No description available.

An animal model of respiratory infection was used to determine the effect of various factors, thought to influence the ability of the host to clear bacteria, on the host?s innate response to an NTHi lung infection. Mucosal immunisation with NTHi has previously been shown to enhance the clearance of NTHi from the lung in an animal model of infection through the increased recruitment of phagocytes. Comparisons of cytokine and chemokine kinetic profiles were made in order to determine differences between innate and acquired immune response and the way in which mucosal immunisation controls the innate immune response to NTHi. Increased production of proinflammatory cytokines and chemokines in the early stages of NTHi lung infection enhanced the ability to clear bacteria from the rat lung in the immune animals through the increased recruitment of phagocytes to the site. Mucosal immunisation was found to alter the cytokine and chemokine mRNA profiles of CD4+ and CD8+ cells, with increased levels of MCP-1 protein being detected in both types of immune cells. An antecedent viral infection has been shown to increase the chance of developing a respiratory bacterial infection. The NTHi model of respiratory infection was used to characterise the effect that a viral infection had on the host response to the host?s innate response to a bacterial infection and the ability to clear the bacteria. The host?s ability to clear NTHi from the rat lung was enhanced by an antecedent viral infection through alterations to the innate immune response and the cytokine and chemokine kinetic profiles. The use of a mutant strain of NTHi deficient in a component of Lipooligosaccharide (LOS), Phosphorylcholine (ChoP), was utilised as a tool to characterise the innate immune response to LOS. Animals challenged with the LOS mutant strain had a reduced inflammatory response to NTHi through the decreased production of pro-inflammatory cytokines and chemokines and the reduced recruitment of phagocytes to the site of infection. This thesis has contributed valuable information to enable a better understanding of the host?s innate immune response to respiratory infection. This study has identified the role of cytokines and chemokines in the innate response to a respiratory bacterial infection and the enhanced ability of the host to clear NTHi from the lung.

Pseudomonas aeruginosa (P. aeruginosa) is a frequently isolated pathogen that causes septicaemia and chronic respiratory infection. It exhibits a higher mortality rate than other gram-negative bacteria and the need for effective immunotherapy is emphasised by the frequency of antibiotic resistance associated with this organism. Mucosal immunisation with a whole killed cell P. aeruginosa vaccine has previously demonstrated a significant immune response in both rodent studies and human trials. This study is a continuation of that research, with the major goal being the identification of a purified protein antigen that could form the basis of a mucosal vaccine against P. aeruginosa. Specifically, the aims of this study were the development of purification protocols for the isolation of previously untested protein antigens, assessment of the efficacy of these antigens to enhance bacterial clearance in an animal model of acute respiratory infection, determination of the immune parameters that are associated with the resolution of P. aeruginosa respiratory infection and finally, cloning of an identified antigen which demonstrated vaccine efficacy. Protocols were established to isolate proteins for use as antigens in immune response studies. The proteins purified in this study were Pa 13, Azurin, acyl carrier protein (ACP), Amidase, Aminopeptidase, KatA and Pa70. These proteins were used to immunise rats by intestinal intra-Peyer's patch (IPP) inoculation and intratracheal (IT) boost. The immunisation protocol employed was designed to target mucosal antigen-specific immune responses where the route of immunisation, Peyer's patch (PP) intestinal inoculation, is akin to the oral delivery of antigens to the gut-associated lymphoid tissue (96). Investigations of a previously uncharacterised antigen, Pa60, later identified this protein as the P. aeruginosa catalase, KatA. This study demonstrated enhanced bacterial clearance of both homologous and heterologous challenge following immunisation with KatA. The level of clearance demonstrated by KatA was promising when compared to that of killed whole cell immunisation. KatA was cloned and studies with the recombinant protein showed enhanced bacterial clearance commensurate with that of the native protein. Immunisations with other proteins identified four additional antigens which enhanced bacterial clearance; Pa13, Pa40, Pa45 and Pa70. Amino acid sequence analysis indicated that Pa13 may be a novel protein, whereas Pa40 was determined to be amidase and Pa45, aminopeptidase. Pa70 was not successfully sequenced. These proteins were effective in significantly enhancing bacterial clearance of homologous P. aeruginosa challenge. For KatA, Pa13 and Pa70, clearance was associated with a marked phagocytic cell recruitment. In contrast, amidase and aminopeptidase demonstrated clearance with a minimal cellular response. Proteins; azurin and ACP were non-protective, failing to clear a live P aeruginosa challenge. Analysis of the antigen-specific responses of these nonprotective proteins and comparison with those antigens which enhanced bacterial clearance were used to determine factors that may contribute to the resolution of an acute pulmonary infection. The study has demonstrated that mucosal immunisation using purified protein antigens can enhance the clearance of pulmonary infection with P. aeruginosa. It has also contributed to the understanding of immune responses to newfound antigens of P. aeruginosa and identified antigen-specific responses which confirm their potential as vaccine candidates.

