Development of a novel DNA microarray to detect bacterial pathogens in patients with chronic obstructive pulmonary disease (COPD)

A novel microarray was constructed with DNA PCR product probes targeting species specific functional genes of nine clinically significant respiratory pathogens, including the Gram-positive organisms (Streptococcus pneumoniae, Streptococcus pyogenes), the Gram-negative organisms (Chlamydia pneumoniae, Coxiella burnetii Haemophilus spp., Legionella pneumophila, Moraxella catarrhalis, and Pseudomonas aeruginosa), as well as the atypical bacterium, Mycoplasma pneumoniae. In a "proof-of-concept" evaluation of the developed microarray, the microarray was compared with real-time PCR from 14 sputum specimens from COPD patients. All of the samples positive for bacterial species in real-time PCR were also positive for the same bacterial species using the microarray. This study shows that a microarray using PCR probes is a potentially useful method to monitor the populations of bacteria in respiratory specimens and can be tailored to specific clinical needs such as respiratory infections of particular patient populations, including patients with cystic fibrosis and bronchiectasis. (C) 2010 Elsevier B.V. All rights reserved.

Immunological Interactions between 2 Common Pathogens, Th1-Inducing Protozoan Toxoplasma gondii and the Th2-Inducing Helminth Fasciola hepatica

Background: The nature of the immune response to infection is dependent on the type of infecting organism. Intracellular organisms such as Toxoplasma gondii stimulate a Th1-driven response associated with production of IL-12, IFN-gamma, nitric oxide and IgG2a antibodies and classical activation of macrophages. In contrast, extracellular helminths such as Fasciola hepatica induce Th2 responses characterised by the production of IL-4, IL-5, IL-10 and IgG1 antibodies and alternative activation of macrophages. As co-infections with these types of parasites commonly exist in the field it is relevant to examine how the various facets of the immune responses induced by each may influence or counter-regulate that of the other.

Investigating the persistence of tick-borne pathogens via the R-0 model

In the epidemiology of infectious diseases, the basic reproduction number, R-0, has a number of important applications, most notably it can be used to predict whether a pathogen is likely to become established, or persist, in a given area. We used the R-0 model to investigate the persistence of 3 tick-borne pathogens; Babesia microti, Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato in an Apodemus sylvaticus-Ixodes ricinus system. The persistence of these pathogens was also determined empirically by screening questing ticks and wood mice by PCR. All 3 pathogens behaved differently in response to changes in the proportion of transmission hosts on which I. ricinus fed, the efficiency of transmission between the host and ticks and the abundance of larval and nymphal ticks found on small mammals. Empirical data supported theoretical predictions of the R-0 model. The transmission pathway employed and the duration of systemic infection were also identified as important factors responsible for establishment or persistence of tick-borne pathogens in a given tick-host system. The current study demonstrates how the R-0 model can be put to practical use to investigate factors affecting tick-borne pathogen persistence, which has important implications for animal and human health worldwide.