The challenge of emerging and re-emerging infectious diseases

Epithelial cell lines of the cotton rat (Sigmodon hispidus) are highly susceptible in vitro models to zoonotic Bunya-, Rhabdo-, and Flaviviruses

Background

Small mammals such as bats and rodents have been increasingly recognized as reservoirs of novel potentially zoonotic pathogens. However, few in vitro model systems to date allow assessment of zoonotic viruses in a relevant host context. The cotton rat (Sigmodon hispidus) is a New World rodent species that has a long-standing history as an experimental animal model due to its unique susceptibility to human viruses. Furthermore, wild cotton rats are associated with a large variety of known or potentially zoonotic pathogens.

Methods

A method for the isolation and culture of airway epithelial cell lines recently developed for bats was applied for the generation of rodent airway and renal epithelial cell lines from the cotton rat. Continuous cell lines were characterized for their epithelial properties as well as for their interferon competence. Susceptibility to members of zoonotic Bunya-, Rhabdo-, and Flaviviridae, in particular Rift Valley fever virus (RVFV), vesicular stomatitis virus (VSV), West Nile virus (WNV), and tick-borne encephalitis virus (TBEV) was tested. Furthermore, novel arthropod-derived viruses belonging to the families Bunya-, Rhabdo-, and Mesoniviridae were tested.

Results

We successfully established airway and kidney epithelial cell lines from the cotton rat, and characterized their epithelial properties. Cells were shown to be interferon-competent. Viral infection assays showed high-titre viral replication of RVFV, VSV, WNV, and TBEV, as well as production of infectious virus particles. No viral replication was observed for novel arthropod-derived members of the Bunya-, Rhabdo-, and Mesoniviridae families in these cell lines.

Conclusion

In the current study, we showed that newly established cell lines from the cotton rat can serve as host-specific in vitro models for viral infection experiments. These cell lines may also serve as novel tools for virus isolation, as well as for the investigation of virus-host interactions in a relevant host species.

Testing the accuracy ratio of the Spatio-Temporal Epidemiological Modeler (STEM) through Ebola haemorrhagic fever outbreaks

Mathematical modelling is an important tool for understanding the dynamics of the spread of infectious diseases, which could be the result of a natural outbreak or of the intentional release of pathogenic biological agents. Decision makers and policymakers responsible for strategies to contain disease, prevent epidemics and fight possible bioterrorism attacks, need accurate computational tools, based on mathematical modelling, for preventing or even managing these complex situations. In this article, we tested the validity, and demonstrate the reliability, of an open-source software, the Spatio-Temporal Epidemiological Modeler (STEM), designed to help scientists and public health officials to evaluate and create models of emerging infectious diseases, analysing three real cases of Ebola haemorrhagic fever (EHF) outbreaks: Uganda (2000), Gabon (2001) and Guinea (2014). We discuss the cases analysed through the simulation results obtained with STEM in order to demonstrate the capability of this software in helping decision makers plan interventions in case of biological emergencies.

Recent advances in hantavirus molecular biology and disease

Hantaviruses are emerging zoonotic pathogens that belong to the Bunyaviridae family. They have been classified as category A pathogens by CDC (centers for disease control and prevention). Hantaviruses pose a serious threat to human health because their infection causes two highly fatal diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS). These pathogens are transmitted to humans through aerosolized excreta of their infected rodent hosts. Hantaviruses have a tripartite-segmented negative-sense RNA genome. The three genomic RNA segments, S, M, and L, encode a nucleocapsid protein (N), a precursor glycoprotein that is processed into two envelope glycoproteins (Gn and Gc) and the viral RNA-dependent RNA polymerase (RdRp), respectively. N protein is the major structural component of the virus, its main function is to protect and encapsidate the three genomic RNAs forming three viral ribonucleocapsids. Recent studies have proposed that N in conjunction with RdRp plays important roles in the transcription and replication of viral genome. In addition, N preferentially facilitates the translation of viral mRNA in cells. Glycoproteins, Gn and Gc, play major roles in viral attachment and entry to the host cells, virulence, and assembly and packaging of new virions in infected cells. RdRp functions as RNA replicase and transcriptase to replicate and transcribe the viral RNA and is also thought to have endonuclease activity. Currently, no antiviral therapy or vaccine is available for the treatment of hantavirus-associated diseases. Understanding the molecular details of hantavirus life cycle will help in the identification of targets for antiviral therapeutics and in the design of potential antiviral drug for the treatment of HFRS and HCPS. Due to the alarming fatality of hantavirus diseases, development of an effective vaccine against hantaviruses is a necessity.

Clinical features and neuroimaging (CT and MRI) findings in presumed Zika virus related congenital infection and microcephaly: retrospective case series study

OBJECTIVE

To report radiological findings observed in computed tomography (CT) and magnetic resonance imaging (MRI) scans of the first cases of congenital infection and microcephaly presumably associated with the Zika virus in the current Brazilian epidemic.

DESIGN

Retrospective study with a case series.

SETTING

Association for Assistance of Disabled Children (AACD), Pernambuco state, Brazil.

PARTICIPANTS

23 children with a diagnosis of congenital infection presumably associated with the Zika virus during the Brazilian microcephaly epidemic.

MAIN OUTCOME MEASURES

Types of abnormalities and the radiological pattern of lesions identified on CT and MRI brain scans.

RESULTS

Six of the 23 children tested positive for IgM antibodies to Zika virus in cerebrospinal fluid. The other 17 children met the protocol criteria for congenital infection presumably associated with the Zika virus, even without being tested for IgM antibodies to the virus--the test was not yet available on a routine basis. Of the 23 children, 15 underwent CT, seven underwent both CT and MRI, and one underwent MRI. Of the 22 children who underwent CT, all had calcifications in the junction between cortical and subcortical white matter, 21 (95%) had malformations of cortical development, 20 (91%) had a decreased brain volume, 19 (86%) had ventriculomegaly, and 11 (50%) had hypoplasia of the cerebellum or brainstem. Of the eight children who underwent MRI, all had calcifications in the junction between cortical and subcortical white matter, malformations of cortical development occurring predominantly in the frontal lobes, and ventriculomegaly. Seven of the eight (88%) children had enlarged cisterna magna, seven (88%) delayed myelination, and six each (75%) a moderate to severe decrease in brain volume, simplified gyral pattern, and abnormalities of the corpus callosum (38% hypogenesis and 38% hypoplasia). Malformations were symmetrical in 75% of the cases.

