Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis (PhD (Pathology. Medical Microbiology))--University of Stellenbosch, 2005. / Pneumocystis jirovecii is a significant contributor to the burden of disease in immunocompromised patients. The polymerase chain reaction (PCR) is more sensitive and specific than microscopy. Cotrimoxazole prophylactic breakthrough and treatment failures have been reported, and associated with mutations at codons 55 and 57 of P. jirovecii dihydropteroate synthase (DHPS). No phylogenetic or population genetic models have been successful in elucidating P. jirovecii intraspecies strain relatedness. Aims: 1) Compare detection rates of nine PCR techniques and immunofluorescence microscopy (IF); 2) Determine the extent of co-infecting pathogens associated with Pneumocystis Pneumonia (PcP); 3) Determine local P. jirovecii ITS1-5.8S-ITS2 rDNA strain types, and model lineage evolution employing a coalescent-theory based statistical parsimony network analysis; 4) Investigate the possible emergence of cotrimoxazole-resistant strains Methods: PCR was evaluated on clinical specimens employing: ITS nested; DHPS single and nested; DHFR nested; major surface glycoprotein (MSG) heminested; mitochondrial large subunit rRNA (mtLSUrRNA) single and nested; 18S rRNA onetube nested, and real-time 5S rRNA PCR. Retrospective analysis of co-infecting pathogens seen in PcP patients was conducted. ITS regions were amplified, cloned and sequenced. Statistical parsimony was applied for coalescence based network genotype analysis. DHPS genome walking was attempted and DHPS and DHFR primer annealing sites explored. Amplified DHPS and DHFR genes were cloned and sequenced. Results: Most sensitive PCR technique was mtLSUrRNA nested followed by 5S realtime PCR. A poor correlation exist between mtLSUrRNA PCR and IF. Review of clinical records suggested a high rate of false-positive IF results. P. jirovecii was detected in 4.3% M. tuberculosis-positive HIV-positive, and 2.5% M. tuberculosispositive HIV-negative patients. P. jirovecii was detected in 45% HIV-negative patients. The most prevalent ITS type was Eg. Four new combinations: Eo, Je, Ge, No; 11 new ITS1 and 13 new ITS2 sequences were identified. A new ITS2 type was detected in three patients and designated u. More than one strain type was detected in 15/19 patients. Analysis of 5.8SrDNA region revealed 13 clones containing 1-2 nucleotide polymorphisms. Of 85 mtLSUrRNA PCR-positive specimens, currently employed primers amplified DHPS and DHFR genes from 53 and 27 specimens, respectively. Newly designed DHPS primers increased detection in 3 / 28 previously DHPS-negative mtLSUrRNA-positive specimens. Of 56 DHPS genes amplified and sequenced, one contained the double mutation (Thr55Aa; Pro57Ser). DHFR Ala67Val was detected in three specimens and a new DHFR genotype (Arg59Gly; C278T) was demonstrated. Conclusions: The study emphasises the need to evaluate PCR primers against local strains. It is recommended that mtLSUrRNA PCR be performed in parallel to IF and discordant results resolved with clinical evaluation. Co-infection with P. jirovecii and M. tuberculosis occurs in South Africa, and treatment for both pathogens is recommended when demonstrated by the laboratory. ITS genotyping employing statistical parsimony network analysis suggests type Eg as major ancestral haplotype, and supports recombination contributing to strain diversity worldwide. DHPS mutations may signal emergence of resistance to cotrimoxazole in South Africa, however, low sensitivity of primers limits surveillance efforts.

