Dissertations / Theses on the topic 'Chronic respiratory infection'

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.

[eng] Chronic respiratory infection (CRI) by Pseudomonas aeruginosa is the main cause of morbidity and mortality in cystic fibrosis (CF). During the progression from early infection to chronic non-eradicable colonization P. aeruginosa undergoes a complex evolutionary adaptation and diversification process which eventually leads to a mixed and persistent infecting population in which multidrug resistant variants frequently rise compromising the selection of appropriate antibiotic therapies. In this work the interplay between three key microbiological aspects of these infections was investigated: the occurrence of transmissible and persistent strains, the emergence of variants with enhanced mutation rates (mutators) and the evolution of resistance to antibiotics. Clonal epidemiology, antibiotic susceptibility profiles, contribution of P. aeruginosa classical resistance mechanisms and the role of mutator variants were investigated in two large collections of CF P. aeruginosa isolates from the Balearic Islands and Spain. As well, whole genome sequencing (WGS) was used to decipher the phylogeny, interpatient dissemination, within-host evolution, WGS mutator genotypes (mutome) and resistome of widespread P. aeruginosa clonal complex 274 (CC274), in isolates from two highly-distant countries, Australia and Spain, covering an 18-year period. Finally, due to the Chronic respiratory infection (CRI) by Pseudomonas aeruginosa is the main cause of morbidity and mortality in cystic fibrosis (CF). During the progression from early infection to chronic non-eradicable colonization P. aeruginosa undergoes a complex evolutionary adaptation and diversification process which eventually leads to a mixed and persistent infecting population in which multidrug resistant variants frequently rise compromising the selection of appropriate antibiotic therapies. In this work the interplay between three key microbiological aspects of these infections was investigated: the occurrence of transmissible and persistent strains, the emergence of variants with enhanced mutation rates (mutators) and the evolution of resistance to antibiotics. Clonal epidemiology, antibiotic susceptibility profiles, contribution of P. aeruginosa classical resistance mechanisms and the role of mutator variants were investigated in two large collections of CF P. aeruginosa isolates from the Balearic Islands and Spain. As well, whole genome sequencing (WGS) was used to decipher the phylogeny, interpatient dissemination, within-host evolution, WGS mutator genotypes (mutome) and resistome of widespread P. aeruginosa clonal complex 274 (CC274), in isolates from two highly-distant countries, Australia and Spain, covering an 18-year period. Finally, due to the relevance of aminoglycosides in the management of CF-CRI, the dynamics of P. aeruginosa resistance development to aminoglycosides was also studied in vitro by WGS approaches. Despite discrepancies between molecular genotyping methods, a high degree of genetic diversity was documented among CF isolates from the Balearic Islands and Spain with scarce representation of CF epidemic strains. However, for the first time in Spain, we documented a superinfection with the multidrug resistant Liverpool Epidemic Strain (LES) in a chronically colonized patient. As well, P. aeruginosa CC274, previously detected in several CF individuals from Austria, Australia and France, was detected in 5 unrelated chronically colonized patients from the Balearic Islands and, therefore, this clone-type should be added to the growing list of CF epidemic clones. Subsequent analysis of the whole genomes sequences of P. aeruginosa isolates from the CC274 P. aeruginosa collection provides evidence of interpatient dissemination of mutator sublineages and denotes their potential for unexpected short-term sequence type (ST) evolution and antibiotic resistance spread, illustrating the complexity of P. aeruginosa population biology in CF. As well, epidemiological studies demonstrated the coexistence of two divergent lineages but without evident geographical barrier. Antibiotic resistance significantly accumulated overtime accompanied by hypersusceptibility to certain antibiotics such as aztreonam, which can be explained in terms of collateral susceptibility. Correlation between phenotypes and WGS genotypes of clonal isolates from the CC274 collection allowed us to define the mutational resistome of CF P. aeruginosa which extends beyond the classical mutational resistance mechanisms. Among the new chromosomic resistance determinants encountered, mutations within the penicillin-binding-protein 3 (PBP3), shaping up beta-lactam resistance, are noteworthy as well as mutations within the fusA1 gene, coding for elongation factor G, which along with MexXY overexpresion contribute to high-level aminoglycoside resistance. Strikingly, we encountered that MexXY overexpression is dispensable for in vitro resistance development to aminoglycosides which suggests an evolutionary advantage of its overexpression in the CF respiratory tract. Altogether this work demonstrates that clonal epidemiology and antibiotic resistance evolution in the CF setting results from the complex interplay among mutation-driven resistance mechanisms, within host diversification and interpatient transmission of epidemic strains.