CONCLUSION

Severe cerebral damage was found on imaging in most of the children in this case series with congenital infection presumably associated with the Zika virus. The features most commonly found were brain calcifications in the junction between cortical and subcortical white matter associated with malformations of cortical development, often with a simplified gyral pattern and predominance of pachygyria or polymicrogyria in the frontal lobes. Additional findings were enlarged cisterna magna, abnormalities of corpus callosum (hypoplasia or hypogenesis), ventriculomegaly, delayed myelination, and hypoplasia of the cerebellum and the brainstem.

An epidemiological study of rates of illness in passengers and crew at a busy Caribbean cruise port

Background

The Caribbean has one of the largest cruise ship industries in the world, with close to 20 million visitors per year. The potential for communicable disease outbreaks on vessels and the transmission by ship between countries is high. Barbados has one of the busiest ports in the Caribbean. Our aim was to describe and analyse the epidemiology of illnesses experienced by passengers and crew arriving at the Bridgetown Port, Barbados between 2009 and 2013.

Methods

Data on the illnesses recorded were extracted from the passenger and crew arrival registers and passenger and crew illness logs for all ships and maritime vessels arriving at Barbados’ Ports and passing through its territorial waters between January 2009 and December 2013. Data were entered into an Epi Info database and most of the analysis undertaken using Epi Info Version 7. Rates per 100,000 visits were calculated, and confidence intervals on these were derived using the software Openepi.

Results

There were 1031 cases of illness from over 3 million passenger visits and 1 million crew visits during this period. The overall event rate for communicable illnesses was 15.7 (95 % CI 14.4–17.1) per 100,000 passengers, and for crew was 24.0 (21.6–26.6) per 100, 000 crew. Gastroenteritis was the predominant illness experienced by passengers and crew followed by influenza. The event rate for gastroenteritis among passengers was 13.7 (12.5–15.0) per 100,000 and 14.4 (12.6, 16.5) for crew. The event rate for non-communicable illnesses was 3.4 per 100,000 passengers with myocardial infarction being the main diagnosis. The event rate for non-communicable illnesses among crew was 2.1 per 100,000, the leading cause being injuries.

Conclusions

The predominant illnesses reported were gastroenteritis and influenza similar to previous published reports from around the world. This study is the first of its type in the Caribbean and the data provide a baseline for future surveillance and for comparison with other countries and regions.

Elucidating the spatio-temporal dynamics of an emerging wildlife pathogen using approximate Bayesian computation

Emerging pathogens constitute a severe threat for human health and biodiversity. Determining the status (native or non-native) of emerging pathogens, and tracing back their spatio-temporal dynamics, is crucial to understand the eco-evolutionary factors promoting their emergence, to control their spread and mitigate their impacts. However, tracing back the spatio-temporal dynamics of emerging wildlife pathogens is challenging because (i) they are often neglected until they become sufficiently abundant and pose socio-economical concerns and (ii) their geographical range is often little known. Here, we combined classical population genetics tools and approximate Bayesian computation (i.e. ABC) to retrace the dynamics of Tracheliastes polycolpus, a poorly documented pathogenic ectoparasite emerging in Western Europe that threatens several freshwater fish species. Our results strongly suggest that populations of T. polycolpus in France emerged from individuals originating from a unique genetic pool that were most likely introduced in the 1920s in central France. From this initial population, three waves of colonization occurred into peripheral watersheds within the next two decades. We further demonstrated that populations remained at low densities, and hence undetectable, during 10 years before a major demographic expansion occurred, and before its official detection in France. These findings corroborate and expand the few historical records available for this emerging pathogen. More generally, our study demonstrates how ABC can be used to determine the status, reconstruct the colonization history and infer key evolutionary parameters of emerging wildlife pathogens with low data availability, and for which samples from the putative native area are inaccessible.

Modelling input-output flows of severe acute respiratory syndrome in mainland China

BACKGROUND

Severe acute respiratory syndrome (SARS) originated in China in 2002, and it spread to 26 provinces in mainland China and 32 countries across five continents in a matter of months. This outbreak resulted in 774 deaths. However, the spatial features and potential determinants of SARS input-output flows remain unclear.

METHODS

We used an adjusted spatial interaction model to examine the spatial effects and potential factors associated with SARS input-output flows.

RESULTS

The presence of origin-based spatial dependence positively affected SARS input-output flows from the neighbours of the origin regions. Two components of the input-output flows, migrant and hospitalization flows, exhibited distinctive features. The origin-based and destination-based spatial dependence positively affected migrant flows (i.e., due to those seeking jobs) from the neighbours of origin and destination locations. Similarly, the destination-based spatial dependence also positively affected hospitalization flows (i.e., due to those seeking treatment) from the neighbours of destination regions. However, the origin-to-destination based spatial dependence negatively affected hospitalisation flows from the neighbours of origin-to-destination regions. The direct effects accounted for 78% of the SARS input-output flows, which was 3.56-fold greater than the indirect effects. Differences in regional income drove the SARS input-output flows. Therefore, urban income had a positive effect, whereas rural income had a negative effect. Total interregional flows increased by 3.54% with a 1% increase in urban income, and intraregional flows increased by 8.35%. In contrast, the total interregional flows decreased by 3.38% with a 1% increase in rural income, and intraregional flows declined by 2.29%. Railway capacity, per person gross domestic product (PGDP), urban rate and the law of distance decay also affected the input-output flows.

CONCLUSIONS

Our results confirm that the SARS input-output flows presented significant geographic spatial heterogeneity and spatial effects. Income differences were the major cause of the flows between pairs of regions. Railway capacity, PGDP, and urban rate also played important roles. These findings provide valuable information for the Chinese government to control the future spread of nationwide epidemics.

Molecular mechanisms underlying the emergence of bacterial pathogens: an ecological perspective

The rapid emergence of new bacterial diseases negatively affects both human health and agricultural productivity. Although the molecular mechanisms underlying these disease emergences are shared between human- and plant-pathogenic bacteria, not much effort has been made to date to understand disease emergences caused by plant-pathogenic bacteria. In particular, there is a paucity of information in the literature on the role of environmental habitats in which plant-pathogenic bacteria evolve and on the stress factors to which these microbes are unceasingly exposed. In this microreview, we focus on three molecular mechanisms underlying pathogenicity in bacteria, namely mutations, genomic rearrangements and the acquisition of new DNA sequences through horizontal gene transfer (HGT). We briefly discuss the role of these mechanisms in bacterial disease emergence and elucidate how the environment can influence the occurrence and regulation of these molecular mechanisms by directly impacting disease emergence. The understanding of such molecular evolutionary mechanisms and their environmental drivers will represent an important step towards predicting bacterial disease emergence and developing sustainable management strategies for crops.