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / BACKGROUND: In order to improve the quality and efficacy of healthcare while reducing the overall cost to deliver that healthcare, it has become increasingly important to manage utilization of services for populations of patients. Healthcare systems are aggressively working to identify patients at risk for hospital readmissions. Although readmission rates have been studied before, parameters for identifying patients at risk for readmission appear to vary depending the patient population. We will examine existing Electronic Health Record (EHR) data at Banner Health to establish what parameters are clinical indicators for readmission risk. Three conditions were identified by the CMS to have high and costly readmissions rates; heart failure (HF), acute myocardial infarction (AMI), and pneumonia. This study will focus on attempting to determine the primary predictive variables for these three conditions in order to have maximum impact on cost savings. METHODS: A literature review was done and 68 possible risk variables were identified. Of these, 30 of the variables were identifiable within the EHR system. Inclusion criteria for individual patient records are that they had an index admission secondary to AMI, heart failure, or pneumonia and that they had a subsequent readmission within 30 days of the index admission. Pediatric populations were not studied since they have unique factors for readmission that are not generalizable. Logistics regression was applied to all data including data with missing data rows. This allowed all coefficients to be interpreted for significance. This model was termed the full model. Variables that were determined to be insignificant were subsequently removed to create a new reduced model. Chi square testing was then done to compare the reduced model to the full model to determine if any significant differences existed between the two. RESULTS: Several variables were determined to be the significant predictors of readmission. The final reduced model had 19 predictors. When analyzed using ROC analysis, the area under the curve (AUC) was 0.64. CONCLUSION: Several variables were identified that could be significant contributors to readmission risk. The final model had an AUC on it ROC of 0.64 suggesting that it would only have poor to moderate clinical value for predicting readmission.

The thesis is focused on ventilator-associated pneumonia and its possible preventive measures during nursing care. In the theoretical part of the work we have included chapters on nosocomial infections emphasizing on the etiology and epidemiology of ventilator-associated pneumonia and its clinical manifestations. We have analyzed the issues of artificial airway management with a detailed focus on the peculiarities of nursing care of the ventilated patients. There, we focus primarily on the care of the patients oral cavity, respiratory tract and the ventilation circuit. A big chapter is dedicated to preventive measures and to the possibilities of prevention in the nursing practice. The empirical part includes research on preventive measures that are implemented in practice and comparative analysis of the measures between different facilities as well as their compliance to the guidelines. We have also determined the level of VAP awareness and its prevention among the nurses. KEYWORDS nosocomials infections, nursing care, prevention, ventilator-associated pneumonia

INTRODUÇÃO: A relevância do parênquima pulmonar distal na fisiopatologia da asma tem sido intensamente enfatizada. Vários estudos sugerem a inibição da Rho quinase como uma intervenção benéfica e promissora na asma. Entretanto, não há estudos anteriores que avaliaram os efeitos destes inibidores na modulação da mecânica do parênquima pulmonar e suas alterações histopatológicas em um modelo animal de inflamação pulmonar alérgica crônica. OBJETIVO: Avaliar a inibição da Rho quinase (Y-27632) na modulação da responsividade, inflamação, remodelamento da matriz extracelular e ativação do estresse oxidativo no parênquima pulmonar de cobaias com inflamação pulmonar alérgica crônica. MÉTODOS: As cobaias receberam sete