Microfluidic-Chip-Based Multiple-Locus Variable-Number Tandem-Repeat Fingerprinting with New Primer Sets for Methicillin-Resistant Staphylococcus aureus

The detection of outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) infections and a rapid and accurate identification of sources and routes of transmission should be conducted in hospital settings as early and swiftly as possible. In this study, we investigated the application potential of a new approach based on multiple-locus variable-number tandem-repeat fingerprinting (MLVF) and microfluidics technology for a rapid discrimination of MRSA lineages in outbreak settings. A total of 206 nonrepetitive MRSA isolates recovered from infected patients at the University Medical Center Groningen between 2000 and 2010 were tested. The results obtained by MLVF using microcapillary electrophoresis with newly designed primers were compared to those obtained by spa typing and multiple-locus variable-number tandem-repeat analysis (MLVA). The discriminatory power was 0.980 (107 patterns), 0.969 (85 allelic profiles), and 0.959 (66 types) for MLVF, MLVA, and spa typing, respectively. All methods tested showed a good concordance of results calculated by the adjusted Rand's coefficient method. Comparisons of data obtained by the three approaches allowed us to propose an 88% cutoff value for the similarity between any two MLVF patterns, which can be used in S. aureus epidemiological studies, including analyses of outbreaks and strain transmission events. Of the three tested methods, MLVF is the cheapest, fastest, and easiest to perform. MLVF applied to microfluidic polymer chips is a rapid, cheap, reproducible, and highly discriminating tool to determine the clonality of MRSA isolates and to trace the spread of MRSA strains over periods of many years. Although spa typing should be used due to its portability of data, MLVF has a high added value because it is more discriminatory

Pandemic influenza and excess intensive-care workload

In the Netherlands a major part of preparedness planning for an epidemic or pandemic consists of maintaining essential public services, e.g., by the police, fire departments, army personnel, and healthcare workers. We provide estimates for peak demand for healthcare workers, factoring in healthcare worker absenteeism and using estimates from published epidemiologic models on the expected evolution of pandemic influenza in relation to the impact on peak surge capacity of healthcare facilities and intensive care units (ICUs). Using various published scenarios, we estimate their effect in increasing the availability of healthcare workers for duty during a pandemic. We show that even during the peak of the pandemic, all patients requiring hospital and ICU admission can be served, including those who have non–influenza-related conditions. For this rigorous task differentiation, clear hierarchical management, unambiguous communication, and discipline are essential and we recommend informing and training non-ICU healthcare workers for duties in the ICU

Interdependence of diagnostics and epidemiology, a European perspective Position paper on the need for an intrinsic cooperation and data sharing: Position paper on the need for an intrinsic cooperation and data sharing

For some well-known pathogens like influenza or RSV, diagnostic and epidemiological data is available and continuously complement each other. For most other pathogens however, data is not always available or severely delayed. Furthermore, clinical data is needed to assess the burden of disease, which will enhance awareness and help to gain knowledge on emerging pathogens. In this position paper, we discuss the interdependence of diagnostics and epidemiology from a European perspective. In 2004, the European Centre for Disease Prevention and Control (ECDC) was founded to coordinate European wide surveillance and control. At present however, the ECDC still relies on university hospitals, public health institutions and other diagnostic institutions. Close collaboration between all stakeholders across Europe is therefore complex, but necessary to optimize the system for the individual patient. From the diagnostic side, data on detected pathogens should be shared with relevant health institutions in real-time. From the public health side, collected information should be made accessible for diagnostic and clinical institutions in real-time. Subsequently, this information needs to be disseminated across relevant medical disciplines to reach its full potential