Microdosed Lipid-Coated (67)Ga-Magnetite Enhances Antigen-Specific Immunity by Image Tracked Delivery of Antigen and CpG to Lymph Nodes

Development of vaccines to prevent and treat emerging new pathogens and re-emerging infections and cancer remains a major challenge. An attractive approach is to build the vaccine upon a biocompatible NP that simultaneously acts as accurate delivery vehicle and radiotracer for PET/SPECT imaging for ultrasensitive and quantitative in vivo imaging of NP delivery to target tissues/organs. Success in developing these nanovaccines will depend in part on having a "correct" NP size and accommodating and suitably displaying antigen and/or adjuvants (e.g., TLR agonists). Here we develop and evaluate a NP vaccine based on iron oxide-selective radio-gallium labeling suitable for SPECT((67)Ga)/PET((68)Ga) imaging and efficient delivery of antigen (OVA) and TLR 9 agonists (CpGs) using lipid-coated magnetite micelles. OVA, CpGs and rhodamine are easily accommodated in the hybrid micelles, and the average size of the construct can be controlled to be ca. 40 nm in diameter to target direct lymphatic delivery of the vaccine cargo to antigen presenting cells (APCs) in the lymph nodes (LNs). While the OVA/CpG-loaded construct showed effective delivery to endosomal TLR 9 in APCs, SPECT imaging demonstrated migration from the injection site to regional and nonregional LNs. In correlation with the imaging results, a range of in vitro and in vivo studies demonstrate that by using this microdosed nanosystem the cellular and humoral immune responses are greatly enhanced and provide protection against tumor challenge. These results suggest that these nanosystems have considerable potential for image-guided development of targeted vaccines that are more effective and limit toxicity.

Small-sized and large-pore dendritic mesoporous silica nanoparticles enhance antimicrobial enzyme delivery

Small-sized silica nanoparticles with large dendritic mesopores demonstrate a superior antimicrobial enzyme delivery efficacy with long-term bacterial inhibition.

Considerations for Use of Investigational Drugs in Public Health Emergencies

The paradigm for the use of investigational drugs in public health emergencies has been recently tested to prevent and treat highly infectious and lethal diseases. Examples include the successful implementation of vaccine and therapeutic clinical trials during the recent Ebola outbreak in West Africa. On the other end of the spectrum was the Emergency Use Authorization (EUA) of peramivir in the treatment of H1N1 influenza virus that did not provide an opportunity to collect data or understand the effectiveness of the EUA program. Between the gold standard of a randomized controlled clinical trial and the problems associated with EUAs are the domain of expanded access protocols that may provide an avenue to make products available while awaiting licensure. This paper will examine the regulatory pathways in the United States (US) for the use of investigational drugs in a public health emergency as well as considerations when making these products available outside the US. Descriptions of the applications of the various approaches will be presented. Regardless of the pathway chosen, public health and clinical research planners need to work together to consider several factors associated with the respective options and maintain a goal of working toward the collection of data to support licensure before faced with future outbreaks. Finally, this paper will consider the lessons learned from public health response in the context of investigational drugs in other diseases where "right to try laws" may pose opportunities, as well as challenges.

Micro-organismen en infectieziekten bij de mens: algemene principes

Infectieziekten zijn te beschouwen als een aparte groep ziekten van de mens. Steeds gaat het om ziekten die het gevolg zijn van een interactie tussen de mens en een ander biologisch agens: een micro-organisme. Bij een infectieziekte is er sprake van een bepaalde vorm van interactie waarbij schade optreedt voor de mens. Verreweg de meeste interacties tussen mensen en micro-organismen zijn echter niet schadelijk voor de mens. Infectieziekten behoren tot de meest prevalente aandoeningen van de mens en op mondiaal niveau zijn ze nog steeds de belangrijkste oorzaak van vermijdbare sterfte. Daarom is het voor het onderwijs in de geneeskunde van groot belang infectieziekten te beschouwen als een aparte groep ziekten, met een unieke etiologie, epidemiologie, pathogenese, diagnostiek, behandeling en preventie. Infecties komen op alle leeftijden voor en kunnen alle organen en weefsels van het lichaam treffen. Infectieziekten zijn daardoor een belangrijk paradigma in de geneeskunde.

Evolutionary Medicine IV. Evolution and Emergence of Novel Pathogens

This article discusses how evolutionary and ecological factors interact to affect the epidemiology of emerging infectious diseases. It further explains how the nascent field of phylodynamics constructs mathematical models, which link evolution and epidemiology, to study pathogen transmission. To illustrate the importance of considering both evolution and ecology – along with the utility of the phylodynamic approach – when studying novel pathogens, the author considers examples from HIV, influenza, and Ebola.

Synergistic Effect of Detection and Separation for Pathogen Using Magnetic Clusters

Early diagnosis of infectious diseases is important for treatment; therefore, selective and rapid detection of pathogenic bacteria is essential for human health. We report a strategy for highly selective detection and rapid separation of pathogenic microorganisms using magnetic nanoparticle clusters. Our approach to develop probes for pathogenic bacteria, including Salmonella, is based on a theoretically optimized model for the size of clustered magnetic nanoparticles. The clusters were modified to provide enhanced aqueous solubility and versatile conjugation sites for antibody immobilization. The clusters with the desired magnetic property were then prepared at critical micelle concentration (CMC) by evaporation-induced self-assembly (EISA). Two different types of target-specific antibodies for H- and O-antigens were incorporated on the cluster surface for selective binding to biological compartments of the flagella and cell body, respectively. For the two different specific binding properties, Salmonella were effectively captured with the O-antibody-coated polysorbate 80-coated magnetic nanoclusters (PCMNCs). The synergistic effect of combining selective targeting and the clustered magnetic probe leads to both selective and rapid detection of infectious pathogens.

Implementing a One Health approach to emerging infectious disease: reflections on the socio-political, ethical and legal dimensions

BACKGROUND

'One Health' represents a call for health researchers and practitioners at the human, animal and environmental interfaces to work together to mitigate the risks of emerging and re-emerging infectious diseases (EIDs). A One Health approach emphasizing inter-disciplinary co-operation is increasingly seen as necessary for effective EID control and prevention. There are, however, socio-political, ethical and legal challenges, which must be met by such a One Health approach.