inalações de ovalbumina (1-5 mg / ml; grupo OVA) ou salina (grupo SAL) ao longo de quatro semanas. A partir da quinta inalação, os animais do grupo Rho quinase foram submetidos a inalação com Y-27632, 10 minutos antes de cada inalação com OVA ou SAL. Setenta e duas horas após a sétima inalação, os animais foram anestesiados e exanguinados, e das tiras do tecido pulmonar foram realizadas a mecânica oscilatória, sob condições basais e após o desafio de ovalbumina (0,1%). Após a mecânica, as fatias de pulmão foram submetidas a análise histológica por meio da morfometria. RESULTADOS: A inibição de Rho quinase nos animais expostos à ovalbumina atenuou a elastância e a resistência tecidual, o número de eosinófilos, a expressão de IL-2, IL-4, IL-5, IL-13, TIMP-1, MMP-9, TGF-, IFN-g, NF-kB e iNOS e o conteúdo de 8-iso-PGF2, fibras elásticas, fibras colágenas e actina em comparação com o grupo OVA (P<0,05). CONCLUSÃO: A inibição da Rho quinase contribui para o controle da capacidade de responsividade do parênquima pulmonar, da inflamação eosinofílica, das respostas Th1/Th2, ao controle do remodelamento da matriz extracelular em um modelo animal de inflamação pulmonar alérgica crônica. Podendo ser considerada uma futura ferramenta farmacológica para o tratamento de doenças pulmonares crónicas. / RATIONALE: Previous studies with Rho-kinase inhibitors suggest a beneficial influence of these drugs in asthma. The relevance of distal lung tissue in functional asthmatic impairment has been intensely emphasized. There have not been any previous studies evaluating the effects of these inhibitors on the modulation of distal lung mechanics and histopathological alterations in an animal model of chronic pulmonary inflammation. OBJECTIVE: To evaluate if Rho-kinase inhibition (Y- 27632) modulates distal lung responsiveness, inflammation, extracellular matrix remodeling and oxidative stress activation in guinea pigs with chronic allergic inflammation. METHODS: Guinea pigs received seven inhalations of ovalbumin (1-5 mg/ml; OVA group) or saline (SAL group) over 4 wk. From the 5th inhalation, the Rho-kinase group animals were submitted to Y-27632 inhalation 10 min before each inhalation with OVA or SAL. Seventy-two hours after the seventh inhalation, the animals were anesthetized and exsanguinated, and oscillatory mechanics of the lung tissue strips were performed under the baseline condition and after the ovalbumin challenge (0.1%). Afterwards, the lung slices were submitted to morphometry. RESULTS: The Rho-kinase inhibition in the ovalbumin-exposed animals attenuated the tissue elastance and resistance, eosinophils, the IL-2, IL-4, IL-5, IL-13, TIMP-1, MMP-9, TGF-, IFN-g, NF-kB, iNOS-positive cells and the 8-iso-PGF2, elastic, collagen and actin content compared with the OVA group (P<0.05). CONCLUSION: Rho-kinase inhibition contributes to the control of distal lung responsiveness and the eosinophilic and Th1/Th2 responses to the control of extracellular matrix remodeling in an animal model of chronic allergic inflammation. It may be considered a future pharmacological tool for the treatment of chronic pulmonary diseases.

Dentre as principais preocupações relacionadas à cadeia de produção do biodiesel está o excedente de glicerina bruta. Esta corresponde a cerca de 10% da massa total resultante do processo de produção do biodiesel e vem sendo acumulada e armazenada nas usinas, formando grandes estoques de resíduos e deixando diversas empresas diante de um passivo ambiental agravante. Uma forma de diminuir esse problema é utilizá-la para formulação de meios de fermentação para obtenção de produtos de interesse econômico. Exemplos são as produções de dióis como; 1,3-Propanodiol (1,3-PD) e 2,3-Butanodiol (2,3-BD). Estes são monômeros de grande aplicação no mercado, sendo o 1,3-PD usado para fabricação de poliuretanos, compostos cíclicos e novos tipos de poliésteres. O 2,3-BD é utilizado como anticongelante, biocombustível e como um importante aromatizante. Assim, no presente trabalho propõe-se valorizar a glicerina residual da fabricação de biodiesel, visando sua bioconversão em 2,3-BD e 1,3-PD, pela bactéria Klebsiella pneumoniae NRRL B199. Para tanto, a proposta deste trabalho compreendeu quatro etapas conjuntas: 1. Estabelecer um tratamento adequado para a glicerina residual de forma a permitir o crescimento bacteriano e formação dos dióis. 