Worker Perceptions of the Multi-Agency Investigation & Support Team (MIST): A Process Evaluation of a Cross-Agency Response to Severe Child Abuse.

The Multi-agency Investigation & Support Team (MIST) was a new approach to abuse investigations that aimed to minimize the distress and uncertainty experienced by children and non-abusive caregivers in dealing with the many agencies typically involved in a case post-disclosure, while also attempting to improve the accessibility of supportive and therapeutic services. As part of a broader evaluation, this study examined worker perceptions early in the implementation of this new approach. Thirty-three (33) interviews were conducted with workers affected by this new pilot. The interviews identified almost exclusively positive perceptions of the changes relative to practice as usual, particularly in terms of improvements to collaboration and communication across agencies, and the benefits of providing support alongside the investigation process. Some areas of difficulty and areas for improvement were identified, particularly the need for stronger governance of the cross-agency protocol and improved connection to some of the groups involved in the response that were not co-located. The study suggests professionals working in the MIST model consider the model beneficial to the quality of the response to severe child abuse while highlighting that the process of change into this new way of working was challenging at times.

Association of Preoperative Frailty With Intraoperative Hemodynamic Instability and Postoperative Mortality.

BACKGROUND: Frailty, a state of decreased physiological reserve, is strongly associated with perioperative mortality in older adults. However, the mechanism by which frailty is associated with mortality is not yet understood. Autonomic dysfunction in the form of decreased intraoperative hemodynamic variability has been shown to be associated with increased mortality. We aimed to see whether frail patients have less hemodynamic variability under anesthesia and whether variability mediates the relationship between frailty and 30-day mortality. METHODS: We performed a single-center retrospective study of 1223 patients ≥65 years of age undergoing surgery between July 2008 and December 2012. We used markers of frailty: age >70, preoperative body mass index <18.5, hematocrit <35%, albumin <3.4 g/dL, and creatinine >2.0 mg/dL. We modeled the outcome of 30-day mortality with number of frailty conditions adjusting for gender, length of surgery, American Society of Anesthesiologists class, and need for transfusion. Intraoperative hemodynamic variability was defined as the count of episodes of absolute change >15% in fractional mean arterial pressure (MAP) between consecutive 5-minute intervals. We evaluated the role of intraoperative hemodynamic variability as a mediator (modifier) of the relationship between frailty and mortality, checking for 3 conditions: (1) frailty must affect episodes of absolute change >15% in fractional MAP; (2) episodes of absolute change >15% in fractional MAP must affect 30-day mortality; and (3) mediation effect is significant. We used the product method, in which the mediation effect was estimated as the product of the first 2 relationships. Then we applied the percentile bootstrap method to obtain the 95% CI for the estimate of mediation effect. RESULTS: Number of frailty conditions and episodes of absolute change >15% in fractional MAP were inversely proportional. Presence of ≥4 frailty conditions was associated with >40% reduction of the number of episodes of absolute change >15% in fractional MAP. Regarding mortality, episodes of absolute change >15% in fractional MAP were protective. The addition of absolute change >15% in fractional MAP in the mortality model resulted in a decrease in the frailty odds ratio from 10.6 to 9.1 (4+ conditions), suggesting that episodes of absolute change >15% in fractional MAP are indeed a mediator. The mediation effect was modest; 5 episodes of absolute change >15% in fractional MAP was 5.2%, 6.4%, 6.9%, and 9.0% for frailty conditions from 1 to 4+, respectively. CONCLUSIONS: Frailty is associated with less intraoperative blood pressure variation, and the relationship of frailty with 30-day mortality is partially mediated by episodes of absolute change >15% in fractional MAP. This suggests that autonomic dysregulation may be a modest part of the mechanism behind the association between frailty and perioperative mortality. Our finding is consistent with recent literature, suggesting that an intact autonomic nervous system confers lower perioperative mortality.

Inactivation of Candida albicans following exposure to 624-nanometer light from a supraluminous diode array.