DISCUSSION

Based on the philosophical review and critical analysis of scholarship around the theory and practice of One Health it is clear that EID events are not simply about pathogens jumping species barriers; they are comprised of complex and contingent sets of relations that involve socioeconomic and socio-political drivers and consequences with the latter extending beyond the impact of the disease. Therefore, the effectiveness of policies based on One Health depends on their implementation and alignment with or modification of public values. Despite its strong motivating rationale, implementing a One Health approach in an integrated and considered manner can be challenging, especially in the face of a perceived crisis. The effective control and prevention of EIDs therefore requires: (i) social science research to improve understanding of how EID threats and responses play out; (ii) the development of an analytic framework that catalogues case experiences with EIDs, reflects their dynamic nature and promotes inter-sectoral collaboration and knowledge synthesis; (iii) genuine public engagement processes that promote transparency, education and capture people's preferences; (iv) a set of practical principles and values that integrate ethics into decision-making procedures, against which policies and public health responses can be assessed; (v) integration of the analytic framework and the statement of principles and values outlined above; and (vi) a focus on genuine reform rather than rhetoric.

Perception of Lay People Regarding Determinants of Health and Factors Affecting It: An Aggregated Analysis from 29 Countries

BACKGROUND

This study aimed to evaluate the perception of lay people regarding determinants of health at global level and factors affecting it.

METHODS

Data was collected from International Social Survey Program (ISSP) and World Bank website. Multilevel regression analysis was done and lay people's perception regarding health behavior, environment, poverty and genes as health determinants was assessed. Various socio demographic factors were used as independent variables.

RESULTS

The highest percentage of people agreed environment as determinant of health. An inverse relationship was observed between GNI quartiles and an individual's agreement with poverty, health behavior, and environment as health determinant. There was a significant negative association of females with health damaging behavior (P<0.05) and positive association with environment and genes (P<0.05) as health determinants. Elderly people agreed with poverty as determinant of health (P<0.05). GNI was negatively related to environment (P<0.05) and poverty (P<0.05) as health determinant.

CONCLUSION

The common public is now becoming aware of a broadened concept of health and people belonging to different backgrounds have different perceptions regarding determinants of health. Our results show that highest percentage of people agreed with environment as determinant of health, which is consistent with scientific view of increased burden of disease, caused by environmental factors. Thus, tailored health programs and policies that address an individual's specific problems are likely to induce a change in behavior and attitude, hence decreasing the disease burden.

Finding a Place for Systems-Based, Collaborative Research in Emerging Disease Research in Asia

The need to adequately predict, prevent and respond to infectious diseases emerging unexpectedly from human-animal-environmental systems has driven interest in multisectoral, socio-economic, systems-based, collaborative (MSC) research approaches such as EcoHealth and One Health. Our goals were to document how MSC research has been used to address EIDs in Asia, and to explore how MSC approaches align with current priorities for EID research in Asia. We gathered priorities for EID research from the peer-reviewed and grey literature, documented organizational descriptions of MCS research approaches, and analysed a series of EID MSC projects. We found that priority areas for EID research in Asia included (1) understanding host-pathogen-environment interactions; (2) improving tools and technologies; (3) changing people's behaviour; and (4) evaluating the effectiveness of interventions. We found that the unifying characteristics of MSC research were that it was action-oriented and sought to inspire change under real-world conditions at the complex interface of human and natural systems. We suggest that MSC research can be considered a type of 'pragmatic research' and might be most useful in describing change in complex human-animal-environmental systems, accelerating research-to-action, and evaluating effectiveness of interventions in 'real world' settings.

Understanding complex clinical reasoning in infectious diseases for improving clinical decision support design

Background

Clinical experts’ cognitive mechanisms for managing complexity have implications for the design of future innovative healthcare systems. The purpose of the study is to examine the constituents of decision complexity and explore the cognitive strategies clinicians use to control and adapt to their information environment.

Methods

We used Cognitive Task Analysis (CTA) methods to interview 10 Infectious Disease (ID) experts at the University of Utah and Salt Lake City Veterans Administration Medical Center. Participants were asked to recall a complex, critical and vivid antibiotic-prescribing incident using the Critical Decision Method (CDM), a type of Cognitive Task Analysis (CTA). Using the four iterations of the Critical Decision Method, questions were posed to fully explore the incident, focusing in depth on the clinical components underlying the complexity. Probes were included to assess cognitive and decision strategies used by participants.

Results

The following three themes emerged as the constituents of decision complexity experienced by the Infectious Diseases experts: 1) the overall clinical picture does not match the pattern, 2) a lack of comprehension of the situation and 3) dealing with social and emotional pressures such as fear and anxiety. All these factors contribute to decision complexity. These factors almost always occurred together, creating unexpected events and uncertainty in clinical reasoning. Five themes emerged in the analyses of how experts deal with the complexity. Expert clinicians frequently used 1) watchful waiting instead of over- prescribing antibiotics, engaged in 2) theory of mind to project and simulate other practitioners’ perspectives, reduced very complex cases into simple 3) heuristics, employed 4) anticipatory thinking to plan and re-plan events and consulted with peers to share knowledge, solicit opinions and 5) seek help on patient cases.

Conclusion

The cognitive strategies to deal with decision complexity found in this study have important implications for design future decision support systems for the management of complex patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12911-015-0221-z) contains supplementary material, which is available to authorized users.

The consequences of human actions on risks for infectious diseases: a review

The human population is growing, requiring more space for food production, and needing more animals to feed it. Emerging infectious diseases are increasing, causing losses in both human and animal lives, as well as large costs to society. Many factors are contributing to disease emergence, including climate change, globalization and urbanization, and most of these factors are to some extent caused by humans. Pathogens may be more or less prone to emergence in themselves, and rapidly mutating viruses are more common among the emerging pathogens. The climate-sensitive vector-borne diseases are likely to be emerging due to climate changes and environmental changes, such as increased irrigation. This review lists the factors within pathogens that make them prone to emergence, and the modes of transmission that are affected. The anthropogenic changes contributing to disease emergence are described, as well as how they directly and indirectly cause either increased numbers of susceptible or exposed individuals, or cause increased infectivity. Many actions may have multiple direct or indirect effects, and it may be difficult to assess what the consequences may be. In addition, most anthropogenic drivers are related to desired activities, such as logging, irrigation, trade, and travelling, which the society is requiring. It is important to research more about the indirect and direct effects of the different actions to understand both the benefits and the risks.

