after 48 h of incubation and K. pneumoniahad the best biofilm formation at the same temperature, after 24 h. Thesimilarity between P. aeruginosa recovered from dental waste and from workerswas low, however, it is important to note that a pathogen was found on aworker’s hands and that improvements in biosafety are required