OBJECTIVE: To determine the potential for visible light (405 or 624 nm) to produce an inhibitory effect on Candida albicans. In addition, the study sought to evaluate a series of doses in terms of their respective inhibiting capabilities. BACKGROUND DATA: The authors have studied the effect of blue light on Staphylococcus aureus and found that a bactericidal outcome can be obtained with low doses of blue light. METHODS: Candida albicans was tested because of its common appearance in human skin and mucous membrane infections. The organism was treated in vitro with 405-nm (blue) and with 624-nm (red) light emitted from a supraluminous diode array. Doses of 3, 9, 15, 30, and 60 J/cm(2) were used. Colony counts were performed and compared with untreated controls using Student t tests and 1-way analysis of variance with Tukey post hoc analysis. RESULTS: The results revealed no inhibition produced by 405 nm on C albicans (F4,20 = 0.901; P = .482). However, 624 nm did inhibit growth of C albicans at 3, 9, and 30 J/cm(2) (F4,20 = 6.064; P = .002). CONCLUSIONS: Appropriate doses of 624-nm light from a supraluminous diode array can inhibit the growth of C albicans in vitro. Three, 9, and 30 J/cm(2) are all effective dose levels.

Single variant, yet "double trouble": TSC and KBG syndrome because of a large de novo inversion.

Despite the advances in high-throughput sequencing, many rare disease patients remain undiagnosed. In particular, the patients with well-defined clinical phenotypes and established clinical diagnosis, yet missing or partial genetic diagnosis, may hold a clue to more complex genetic mechanisms of a disease that could be missed by available clinical tests. Here, we report a patient with a clinical diagnosis of Tuberous sclerosis, combined with unusual secondary features, but negative clinical tests including TSC1 and TSC2 Short-read whole-genome sequencing combined with advanced bioinformatics analyses were successful in uncovering a de novo pericentric 87-Mb inversion with breakpoints in TSC2 and ANKRD11, which explains the TSC clinical diagnosis, and confirms a second underlying monogenic disorder, KBG syndrome. Our findings illustrate how complex variants, such as large inversions, may be missed by clinical tests and further highlight the importance of well-defined clinical diagnoses in uncovering complex molecular mechanisms of a disease, such as complex variants and "double trouble" effects.

The international experience of in-situ recovery of the DCD heart: a multicentre retrospective observational study.

Background: Heart transplantation is an effective treatment offering the best recovery in both quality and quantity of life in those affected by refractory, severe heart failure. However, transplantation is limited by donor organ availability. The reintroduction of heart donation after the circulatory determination of death (DCD) in 2014 offered an uplift in transplant activity by 30%. Thoraco-abdominal normothermic regional perfusion (taNRP) enables in-situ reperfusion of the DCD heart. The objective of this paper is to assess the clinical outcomes of DCD donor hearts recovered and transplanted from donors undergoing taNRP. Method: This was a multicentre retrospective observational study. Outcomes included functional warm ischaemic time, use of mechanical support immediately following transplantation, perioperative and long-term actuarial survival and incidence of acute rejection requiring treatment. 157 taNRP DCD heart transplants, performed between February 2, 2015, and July 29, 2022, have been included from 15 major transplant centres worldwide including the UK, Spain, the USA and Belgium. 673 donations after the neurological determination of death (DBD) heart transplantations from the same centres were used as a comparison group for survival. Findings: taNRP resulted in a 23% increase in heart transplantation activity. Survival was similar in the taNRP group when compared to DBD. 30-day survival was 96.8% ([92.5%-98.6%] 95% CI, n = 156), 1-year survival was 93.2% ([87.7%-96.3%] 95% CI, n = 72) and 5-year survival was 84.3% ([69.6%-92.2%] 95% CI, n = 13). Interpretation: Our study suggests that taNRP provides a significant boost to heart transplantation activity. The survival rates of taNRP are comparable to those obtained for DBD transplantation in this study. The similar survival may in part be related to a short warm ischaemic time or through a possible selection bias of younger donors, this being an uncontrolled observational study. Therefore, our study suggests that taNRP offers an effective method of organ preservation and procurement. This early success of the technique warrants further investigation and use. Funding: None of the authors have a financial relationship with a commercial entity that has an interest in the subject.