Role of Vibrio cholerae exochitinase ChiA2 in horizontal gene transfer

Vibrio cholerae exochitinase ChiA2 plays a key role in acquisition of nutrients by chitin hydrolysis in the natural environment as well as in pathogenesis in the intestinal milieu. In this study we demonstrate the importance of ChiA2 in horizontal gene transfer in the natural environment. We found that the expression of ChiA2 and TfoX, the central regulator of V. cholerae horizontal gene transfer, varied with changes in environmental conditions. The activity of ChiA2 was also dependent on these conditions. In 3 different environmental conditions tested here, we observed that the supporting environmental condition for maximum expression and activity of ChiA2 was 20 °C, pH 5.5, and 100 mmol/L salinity in the presence of chitin. The same condition also induced TfoX expression and was favorable for horizontal gene transfer in V. cholerae. High-performance liquid chromatography analysis showed that ChiA2 released a significant amount of (GlcNAc)2 from chitin hydrolysis under the favorable condition. We hypothesized that under the favorable environmental condition, ChiA2 was upregulated and maximally active to produce a significant amount of (GlcNAc)2 from chitin. The same environmental condition also induced tfoX expression, followed by its translational activation by the (GlcNAc)2 produced, leading to efficient horizontal gene transfer.

Occurrence of Borrelia burgdorferi s.l. in different genera of mosquitoes (Culicidae) in Central Europe

Lyme disease or Lyme borreliosis is a vector-borne infectious disease caused by spirochetes of the Borrelia burgdorferi sensu lato complex. Some stages of the borrelial transmission cycle in ticks (transstadial, feeding and co-feeding) can potentially occur also in insects, particularly in mosquitoes. In the present study, adult as well as larval mosquitoes were collected at 42 different geographical locations throughout Germany. This is the first study, in which German mosquitoes were analyzed for the presence of Borrelia spp. Targeting two specific borrelial genes, flaB and ospA encoding for the subunit B of flagellin and the outer surface protein A, the results show that DNA of Borrelia afzelii, Borrelia bavariensis and Borrelia garinii could be detected in ten Culicidae species comprising four distinct genera (Aedes, Culiseta, Culex, and Ochlerotatus). Positive samples also include adult specimens raised in the laboratory from wild-caught larvae indicating that transstadial and/or transovarial transmission might occur within a given mosquito population.

An integrated slidable and valveless microdevice with solid phase extraction, polymerase chain reaction, and immunochromatographic strip parts for multiplex colorimetric pathogen detection

A total integrated genetic analysis microsystem was developed, which consisted of solid phase extraction (SPE), polymerase chain reaction (PCR), and immunochromatographic strip (ICS) parts for multiplex colorimetric detection of pathogenic Staphylococcus aureus (S. aureus) and Escherichia coli O157:H7 (E. coli O157:H7) on a portable genetic analyzer. Utilizing a slidable chamber, which is a movable glass wafer, complex microvalves could be eliminated for fluidic control in the microchannel, which could simplify the chip design and chip operation. The integrated slidable microdevice was composed of 4 layers: a 4-point Pt/Ti resistance temperature detector (RTD) wafer, a micro-patterned channel wafer, a 2 μL volume slidable chamber, and an ICS. The entire process from the DNA extraction in the SPE chamber to the detection of the target gene expression by the ICS was serially performed by simply sliding the slidable chamber from one part to another functional part. The total process for multiplex pathogenic S. aureus and E. coli O157:H7 detection on the integrated slidable microdevice was accomplished within 55 min with a detection limit of 5 cells. Furthermore, spiked bacteria samples in milk were also successfully analysed on the portable genetic analysis microsystem with sample-in-answer-out capability. The proposed total integrated microsystem is adequate for point-of-care DNA testing in that no microvalves and complex tubing systems are required due to the use of the slidable chamber and the bulky and expensive fluorescence or electrochemical detectors are not necessary due to the ICS based colorimetric detection.

Self-disseminating vaccines for emerging infectious diseases

Modern human activity fueled by economic development is profoundly altering our relationship with microorganisms. This altered interaction with microbes is believed to be the major driving force behind the increased rate of emerging infectious diseases from animals. The spate of recent infectious disease outbreaks, including Ebola virus disease and Middle East respiratory syndrome, emphasize the need for development of new innovative tools to manage these emerging diseases. Disseminating vaccines are one such novel approach to potentially interrupt animal to human (zoonotic) transmission of these pathogens.

Dissociation of Tissue Destruction and Bacterial Expansion during Bubonic Plague

Activation and/or recruitment of the host plasmin, a fibrinolytic enzyme also active on extracellular matrix components, is a common invasive strategy of bacterial pathogens. Yersinia pestis, the bubonic plague agent, expresses the multifunctional surface protease Pla, which activates plasmin and inactivates fibrinolysis inhibitors. Pla is encoded by the pPla plasmid. Following intradermal inoculation, Y. pestis has the capacity to multiply in and cause destruction of the lymph node (LN) draining the entry site. The closely related, pPla-negative, Y. pseudotuberculosis species lacks this capacity. We hypothesized that tissue damage and bacterial multiplication occurring in the LN during bubonic plague were linked and both driven by pPla. Using a set of pPla-positive and pPla-negative Y. pestis and Y. pseudotuberculosis strains in a mouse model of intradermal injection, we found that pPla is not required for bacterial translocation to the LN. We also observed that a pPla-cured Y. pestis caused the same extensive histological lesions as the wild type strain. Furthermore, the Y. pseudotuberculosis histological pattern, characterized by infectious foci limited by inflammatory cell infiltrates with normal tissue density and follicular organization, was unchanged after introduction of pPla. However, the presence of pPla enabled Y. pseudotuberculosis to increase its bacterial load up to that of Y. pestis. Similarly, lack of pPla strongly reduced Y. pestis titers in LNs of infected mice. This pPla-mediated enhancing effect on bacterial load was directly dependent on the proteolytic activity of Pla. Immunohistochemistry of Pla-negative Y. pestis-infected LNs revealed extensive bacterial lysis, unlike the numerous, apparently intact, microorganisms seen in wild type Y. pestis-infected preparations. Therefore, our study demonstrates that tissue destruction and bacterial survival/multiplication are dissociated in the bubo and that the primary action of Pla is to protect bacteria from destruction rather than to alter the tissue environment to favor Y. pestis propagation in the host.

The hallmark of bubonic plague, a disease that ravaged Medieval Europe and is still prevalent in several countries, is the bubo, a highly inflammatory and painful lymph node, which is characterized by high concentrations of bacteria within a severely damaged organ. Yersinia pestis, the causative agent, expresses a surface protease, Pla, critical to the development of bubonic plague. This multitarget protease has the potential to activate the fibrinolytic pathway and to promote destruction of extracellular protein networks within tissues. Hence, it was expected that Pla was responsible for the tissue destructions of the bubo, and consequently, for bacterial propagation and virulence. However, we found, using various engineered Yersinia strains in a mouse model of bubonic plague, that Pla proteolytic activity was dispensable for lymph node alteration, but was required to achieve high bacterial loads in the organ. Further analysis showed that Pla is essential for preventing the bacteria from being destroyed in the host. Therefore, the role of Pla as a virulence factor is to protect Y. pestis survival and integrity in the host, rather than to assist its spread through tissue destruction.