[spa] La infección respiratoria crónica por P. aeruginosa es la principal causa de morbilidad y mortalidad en pacientes con fibrosis quística (FQ). Durante la progresión desde la infección temprana a la colonización crónica, P. aeruginosa experimenta un complejo proceso adaptativo y de diversificación que resulta en una población heterogénea y persistente en la que la aparición de resistencias a los antibióticos comprometen la selección de terapias apropiadas. En este trabajo se investigó la interacción entre tres aspectos microbiológicos clave de estas infecciones: la presencia de cepas transmisibles y persistentes, la aparición de variantes con tasas de mutación incrementadas y la evolución de la resistencia a los antibióticos. La epidemiología clonal, los perfiles de sensibilidad antibiótica, la contribución de los mecanismos clásicos de resistencia de P. aeruginosa y el papel de las variantes hipermutadoras se estudiaron en dos grandes colecciones de aislados procedentes de pacientes con fibrosis quística de las Islas Baleares y España. Asimismo, mediante secuenciación de genoma completo, se determinó la filogenia, diseminación interpaciente, evolución intrapaciente, genotipo hipermutador y resistoma de una colección de aislados clonales pertenecientes al complejo clonal 274 (CC274), proviniendo dichos aislados de dos países muy distantes, Australia y España, y cubriendo un período de 18 años. Finalmente, dada la relevancia de los aminoglucósidos en el manejo de estos pacientes, se estudió la dinámica del desarrollo de resistencia a aminoglucósidos in vitro mediante secuenciación de genoma completo. A pesar de encontrarse discrepancias entre los métodos de genotipado molecular, se documentó un alto grado de diversidad genética en las colecciones de las Islas Baleares y España, siendo escasa la representación de cepas epidémicas. No obstante, por primera vez en España, se documentó un caso de sobreinfección con el clon epidémico multirresistente de Liverpool. Además, en 5 pacientes de Baleares, crónicamente colonizados y sin aparente relación epidemiológica, se detectó el CC274. Puesto que este complejo clonal también ha sido detectado en pacientes de países como Austria, Australia y Francia, éste debería incluirse en la creciente lista de cepas epidémicas. El análisis posterior de las secuencias de genoma completo de los aislados del CC274 evidenció la diseminación interpaciente de un sublinaje hipermutador, denotando además el potencial de estas variantes para la inesperada evolución a corto plazo del secuenciotipo y la rápida diseminación de resistencias. Además, los estudios epidemiológicos demostraron la coexistencia de dos linajes divergentes, no evidenciándose barrera geográfica. Asimismo se documentó una tendencia generalizada a la acumulación de resistencias a los antibióticos en el tiempo, acompañada de hipersensibilidad a ciertos antibióticos como aztreonam, lo cual se puede explicar en términos de sensibilidad colateral. La correlación entre los fenotipos y genotipos determinados mediante secuenciación del genoma completo de los aislados pertenecientes al CC274 nos permitió definir el resistoma mutacional de P. aeruginosa en la FQ, el cual se extiende más allá de los mecanismos mutacionales clásicos. Entre los nuevos determinantes de resistencia cromosómica encontrados caben destacar tanto las mutaciones en la proteína fijadora de penicilina PBP3, que confieren resistencia a betalactámicos, como las mutaciones en fusA1, que codifica para el factor de elongación G, y que junto con la hiperexpresión de MexXY contribuyen a la resistencia de alto nivel a aminoglucósidos. Paradójicamente, encontramos que la hiperexpresión de MexXY es prescindible para el desarrollo de resistencia in vitro a aminoglucósidos, lo que sugiere que dicha hiperexpresión confiere una ventaja evolutiva in vivo. En conjunto, este trabajo demuestra que, en la FQ, la epidemiología clonal y la evolución de la resistencia a los antibióticos son el resultado de una compleja interacción entre los mecanismos de resistencia mutacionales, la diversificación de la población infectante y la transmisión interpaciente de cepas epidémicas.
