Kelly Withum

The BEACHES Study: health effects and exposures from non-point source microbial contaminants in subtropical recreational marine waters

BACKGROUND Microbial water-quality indicators, in high concentrations in sewage, are used to determine whether water is safe for recreational purposes. Recently, the use of these indicators to regulate recreational water bodies, particularly in sub/tropical recreational marine waters without known sources of sewage, has been questioned. The objectives of this study were to evaluate the risk to humans from exposure to subtropical recreational marine waters with no known point source, and the possible relationship between microbe densities and reported symptoms in human subjects with random-exposure assignment and intensive individual microbial monitoring in this environment. METHODS A total of 1303 adult regular bathers were randomly assigned to bather and non-bather groups, with subsequent follow-up for reported illness, in conjunction with extensive environmental sampling of indicator organisms (enterococci). RESULTS Bathers were 1.76 times more likely to report gastrointestinal illness [95% confidence interval (CI) 0.94-3.30; P = 0.07]; 4.46 times more likely to report acute febrile respiratory illness (95% CI 0.99-20.90; P = 0.051) and 5.91 times more likely to report a skin illness (95% CI 2.76-12.63; P < 0.0001) relative to non-bathers. Evidence of a dose-response relationship was found between skin illnesses and increasing enterococci exposure among bathers [1.46 times (95% CI 0.97-2.21; P = 0.07) per increasing log(10) unit of enterococci exposure], but not for gastrointestinal or respiratory illnesses. CONCLUSIONS This study indicated that bathers may be at increased risk of several illnesses relative to non-bathers, even in the absence of any known source of domestic sewage impacting the recreational marine waters. There was no dose-response relationship between gastroenteritis and increasing exposure to enterococci, even though many current water-monitoring standards use gastroenteritis as the major outcome illness.

Traditional and molecular analyses for fecal indicator bacteria in non-point source subtropical recreational marine waters.

The use of enterococci as the primary fecal indicator bacteria (FIB) for the determination of recreational water safety has been questioned, particularly in sub/tropical marine waters without known point sources of sewage. Alternative FIB (such as the Bacteroidales group) and alternative measurement methods (such as rapid molecular testing) have been proposed to supplement or replace current marine water quality testing methods which require culturing enterococci. Moreover, environmental parameters have also been proposed to supplement current monitoring programs. The objective of this study was to evaluate the health risks to humans from exposure to subtropical recreational marine waters with no known point source. The study reported symptoms between one set of human subjects randomly assigned to marine water exposure with intensive environmental monitoring compared with other subjects who did not have exposure. In addition, illness outcomes among the exposed bathers were compared to levels of traditional and alternative FIB (as measured by culture-based and molecular-based methods), and compared to easily measured environmental parameters. Results demonstrated an increase in self-reported gastrointestinal, respiratory and skin illnesses among bathers vs. non-bathers. Among the bathers, a dose-response relationship by logistic regression modeling was observed for skin illness, where illness was positively related to enterococci enumeration by membrane filtration (odds ratio = 1.46 [95% confidence interval = 0.97-2.21] per increasing log10 unit of enterococci exposure) and positively related to 24 h antecedent rain fall (1.04 [1.01-1.07] per increasing millimeters of rain). Acute febrile respiratory illness was inversely related to water temperature (0.74 [0.56-0.98] per increasing degree of water temperature). There were no significant dose-response relationships between report of human illness and any of the other FIB or environmental measures. Therefore, for non-point source subtropical recreational marine waters, this study suggests that humans may be at increased risk of reported illness, and that the currently recommended and investigational FIB may not track gastrointestinal illness under these conditions; the relationship between other human illness and environmental measures is less clear.

Shedding of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus from adult and pediatric bathers in marine waters

BackgroundStaphylococcus aureus including methicillin resistant S. aureus, MRSA, are human colonizing bacteria that commonly cause opportunistic infections primarily involving the skin in otherwise healthy individuals. These infections have been linked to close contact and sharing of common facilities such as locker rooms, schools and prisons Waterborne exposure and transmission routes have not been traditionally associated with S. aureus infections. Coastal marine waters and beaches used for recreation are potential locations for the combination of high numbers of people with close contact and therefore could contribute to the exposure to and infection by these organisms. The primary aim of this study was to evaluate the amount and characteristics of the shedding of methicillin sensitive S. aureus, MSSA and MRSA by human bathers in marine waters.ResultsNasal cultures were collected from bathers, and water samples were collected from two sets of pools designed to isolate and quantify MSSA and MRSA shed by adults and toddlers during exposure to marine water. A combination of selective growth media and biochemical and polymerase chain reaction analysis was used to identify and perform limited characterization of the S. aureus isolated from the water and the participants. Twelve of 15 MRSA isolates collected from the water had identical genetic characteristics as the organisms isolated from the participants exposed to that water while the remaining 3 MRSA were without matching nasal isolates from participants. The amount of S. aureus shed per person corresponded to 105 to 106 CFU per person per 15-minute bathing period, with 15 to 20% of this quantity testing positive for MRSA.ConclusionsThis is the first report of a comparison of human colonizing organisms with bacteria from human exposed marine water attempting to confirm that participants shed their own colonizing MSSA and MRSA into their bathing milieu. These findings clearly demonstrate that adults and toddlers shed their colonizing organisms into marine waters and therefore can be sources of potentially pathogenic S. aureus and MRSA in recreational marine waters. Additional research is needed to evaluate recreational beaches and marine waters as potential exposure and transmission pathways for MRSA.