Design an easy-to-use infection screening system for non-contact monitoring of vital-signs to prevent the spread of pandemic diseases

The outbreak of infectious diseases such as influenza, dengue fever, and severe acute respiratory syndrome (SARS) are threatening the global health. Especially, developing countries in the South-East Asia region have been at serious risk. Rapid and highly reliable screening of infection is urgently needed during the epidemic season at mass gathering places, such as airport quarantine facilities, public health centers, and hospital outpatients units, etc. To meet this need, our research group is currently developing a multiple vital-signs based infection screening system that can perform human medical inspections within 15 seconds. This system remotely monitors facial temperature, heart and respiration rates using a thermopile array and a 24-GHz microwave radar, respectively. In this work, we redesigned our previous system to make a higher performance with a user-friendly interface. Moreover, the system newly included a multivariable logistic regression model (MLRM) to determine the possibility of infection. We tested the system on 34 seasonal influenza patients and 35 normal control subjects at the Japan Self-Defense Forces Central Hospital. The sensitivity and specificity of the screening system using the MLRM were 85.3% and 88.6%, respectively.

On-chip Extraction of Intracellular Molecules in White Blood Cells from Whole Blood

The extraction of virological markers in white blood cells (WBCs) from whole blood--without reagents, electricity, or instruments--is the most important first step for diagnostic testing of infectious diseases in resource-limited settings. Here we develop an integrated microfluidic chip that continuously separates WBCs from whole blood and mechanically ruptures them to extract intracellular proteins and nucleic acids for diagnostic purposes. The integrated chip is assembled with a device that separates WBCs by using differences in blood cell size and a mechanical cell lysis chip with ultra-sharp nanoblade arrays. We demonstrate the performance of the integrated device by quantitatively analyzing the levels of extracted intracellular proteins and genomic DNAs. Our results show that compared with a conventional method, the device yields 120% higher level of total protein amount and similar levels of gDNA (90.3%). To demonstrate its clinical application to human immunodeficiency virus (HIV) diagnostics, the developed chip was used to process blood samples containing HIV-infected cells. Based on PCR results, we demonstrate that the chip can extract HIV proviral DNAs from infected cells with a population as low as 10(2)/μl. These findings suggest that the developed device has potential application in point-of-care testing for infectious diseases in developing countries.

Dynamics and drivers of hantavirus prevalence in rodent populations

Human encroachment on wildlife habitats has contributed to the emergence of several zoonoses. Pathogenic hantaviruses are hosted by rodents and cause severe diseases in the Americas and Eurasia. We reviewed several factors that potentially drive prevalence (the proportion of infected rodents) in host populations. These include demography, behavior, host density, small mammal diversity, predation, and habitat and landscape characteristics. This review is the first to include a quantitative summary of the literature investigating hantavirus prevalence in rodents. Demographic structure and density were investigated the most and predation the least. Reported effects of demographic structure and small mammal diversity were consistent, whereby reproductive males were most likely to be infected and prevalence decreased with small mammal diversity. The influences of habitat and landscape properties are often complex and indirect. The relationship between density and prevalence merits more investigation. Most hantavirus hosts are habitat generalists and their control is challenging. Incorporating all potential factors and their interactions is essential to understanding and controlling infection in host populations.

Clinical Complexity in Medicine: A Measurement Model of Task and Patient Complexity

BACKGROUND

Complexity in medicine needs to be reduced to simple components in a way that is comprehensible to researchers and clinicians. Few studies in the current literature propose a measurement model that addresses both task and patient complexity in medicine.

OBJECTIVE

The objective of this paper is to develop an integrated approach to understand and measure clinical complexity by incorporating both task and patient complexity components focusing on the infectious disease domain. The measurement model was adapted and modified for the healthcare domain.

METHODS

Three clinical infectious disease teams were observed, audio-recorded and transcribed. Each team included an infectious diseases expert, one infectious diseases fellow, one physician assistant and one pharmacy resident fellow. The transcripts were parsed and the authors independently coded complexity attributes. This baseline measurement model of clinical complexity was modified in an initial set of coding processes and further validated in a consensus-based iterative process that included several meetings and email discussions by three clinical experts from diverse backgrounds from the Department of Biomedical Informatics at the University of Utah. Inter-rater reliability was calculated using Cohen's kappa.

RESULTS

The proposed clinical complexity model consists of two separate components. The first is a clinical task complexity model with 13 clinical complexity-contributing factors and 7 dimensions. The second is the patient complexity model with 11 complexity-contributing factors and 5 dimensions.

CONCLUSION

The measurement model for complexity encompassing both task and patient complexity will be a valuable resource for future researchers and industry to measure and understand complexity in healthcare.

Targeting Lysine Deacetylases (KDACs) in Parasites

Due to an increasing problem of drug resistance among almost all parasites species ranging from protists to worms, there is an urgent need to explore new drug targets and their inhibitors to provide new and effective parasitic therapeutics. In this regard, there is growing interest in exploring known drug leads of human epigenetic enzymes as potential starting points to develop novel treatments for parasitic diseases. This approach of repurposing (starting with validated targets and inhibitors) is quite attractive since it has the potential to reduce the expense of drug development and accelerate the process of developing novel drug candidates for parasite control. Lysine deacetylases (KDACs) are among the most studied epigenetic drug targets of humans, and a broad range of small-molecule inhibitors for these enzymes have been reported. In this work, we identify the KDAC protein families in representative species across important classes of parasites, screen a compound library of 23 hydroxamate- or benzamide-based small molecules KDAC inhibitors, and report their activities against a range of parasitic species, including the pathogen of malaria (Plasmodium falciparum), kinetoplastids (Trypanosoma brucei and Leishmania donovani), and nematodes (Brugia malayi, Dirofilaria immitis and Haemonchus contortus). Compound activity against parasites is compared to that observed against the mammalian cell line (L929 mouse fibroblast) in order to determine potential parasite-versus-host selectivity). The compounds showed nanomolar to sub-nanomolar potency against various parasites, and some selectivity was observed within the small panel of compounds tested. The possible binding modes of the active compounds at the different protein target sites within different species were explored by docking to homology models to help guide the discovery of more selective, parasite-specific inhibitors. This current work supports previous studies that explored the use of KDAC inhibitors in targeting Plasmodium to develop new anti-malarial treatments, and also pioneers experiments with these KDAC inhibitors as potential new anthelminthics. The selectivity observed begins to address the challenges of targeting specific parasitic diseases while limiting host toxicity.