2. Adequar à composição do meio de fermentação, quanto às concentrações de glicerol, com suplementação de glicose, extrato de levedura e elementos traço Fe2+, Zn2+ e Mn2+ no processo fermentativo. 3. Definir a melhor condição de transferência de oxigênio em sistema descontínuo, associada à concentração de substrato, para a melhor formação de produtos. 4. Avaliar o procedimento de separação dos produtos do meio pela técnica de salting-out. Os estudos da etapa 1 e 2 foram realizados em frascos Erlenmeyer de 250 mL com 50 mL de meio. Na etapa 3, o estudo de aeração e agitação foi realizado em fermentador Bioflo III (New Brunswick Sci. Co.) de 1,25 L. Com os resultados obtidos, concluiu-se que o tratamento realizado foi adequado para o emprego da glicerina residual como fonte de carbono para o crescimento da bactéria Klebsiella pneumoniae. Além disso, os trabalhos realizados em frascos revelaram uma produção máxima, em agitação de 200 rpm, de 0,545 g/L.h de 2,3-BD e produção de 0,180 g/L.h de 1,3-PD em agitação de 160 rpm. Sendo que a glicose e o extrato de levedura tiveram efeitos positivos e significativos na produtividade de 2,3-BD e 1,3-PD. Nos ensaios onde foram utilizados maiores transferência de oxigênio observou-se decréscimos na produção de 1,3-PD e uma melhora significativa na produção de 2,3-BD. No estudo de recuperação dos dióis, foi possível recuperar 82% dos dióis utilizando carbonato de potássio 70% na temperatura de 20 ºC e no tempo de reação de 6 horas. / Among the main concerns related to the production of biodiesel is the surplus of crude glycerine. This corresponds to approximately 10% of the total mass of the biodiesel production process and has been accumulated and stored in the biodiesel plants, creating enormous amounts of waste and serious environmental problems. A way to lessen this problem is to use it for the formulation of fermentation medium to obtain products of economic interest. Examples are the production of diols such as, 1,3-propanediol (1,3-PD) and 2,3-butanediol (2,3-BD). These monomers are large market application, and the 1,3-PD used for the manufacture of polyurethanes, cyclic compounds and new types of polyesters. The 2,3-BD is used as antifreeze, biofuel and as an important flavoring. Thus, in present work aims to enrich the residual glycerine from biodiesel production to its bioconversion in 2,3-BD and 1,3-PD by bacterium Klebsiella pneumoniae NRRL B199. Therefore, the purpose of this consisted of four joint steps: 1st. Establish an appropriate treatment for residual glycerine to allow bacterial growth and diols formation. 2nd. To adapt the composition of fermentation medium, as concentrations of residual glycerine, with glucose supplementation, yeast extract and trace elements of Fe2+, Zn2+ e Mn2+ in the fermentation process. 3rd. Define the best condition of oxygen transfer in a batch system, associated with substrate concentration for the best product formation. 4th. To evaluate the separation procedure of products through the of salting-out technique. Studies of step 1 and 2 were conducted in 250 mL Erlenmeyer flasks with 50 mL medium. In step 3, the study aeration and agitation was performed in Bioflo III fermentor (New Brunswick Sci Co.) was 1,25 L. With the results, it was concluded that the treatment was adequate for use of residual glycerine as carbon source for growth of the bacterium Klebsiella pneumoniae. Furthermore, the work carried out on bottles showed a maximum production 2,3-BD of 0.545 g/L.h in agitation of 200 rpm and production 1,3-PD of 0.180 g/Lh in agitation of 160 rpm. With glucose and yeast extract had positive and significant effects on productivity of 2,3-BD and 1,3-PD. For tests were used higher oxygen transfer observed decrease in the production of 1,3-PD and a significant improvement in the production of 2,3-BD. In the study of recovery of diols, it was possible to recover 82% of diols using 70% potassium carbonate at temperature of 20 °C and in reaction time of 6 hours.