[cat] La infecció respiratòria crònica per P. aeruginosa és la principal causa de morbiditat i mortalitat en els pacients amb fibrosi quística (FQ). Durant la progressió des de la infecció primerenca a la colonització crònica, P. aeruginosa experimenta un complexe procés adaptatiu i de diversificació que resulta en una població heterogènia i persistent en la qual l'aparició de variants resistents a múltiples antibiòtics comprometen la selecció de teràpies antibiòtiques apropiades. En aquest treball es va investigar la interacció entre tres aspectes microbiològics clau: la presència de soques transmissibles i persistents, l'aparició de variants amb taxes de mutació incrementades i l'evolució de la resistència als antibiòtics. L'epidemiologia clonal, els perfils de sensibilitat antibiòtica, la contribució dels mecanismes clàssics de resistència i el paper de les variants hipermutadores es van estudiar en dos grans col·leccions d'aïllats procedents de pacients amb FQ de les Illes Balears i Espanya. Així mateix, mitjançant seqüenciació del genoma complet, es va determinar la filogènia, disseminació interpacient, evolució intrapacient, genotip hipermutador i resistoma d'una col·lecció d'aïllats pertanyents al complexe clonal 274 (CC274), provenint de dos països molt distants, Austràlia i Espanya, i cobrint un període de 18 anys. Finalment, donada la rellevància dels aminoglicòsids en el maneig d’aquests pacients, es va estudiar la dinàmica del desenvolupament de resistència a aminoglicòsids in vitro mitjançant seqüenciació de genoma complet. Tot i trobar discrepàncies entre els mètodes de genotipat molecular, es va documentar un alt grau de diversitat genètica en les col·leccions de les Illes Balears i Espanya, sent escassa la representació de soques epidèmiques. No obstant això, per primera vegada a Espanya, es va documentar un cas de sobreinfecció amb el clon epidèmic multiresistent de Liverpool. A més, en 5 pacients de les Illes Balears, crònicament colonitzats i sense aparent relació epidemiològica, es va detectar el CC274. Ja que aquest complexe clonal també ha estat detectat en països com Àustria, Austràlia i França, aquest clon hauria d'incloure a la creixent llista de soques epidèmiques. L'anàlisi posterior de les seqüències de genoma complet dels aïllats pertanyents al CC274, va evidenciar la disseminació interpaciente d'un subllinatge hipermutador, denotant a més el potencial d'aquestes variants per a la inesperada evolució a curt termini del sequenciotip i per a la ràpida disseminació de la resistència antibiòtica. A més, els estudis epidemiològics van demostrar la coexistència de dos llinatges divergents, no existint barrera geogràfica. Així mateix es va evidenciar una tendència generalitzada a l'acumulació de resistències en el temps, acompanyada d'hipersensibilitat a certs antibiòtics com l’aztreonam, la qual cosa es pot explicar en termes de sensibilitat col·lateral. La correlació entre els fenotips i genotips determinats mitjançant seqüenciació del genoma complet dels aïllats pertanyents al CC274 ens va permetre definir el resistoma mutacional de P. aeruginosa en la FQ, el qual s'estén més enllà dels mecanismes de resistència mutacionals clàssics. Entre els nous determinants de resistència cromosòmica trobats cal destacar tant les mutacions en la proteïna fixadora de penicil·lina PBP3, que confereixen resistència a betalactàmics, així com les mutacions en fusA1, que codifica per al factor d'elongació G, i que juntament amb la hiperexpressió de MexXY contribueixen a la resistència d'alt nivell a aminoglucòsids. Paradoxalment, vam trobar a més que la hiperexpressió de MexXY és prescindible per al desenvolupament de resistència in vitro a aminoglucòsids, el que suggereix que aquesta hiperexpressió suposa un avantatge evolutiu in vivo. En conjunt, aquest treball demostra que l'epidemiologia clonal i l'evolució de la resistència als antibiòtics en el context de la FQ són el resultat d'una complexa interacció entre els mecanismes de resistència mutacionals, la diversificació de la població infectant i la transmissió interpaciente de ceps epidèmiques.