Objective: The main objective of this study was to detect the presence of 14 respiratory viruses and atypical bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae), via polymerase chain reaction in patients under 18 years old hospitalized due to community-acquired pneumonia (CAP) from Lima, Peru. Results: Atypical pathogens were detected in 40% (58/146); viral etiologies in 36% (52/146) and coinfections in 19% (27/146). The most common etiological agent was M. pneumoniae (n = 47), followed by C. pneumoniae (n = 11). The most frequent respiratory viruses detected were: respiratory syncytial virus A (n = 35), influenza virus C (n = 21) and parainfluenza virus (n = 10). Viral-bacterial and bacterium-bacterium coinfections were found in 27 cases. In our study population, atypical bacteria (40%) were detected as frequently as respiratory viruses (36%). The presence of M. pneumoniae and C. pneumoniae should not be underestimated as they can be commonly isolated in Peruvian children with CAP.

Background: Neutrophil extracellular traps (NETs) constitute a network of chromatin fibres containing histone and antimicrobial peptides that are released by activated neutrophils. NETs protect the host against infection by trapping and facilitating phagocytosis of potentially harmful pathogens. Objectives: The aim of the current study was to investigate the effects cigarette smoke condensate (CSC) on phorbol-ester (PMA)-mediated NETosis in vitro, as well as the effects of cigarette. Methods: Isolated human blood neutrophils were exposed to PMA (6.25 ng/ml) in the presence or absence of CSC (40-80 μg/ml) for 90 min at 37oC. Alternatively neutrophils of non-smokers and smokers were activated with PMA (6.25 ng/ml) for 90 min at 37oC. NET formation was measured using a spectrofluorimetric procedure to detect extracellular DNA and fluorescence microscopy was used to visualize nets. Oxygen consumption by PMA-activated neutrophils was measured using an oxygen sensitive electrode. Cotinine levels were measured in smokers and non-smokers for objective confirmation of smoking status Results: Activation of neutrophils with PMA was associated with induction of NETosis that was significantly attenuated in the presence of CSC (40 and 80 μg/ml), with mean fluorescence intensities of 65% and 66% of that observed with untreated cells, respectively, and confirmed by fluorescence microscopy. The rate and magnitude of oxygen consumption by activated neutrophils pre-treated with CSC (80 μg/ml) was significantly less than that observed with untreated cells (73% of the control system), indicative of decreased production of reactive oxidant species in the presence of CSC. When comparing smokers and non- smokers, neutrophils from smokers showed a decrease in both oxygen consumption and the number of NET-forming cells consistent with attenuation of NET formation due to inhalation of cigarette smoke. Conclusion: The inhibition of NETosis observed in the presence of CSC and CS (in smokers) correlated with attenuation of oxygen consumption by PMA-activated neutrophils suggesting a mechanistic relationship between these events. Smoking-related attenuation of NETosis may impair host immune responses and increase the risk of respiratory infections, in vivo. / Dissertation (MSc)--University of Pretoria, 2016. / Immunology / MSc / Unrestricted

No description available.

jdelvall@upc.edu.pe / Acute respiratory infections are responsible for high morbi–mortality in Peruvian children. However, the etiological agents are poorly identified. This study, conducted during the pandemic outbreak of H1N1 influenza in 2009, aims to determine the main etiological agents responsible for acute respiratory infections in children from Lima, Peru. Nasopharyngeal swabs collected from 717 children with acute respiratory infections between January 2009 and December 2010 were analyzed by multiplex RT-PCR for 13 respiratory viruses: influenza A, B, and C virus; parainfluenza virus (PIV) 1, 2, 3, and 4; and human respiratory syncytial virus (RSV) A and B, among others. Samples were also tested with direct fluorescent-antibodies (DFA) for six respiratory viruses. RT-PCR and DFA detected respiratory viruses in 240 (33.5%) and 85 (11.9%) cases, respectively. The most common etiological agents were RSV-A (15.3%), followed by influenza A (4.6%), PIV-1 (3.6%), and PIV-2 (1.8%). The viruses identified by DFA corresponded to RSV (5.9%) and influenza A (1.8%). Therefore, respiratory syncytial viruses (RSV) were found to be the most common etiology of acute respiratory infections. The authors suggest that active surveillance be conducted to identify the causative agents and improve clinical management, especially in the context of possible circulation of pandemic viruses

