Risk assessment for the spread of Serratia marcescens within dental-unit waterline systems using Vermamoeba vermiformis

Vermamoeba vermiformis is associated with the biofilm ecology of dental-unit waterlines (DUWLs). This study investigated whether V. vermiformis is able to act as a vector for potentially pathogenic bacteria and so aid their dispersal within DUWL systems. Clinical dental water was initially examined for Legionella species by inoculating it onto Legionella selective-medium plates. The molecular identity/profile of the glassy colonies obtained indicated none of these isolates were Legionella species. During this work bacterial colonies were identified as a non-pigmented Serratia marcescens. As the water was from a clinical DUWL which had been treated with Alpron™ this prompted the question as to whether S. marcescens had developed resistance to the biocide. Exposure to Alpron™ indicated that this dental biocide was effective, under laboratory conditions, against S. marcescens at up to 1x108 colony forming units/millilitre (cfu/ml). V. vermiformis was cultured for eight weeks on cells of S. marcescens and Escherichia coli. Subsequent electron microscopy showed that V. vermiformis grew equally well on S. marcescens and E. coli (p = 0.0001). Failure to detect the presence of S. marcescens within the encysted amoebae suggests that V. vermiformis is unlikely to act as a vector supporting the growth of this newly isolated, nosocomial bacterium

Level of knowledge and understanding of informed consent amongst the training grade group orthodontists in England, Wales and Northern Ireland.

OBJECTIVE: To assess the level of knowledge and understanding of informed consent in UK orthodontic trainees. DESIGN AND SETTING: A cross-sectional, written questionnaire-based study. SETTING: Hospital orthodontic departments in England, Wales and Northern Ireland. SUBJECTS AND METHOD: A one page questionnaire which covered a range of legal issues pertinent to informed consent was circulated to 207 members of the Training Grades Group (TGG) of the British Orthodontic Society (BOS). The questionnaire consisted of four open questions with 11 responses, which the investigators considered to be ideal, seven closed questions requiring yes/no responses and one question requiring a yes/no response followed by two open responses. Following the initial circulation, a second posting to non-responders was conducted. RESULTS: The response rate was 61% (N=126). The mean number of complete answers to the 21 questions was 13 (62%; median 13; mode 14). There were a low number of complete responses to specific questions in the following areas - explanations patients need from clinicians prior to obtaining consent; how to fully judge if a patient is capable of consenting; how to manage a patient incapable of giving consent; the legal status of fathers consenting on behalf of their children; whether consent forms have to be re-signed if the start of treatment is delayed by six months or more and responsibility for obtaining consent for dental treatment under general anaesthesia. CONCLUSIONS: There was a disappointingly high proportion of incomplete answers to questions testing the knowledge and understanding of the law as it pertains to informed consent exists amongst members of the TGG of BOS