Aims To assess the impact of RSV and other viral lower respiratory tract infections (LRTIs) on chronic respiratory morbidity in prematurely born infants and to investigate whether there were any functional or genetic predisposing factors. Methods One hundred and fifty three prematurely born infants were followed until one year corrected age with approximately half followed until two years of age. Lung function was measured at 36 weeks postmenstrual age (PMA) and one year corrected age. Blood or buccal swabs were taken for single nucleotide polymorphism (SNP) analysis. Following neonatal unit discharge, a nasopharyngeal aspirate (NPA) was taken whenever an infant had a LRTI. NPAs were analysed by real time PCR for 13 viruses. At one and two years corrected age healthcare utilisation and costs of care were calculated and parents completed a respiratory health related questionnaire and a diary card for one month. Results Infants developing RSV or other viral LRTIs requiring hospitalisation had reduced premorbid lung function compared to infants not hospitalised. Infants developing rhinovirus LRTIs had increased healthcare utilisation, cost of care and wheeze at one year corrected age. Infants developing RSV LRTIs had reduced lung function at one year corrected age. Prematurity was found to be a risk factor for developing RSV or other viral LRTIs but not influenza A (H1N1) LRTIs. A SNP in ADAM33 was associated with an increased risk of developing RSV LRTIs, but not with significant differences in 36 week PMA lung function results. SNPs in several genes were associated with increased chronic respiratory morbidity (IL10, NOS2A, SFTPC, MMP16 and VDR) and reduced lung function at one year (MMP16, NOS2A, SFTPC and VDR) in infants who had had RSV LRTIs. Conclusion In prematurely born infants, RSV and other viral LRTIs were associated with increased chronic respiratory morbidity at follow up, with some infants being genetically predisposed to this after RSV LRTI. Premorbid abnormal lung function predisposed to severe RSV and a SNP in the ADAM33 gene predisposed to RSV LRTIs.

In Enterobacteriaceae, the transcriptional regulator AmpR, a member of the LysR family, regulates the expression of a chromosomal β-lactamase AmpC. The regulatory repertoire of AmpR is broader in Pseudomonas aeruginosa, an opportunistic pathogen responsible for numerous acute and chronic infections including cystic fibrosis. Previous studies showed that in addition to regulating ampC, P. aeruginosa AmpR regulates the sigma factor AlgT/U and production of some quorum sensing (QS)-regulated virulence factors. In order to better understand the ampR regulon, the transcriptional profiles generated using DNA microarrays and RNA-Seq of the prototypic P. aeruginosa PAO1 strain with its isogenic ampR deletion mutant, PAO∆ampR were analyzed. Transcriptome analysis demonstrates that the AmpR regulon is much more extensive than previously thought influencing the differential expression of over 500 genes. In addition to regulating resistance to β-lactam antibiotics via AmpC, AmpR also regulates non-β-lactam antibiotic resistance by modulating the MexEF-OprN efflux pump. Virulence mechanisms including biofilm formation, QS-regulated acute virulence, and diverse physiological processes such as oxidative stress response, heat-shock response and iron uptake are AmpR-regulated. Real-time PCR and phenotypic assays confirmed the transcriptome data. Further, Caenorhabditis elegans model demonstrates that a functional AmpR is required for full pathogenicity of P. aeruginosa. AmpR, a member of the core genome, also regulates genes in the regions of genome plasticity that are acquired by horizontal gene transfer. The extensive AmpR regulon included other transcriptional regulators and sigma factors, accounting for the extensive AmpR regulon. Gene expression studies demonstrate AmpR-dependent expression of the QS master regulator LasR that controls expression of many virulence factors. Using a chromosomally tagged AmpR, ChIP-Seq studies show direct AmpR binding to the lasR promoter. The data demonstrates that AmpR functions as a global regulator in P. aeruginosa and is a positive regulator of acute virulence while negatively regulating chronic infection phenotypes. In summary, my dissertation sheds light on the complex regulatory circuit in P. aeruginosa to provide a better understanding of the bacterial response to antibiotics and how the organism coordinately regulates a myriad of virulence factors.