Anterolateral thigh, radial forearm and superficial circumflex iliac perforator flaps in oral reconstruction: a comparative analysis.

BACKGROUND: Anterolateral thigh (ALT) and Radial forearm free flaps (RFFF) are historically the most common methods of oral reconstruction. The Superficial circumflex iliac artery perforator flap (SCIP) is an alternative providing a donor site that can be readily closed primarily with improved cosmesis in younger patients, due to its concealability. METHODS: We reviewed 135 patients who received ALT, RFFF or SCIP flaps for oral reconstruction in our institution. Our aim was to compare operative and perioperative outcomes between each cohort. ANOVA and χ2 test were used for statistical analysis. RESULTS: There were 37 ALT, 64 RFFF and 35 SCIP reconstructions. Patients reconstructed with SCIP flaps had smaller resection volumes (P < 0.001) and earlier T and N classifications (P = 0.001, P = 0.008), and consequently reduced tracheostomy rates (P < 0.001), reduced need for enteral feeding at discharge (P < 0.001) and shorter length of stay and perioperative times (P < 0.001). SCIP flaps were more common in younger patients (P < 0.01). ALT flaps were used for more advanced disease (P = 0.001) and had larger resection volumes (P < 0.001) and increased need for assisted enteral feeding (P < 0.001). There were no significant differences in flap or donor site outcomes. There were two flap failures, both RFFF. CONCLUSION: Each flap plays an important role in the reconstruction of oral defects, with larger defects preferentially reconstructed with ALT flaps. SCIP appears to be a reliable alternative in small defects with excellent perioperative and postoperative outcomes.

Going Asexual: A Survey of Mites of the Genus Thyreophagus (Acari: Acaridae) Revealing a Large Number of New Parthenogenetic Species in the Holarctic Region.

Mites of the genus Thyreophagus (Acari: Acaridae) are distributed worldwide; they inhabit concealed habitats and include several beneficial and economically important species. However, species identification is difficult because many species are poorly described or delimited and their phoretic stages are unknown or uncorrelated. Furthermore, Thyreophagus is interesting because it includes entirely asexual (parthenogenetic) species. However, among the 34 described species of Thyreophagus, the asexual status is confirmed through laboratory rearing for only two species. Here, we provide detailed descriptions of five new species from North America (four) and Europe (one) based on adults and phoretic heteromorphic deutonymphs. Four of these species were asexual, while one was sexual. For most of these mites, the asexual status was confirmed and phoretic deutonymphs were obtained through rearing in the lab. We show that asexual mites retain seemingly functional copulatory and sperm storage systems, indicating that these lineages have relatively short evolutionary lifespans. One North American species, Thyreophagus ojibwe, was found in association with the native American chestnut Castanea dentata, suggesting a possibility that this mite can be used to control chestnut blight in North America. We also provide a diagnostic key to females, males, and heteromorphic deutonymphs of the Thyreophagus species in the world.

A Study of Evaluation Influence in Two Child Protection Programs.

Evaluation influence is a reconceptualization of evaluation use that reflects the broad and diffuse impacts an evaluation can have on social programs and policies. This way of thinking about impact provides an opportunity to investigate how and why evaluations influence social programs and policy. Twenty participants (practitioners and managers) from two child protection programs evaluated in the previous 24 months were interviewed about the influence of these evaluations, which was complemented with the collection of internal documents about changes to the programs. A qualitative case study analysis of evaluation influence was conducted using the interviews and documents to investigate the influence of two evaluations at different stages in the dissemination process. The participants identified that the evaluations appeared to have significant high-level policy level influence; however, limited examples of influence on practices in the programs were identified. There was some suggestion that the evaluations had increased practitioner interest in working with and participating in program evaluations. The findings suggest the importance of developmental evaluation approaches and practitioner engagement in evaluation to improve the influence and adoption of new knowledge from the evaluation of social programs.