Due to pandemic drug resistance in the treatment of parasitic infections, there is an urgent need to identify novel drug targets and their associated drug compounds. Although “drug repurposing”, i.e. the application of known drugs and compounds to new indications such as infectious diseases, provides a cost effective approach in the development of novel therapeutics, selectivity is one of the major obstacles to overcome in getting such compounds into clinical trials as anti-parasitic drugs. Using the lysine deacetylases (KDACs) as an example, we explored the activities of a panel of known inhibitors against the KDAC targets in a range of parasitic organisms. The computational study of their binding modes to the targets (by docking the compounds to the homology models within different organisms in comparison with the human proteins) helps to rationalize the different activities observed and provide insight on the optimization of lead compounds to improve selectivity. Our work provides support of “drug repurposing” in the treatment of parasitic diseases, and demonstrates the necessity of optimizing these leads for the ultimate goal of preparing them for clinical use.

An intracellular replication niche for Vibrio cholerae in the amoeba Acanthamoeba castellanii

Vibrio cholerae is a human pathogen and the causative agent of cholera. The persistence of this bacterium in aquatic environments is a key epidemiological concern, as cholera is transmitted through contaminated water. Predatory protists, such as amoebae, are major regulators of bacterial populations in such environments. Therefore, we investigated the interaction between V. cholerae and the amoeba Acanthamoeba castellanii at the single-cell level. We observed that V. cholerae can resist intracellular killing. The non-digested bacteria were either released or, alternatively, established a replication niche within the contractile vacuole of A. castellanii. V. cholerae was maintained within this compartment even upon encystment. The pathogen ultimately returned to its aquatic habitat through lysis of A. castellanii, a process that was dependent on the production of extracellular polysaccharide by the pathogen. This study reinforces the concept that V. cholerae is a facultative intracellular bacterium and describes a new host–pathogen interaction.

Species Diversity, Abundance, and Host Preferences of Mosquitoes (Diptera: Culicidae) in Two Different Ecotypes of Madagascar With Recent RVFV Transmission

Mosquito diversity and abundance were examined in six Madagascan villages in either arid (Toliary II district) or humid (Mampikony district) ecotypes, each with a history of Rift Valley fever virus transmission. Centers for Disease Control and Prevention light traps without CO2 (LT) placed near ruminant parks and animal-baited net trap (NT) baited with either zebu or sheep/goat were used to sample mosquitoes, on two occasions between March 2011 and October 2011. Culex tritaeniorhynchus (Giles) was the most abundant species, followed by Culex antennatus (Becker) and Anopheles squamosus/cydippis (Theobald/de Meillon). These three species comprised more than half of all mosquitoes collected. The NT captured more mosquitoes in diversity and in abundance than the LT, and also caught more individuals of each species, except for An. squamosus/cydippis. Highest diversity and abundance were observed in the humid and warm district of Mampikony. No host preference was highlighted, except for Cx. tritaeniorhynchus presenting a blood preference for zebu baits. The description of species diversity, abundance, and host preference described herein can inform the development of control measures to reduce the risk of mosquito-borne diseases in Madagascar.

Spatio-temporal surveillance of water based infectious disease (malaria) in Rawalpindi, Pakistan using geostatistical modeling techniques

One of the features of medical geography that has made it so useful in health research is statistical spatial analysis, which enables the quantification and qualification of health events. The main objective of this research was to study the spatial distribution patterns of malaria in Rawalpindi district using spatial statistical techniques to identify the hot spots and the possible risk factor. Spatial statistical analyses were done in ArcGIS, and satellite images for land use classification were processed in ERDAS Imagine. Four hundred and fifty water samples were also collected from the study area to identify the presence or absence of any microbial contamination. The results of this study indicated that malaria incidence varied according to geographical location, with eco-climatic condition and showing significant positive spatial autocorrelation. Hotspots or location of clusters were identified using Getis-Ord Gi* statistic. Significant clustering of malaria incidence occurred in rural central part of the study area including Gujar Khan, Kaller Syedan, and some part of Kahuta and Rawalpindi Tehsil. Ordinary least square (OLS) regression analysis was conducted to analyze the relationship of risk factors with the disease cases. Relationship of different land cover with the disease cases indicated that malaria was more related with agriculture, low vegetation, and water class. Temporal variation of malaria cases showed significant positive association with the meteorological variables including average monthly rainfall and temperature. The results of the study further suggested that water supply and sewage system and solid waste collection system needs a serious attention to prevent any outbreak in the study area.

Serological survey of Bartonella spp., Borrelia burgdorferi, Brucella spp., Coxiella burnetii, Francisella tularensis, Leptospira spp., Echinococcus, Hanta-, TBE- and XMR-virus infection in employees of two forestry enterprises in North Rhine-Westphalia, Germany, 2011-2013

We initiated a survey to collect basic data on the frequency and regional distribution of various zoonoses in 722 employees of forestry enterprises in the German state of North Rhine-Westphalia (NRW) from 2011 to 2013. Exposures associated with seropositivity were identified to give insight into the possible risk factors for infection with each pathogen. 41.2% of participants were found to be seropositive for anti-Bartonella IgG, 30.6% for anti-Borrelia burgdorferi IgG, 14.2% for anti-Leptospira IgG, 6.5% for anti-Coxiella burnetii IgG, 6.0% for anti-Hantavirus IgG, 4.0% for anti-Francisella tularensis IgG, 3.4% for anti-TBE-virus IgG, 1.7% for anti-Echinococcus IgG, 0.0% for anti-Brucella IgG and anti-XMRV IgG. Participants seropositive for B. burgdorferi were 3.96 times more likely to be professional forestry workers (univariable analysis: OR 3.96; 95% CI 2.60-6.04; p<0.001); and participants seropositive for Hantavirus 3.72 times more likely (univariable analysis: OR 3.72; 95% CI 1.44-9.57; p=0.007). This study found a surprisingly high percentage of participants seropositive for anti-B. henselae IgG and for anti-F. tularensis IgG. The relatively high seroprevalence for anti-Leptospira IgG seen in this study could be related to living conditions rather than to exposure at work. No specific risk for exposure to C. burnetii and Echinococcus was identified, indicating that neither forestry workers nor office workers represent a risk population and that NRW is not a typical endemic area. Forestry workers appear to have higher risk for contact with B. burgdorferi-infected ticks and a regionally diverse risk for acquiring Hantavirus-infection. The regional epidemiology of zoonoses is without question of great importance for public health. Knowledge of the regional risk factors facilitates the development of efficient prevention strategies and the implementation of such prevention measures in a sustainable manner.