As infecções respiratórias agudas são responsáveis por elevados índices de morbimortalidade. Desde sua descoberta em 2005, foi relatada presença de bocavírus humano (HBoV) com prevalência variando de 1,5% a 19%. Durante o período de estudo foram detectadas 153 amostras positivas para HBoV (14%) de 1113 amostras coletadas, sendo sete HBoV positivos na unidade neonatal. O HBoV ocupou a terceira posição em frequência de vírus respiratórios detectados. As crianças positivas para HBoV eram mais velhas, utilizaram mais antibióticos e apresentaram o diagnóstico de pneumonia com maior frequência (independente da presença de outros vírus coinfectantes) do que as crianças negativas. O HBoV circulou ao longo de todos os meses, com maior prevalência entre maio a agosto. Houve uma elevada taxa de codetecção (84%) com os demais 20 vírus respiratórios pesquisados. A análise filogenética encontrou apenas HBoV1. Esse achado contribui para a consolidação do HBoV1 como causador de doença respiratória aguda. / It is well established that respiratory viruses are an important cause of hospitalizations in young children worldwide. Since its discovery in 2005, many authors have reported detection of human bocavirus (HBoV) in children with respiratory infection with prevalence varying from 1.5% to 19%. During the study period we detected HBoV in 153 samples (14%) from 1113-screened samples; seven were from the neonatal unit. HBoV was the third most frequently detected virus. Children infected with HBoV were significantly older, used more antibiotics and had pneumonia more frequently diagnosed (irrespective of presence of other virus coinfection than those negative for HBoV. Seasonality of HBoV was characterized by year-round circulation with peaks in months of May through August. There was a high rate of co-detection (84%) with the other 20 respiratory viruses. Phylogenetic analysis revealed only HBoV1. This finding contributes to consolidate HBoV1 as cause of acute respiratory infection in children.

abstract: The antioxidant, antihistamine, and chemotactic properties of vitamin C provide the theoretical basis linking vitamin C supplementation to combating the common cold; yet, the clinical evidence is mixed. To date, vitamin C intervention trials have not systematically recorded cold symptoms daily or looked at fluctuations in plasma histamine over an extended period. Also, trials have not been conducted in individuals with marginal vitamin C status. This study examined the impact of vitamin C supplementation during cold season on specific cold symptoms in a population with low plasma vitamin C concentrations. Healthy young males who were not regular smokers or training for competitive sports between the ages of 18 and 35 with below average plasma vitamin C concentrations were stratified by age, body mass index, and vitamin C status into two groups: VTC (500 mg vitamin C capsule ingested twice daily) or CON (placebo capsule ingested twice daily). Participants were instructed to fill out the validated Wisconsin Upper Respiratory Symptom Survey-21 daily for 8 weeks. Blood was sampled at trial weeks 0, 4, and 8. Plasma vitamin C concentrations were significantly different by groups at study week 4 and 8. Plasma histamine decreased 4.2% in the VTC group and increased 17.4% in the CON group between study weeks 0 and 8, but these differences were not statistically significant (p>0.05). Total cold symptom scores averaged 43±15 for the VTC group compared to 148±36 for the CON group, a 244% increase in symptoms for CON participants versus VTC participants (p=0.014). Additionally, recorded symptom severity and functional impairment scores were lower in the VCT group than the CON group (p=0.031 and 0.058, respectively). Global perception of sickness was 65% lower in the VTC group compared to the CON group (p=0.022). These results suggest that 1000 mg of vitamin C in a divided dose daily may lower common cold symptoms, cold symptom severity, and the perception of sickness. More research is needed to corroborate these findings. / Dissertation/Thesis / M.S. Nutrition 2012