O presente estudo se baseou em levantamentos retrospectivos e prospectivos obtidos de bovinos abatidos no Frigorífico Bertin, em Lins-SP. No primeiro levantamento consultaram-se os registros do Serviço de Inspeção Federal de ocorrência de alterações hepáticas em 1.568.821 bovinos (85% machos e 15% fêmeas), proveniente de seis Estados (SP, MS, PR, GO, MT e MG) durante os anos de 2002 a 2006. Consideraram-se os animais abatidos no último trimestre de cada ano como terminados em confinamento, sendo os demais criados continuamente em regime extensivo. Os abscessos hepáticos (1,60%) foram a segunda mais freqüente alteração hepática após a teleangectasia (1,67%). A freqüência desses abscessos foi maior em bovinos confinados (2,54%) que nos criados extensivamente (1,28%) e em fêmeas (1,85%) que em machos (1,56%). O confinamento aumenta o fator de risco (FR) de surgimento de abscessos hepáticos na ordem de 2,01 vezes. Maior freqüência de abscessos foi registrada em bovinos oriundos do Paraná, em ambos os sistemas de terminação. No levantamento prospectivo foram acompanhados o abate de 1.617 bovinos nos meses de dezembro de 2007 (n=858) e outubro de 2008 (n=759). Os abscessos hepáticos foram registrados de acordo com a freqüência, tamanho, número e localização dos mesmos em 1.617 animais; a mucosa ruminal foi avaliada (n=1.397) quanto à presença de ruminite, sua classificação e área afetada; e os pulmões (n=759) examinados para a detecção de hepatização pulmonar nas diferentes regiões, lóbos e lóbulos pulmonares, assim como grau de acometimento nos lóbulos. Foram detectados abscessos hepáticos, ruminites e pulmões hepatizados em 3,29%, 11,88% e 8,30% dos animais, respectivamente. Os abscessos estiveram igualmente distribuídos em todas as quatro regiões hepáticas, e na maioria dos casos (78,26%) os mesmos eram de pequeno tamanho (< 2,5cm) e número (até dois/órgão). Foram encontrados quatro tipos de ruminites, sendo a mais freqüente a retração cicatricial (54,22%), seguido de retalhos aderentes (24,10%), vilosidades aderidas (13,25%) e ruminite erosiva (8,43%). Em 32,53% desses casos à área afetada do rúmen ultrapassava os 300cm2. Animais com ruminite apresentavam um altíssimo risco (FR=12,67x) de manifestar abscessos hepáticos e hepatização pulmonar (FR=5,8x), com destaque para a ruminite erosiva. A hepatização pulmonar foi mais freqüente na região ventral (71,4%) que dorsal (28,6%), nos lóbulos esquerdos (59,79%) que direitos (40,21%) e na maioria dos casos acometia apenas um lóbulo (53,97%) não atingindo a hepatização mais do que 50% deste (66,6%). Abscessos hepáticos ocorreram com maior freqüência quando concomitantemente um único lóbulo pulmonar era acometido (FR=3,0x) e este se apresentava com menos de 50% de seu parênquima hepatizado (FR=11,61x). / A retrospective and prospective survey was carried out in cattle slaughtered in a private abattoir in the State of Sao Paulo, Brazil. The first survey was based on the reports done by the Federal Inspection Service of the liver condemnations among 1,568,821 cattle (85% steers; 15% cows and heifers) from six different Brazilian states during 2002 and 2006. Feedlot cattle were mostly slaughtered in the last trimester of each year, while the cattle bred extensively were in the remaining months. The abscesses (1.60%) were the second highest cause of liver condemnation after telangiectasis (1.67%). The frequency of liver abscesses were higher in feedlot cattle (2.54%) than those bred extensively (1.28%), female (1.85%) than male (1.56%). Feedlot increased the outcome (odds ratio OD= 2.01x) of liver abscess. The highest frequency of liver abscess was detected in feedlot and extensively bred cattle from the Parana state. The prospective survey was carried out following the slaughtering of 1,617 cattle during the months of December 2007 (n=858) and October 2008 (n=759). The abscesses frequency, size, number and location in the liver were recorded in all animals; the rumen mucosa (n=1,397) was examined for the presence, type and size of ruminitis; the lungs (n=759) were also examined for detection of consolidation, evaluating the affected region, number of lobes and lesion score. The following frequencies were seen: liver abscess (3.29%), ruminitis (11.88%) and lung consolidation (8.30%). The abscesses were equally distributed in all hepatic regions; most abscesses (78.2%) were small (< 2.5cm) and present in low number (1-2/liver). Four different types of ruminitis were seen: scars (54.22%), adherent contents (21.10%), clumped villi (13.25%) and erosive ruminitis (8.43%). In many cases (32.53%) the ruminitis spread to an area larger than 300cm2. Cattle with ruminitis had a very high risk of contracting liver abscesses (OD=12.67x) and lung consolidation (OR= 5.8x), principally with erosive ruminitis. Lung consolidation was mostly seen in the ventral (71.4%) than dorsal areas (28.6%), in the left (59.79%) than right lobes (40.21%); in most cases a single lobe was affected (53.97%) and less than 50% of the lobe was consolidated (66.6%). Liver abscesses were commonly seen in cattle with a single lobe (OD=3.0x) and less than 50% of this lobe consolidated (OR=11.61x).