Velopharyngeal dysfunction following botulinum toxin type A injection to the lateral pterygoid muscles for recurrent jaw dislocation.

Complications related to lateral pterygoid muscle (LPM) botulinum toxin A (BtA) injection for recurrent temporomandibular joint dislocation are uncommon. No cases of velopharyngeal dysfunction (VPD) following LPM BtA injection have been reported to date. This report details the perioperative and follow-up findings for a patient developing VPD following LPM BtA injection.

A quasi-experimental study of the Multi-Agency Investigation & Support Team (MIST): A collaborative response to child sexual abuse.

To improve the holistic response to child sexual abuse in Perth, Western Australia, a group consisting of government and community support agencies developed a new co-located approach that combined support services with investigations, called the Multi-agency Investigation & Support Team (MIST). The model was comparable to the prominent Children's Advocacy Centre approach, with adaptations for Australian conditions. This study evaluated the fidelity with which this new program was delivered and examined whether it resulted in improved criminal justice, child protection, and service outcomes compared to existing practice. Drawing on service data linked across participating agencies the study found MIST was delivered with reasonable fidelity to its planned procedure, but with some challenges for delivery of the program due to the relative workload for staff in the MIST condition. The service demonstrated high levels of caregiver satisfaction with the response and high rates of children's engagement with therapy. A quasi-experimental comparison between MIST (n = 126) and Practice as Usual (n = 276) found MIST was significantly faster throughout the criminal justice and child protection processes, but the conditions did not differ in the rate of arrest or child protection actions. While embedding support services within the investigation process may not have a dramatic influence on criminal justice and child protection outcomes, the high rates of uptake of therapeutic services and parental satisfaction suggest other benefits that require future exploration.

Mainstreaming Genetic Testing for Adult Patients With Autosomal Dominant Polycystic Kidney Disease.

PURPOSE: Genetic testing results are currently obtained approximately 1 year after referral to a medical genetics team for autosomal dominant polycystic kidney disease (ADPKD). We evaluated a mainstream genetic testing (MGT) pathway whereby the nephrology team provided pre-test counseling and selection of patients with suspected ADPKD for genetic testing prior to direct patient interaction by a medical geneticist. SOURCES OF INFORMATION: A multidisciplinary team of nephrologists, genetic counselors, and medical geneticists developed an MGT pathway for ADPKD using current testing criteria for adult patient with suspected ADPKD and literature from MGT in oncology. METHODS: An MGT pathway was assessed using a prospective cohort and compared to a retrospective cohort of 56 patients with ADPKD who received genetic testing using the standard, traditional pathway prior to implementing the MGT for ADPKD. The mainstream pathway was evaluated using time to diagnosis, diagnostic yield, and a patient survey to assess patient perceptions of the MGT pathway. KEY FINDINGS: We assessed 26 patients with ADPKD using the MGT and 18 underwent genetic testing with return of results. Of them, 52 patients had data available for analysis in the traditional control cohort. The time for return of results using our MGT pathway was significantly shorter with a median time to results of 6 months compared to 12 months for the traditional pathway. We identified causative variants in 61% of patients, variants of uncertain significance in 28%, and 10% had negative testing which is in line with expectations from the literature. The patient surveys showed high satisfaction rates with the MGT pathway. LIMITATIONS: This report is an evaluation of a new genetic testing pathway restricted to a single, publicly funded health care center. The MGT pathway involved a prospective collection of a limited number of patients with ADPKD with comparison to a retrospective cohort of patients with ADPKD evaluated by standard testing. IMPLICATIONS: A MGT pathway using clearly defined criteria and commercially available gene panels for ADPKD can be successfully implemented in a publicly funded health care system to reduce the time required to obtain genetic results.

