A wireless sensor network to measure the health care workers exposure to tuberculosis

International audienceIn parallel to the advances in modern medicine, health sciences and public health policy, epidemic models aided by computer simulations and information technologies offer an important alternative for the understanding of transmission dynamics and epidemic patterns. In this paper, we focus on the first steps that may lead towards the design of epidemic models, i.e. the measure and analysis of interactions within a closed socio-professional context. More precisely, this project was motivated by the study of the Health Care Workers (HCWs) exposure to tuberculosis in their work environment. Despite the progresses in treatment and prevention, tuberculosis remains a disease in expansion and represents the third cause of death by infectious pathologies in the world. In the health care context, if the transmission is globally controlled, the HCWs exposure remains obscure. Individual factors associated to the contamination of HCWs in their work environment are not precisely known. Our study focus on the evaluation of the intensity and the frequency of contacts between tuberculosis infected patients and HCWs. To gather this information, classical methods consist in performing audits, consulting medical and administrative files or using self-reports of conversations and trusting HCW souvenirs. All these methods are time-consuming, subject to memory failures and interpretations. As an alternate method, we have chosen to dedicate a Wireless Sensor Network (WSN) to gather these interactions inside a Service of Infectious and Tropical Diseases (Bichat-Claude Bernard Hospital, Paris) and a Service of Pneumology (La Piti ´ e Salp ´ etri ` ere Hospital, Paris). Within the two services, each room has been equipped with a sensor node and each HCW carries an autonomous sensor during his presence in the service. An important characteristic of this measurement campaign is that it was performed in a closed environment, over a closed population and during a large continuous period of time. That is, the presence of all HCWs of the units was monitored in all patient rooms, 24/7 during a three months period. In addition to the experimental measure system description, this paper main contributions are the analysis and characterization of this huge and unique data set describing a complex dynamic interaction network, and the impact study of the measurement process bias on the network dynamic. The analyze of large dynamic in situ interaction networks provides an opportunity to study dynamical processes occurring on dynamical networks, such as spreading or epidemical processes, taking into account the dynamics both on and of the network structure

Reconstructing Social Interactions Using an unreliable Wireless Sensor Network

International audienceIn the very active field of complex networks, research advances have largely been stimulated by the availability of empirical data and the increase in computational power needed for their analysis. These works have led to the identification of similarities in the structures of such networks arising in very different fields, and to the development of a body of knowledge, tools and methods for their study. While many interesting questions remain open on the subject of static networks, challenging issues arise from the study of dynamic networks. In particular, the measurement, analysis and modeling of social interactions are first class concerns. In this article, we address the challenges of capturing physical proximity and social interaction by means of a wireless network. In particular, as a concrete case study, we exhibit the deployment of a wireless sensor network applied to the measurement of Health Care Workers' exposure to tuberculosis infected patients in a service unit of the Bichat-Claude Bernard hospital in Paris, France. This network has continuously monitored the presence of all HCWs in all rooms of the service during a 3 month period. We both describe the measurement system that was deployed and some early analysis on the measured data. We highlight the bias introduced by the measurement system reliability and provide a reconstruction method which not only leads to a significantly more coherent and realistic dataset but also evidences phe- nomena a priori hidden in the raw data. By this analysis, we suggest that a processing step is required prior to any adequate exploitation of data gathered thanks to a non-fully reliable measurement architecture

Comparison of four skin preparation strategies to prevent catheter-related infection in intensive care unit (CLEAN trial): a study protocol for a randomized controlled trial