The aim of this research project was to determine whether temperate bacteriophages could be used as markers for bacterial evolution in chronic microbial infections and in the progression of respiratory diseases [Cystic Fibrosis (CF) and Bronchiectasis (BR)]. CF and BR have diverse clinical origins but similar pathophysiological burdens including inflammation and the production of a nutrient rich mucus. This thick, dehydrated mucus is an ideal colonisation site for opportunistic bacteria such as Pseudomonas aeruginosa (P. aeruginosa). Some strains of P. aeruginosa have been found to harbour multiple inducible temperate bacteriophages that are believed to have an effect on P. aeruginosa functionality. In order to try and answer the research question proposed, the research was split into three subgroups: (1) a cross-infection study utilising 94 clinical P. aeruginosa isolates and their associated mixed phage communities to determine changes in phage-host interactions alongside the progression of the clinical disease. We here illustrate that phages induced from the older CF patient isolates were the most infective, whilst the phages originating from the youngest CF patients or the patients with < 10 years of BR diagnosis were the least infective. (2) Metagenome analysis of the total induced viral DNA from each of these 94 P. aeruginosa isolates was used to determine whether disease progression offered complexity or additional gene function that would offer a selective advantage for the bacterium or virus in these clinical backgrounds. This research importantly shows differences in phage metagenome complexity and an increase in gene function that correlates with the advancement of disease progression. Therefore, phage metagenomes originating from the older CF patients were the most enriched in functions relating to survival within the chronic lung. It also shows a snapshot of phage evolution and their impact on the bacteria colonising the lower lung. If higher numbers of phage genes with defined function is a marker of the levels of adaptation and evolution that has occurred, then this research determines that phages isolated from CF metagenomes had undergone more rounds of evolution compared to the BR metagenomes. (3) Changes in metabolite profiles in the bacterium when infected with a single phage may further show the involvement and subversion of host cell functionality by these phages. A panel of plaque-purified phages were used to create lysogens of lab strain PAO1. Changes in the metabolite profiles between naïve and infected PAO1 were investigated throughout pellicle growth where distinct differences were seen and further show the impact of prophage formation on the core gene function of respiring bacteria. Both the E. coli metabolome database and the human metabolome database were utilised in order to identify potential metabolites that were both statistically significant and had a low CV score. We illustrate different metabolite profiles when comparing naïve bacterial strain to lysogen and thus, we establish the intricacy of how the virus subverts host cell functionality. One metabolite was observed that was present in a lysogenic strain and not in the naïve host cell, so potentially leading to the assumption that this metabolite is phage derived. Further LCMS work is required in order to confirm this preliminary finding.

Pseudomonas aeruginosa is an important pathogen in cystic fibrosis (CF) chronically colonising most adult CF patients (McCallum et al, 2001). However, mechanisms by which P. aeruginosa thrives in the CF airway remain unclear because its nutritional requirements are not fully understood. Because mucus is in abundance, a potential nutrient source may come from mucin glycoproteins. Therefore, the purpose of this study was to investigate whether P. aeruginosa could utilise airway mucin as a nutrient source for growth. P. aeruginosa was grown in mucins purified from CF sputum. It was found that P. aeruginosa was unable to utilise mucin, but following DNase treatment growth of P. aeruginosa was significantly promoted. Analysis of gene expression following exposure to DNase treated CF sputum revealed that codA which encodes cytosine deaminase and catalyses the conversion of cytosine to uracil and 5-methylcytosine to thymine was significantly upregulated. The gene, gapA, involved in carbon metabolism was also upregulated. Previous studies have demonstrated that uracil promotes biofilm formation and that uracil and thymine can be metabolised by P. aeruginosa via the reductive pathway of pyrimidine catabolism (Ueda et al, 2009; Kim and West, 1991). Additionally, DNA is in abundance in the CF airway (Lethem et al, 1990). Therefore, it is likely that following dornase alfa treatment, when degraded DNA is liberated it may alter the CF airway mucus composition so that P. aeruginosa growth is promoted. Degraded DNA may have an important role in the pathogenicity of P. aeruginosa and CF disease. This PhD thesis demonstrates novel findings that P. aeruginosa is unable to utilise purified CF patient mucin as a nutrient source for growth, but degraded DNA originating from CF patient sputum can be utilised by P. aeruginosa to produce uracil or thymine which are known to be catabolised via the reductive pathway of pyrimidine catabolism.