Pandemic influenza and pediatric intensive care

Objective: To assess the adequacy of preparedness planning for an influenza pandemic by modeling the pediatric surge capacity of healthcare facility and pediatric intensive care unit (PICU) requirements over time. Governments and Public Health authorities have planned preparedness activities and training for a flu pandemic. PICU facilities will be the limiting factor in healthcare provision for children but detailed analyses for needs and demands in PICU care have not been published. Design: Based on the Center for Disease Control and Prevention and World Health Organization estimates and published models of the expected evolution of pandemic flu, we modeled the pediatric surge capacity of healthcare facility and PICU requirements over time. Various scenarios with different assumptions were explored. We compared these demands with estimates of maximal PICU capacity factoring in healthcare worker absenteeism as well as reported and more realistic estimates derived from semistructured telephone interviews with key stakeholders in ICUs in the study area. Setting: All hospitals and intensive care facilities in the Northern Region in The Netherlands with near 1.7 million inhabitants, of whom approximately 25% is Measurements and Main Results: Using well-established modeling techniques, evidence-based medicine, and incorporating estimates from the Centers for Disease Control and Prevention and World Health Organization, we show that PICU capacity may suffice during an influenza pandemic. Even during the peak of the pandemic, most children requiring PICU admission may be served, even those who have nonflu-related conditions, provided that robust indications and decision rules are maintained, both for admission, as well as continuation (or discontinuation) of life support. Conclusions: We recommend that a model, with assumptions that can be adapted with new information obtained during early stages of the pandemic that is evolving, be an integral part of a preparedness plan for a pandemic influenza with new human transmissible agent like influenza A virus. (Pediatr Crit Care Med 2010; 11: 185-198

Chemotherapy Treatment in Pediatric Patients with Acute Myeloid Leukemia Receiving Antimicrobial Prophylaxis Leads to a Relative Increase of Colonization with Potentially Pathogenic Bacteria in the Gut

Background. Normally, humans are protected against infections by their anaerobic intestinal microorganisms providing colonization resistance. In immunocompromised patients, the endogenous intestinal gram-positive and gram-negative pathogens often cause infectious complications. Therefore, we analyzed the effect of chemotherapy treatment and antimicrobial prophylaxis on intestinal bacterial populations (microbiota) among pediatric patients with acute myeloid leukemia who are prone to intestinal mucositis and infections. Methods. During 36 chemotherapy cycles, fecal samples were collected from pediatric patients with acute myeloid leukemia. Fecal bacterial populations were analyzed by polymerase chain reaction denaturing gradient gel electrophoresis fingerprinting. Fluorescent in situ hybridization analysis with specific bacterial oligonucleotide probes was used to quantify the fecal bacteria. Results. During chemotherapy treatment, the total number of bacteria in fecal samples was 109 per gram of dry weight feces, which was 100-fold lower than than in healthy control samples. Fluorescent in situ hybridization analysis showed that this decrease was the result of an up to 10,000-fold decrease in anaerobic bacteria, partly compensated for by a 100-fold increase in potentially pathogenic enterococci. Additional experiments showed that both prophylactic and therapeutic use of antibiotics could not sufficiently explain the tremendous changes in intestinal microbial composition. In vitro tests showed a direct bacteriostatic effect of chemotherapeutics. Conclusions. Patients with acute myeloid leukemia treated with chemotherapy and prophylactic antibiotics are unable to maintain colonization resistance because of a decrease in anaerobic bacteria and an increase in potentially pathogenic aerobic enterococci. We hypothesize that this disturbance in the balance between anaerobic and aerobic bacteria will further increase the risk of gram-positive aerobic infections among immunocompromised patients with cancer

Cold Spots in Neonatal Incubators Are Hot Spots for Microbial Contamination▿

Thermal stability is essential for the survival and well-being of preterm neonates. This is achieved in neonatal incubators by raising the ambient temperature and humidity to sufficiently high levels. However, potentially pathogenic microorganisms also can thrive in such warm and humid environments. We therefore investigated whether the level of microbial contamination (i.e., the bacterial load) inside neonatal incubators can be predicted on the basis of their average temperature and relative humidity settings, paying special attention to local temperature differences. Swab samples were taken from the warmest and coldest spots found within Caleo incubators, and these were plated to determine the number of microbial CFU per location. In incubators with high average temperature (≥34°C) and relative humidity (≥60%) values, the level of microbial contamination was significantly higher at cold spots than at hot spots. This relates to the fact that the local equilibrium relative humidity at cold spots is sufficiently high to sustain microbial growth. The abundance of staphylococci, which are the main causative agents of late-onset sepsis in preterm neonates, was found to be elevated significantly in cold areas. These findings can be used to improve basic incubator hygiene