MOTIF: Actuellement, les résultats du dépistage génétique pour la maladie polykystique rénale autosomique dominante (ADPKD) sont obtenus environ un an après l'aiguillage en médecine génique. Nous avons évalué un parcours de dépistage génétique intégré (DGI) où l'équipe de néphrologie fournit des conseils pré-dépistage et sélectionne les patients soupçonnés d'ADPKD pour un test génétique avant l'interaction directe du patient avec un généticien médical. SOURCES: Une équipe multidisciplinaire constituée de néphrologues, de conseillers en génétique et de généticiens médicaux a développé un parcours de DGI à partir des critères existants pour les patients adultes soupçonnés d'ADPKD et de la littérature portant sur le DGI en oncologie. MÉTHODOLOGIE: Le parcours de DGI a été évalué dans une cohorte prospective puis comparé à une cohorte rétrospective de 56 patients atteints d'ADPKD ayant subi un dépistage génétique selon le parcours traditionnel, avant la mise en œuvre d'un parcours de DGI pour l'ADPKD. Le parcours intégré a été évalué en tenant compte du temps requis pour poser le diagnostic, du rendement diagnostique et d'un sondage auprès des patients évaluant leurs perceptions à l'égard du parcours lui-même. PRINCIPAUX RÉSULTATS: Le parcours de DGI a permis d'évaluer 26 patients atteints d'ADPKD, dont 18 ont subi des tests génétiques avec retour des résultats. Dans la cohorte témoin (dépistage traditionnel), 52 patients disposaient de données disponibles pour l'analyse. Le délai médian pour l'obtention des résultats était significativement plus court avec le parcours de DGI qu'avec le parcours traditionnel (6 mois c. 12 mois). Des variantes causales ont été relevées chez 61 % des patients, 28 % des patients présentaient des variantes de signification incertaine et 10 % ont obtenu des résultats négatifs, ce qui est conforme aux attentes posées par les résultats rapportés dans la littérature. Les sondages menés auprès des patients ont montré des taux de satisfaction élevés à l'égard du parcours de DGI. LIMITES: Ce rapport constitue l'évaluation d'un nouveau parcours de dépistage génétique limitée à un seul centre de soins de santé public. Ce parcours de DGI a été évalué dans une cohorte prospective formée d'un nombre limité de patients atteints d'ADPKD par rapport à une cohorte rétrospective de patients atteints d'ADPKD évalués par la méthode traditionnelle. IMPLICATIONS: Un parcours de DGI utilisant des critères clairement définis et des panels génétiques pour l'ADPKD disponible commercialement peut être mis en œuvre avec succès dans un système de santé public et accélérer l'obtention des résultats génétiques.

Immediate pools of malaria infections at diagnosis combined with targeted deep sequencing accurately quantifies frequency of drug resistance mutations.

Antimalarial resistance surveillance in sub-Saharan Africa is often constrained by logistical and financial challenges limiting its breadth and frequency. At two sites in Ghana, we have piloted a streamlined sample pooling process created immediately by sequential addition of positive malaria cases at the time of diagnostic testing. This streamlined process involving a single tube minimized clinical and laboratory work and provided accurate frequencies of all known drug resistance mutations after high-throughput targeted sequencing using molecular inversion probes. Our study validates this method as a cost-efficient, accurate and highly-scalable approach for drug resistance mutation monitoring that can potentially be applied to other infectious diseases such as tuberculosis.

Better Together? A Review of Evidence for Multi-Disciplinary Teams Responding to Physical and Sexual Child Abuse.