In der vorliegenden Arbeit wurde anhand der im Rahmen des Vermont-Oxford-Neonatal-Networks erhobenen Daten an der Berliner Klinik für Neonatologie der Charité Campus Mitte und der Abteilung für neonatologische Intensivmedizin der Universitätskinderklinik in Innsbruck ein Benchmarking-Projekt für die Jahre 1997 bis 2001 durchgeführt. Nach der Analyse des Outcomes wurde eine Analyse der externen Evidenz anhand von Literatursuche in PubMed und der Cochrane Datenbank für systematische Reviews durchgeführt. Danach wurde ein Fragebogen entworfen, der gezielt Handlungsstrategien und -richtlinien bezüglich der relevanten Outcome-Parameter erfragt. Für das Benchmarking-Projekt wurden das Atemnotsyndrom, die nekrotisierende Enterokolitis und die bakteriellen Infektionen ausgewählt. Die Analyse der Handlungsstrategien durch den Fragebogen zeigte, dass in den drei Bereichen respiratorische Interventionen, Nahrung und Ernährung sowie im Infektionsmanagement Unterschiede vorlagen. In der Diskussion zeigte sich, dass in vielen Bereichen noch Bedarf nach guter externer Evidenz und weiterer Forschung besteht.
This dissertation presents the results of a 1997 - 2001 benchmark project in co-operation with the "Berliner Klinik für Neonatologie der Charité Campus Mitte" and the "Abteilung für neonatologische Intensivmedizin der Universitätskinderklinik" in Innsbruck. The study is based on the Vermont-Oxford-Neonatal-Network''s data. After analysing the results, further evidence was analysed by way of literary research in PubMed and the Cochrane Database of Systematic Reviews. Afterwards, a questionnaire was created, lining out the clinical guidelines of the relevant outcome parameters. The respiratory distress syndrom, the necrotising enterocolitis and the bacterial infections were selected for the benchmark. The internal guidelines'' analysis showed that there were differences between the two clinics'' results in respiratory interventions, feeding and the management of infections. The discussion made clear that research based on further evidence is necessary in many fields.

A cárie dentária é considerada uma das doenças crónicas mais comuns em crianças, sendo de origem multifatorial, resultante da interação entre um hospedeiro suscetível, os microrganismos cariogénicos e as dietas cariogénicas. Podem-se considerar como fatores de risco da cárie dentária, o fluxo salivar inadequado, baixa capacidade tampão salivar, altos níveis de bactérias cariogénicas, reduzida exposição ao flúor e consumo frequente de açúcares. Os problemas otorrinolaringológicos referem-se às patologias do ouvido, nariz e garganta, sendo estes a otite média, sinusite, rinite alérgica, amigdalites e adenoidites. O objetivo desta revisão bibliográfica é verificar se existe uma relação entre os problemas otorrinolaringológicos e a cárie dentária.
Dental caries is considered one of the most common chronic diseases in children, being of multifactorial origin, resulting from the interaction between a susceptible host, cariogenic microorganisms and cariogenic diets. As risk factors for dental caries, inadequate salivary flow, low salivary buffer capacity, high levels of bacteria cariogenic, reduced exposure to fluoride and frequent sugar consumption can be considered. Otorhinolaryngological problems refer to pathologies of the ear, nose and throat, which are otitis media, sinusitis, allergic rhinitis, tonsillitis and adenoiditis. The purpose of this literature review is to verify whether there is a relationship between otorhinolaryngological problems and dental caries.