Emerging infectious disease: trends in the literature on SARS and H7N9 influenza

Severe acute respiratory syndrome (SARS) and human infection H7N9 influenza are emerging infectious diseases having a relatively high mortality. Epidemics of each began in China. By searching through Science Citation Index, this study analyzed the article literature on SARS and H7N9 influenza, particularly papers in the leading journals The Lancet, New England Journal of Medicine (NEJM), Nature and Science. The results show that the quantity and quality of SARS and H7N9 influenza literature from mainland China changed distinctly over the course of 10 years. Researchers from mainland China published 12 article literature in the The Lancet, NEJM, Nature and Science about H7N9 influenza, whereas mainland China had only 2 article literature about SARS in the same journals. The literature reflects China's growing strength in the science and technology of emerging infectious disease.

Real-Time Microbiology Laboratory Surveillance System to Detect Abnormal Events and Emerging Infections, Marseille, France

Infectious diseases are a major threat to humanity, and accurate surveillance is essential. We describe how to implement a laboratory data-based surveillance system in a clinical microbiology laboratory. Two historical Microsoft Excel databases were implemented. The data were then sorted and used to execute the following 2 surveillance systems in Excel: the Bacterial real-time Laboratory-based Surveillance System (BALYSES) for monitoring the number of patients infected with bacterial species isolated at least once in our laboratory during the study periodl and the Marseille Antibiotic Resistance Surveillance System (MARSS), which surveys the primary β-lactam resistance phenotypes for 15 selected bacterial species. The first historical database contained 174,853 identifications of bacteria, and the second contained 12,062 results of antibiotic susceptibility testing. From May 21, 2013, through June 4, 2014, BALYSES and MARSS enabled the detection of 52 abnormal events for 24 bacterial species, leading to 19 official reports. This system is currently being refined and improved.

Control of epidemics on complex networks: Effectiveness of delayed isolation

We study isolation as a means to control epidemic outbreaks in complex networks, focusing on the consequences of delays in isolating infected nodes. Our analysis uncovers a tipping point: if infected nodes are isolated before a critical day dc, the disease is effectively controlled, whereas for longer delays the number of infected nodes climbs steeply. We show that dc can be estimated explicitly in terms of network properties and disease parameters, connecting lowered values of dc explicitly to heterogeneity in degree distribution. Our results reveal also that initial delays in the implementation of isolation protocols can have catastrophic consequences in heterogeneous networks. As our study is carried out in a general framework, it has the potential to offer insight and suggest proactive strategies for containing outbreaks of a range of serious infectious diseases.

Modeling Heterogeneous Bacterial Populations Exposed to Antibiotics: The Logistic-Dynamics Case

In typical in vitro tests for clinical use or development of antibiotics, samples from a bacterial population are exposed to an antibiotic at various concentrations. The resulting data can then be used to build a mathematical model suitable for dosing regimen design or for further development. For bacterial populations that include resistant subpopulations-an issue that has reached alarming proportions-building such a model is challenging. In prior work, we developed a related modeling framework for such heterogeneous bacterial populations following linear dynamics when exposed to an antibiotic. We extend this framework to the case of logistic dynamics, common among strongly resistant bacterial strains. Explicit formulas are developed that can be easily used in parameter estimation and subsequent dosing regimen design under realistic pharmacokinetic conditions. A case study using experimental data from the effect of an antibiotic on a gram-negative bacterial population exemplifies the usefulness of the proposed approach.

Considerations of the chemical biology of microbial natural products provide an effective drug discovery strategy

Conventional approaches to natural product drug discovery rely mainly on random searches for bioactive compounds using bioassays. These traditional approaches do not incorporate a chemical biology perspective. Searching for bioactive molecules using a chemical and biological rationale constitutes a powerful search paradigm. Here, the authors review recent examples of the discovery of bioactive natural products based on chemical and biological interactions between hosts and symbionts, and propose this method provides a more effective means of exploring natural chemical diversity and eventually of discovering new drugs.

Antibacterial and Antifungal Activity of ZnO Containing Glasses

A new family of non-toxic biocides based on low melting point (1250°C) transparent glasses with high content of ZnO (15–40wt%) belonging to the miscibility region of the B₂O₃-SiO₂-Na₂O-ZnO system has been developed. These glasses have shown an excellent biocide activity (logarithmic reduction >3) against Gram- (E. coli), Gram+ (S. aureus) and yeast (C. krusei); they are chemically stable in different media (distilled water, sea-like water, LB and DMEN media) as well as biocompatible. The cytotoxicity was evaluated by the Neutral Red Uptake using NIH-3T3 (mouse embryonic fibroblast cells) and the cell viability was >80%. These new glasses can be considered in several and important applications in the field of inorganic non-toxic biocide agents such as medical implants, surgical equipment, protective apparels in hospitals, water purifications systems, food packaging, food storages or textiles.

Direct Detection of Erythromycin-Resistant Bordetella pertussis in Clinical Specimens by PCR

Resistance of Bordetella pertussis to erythromycin has been increasingly reported. We developed an allele-specific PCR method for rapid detection of erythromycin-resistant B. pertussis directly from nasopharyngeal (NP) swab samples submitted for diagnostic PCR. Based on the proven association of erythromycin resistance with the A2047G mutation in the 23S rRNA of B. pertussis, four primers, two of which were designed to be specific for either the wild-type or the mutant allele, were used in two different versions of the allele-specific PCR assay. The methods were verified with results obtained by PCR-based sequencing of 16 recent B. pertussis isolates and 100 NP swab samples submitted for diagnostic PCR. The detection limits of the two PCR assays ranged from 10 to 100 fg per reaction for both erythromycin-susceptible and -resistant B. pertussis. Two amplified fragments of each PCR, of 286 and 112 bp, respectively, were obtained from a mutant allele of the isolates and/or NP swab samples containing B. pertussis DNAs. For the wild-type allele, only a 286-bp fragment was visible when the allele-specific PCR assay 1 was performed. No amplification was found when a number of non-Bordetella bacterial pathogens and NP swab samples that did not contain the DNAs of B. pertussis were examined. This assay can serve as an alternative for PCR-based sequencing, especially for local laboratories in resource-poor countries.