International audienceBackgroundCatheter-related infection is the third cause of infections in intensive care units (ICU), increasing the length of stay in ICU and hospital, mortality, and costs. Skin antisepsis is one of the most prevalent preventive measures. In this respect, it would appear preferable to recommend the use of alcoholic povidone iodine or chlorhexidine rather than aqueous povidone iodine. However, the data comparing chlorhexidine to povidone-iodine, both of them in alcoholic solutions, remain limited. Moreover, the benefits of enhanced cleaning prior to disinfection of skin that is not visibly soiled have yet to be confirmed in a randomized study.MethodsA prospective multicenter, 2×2 factorial, randomized-controlled, assessor-blind trial will be conducted in 11 intensive care units in six French hospitals. All adult patients aged over 18 years requiring the insertion of at least one peripheral arterial catheter and/or a non-tunneled central venous catheter and/or a hemodialysis catheter and/or an arterial pulmonary catheter will be randomly assigned to have all their catheters cared with one of four skin preparation strategies (2% chlorhexidine/70% isopropyl alcohol or 5% povidone iodine/69% ethanol with or without prior skin scrubbing). At catheter removal, catheter tips will be quantitatively cultured. Sets of aerobic and anaerobic blood cultures will be routinely obtained when a patient has fever, hypothermia, or other indications. In case of suspected catheter-related infection the patient's form will be reviewed by an independent adjudication committee. We plan to enroll 2,400 patients (4,800 catheters). The main objective is to demonstrate that use of 2% alcoholic chlorhexidine compared to 5% alcoholic povidone iodine in skin preparation lowers the rate of catheter-related infection. The second endpoint is to demonstrate that enhanced skin cleaning prior to disinfection of skin that is not visibly soiled does not reduce catheter colonization. Other outcomes include comparison of skin colonization at catheter insertion site, comparison of catheter colonization and catheter-related bacteremia taking place during implementation of the four strategies of skin preparation, and cutaneous tolerance, length of hospitalization, mortality, and costs.DiscussionThis study will help to update recommendations on the choice of an antiseptic agent to use in skin preparation prior to insertion of a vascular catheter and, by extension, of an epidural catheter and it will likewise help to update recommendations on the usefulness of skin scrubbing prior to disinfection when the skin is not visibly soiled.Trial registrationClinicaltrials.gov number NCT0162955

Resistance of Staphylococcus aureus Recovered from Infected Foreign Body In Vivo to Killing by Antimicrobials

Because persistence of infections associated with prosthetic material despite the use of appropriate antibioticsis a major clinical problem,the antimicrobial susceptibility of bacteria responsible for a chronic subcutaneous tissue cage infection in rat was investigated ex vivo. Three to 6 weeks after the initiation of infection, suspensions of two strains of Staphylococcus aureus recovered from the foreign body surface and surrounding fluid wereexposed to either oxacillin, vancomycin, fleroxacin, gentamicin, or rifampin. The MBCs of these bacteria were markedly elevated, in most cases 128 to >256 times higher than the MBCof batch culture S. aureus in either logarithmic or stationary phase. Kinetic studies showed the bacteria did not growwhen incubated for 2 h in Mueller-Hinton broth, possibly reflecting dormancy. Their killing wasslow and incompleteby all antibioticsat > 8 times their MIC. These data provide direct evidence of a decreased susceptibility of S. aureus to the killing effect of antimicrobials during chronic foreign body infections in viv

Relationship between Fungal Colonisation of the Respiratory Tract in Lung Transplant Recipients and Fungal Contamination of the Hospital Environment