O tratamento das infecções do trato respiratório inferior – em especial as pneumonias adquiridas na comunidade – fundamenta-se em critérios clínico-radiológicos, de acordo com consensos e publicações sobre o assunto. A valorização diagnóstica do exame bacteriológico do escarro nessas infecções tem se mostrado controversa, esbarrando em diversos obstáculos, entre eles o fato de o material transitar pela orofaringe e boca, sofrendo a contaminação por microorganismos residentes nessas estruturas. No presente estudo procurou-se verificar se era possível identificar a flora bacteriana envolvida em infecções bronco-pulmonares de indivíduos adultos, diferenciando-a daquela presente nas estruturas supra-glóticas, particularmente na boca, examinando-se simultaneamente o escarro “dessalivado”, cuidadosamente obtido e processado, e a saliva. Nos períodos 1995-1997 e 2005-2007 foram estudados 164 pacientes adultos, 80 homens e 84 mulheres, com idades entre 22 e 92 anos (média de 57 anos), todos com escarro purulento, e evidências clínicas e radiográficas de infecção do trato respiratório inferior. Casos de tuberculose e de micose foram excluídos. De cada um desses 164 indivíduos, amostras de escarro foram cuidadosamente colhidas em frascos esterilizados. Com uma alça de platina, recolhia-se um grumo do material purulento, o qual, após ser arrastado pela margem de uma lâmina ou parede do frasco, onde o excesso de saliva ficava retido (“dessalivação” do material), ele era distendido no centro da mesma lâmina e corado (gram), e também cultivado em meio apropriado (ágarsangue). Com outra alça de platina buscava-se, no mesmo frasco, o material não purulento (saliva) que ficava em torno do grumo, o qual era distendido em outra lâmina, e também corado pelo método de gram, e cultivado no mesmo tipo de meio usado para a cultura do material purulento. Os germes identificados e a celularidade encontrada ao exame direto (gram), tanto do grumo de pus (escarro) como da saliva, e os resultados das culturas de ambos os materiais eram registrados. As lâminas foram inicialmente examinadas por algum dos diferentes microbiologistas do Serviço, e finalmente por um único deles (referência). Ao exame direto, os tipos de germes encontrados no escarro (grumo purulento) mostraram-se significativamente diferentes dos que foram vistos na saliva (p < 0,001). No grumo purulento observou-se, em geral, um único ou predominante tipo de bactéria, enquanto que na saliva, contendo células epiteliais, uma flora mista foi mais vezes identificada. A mesma diferenciação, entretanto, não foi observada nas culturas, mais freqüentemente crescendo um mesmo tipo de bactéria em ambos os materiais (Streptococcus sp.), comumente presente em orofaringe e boca. A presença de macrófagos e ausência de células epiteliais foram verificadas quase que exclusivamente no escarro (p < 0,0001), enquanto que polimorfonucleares foram igualmente observados em ambos os materiais. Em conclusão, em indivíduos com infecções pulmonares diversas, o exame direto do escarro adequadamente obtido e processado, “dessalivado”, corado pelo método de gram, e mostrando a presença de macrófagos, pareceu discriminar – de modo superior à cultura – os germes provenientes do trato respiratório inferior. / The treatment of the lower respiratory tract infections – in special community acquired pneumonias – is today based in clinical and radiographic criteria, according to guidelines and publications about the subject. The diagnostic value of the sputum examination in these infections have been considered controversial. Among the several obstacles for its natural acceptance is the fact of the material to transit through pharynx and mouth suffering contamination by resident microorganisms of these structures. The aim of this study was to verify the possibility to identify the bacteriological flora involved in adult pulmonary infections, and differentiate it from those of the upper structures, particularly the mouth, through the simultaneous examination of a valid sample of sputum and saliva. In two periods (1995-1997; 2005-2007), 164 adult patients – 80 males, 84 females; age 22 to 92 years (mean 57) – all with purulent sputum and clinical-radiographic features of a lower respiratory tract infection. Cases of tuberculosis and mycosis were excluded. In sterilized bottles sputum samples were carefully obtained from every of the 164 individuals. With a platinum wire, a bit of purulent portion of the material was token and dragged by the inner surface of the bottle or over the glass slide, until the excess of saliva was reduced (“de-salivation”). The material was then distended on the center of the slide and stained (gram) for microscopic examination, and also cultivated in an appropriate media. From the same sample, saliva near the purulent material was token, fixed, stained (gram), and cultivated. The germs and cell types found at the direct examination and the culture results of both materials (sputum and saliva) were registered. The smears were at first examined by one of different microbiologists of the service, and finally by one of them (reference) in each period of the study. At the bacterioscopy, the germs found in the sputum smears were significantly different of those found in saliva (p < 0.001). There were either one or a predominant type of bacteria in the sputum, whereas in saliva (containing epitelial cells) a mixed flora was often observed. In the cultures, however, the results were others, growing more frequently a type of microorganism in both materials, often Streptococcus sp, germ commonly present in mouth and pharynx. Presence of macrophages and absence of epitelial cells were found almost exclusively in the sputum (p < 0.0001), whereas the inverse were observed in saliva. Polymorphonuclear cells were identified in both materials of all patients. In conclusion, individuals with different pulmonary infections, the direct examination of the properly collected and processed (“dessalived”) purulent sputum , stained by gram method, and with presence of macrophages, seemed indicate – better than the culture – the germs from the lower respiratory tract.