Multi-Disciplinary teams (MDTs) have often been presented as the key to dealing with a number of intractable problems associated with responding to allegations of physical and sexual child abuse. While these approaches have proliferated internationally, researchers have complained of the lack of a specific evidence base identifying the processes and structures supporting multi-disciplinary work and how these contribute to high-level outcomes. This systematic search of the literature aims to synthesize the existing state of knowledge on the effectiveness of MDTs. This review found that overall there is reasonable evidence to support the idea that MDTs are effective in improving criminal justice and mental health responses compared to standard agency practices. The next step toward developing a viable evidence base to inform these types of approaches seems to be to more clearly identify the mechanisms associated with effective MDTs in order to better inform how they are planned and implemented.

A national survey of characteristics of child advocacy centers in the United States: Do the flagship models match those in broader practice?

Child Advocacy Centers (CAC) emphasize developing effective cross-agency collaborations between workers involved in serious abuse investigations to foster improvements in agency outcomes, and to minimize distress, confusion and uncertainty for children and families. This study examined the characteristics of CACs, whether models in practice match the predominant model presented in the research literature. Directors of CACs in the United States that were members of the National Children's Alliance (NCA) mailing list (n=361) completed an online survey in 2016. While some core characteristics were ubiquitous across CACs, the data suggests that different types of CACs exist defined by characteristics that are not prescribed under NCA principles, but which are arguably relevant to the quality of the response. From the results of a cluster analysis, the researchers propose a typology of CACs that reflects the development and integration of centers: (a) core CAC services (i.e. interviewing & cross-agency case review); (b) an aggregator of external services, and (c) a more centralized full-service CAC. Further research is needed to understand how these variations may impact practice and outcomes; this is particularly important considering many CACs do not match the full-service models most commonly examined in the research literature, which limits the degree to which these findings apply to CACs generally. This article proposes further research framed by the need to better understand how different parts of the response impact on outcomes for children and families affected by abuse.

Gut microbiota, chemotherapy and the host: the influence of the gut microbiota on cancer treatment.

The gut microbiota exists in a dynamic balance between symbiosis and pathogenesis and can influence almost any aspect of host physiology. Growing evidence suggests that the gut microbiota not only plays a key role in carcinogenesis but also influences the efficacy and toxicity of anticancer therapy. The microbiota modulates the host response to chemotherapy via numerous mechanisms, including immunomodulation, xenometabolism and alteration of community structure. Furthermore, exploitation of the microbiota offers opportunities for the personalisation of chemotherapeutic regimens and the development of novel therapies. In this article, we explore the host-chemotherapeutic microbiota axis, from basic science to clinical research, and describe how it may change the face of cancer treatment.

The impacts of institutional child sexual abuse: A rapid review of the evidence.

While awareness of institutional child sexual abuse has grown in recent years, there remains limited understanding of its occurrence and outcomes as a distinct form of abuse. Drawing on research commissioned by the Australian Royal Commission into Institutional Responses to Child Sexual Abuse, this article presents a rapid review of available evidence on the impacts of institutional abuse on victim/survivors. Literature searches identified 75 sources spanning international peer reviewed work and reports to Government that document or quantify the impacts of mostly historical child sexual abuse occurring in religious, educational, sporting and residential or out-of-home care settings. Consistent with child sexual abuse in other contexts, institutional child sexual abuse is found to be associated with numerous, pervasive and connected impacts upon the psychological, physical, social, educative and economic wellbeing of victims/survivors. Further, institutional child sexual abuse is associated with vicarious trauma at the individual, family and community level, and with impacts to the spiritual wellbeing of victims/survivors of abuse that occurs in religious settings. The identified literature suggests the trauma of institutional child sexual abuse may be exacerbated by the interplay of abuse dynamics in institutional settings, which may reduce or impede circumstances supporting disclosure, belief, support and protection from future harm. Acknowledging the limitations of the present study and the available evidence, this narrative synthesis provides insights into the complex impacts of institutional child sexual abuse.

Evidence for the Efficacy of the Child Advocacy Center Model: A Systematic Review.