Use of mobile learning module improves skills in chest tube insertion

BACKGROUND Just-In-Time Learning is a concept increasingly applied to medical education, and its efficacy must be evaluated. MATERIALS AND METHODS A 3-minute video on chest tube insertion was produced. Consenting participants were assigned to either the video group, which viewed the video on an Apple® iPod Touch immediately before chest tube insertion, or the control group, which received no instruction. Every participant filled out a questionnaire regarding prior chest tube experience. A trained clinician observed participants insert a chest tube on the TraumaMan® task simulator, and assessed performance using a 14-item skills checklist. RESULTS Overall, 128 healthcare trainees participated, with 50% in the video group. Participants included residents (34.4%, n = 44), medical students (32.8%, n = 42), and U.S. Army Forward Surgical Team members (32.8%, n = 42). Sixty-nine percent of all participants responded that they had never placed a chest tube, but 7% had placed more than 20. Only 25% of the participants had previously used TraumaMan®. Subjects who viewed the video scored better on the skills checklist than the control group (11.09 ± 3.09 versus 7.17 ± 3.56, P < 0.001, Cohens D = 1.16). Medical students (9.33 ± 2.65 versus 4.52 ± 3.64, P < 0.001), Forward Surgical Team members (10.07 ± 2.52 versus 8.57 ± 3.22, P < 0.001), anesthesia residents (8.25 ± 2.56 versus 5.9 ± 2.23, P = 0.017), and subjects who had placed fewer than 10 chest tubes (9.7 ± 3 versus 6.6 ± 3.9, P < 0.001) performed significantly better with the video. CONCLUSIONS The procedural animation video is an effective medium for teaching procedural skills. Embedding the video on a mobile device, and allowing trainees to access it immediately before chest tube insertion, may enhance and standardize surgical education for civilians and military personnel.

Quantitative evaluation of enterococci and Bacteroidales released by adults and toddlers in marine water

Traditionally, the use of enterococci has been recommended as the fecal indicator bacteria of choice for testing marine recreational water quality, and prior studies have shown that bathers shed large numbers of enterococci into the water. The current study expands upon prior research by evaluating shedding from both toddlers and adults, and by the expansion of measurements to include enterococci shedding via three different methods (membrane filter (MF), chromogenic substrate (CS), and quantitative polymerase chain reaction (qPCR)) and shedding of alternative fecal indicator bacteria (Bacteroidales human markers UCD and HF8 via qPCR). Two sets of experiments were conducted. The first experiment consisted of two groups of 10 adults who bathed together in a large pool. The second study consisted of 14 toddlers who bathed individually in a small pool which allowed for sand recovery. Sand recovery was used to estimate the amount of sand transported on the bodies of toddlers and to estimate the number of fecal indicator bacteria released from this sand. The numbers of estimated enterococci shed per adult ranged from 1.8 x 10(4) to 2.8 x 10(6) CFU, from 1.9 x 10(3) to 4.5 x 10(6) MPN, and from 3.8 x 10(5) to 5.5 x 10(6) GEU based on the MF, CS, and qPCR methods, respectively. The estimated numbers of Bacteroidales human markers ranged from 1.8 x 10(4) to 1.3 x 10(6) for UCD, and ranged from the below detection limit to 1.6 x 10(5) for HF8. The estimated amount of sand transported per toddler (n=14) into the water column after sand exposure was 8+/-6g on average. When normalizing the numbers of enterococci shed from toddlers via sand by the 3.9 body surface area ratio, the differences between toddlers and adults were insignificant. Contributions of sands to the total enterococci (MF) shed per toddler was 3.7+/-4.4% on average. Although shedding via beach sand may contribute a small fraction of the microbial load during initial bathing, it may have a significant role if bathers go to water repetitively after sand exposure.