Le virus influenza peut être responsable d’infections respiratoires sévères. Les pneumonies bactériennes post-influenza font partie des complications les plus graves et S. aureus est l’une des bactéries les plus fréquemment retrouvée dans ce contexte. L’efficacité des traitements dans ces infections graves est modérée ce qui souligne l’importance de progresser dans la compréhension de la physiopathologie de ces infections graves. Une réponse immunitaire inadéquate (soit excessive, soit trop faible) à l’infection pulmonaire joue un rôle considérable dans la gravité du tableau clinique et le pronostic du patient. Nous avons montré que le virus influenza potentialise l’inflammation et la cytotoxicité engendrée par des facteurs de virulence de S. aureus dans des monocytes isolés de témoins sains. Cependant l’étude du système immunitaire de patients hospitalisés pour grippe grave, a montré qu’au lieu d’être dans un état d’activation massive, il était en phase d’anergie et possédait une altération de la réponse immunitaire fonctionnelle en cas d’exposition à des facteurs de virulence de S. aureus. L’immunomonitoring de ces patients au pronostic sévère, qui permet la détermination de l’état pro- ou anti-inflammatoire dans lequel se trouve le patient pourrait participer à l’amélioration de la prise en charge de ces patients en permettant l’utilisation de traitements immunomodulateurs adaptés à la situation clinique de chaque patient. Cette problématique peut être étendue à d’autres co-infections virus bactérie et notamment au VRS. Nous avons étudié l’épidémiologie des co-infections VRS/bactérie chez l’adulte dans le contexte d’une pneumonie et nous avons observé qu’elle était similaire à celle des co-infections influenza bactérie. Cette connaissance de l’épidémiologie est importante afin d’adapter la prise en charge des patients / Post-influenza bacterial pneumonia is a leading cause of morbidity and mortality with severe influenza virus illness. Staphylococcus aureus is one of the most common pathogen found in this context. The severity of post-influenza Staphylococcus aureus pneumonia is due both to an inadequate responsiveness of the immune system (either too important or too weak) and to the weak efficacy of treatments used during these severe infections. A better knowledge of the pathophysiology of influenza/S. aureus co-infection is needed in order to improve patients care. In this study, we showed using in vitro experiments that influenza virus increased the inflammation and cytotoxicity induced by S. aureus virulence factors in human monocytes. However ex vivo experiments performed on leucocytes isolated from hospitalized patients with severe influenza showed an anergy of the immune system after exposition to S. aureus virulence factors. Immunomonitoring of patients with severe post-influenza Staphylococcus aureus pneumonia may allow to optimize the therapeutic regimen towards a more individualized immunomodulatory therapy. This can be extended to other viral bacterial co-infections including RSV. We studied the epidemiology of bacterial superinfections associated with RSV pneumonia in adults. Our results suggested that there was no main differences between the microbiological epidemiology of RSV/bacterial co-infections and influenza/bacterial co-infections. Knowledge of this epidemiology is important to assess to improve patients care

Pneumonia is the second leading cause of disability-adjusted life-years lost worldwide and the eighth leading cause of death in the United States. Traumatic brain injury (TBI) patients have classically been considered immunosuppressed, but recent research reported that mild head trauma patients have reduced incidence of pneumonia compared to blunt trauma patients. Using our mild TBI model followed by bacterial pneumonia, we investigated the effect of neuronal signaling on innate immune function. To test whether any mild injury primes host immune responses to pneumonia, we generated a mild tail trauma (TT) model. mTBI mice showed protection from bacterial pneumonia while TT mice did not. Using an FDA-approved neurokinin-1 receptor (NK1R) antagonist, aprepitant, we confirmed our previous findings that substance P (SP) is a key mediator of enhanced resistance to pneumonia. Blocking