The Child Advocacy Center (CAC) model has been presented as the solution to many of the problems inherent in responses by authorities to child sexual abuse. The lack of referral to therapeutic services and support, procedurally flawed and potentially traumatic investigation practices, and conflict between the different statutory agencies involved are all thought to contribute to low conviction rates for abuse and poor outcomes for children. The CAC model aims to address these problems through a combination of multidisciplinary teams, joint investigations, and services, all provided in a single child friendly environment. Using a systematic search strategy, this research aimed to identify and review all studies that have evaluated the effectiveness of the approach as a whole, recognizing that a separate evidence base exists for parts of the approach (e.g., victim advocacy and therapeutic responses). The review found that while the criminal justice outcomes of the model have been well studied, there was a lack of research on the effect of the model on child and family outcomes. Although some modest outcomes were clear, the lack of empirical research, and overreliance on measuring program outputs, rather than outcomes, suggests that some clarification of the goals of the CAC model is needed.

Researching evaluation influence: a review of the literature.

BACKGROUND: The impact of an evaluation is an important consideration in designing and carrying out evaluations. Evaluation influence is a way of thinking about the effect that an evaluation can have in the broadest possible terms, which its proponents argue will lead to a systematic body of evidence about influential evaluation practices. METHOD: This literature review sets out to address three research questions: How have researchers defined evaluation influence; how is this reflected in the research; and what does the research suggest about the utility of evaluation influence as a conceptual framework. Drawing on studies that had cited one of the key evaluation influence articles and conducted original research on some aspect of influence this article reviewed the current state of the literature toward the goal of developing a body of evidence about how to practice influential evaluation. RESULTS: Twenty-eight studies were found that have drawn on evaluation influence, which were categorized into (a) descriptive studies, (b) analytical studies, and (c) hypothesis testing. CONCLUSION: Despite the prominence of evaluation influence in the literature, there is slow progress toward a persuasive body of literature. Many of the studies reviewed offered vague and inconsistent definitions and have applied influence in an unspecified way in the research. It is hoped that this article will stimulate interest in the systematic study of influence mechanisms, leading to improvements in the potential for evaluation to affect positive social change.

Inactivation of mycobacterium smegmatis following exposure to 405-nanometer light from a supraluminous diode array.

OBJECTIVE: To determine the potential for blue light (405 nm) to produce a bactericidal effect on Mycobacterium smegmatis. Additionally, the study sought to evaluate a series of doses in terms of their respective bactericidal capabilities. BACKGROUND DATA: The effect of blue light on Staphylococcus aureus has been studied and it was found that a bactericidal outcome can be obtained with low doses of blue light. METHODS: M. smegmatis was tested because of the recent appearance of the Mycobacterium family of organisms as a public health threat among persons receiving tattoos. The organism was treated in vitro with 405 nm light emitted from a supraluminous diode (SLD) array. Doses of 60 Jcm-2, 90 Jcm-2, 120 Jcm-2, 150 Jcm-2, 180 Jcm-2, 215 Jcm-2, and 250 Jcm-2 were used. Colony counts were performed and compared to untreated controls using Student t tests and one-way ANOVA with Tukey post hoc analysis. RESULTS: The results revealed statistically significant bactericidal effects of the blue light on M. smegmatis (F6, 28 = 50.518, P = 0.000). The treatment reduced the number of bacterial colonies at all doses, but 60 Jcm-2 did not produce a statistically significant kill rate. All other doses produced a significant kill rate with 120 Jcm-2, 150 Jcm-2, and 215 Jcm-2, demonstrating the most effective kill rates of 98.3%, 96.7%, and 100%, respectively. CONCLUSIONS: Appropriate doses of 405 nm light from an SLD array can kill M. smegmatis in vitro. A dose of at least 100 Jcm-2 dose is needed for the most effective inactivation of the organism. The dose response for this organism to blue light is not linear. Some degree of effectiveness is lost at 180 Jcm-2 and 250 Jcm-2. .