Daily measures of microbes and human health at a non-point source marine beach

Studies evaluating the relationship between microbes and human health at non-point source beaches are necessary for establishing criteria which would protect public health while minimizing economic burdens. The objective of this study was to evaluate water quality and daily cumulative health effects (gastrointestinal, skin, and respiratory illnesses) for bathers at a non-point source subtropical marine recreational beach in order to better understand the inter-relationships between these factors and hence improve monitoring and pollution prevention techniques. Daily composite samples were collected, during the Oceans and Human Health Beach Exposure Assessment and Characterization Health Epidemiologic Study conducted in Miami (Florida, USA) at a non-point source beach, and analyzed for several pathogens, microbial source tracking markers, indicator microbes, and environmental parameters. Analysis demonstrated that rainfall and tide were more influential, when compared to other environmental factors and source tracking markers, in determining the presence of both indicator microbes and pathogens. Antecedent rainfall and F+ coliphage detection in water should be further assessed to confirm their possible association with skin and gastrointestinal (GI) illness outcomes, respectively. The results of this research illustrate the potential complexity of beach systems characterized by non-point sources, and how more novel and comprehensive approaches are needed to assess beach water quality for the purpose of protecting bather health.

Influence of social networking websites on medical school and residency selection process

Background Social networking (SN) has become ubiquitous in modern culture. The potential consequences of revealing personal information through SN websites are not fully understood. Objective To assess familiarity with, usage of, and attitudes towards, SN websites by admissions offices at US medical schools and residency programmes. Methods A 26-question survey was distributed in autumn 2009 to 130 US medical school admissions officers and 4926 residency programme directors accredited by the Accreditation Council for Graduate Medical Education. Results A total of 600 surveys were completed, with 46 (8%) respondents who self-identified as reviewing only medical school applications, 511 (85%) who reported reviewing residency programme applications and 43 (7%) who reported reviewing both. 90/600 (15%) medical schools or programmes maintain profiles on SN websites and 381/600 (64%) respondents reported being somewhat or very familiar with searching individual profiles on SN websites. While a minority of medical schools and residency programmes routinely use SN websites in the selection process (53/600; 9%), more than half of respondents felt that unprofessional information on applicants’ SN websites could compromise their admission into medical school or residency (315/600; 53%). Conclusions SN websites will affect selection of medical students and residents. Formal guidelines for professional behaviour on SN websites might help applicants avoid unforeseen bias in the selection process.

Mobile Learning Module Improves Knowledge of Medical Shock for Forward Surgical Team Members

OBJECTIVE Acute trauma care is characterized by dynamic situations that require adequate preparation to ensure success for military health professionals. The use of mobile learning in this environment can provide a solution that standardizes education and replaces traditional didactic lectures. METHODS A comparative evaluation with a pre-post test design regarding medical shock was delivered via either a didactic lecture or a mobile learning video module to U.S. Army Forward Surgical Team (FST) members. Participants completed a pretest, were randomly assigned to treatment group by FST, and then completed the post-test and scenario assessment. RESULTS One-hundred and thirteen FST members participated with 53 in the mobile learning group and 60 in the lecture group (control). The percent mean score for the mobile learning group increased from 43.6 to 70 from pretest to post-test, with a scenario mean score of M = 56.2. The percent mean score for the control group increased from 41.5 to 72.5, with a scenario mean score of M = 59.7. The two-way analysis of variance mean score difference was 26.4 for the mobile learning group and 31.0 for the control, F = 2.18, (p = 0.14). CONCLUSIONS Mobile learning modules, coupled with a structured assessment, have the potential to improve educational experiences in civilian and military settings.

Just-in-time learning is effective in helping first responders manage weapons of mass destruction events

BACKGROUND Chemical, biologic, radiologic, nuclear, and explosive (CBRNE) incidents require specialized training. The low frequency of these events leads to significant skill decay among first responders. To address skill decay and lack of experience with these high-impact events, educational modules were developed for mobile devices to provide just-in-time training to first responders en route to a CBRNE event. This study assessed the efficacy and usability of the mobile training. METHODS Ninety first responders were randomized to a control or an intervention group. All participants completed a pretest to measure knowledge of CBRNE topics. The intervention group then viewed personal protective equipment and weapons of mass destruction field management videos as an overview. Both groups were briefed on a disaster scenario (chemical nerve agent, radiologic, or explosives) requiring them to triage, assess, and manage a patient. Intervention group participants watched a mobile training video corresponding to the scenario. The control group did not receive prescenario video training. Observers rated participant performance in each scenario. After completing the scenarios, all participants answered a cognitive posttest. Those in the intervention group also answered a questionnaire on their impressions of the training. RESULTS The intervention group outperformed the control group in the explosives and chemical nerve agent scenarios; the differences were statistically significant (explosives, mean of 26.32 for intervention and 22.85 for control, p < 0.01; nerve agent, mean of 23.14 for intervention and 16.61 for control, p < 0.01). There was no statistically significant difference between the groups in the radiologic scenario (mean, 12.7 for intervention and 11.8 for control; p = 0.51). The change in pretest to posttest cognitive scores was significantly higher in the intervention group than in the control group (t = 3.28, p < 0.05). CONCLUSION Mobile just-in-time training improved first-responder knowledge of CBRNE events and is an effective tool in helping first responders manage simulated explosive and chemical agent scenarios. LEVEL OF EVIDENCE Therapeutic/care management study, level II.