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1.
HIV Med ; 2024 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-39444189

RESUMO

OBJECTIVES: This survey was conducted to describe current European postnatal prophylaxis (PNP) and infant feeding policies with the aim of informing future harmonized guidelines. METHODS: A total of 32 senior clinicians with relevant expertise, working in 20 countries within the European Region, were invited to complete a REDCap questionnaire between July and September 2023. RESULTS: Twenty-three of the 32 invited paediatricians responded, representing 16/20 countries. There were multiple respondents from the same country for Italy (n = 5), the UK (n = 2), Germany (n = 2) and France (n = 2). All countries use risk stratification to guide PNP regimen selection. Nine out of 16 countries reported three risk categories, six out of 16 reported two, and one country reported differences in categorization. Criteria used to stratify risk varied between and within countries. For the lowest risk category, the PNP regimen reported ranged from no PNP to up to four weeks of one drug; the drug of choice reported was zidovudine, apart from one country which reported nevirapine. For the highest risk category, the most common regimen was zidovudine/lamivudine/nevirapine (20/23 respondents); regimen duration varied from two to six weeks with variation in recommended dosing. Guidelines support breastfeeding for infants born to people living with HIV in eight out of 16 countries; in the other eight, guidelines do not support/specify. CONCLUSIONS: Guidelines and practice for PNP and infant feeding vary substantially across Europe and within some countries, reflecting the lack of robust evidence. Effort is needed to align policies and practice to reflect up-to-date knowledge to ensure the vertical transmission risk is minimized and unnecessary infant HIV testing and PNP avoided, while simultaneously supporting families to make informed decisions on infant feeding choice.

2.
Euro Surveill ; 28(4)2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36700867

RESUMO

We analysed SARS-CoV-2 PCR Cq values from 3,183 healthcare workers who tested positive between January and August 2022. Median Cq values were lower in symptomatic than in asymptomatic HCW. The difference in Cq values between HCW with mild vs moderate/severe symptoms was statistically significant but negligibly small. To prevent nosocomial infections, all symptomatic HCW should be tested irrespective of symptom severity. This information can support decisions on testing and isolation, in the context of ongoing pressure on healthcare systems.


Assuntos
COVID-19 , Infecção Hospitalar , Humanos , COVID-19/diagnóstico , SARS-CoV-2 , Países Baixos/epidemiologia , Pessoal de Saúde
3.
J Clin Immunol ; 42(6): 1223-1229, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35536474

RESUMO

Although fatigue is a common symptom in adult patients with primary immunodeficiencies (PID), data in pediatric patients are limited. The goal of this study is to estimate the prevalence and impact of fatigue in children with PID as reported by patients, parents, and health-care providers. A retrospective single-center observational study was performed. Prevalence of fatigue was measured by reviewing medical charts of 54 children in our department who are on immunoglobulin replacement therapy. Both prevalence and impact were also measured by the PedsQL-Multidimensional Fatigue Scale (MFS) in 27 patients and 32 of their parents. This is an age-appropriate questionnaire for self-report of fatigue symptoms in patients aged 5-18 years and for parent proxy reports for patients aged 2-18 years. General, cognitive, and sleep-rest fatigue was measured, and a total fatigue score was calculated. Means, standard deviation and Z scores were calculated using age-specific reference values. Intraclass correlation coefficients (ICC) were calculated for comparison of scores provided by parents vs children's self-reported scores. Both chart review data and PedsQL-MFS showed fatigue rates of 65%. Pediatric PID patients of all ages had significantly lower scores on all subscales and total score of the PedsQL-MFS compared to healthy children, indicating greater perceived symptoms of fatigue. General fatigue was the most affected subscale in PID patients, suggesting that fatigue in these patients is mainly physical. Seventy-four percent of PID patients had a Z score lower than - 1 on the general fatigue subscale indicating severe fatigue. Child-parent concordance varied between 0.24 and 0.93. Our results show the feasibility of the PedsQL-MFS survey to evaluate the prevalence and severity of fatigue in children with PID and underscore the importance of this issue in our patient care.


Assuntos
Doenças da Imunodeficiência Primária , Qualidade de Vida , Criança , Fadiga/diagnóstico , Fadiga/epidemiologia , Fadiga/etiologia , Humanos , Pais/psicologia , Prevalência , Estudos Retrospectivos , Inquéritos e Questionários
4.
Med Microbiol Immunol ; 202(6): 407-15, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23775521

RESUMO

We have previously found that non-typeable Haemophilus influenzae (NTHi) collected from the middle ear of children with otitis media (OM) exhibit increased levels of complement resistance compared to NTHi collected from the nasopharynx. However, it is unknown whether bacteria develop complement resistance in the middle ear, or whether resistance is present when residing in the nasopharynx. The objective of this study was to investigate whether the levels of complement resistance of isolates collected from the middle ear were similar to those of isolates from the nasopharynx with an identical MLST type. We included 62 children with recurrent acute OM, chronic OM with effusion or acute tympanostomy tube otorrhea. NTHi was simultaneously isolated from the nasopharynx and middle ear fluid. MLST, resistance to complement-mediated killing, IgG binding, IgM binding and phosphorylcholine expression was determined. In 41 children, NTHi isolated from the middle ear and nasopharynx showed to have an identical MLST type. Isolates collected from the middle ear showed a highly similar level of complement resistance and IgM binding with isolates collected from the nasopharynx, whereas this was not the case for IgG binding and phosphorylcholine incorporation into lipooligosaccharide. Resistance to complement-mediated killing and IgM binding of NTHi isolates with an identical MLST type collected from the middle ear and nasopharynx of children with OM was highly similar.


