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Bueno S.M.,University of Santiago de Chile | Gonzalez P.A.,University of Santiago de Chile | Riedel C.A.,University of Santiago de Chile | Riedel C.A.,Andres Bello University | And 3 more authors.
Immunology Letters | Year: 2011

Respiratory syncytial virus (RSV) is the leading cause of childhood hospitalization and respiratory distress and has been recognized for several decades as a major health and economic burden worldwide. This virus has developed several virulence mechanisms to impair the establishment of a protective immune response to re-infection. Accordingly, inefficient immunological memory is usually generated after exposure to this pathogen. Furthermore, it has been shown that RSV can actively promote the induction of an inadequate cellular immune response at the site of infection that causes exacerbated inflammation in the respiratory tract. Such an inflammatory response is both inefficient for clearing the virus and can be responsible for detrimental symptoms, such as asthma and wheezing. Recent data suggest that RSV possesses molecular mechanisms to induce the secretion of pro-inflammatory cytokines that modulate the immune response and impair viral clearance by reducing IFN-γ production. Here, we discuss recent research leading to the identification of RSV virulence factors that are responsible of promoting a pro-inflammatory environment at the airways and their implications on pathogenicity. © 2010 Elsevier B.V.

Guzman L.M.,Pontifical Catholic University of Valparaiso | Castillo D.,Institute Salud Publica Of Chile | Aguilera S.O.,Andres Bello University
Clinical and Experimental Immunology | Year: 2010

Sjögren's syndrome (SS) is an autoimmune disease characterized by clonal B cell attack of the exocrine glands and dysregulated expression of B cell-activating factor (BAFF). Based upon the current data of increased rates of lymphoid malignancy, as non-Hodgkin's lymphoma (NHL) is associated with SS, we propose the detection of clonal rearrangements of immunoglobulin heavy chain (IgH) gene in those patients as a predictor of malignant clonal expansion. To test our proposal, we examined the IgH clonal rearrangements in SS patients (60) and healthy control subjects (42) having chronic non-specific sialadenitis, to determine the presence of clonal B cells in minor labial salivary glands (MSG) of SS patients. Clonal B cell expansion was assessed by two polymerase chain reaction (PCR) assays: (i) semi-nested PCR, against sequences encoding framework regions FR3, FR2 and FR1c of the variable chain IgH gene in B cells present in the MSG infiltrate; and (ii) the PCR-enzyme-linked immunosorbent assay (ELISA) technique, against the major and minor breakpoint regions of the Bcl-2 oncogene coupled with a variable segment of the IgH to assess the Bcl-2/JH translocation. When FR3, FR2 and FR1c primers were employed, we detected B cell monoclonality in 87% of the SS patients and 19% of the control subjects. The association between inflammation severity of the MSG pattern and the presence of B cell clonality was found to be statistically significant (P < 0·01). We concluded that the presence of B cell clonality in MSG can be used as a index of an altered microenvironment favouring the development of lymphoma in SS patients. © 2010 British Society for Immunology.

Objective: Identification for Mycobacterium assay based in the new technology of reverse hybridization DNA probe assay was evaluated (Line Probe Assays-LiPAs). Methods: 74 strains belonging to 23 mycobacterial species or complex classified previously by classical biochemical methods, genetic probes and PRA (patterns of restriction analysis), with and without specific pattern expected to be identified at specie level were analysed.The utilized test, GenoType CM (Hain Lifescience, Nehren, Alemania), is able of identifying 14 of the most common mycobacterial species after a multiplex PCR technique targeting a 23S rRNA gene region followed by reverse hybridization technology. Results: Sensitivity of 94.0% (95% CI: 84.4-98.0%) and specificity of 88.0% (95% CI:46.7-99.3%) were obtained with the assay. Conclusion: GenoType CM is an appropriated tool for the identification of Mycobacteria, rapid, sensitive, operational in the current working conditions of the National Reference Laboratory of Mycobacteria in Chile and it might constitute a real breakthrough for shortening the time delay in the procedure, providing a better opportunity to use treatment only in cases where it is required.

Dauros P.,University of Concepcion | Bello H.,University of Concepcion | Dominguez M.,University of Concepcion | Hormazabal J.C.,Institute Salud Publica Of Chile | Gonzalez G.,University of Concepcion
Journal of Infection in Developing Countries | Year: 2011

Introduction: Vibrio (V.) parahaemolyticus has endemically established in Chilean sea shores, causing outbreaks every year, with an important number of cases. In order to know the genetic relationship, genotype dominance and antibiotic resistance of isolates obtained from two outbreaks, this study characterized 110 strains isolated from environmental and clinical samples in years 2005 and 2007 in Chile. Methodology: Genotyping was performed by determination of PFGE profiles, and pandemic group and integrons were screened by PCR. Antimicrobial susceptibility was studied by the disk diffusion method. Results: High antibiotic susceptibility frequency was found, mainly among 2007 isolates, except to ampicillin, cephalothin, cefoxitin, cefpodoxime, amikacin, streptomycin and kanamycin. Strains belonging to the pandemic group in clinical isolates account for 88% in 2005, decreasing to 66% in 2007 and among environmental isolates were detected in 20% of the strains from 2005, rising to 36% in 2007. In 2005, nine different PFGE profiles were identified, with 78% of the strains corresponding to a single clone. In 2007, sixteen different PFGE profiles were detected, with 61% of the strains included into a sole clone. The same clone was prevalent in both years. None of class 1, 2, 3 and SXT integrases genes was detected; however, the superintegron integrase gene (intIA) was present in almost all strains. Conclusions: These results suggest the persistence and dominance of a unique PFGE clone of V. parahaemolyticus during 2005 and 2007, and the absence of genetic elements that capture antibiotic resistance genes described in other species of Vibrio. © 2011 Dauros et al.

Luchsinger V.,University of Chile | Ruiz M.,University of Chile | Martinez M.A.,University of Chile | Machado C.,University of Sao Paulo | And 6 more authors.
Thorax | Year: 2013

Background Adult community-acquired pneumonia (CAP) is a relevant worldwide cause of morbidity and mortality, however the aetiology often remains uncertain and the therapy is empirical. We applied conventional and molecular diagnostics to identify viruses and atypical bacteria associated with CAP in Chile. Methods We used sputum and blood cultures, IgG/IgM serology and molecular diagnostic techniques (PCR, reverse transcriptase PCR) for detection of classical and atypical bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumoniae) and respiratory viruses (adenovirus, respiratory syncytial virus (RSV), human metapneumovirus, influenza virus, parainfluenzavirus, rhinovirus, coronavirus) in adults >18 years old presenting with CAP in Santiago from February 2005 to September 2007. Severity was qualified at admission by Fine's pneumonia severity index. Results Overall detection in 356 enrolled adults were 92 (26%) cases of a single bacterial pathogen, 80 (22%) cases of a single viral pathogen, 60 (17%) cases with mixed bacterial and viral infection and 124 (35%) cases with no identified pathogen. Streptococcus pneumoniae and RSV were the most common bacterial and viral pathogens identified. Infectious agent detection by PCR provided greater sensitivity than conventional techniques. To our surprise, no relationship was observed between clinical severity and sole or coinfections. Conclusions The use of molecular diagnostics expanded the detection of viruses and atypical bacteria in adults with CAP, as unique or coinfections. Clinical severity and outcome were independent of the aetiological agents detected.

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