International audienceBackgroundAspergillus colonisation is frequently reported after lung transplantation. The question of whether aspergillus colonisation is related to the hospital environment is crucial to prevention.MethodTo elucidate this question, a prospective study of aspergillus colonisation after lung transplantation, along with a mycological survey of the patient environment, was performed.ResultsForty-four consecutive patients were included from the day of lung transplantation and then examined weekly for aspergillus colonisation until hospital discharge. Environmental fungal contamination of each patient was followed weekly via air and surface sampling. Twelve patients (27%) had transient aspergillus colonisation, occurring 1–13 weeks after lung transplantation, without associated manifestation of aspergillosis. Responsible Aspergillus species were A. fumigatus (6), A. niger (3), A. sydowii (1), A. calidoustus (1) and Aspergillus sp. (1). In the environment, contamination by Penicillium and Aspergillus was predominant. Multivariate analysis showed a significant association between occurrence of aspergillus colonisation and fungal contamination of the patient’s room, either by Aspergillus spp. in the air or by A.fumigatus on the floor. Related clinical and environmental isolates were genotyped in 9 cases of aspergillus colonisation. For A. fumigatus (4 cases), two identical microsatellite profiles were found between clinical and environmental isolates collected on distant dates or locations. For other Aspergillus species, isolates were different in 2 cases; in 3 cases of aspergillus colonisation by A. sydowii, A. niger and A. calidoustus, similarity between clinical and environmental internal transcribed spacer and tubulin sequences was >99%.ConclusionTaken together, these results support the hypothesis of environmental risk of hospital acquisition of aspergillus colonisation in lung transplant recipients

Considerations for de-escalating universal masking in healthcare centers

Three years after the beginning of the COVID-19 pandemic, better knowledge on the transmission of respiratory viral infections (RVI) including the contribution of asymptomatic infections encouraged most healthcare centers to implement universal masking. The evolution of the SARS-CoV-2 epidemiology and improved immunization of the population call for the infection and prevention control community to revisit the masking strategy in healthcare. In this narrative review, we consider factors for de-escalating universal masking in healthcare centers, addressing compliance with the mask policy, local epidemiology, the level of protection provided by medical face masks, the consequences of absenteeism and presenteeism, as well as logistics, costs, and ecological impact. Most current national and international guidelines for mask use are based on the level of community transmission of SARS-CoV-2. Actions are now required to refine future recommendations, such as establishing a list of the most relevant RVI to consider, implement reliable local RVI surveillance, and define thresholds for activating masking strategies. Considering the epidemiological context (measured via sentinel networks or wastewater analysis), and, if not available, considering a time period (winter season) may guide to three gradual levels of masking: (i) standard and transmission-based precautions and respiratory etiquette, (ii) systematic face mask wearing when in direct contact with patients, and (iii) universal masking. Cost-effectiveness analysis of the different strategies is warranted in the coming years. Masking is just one element to be considered along with other preventive measures such as staff and patient immunization, and efficient ventilation

Rapid detection of glycopeptide-resistant enterococci: impact on decision-making and costs.

International audienceBACKGROUND: According to French national recommendations, the detection of a patient colonized with glycopeptide-resistant enterococci (GRE) leads to interruption of new admissions and transfer of contact patients (CPs) to another unit or healthcare facility, with weekly screening of CPs. FINDINGS: We evaluated the medical and economic impact of a pragmatic adaptation of national guidelines associated with a real-time PCR (RTP) (Cepheid XpertTM vanA/vanB) as part of the strategy for controlling GRE spread in two medical wards. Screening was previously performed using chromogenic selective medium (CSM). Turn around time (TAT), costs of tests and cost of missed patient days were prospectively collected. In February 2012, the identification of GRE in one patient in the diabetology ward led to the screening of 31 CPs using CSM; one secondary case was identified in a CP already transferred to the Nephrology ward. Awaiting the results of SCM (median TAT, 70.5 h), 41 potential patient days were missed, due to interruption of admissions. The overall cost (screening tests + missing patient.days) was estimated at 14, 302.20 [euro sign]. The secondary case led to screening of 22 CPs in the Nephrology ward using RTP. Because of a short median TAT of 4.6 h, we did not interrupt admissions and patients' transfers. Among 22 CPs, 19 (86%) were negative for vanA, 2 were positive for vanB and 3 had invalid results needing CSM. The overall cost of the strategy was estimated at 870.40 [euro sign] (cost of screening tests only), without missing patient days. CONCLUSION: The rapid PCR test for vanA-positive GRE detection both allowed rapid decision about the best infection control strategy and prevented loss of income due to discontinuation of patient transfers and admissions