NK1R showed that mTBI-induced release of SP augments pulmonary neutrophil recruitment and microbicidal activity to pulmonary bacterial pathogens. In TT mice, NK1R agonism enhanced the same neutrophil functions, further supporting the hypothesis. No differences were found between mTBI and TT neutrophils’ ability to phagocytose, generate oxidative burst, or acidify phagosomes. However, neutrophils from mTBI mice produced more neutrophil extracellular traps in response to bacterial challenge. These studies show that neurokinin signaling in our model contributes to enhanced bacterial clearance. Cholinergic anti-inflammatory pathway signaling though the α7 nicotinic acetylcholine receptor (α7 nAChR) is also a critical component of improved survival. Blockade of α7 nAChR abrogated the mTBI survival benefit. Mimicking cholinergic signaling using α7 nAChR agonist recapitulated the mTBI reduced pro-inflammatory cytokine production and improved survival. No physiologic differences emerged within 24h following pneumonia, but mTBI and α7 agonist treated mice had significantly lower TNFα in bronchoalveolar fluid, suggesting reduced injurious pulmonary inflammation. However, replacing early TNFα during pneumonia did not increase mortality. Western blot analysis showed downregulation of HMGB1 release in mTBI mice, suggesting that vagal cholinergic signaling reduces late mediators of organ damage. Our experiments show that mTBI enhances resistance to pneumonia by activating the vagus nerve signaling through neurokinin and cholinergic pathways. Translation of these findings could be innovative solutions to fighting or preventing infections.

Acute lower respiratory tract infections are a persistent and pervasive public health burden, often caused by Streptococcus pneumoniae. Hospitalization rates due to pneumonia fall dramatically during early childhood, remain low during early adult years, and then increase steadily around middle age. The low-susceptibility period of early adulthood is likely due to frequent respiratory exposures to diverse pneumococcal serotypes resulting in serotype-independent heterotypic immunity. We hypothesize that resolution of repeated respiratory pneumococcal infections establish capsule-independent, lung-resident adaptive immunity that protects against subsequent unrelated pneumococcal pneumonia. In our model of naturally acquired heterotypic immunity, mice are infected with diverse serotypes of pneumococci in the respiratory tract, given time to recover, and then challenged by pulmonary infection with a highly virulent serotype 3 pneumococcus (Sp3). Prior exposures to unrelated pneumococci resulted in multi-log reductions in Sp3 bacterial lung burdens and long-term sterilizing immunity. The enhanced lung defense during pneumonia included more Th17 cells in the lung and significantly elevated IL-17A as well as neutrophils in the airspaces. Depletion of CD4+ cells resulted in less effective antibacterial defense. Upon ex vivo stimulation with pneumococcus lung-resident CD4+ cells produced multiple protective cytokines including IL-17A, IFN-γ, IL-22, IL-2, and TNF-α. In protected lungs, there were increased numbers of CD4+ resident memory T (TRM) cells, confined to the anatomic region of the initial infections. Heterotypic protection was also confined to the site of previous pneumococcal infections. Previously-exposed mice challenged in their contralateral lobes were not protected. RNAseq analysis of heterotypic lungs 24h after Sp3 infection revealed an enrichment of lymphocyte-related pathways including immunoglobulin and other B cell-related genes. B cell-deficient µMT-/- mice exposed to pneumococci had intermediate protection against Sp3 pneumonia, better than naïve mice but less effective than fully immunocompetent peers. Plasma from mice previously exposed to pneumococci was sufficient to protect naïve mice against Sp3 pneumonia. We conclude that mechanisms of naturally-acquired heterotypic protection against pneumococcus involve both lung-resident cell-mediated and humoral immunity and importantly this protection can be compartmentalized within the lung. Advancing our understanding of these mechanisms will guide future vaccine development and treatment strategies for lung disease.