Assuntos
Proteínas do Sistema Complemento/imunologia , Orelha Média/microbiologia , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/imunologia , Imunoglobulina M/imunologia , Nasofaringe/microbiologia , Otite Média/microbiologia , Anticorpos Antibacterianos/imunologia , Criança , Pré-Escolar , Estudos de Coortes , DNA Bacteriano/genética , Feminino , Haemophilus influenzae/classificação , Haemophilus influenzae/genética , Haemophilus influenzae/isolamento & purificação , Humanos , Imunoglobulina G/imunologia , Lactente , Masculino , Viabilidade Microbiana , Tipagem de Sequências Multilocus , Fosforilcolina/análise
5.
Pediatr Infect Dis J ; 42(4): e122-e124, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36728741

RESUMO

Following an increase in notifiable invasive group A streptococcal (iGAS) infections in the Netherlands, we conducted a survey among 7 hospitals. Pediatric iGAS case numbers were 2-fold higher between July 2021 and June 2022 versus pre-COVID-19. A sharp increase occurred early 2022, most pronounced in <5 years old and for diagnoses empyema and necrotizing fasciitis. This recent pediatric iGAS surge warrants investigation and vigilance.


Assuntos
COVID-19 , Fasciite Necrosante , Infecções Estreptocócicas , Criança , Humanos , Pré-Escolar , Países Baixos/epidemiologia , Infecções Estreptocócicas/epidemiologia , Streptococcus pyogenes , Fasciite Necrosante/epidemiologia , Hospitais
6.
PLoS Pathog ; 6(8): e1001044, 2010 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-20714350

RESUMO

The Pneumococcal serine-rich repeat protein (PsrP) is a pathogenicity island encoded adhesin that has been positively correlated with the ability of Streptococcus pneumoniae to cause invasive disease. Previous studies have shown that PsrP mediates bacterial attachment to Keratin 10 (K10) on the surface of lung cells through amino acids 273-341 located in the Basic Region (BR) domain. In this study we determined that the BR domain of PsrP also mediates an intra-species interaction that promotes the formation of large bacterial aggregates in the nasopharynx and lungs of infected mice as well as in continuous flow-through models of mature biofilms. Using numerous methods, including complementation of mutants with BR domain deficient constructs, fluorescent microscopy with Cy3-labeled recombinant (r)BR, Far Western blotting of bacterial lysates, co-immunoprecipitation with rBR, and growth of biofilms in the presence of antibodies and competitive peptides, we determined that the BR domain, in particular amino acids 122-166 of PsrP, promoted bacterial aggregation and that antibodies against the BR domain were neutralizing. Using similar methodologies, we also determined that SraP and GspB, the Serine-rich repeat proteins (SRRPs) of Staphylococcus aureus and Streptococcus gordonii, respectively, also promoted bacterial aggregation and that their Non-repeat domains bound to their respective SRRPs. This is the first report to show the presence of biofilm-like structures in the lungs of animals infected with S. pneumoniae and show that SRRPs have dual roles as host and bacterial adhesins. These studies suggest that recombinant Non-repeat domains of SRRPs (i.e. BR for S. pneumoniae) may be useful as vaccine antigens to protect against Gram-positive bacteria that cause infection.


Assuntos
Adesinas Bacterianas/metabolismo , Aderência Bacteriana/fisiologia , Biofilmes/crescimento & desenvolvimento , Streptococcus pneumoniae/fisiologia , Streptococcus pneumoniae/patogenicidade , Adesinas Bacterianas/química , Adesinas Bacterianas/genética , Motivos de Aminoácidos , Animais , Western Blotting , Feminino , Imunoprecipitação , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Confocal , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Estrutura Terciária de Proteína/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Streptococcus pneumoniae/metabolismo
7.
AIDS ; 36(14): 2077-2079, 2022 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-36111542

RESUMO

Dolutegravir 50 mg is registered for use in children weighing 20-40 kg. This approval is based on data from an African paediatric cohort, and no pharmacokinetic data was available from children outside of Africa. This study provides further evidence of the effective use of dolutegravir 50 mg in children weighing 20 to 40 kg by showing that concentration data gathered in clinical practice shows adequate concentration levels in Dutch children without a safety signal.


Assuntos
Infecções por HIV , Humanos , Criança , Infecções por HIV/tratamento farmacológico , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Oxazinas , Piridonas , África Subsaariana
8.
BMC Genomics ; 12: 70, 2011 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-21269504

RESUMO

BACKGROUND: M. catarrhalis is a gram-negative, gamma-proteobacterium and an opportunistic human pathogen associated with otitis media (OM) and exacerbations of chronic obstructive pulmonary disease (COPD). With direct and indirect costs for treating these conditions annually exceeding $33 billion in the United States alone, and nearly ubiquitous resistance to beta-lactam antibiotics among M. catarrhalis clinical isolates, a greater understanding of this pathogen's genome and its variability among isolates is needed. RESULTS: The genomic sequences of ten geographically and phenotypically diverse clinical isolates of M. catarrhalis were determined and analyzed together with two publicly available genomes. These twelve genomes were subjected to detailed comparative and predictive analyses aimed at characterizing the supragenome and understanding the metabolic and pathogenic potential of this species. A total of 2383 gene clusters were identified, of which 1755 are core with the remaining 628 clusters unevenly distributed among the twelve isolates. These findings are consistent with the distributed genome hypothesis (DGH), which posits that the species genome possesses a far greater number of genes than any single isolate. Multiple and pair-wise whole genome alignments highlight limited chromosomal re-arrangement. CONCLUSIONS: M. catarrhalis gene content and chromosomal organization data, although supportive of the DGH, show modest overall genic diversity. These findings are in stark contrast with the reported heterogeneity of the species as a whole, as wells as to other bacterial pathogens mediating OM and COPD, providing important insight into M. catarrhalis pathogenesis that will aid in the development of novel therapeutic regimens.


Assuntos
Genoma Bacteriano , Moraxella catarrhalis/genética , Técnicas de Tipagem Bacteriana , Códon , DNA Bacteriano/genética , Sequências Repetitivas Dispersas , Modelos Genéticos , Moraxella catarrhalis/isolamento & purificação , Família Multigênica , Tipagem de Sequências Multilocus , Alinhamento de Sequência , Análise de Sequência de DNA , Fatores de Virulência/genética
9.
Pediatr Crit Care Med ; 12(1): e14-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20228690

RESUMO

OBJECTIVES: To evaluate availability and reliability of pediatric drug dosing guidelines in selected formularies for intensive care patients. Most drugs used in the pediatric intensive care unit are prescribed off-label, often on the guidance of limited information from commonly used drug formularies. DESIGN: Availability of dosing information on prescribed drugs in a Dutch intensive care unit from January 1, 2005 to December 31, 2006 was compared among four selected formularies (Micromedex, Lexi-Comp, Drug Formulary for Children, Drug Doses). Reliability of dosing guidelines was assessed by evaluating labeling status and literature data for the three most (midazolam, acetaminophen, and amoxicillin/clavulanic acid) and the three least (bosentan, ketanserin, and iloprost) prescribed drugs. MEASUREMENTS AND MAIN RESULTS: The selected formularies covered 68% to 86% of all 257 prescribed drugs. Guidelines differ widely on daily doses per kilogram, dose description, dosing regimen, and age ranges. For the three most prescribed and one of the least prescribed drugs (bosentan), dosing guidelines adequately reflected labeling status and existing (but scarce) literature. No dosing guidelines were available for iloprost, and only one dosing guideline was available for ketanserin. CONCLUSIONS: This study shows that four commonly used drug formularies give few and widely differing dosing guidelines for drugs prescribed in the intensive care unit. If guidelines exist, they seem to reflect labeling status (if present) and limited literature available. Findings from this study likely reflect the scarcity of drug studies in this population. Physicians should be aware of the limitations of these formularies for daily practice in this group of vulnerable patients.


Assuntos
Prescrições de Medicamentos/estatística & dados numéricos , Formulários de Hospitais como Assunto , Unidades de Terapia Intensiva Pediátrica , Humanos , Países Baixos , Reprodutibilidade dos Testes , Estatísticas não Paramétricas
10.
Pediatr Infect Dis J ; 40(5S): S26-S30, 2021 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-34042907

RESUMO

Ureaplasma species are increasingly recognized as relevant pathogens in prenatal, perinatal and postnatal morbidity. They are commonly found as commensals on the mucous membranes of the lower urogenital tract of pregnant women, but when ascending, they can cause bacterial vaginosis, chorioamnionitis, premature birth and postnatal morbidities such as bronchopulmonary dysplasia, and early-onset neonatal sepsis and meningitis. The detection of Ureaplasma species is challenging and is not covered by routine diagnostics, and current empiric antibiotic treatment in neonates suspected of infection is not directed against Ureaplasma species. The aim of this review is to discuss the pathophysiology of Ureaplasma infections, the clinical consequences and the current difficulties in diagnosis and treatment by providing an overview of the current literature.


Assuntos
Doenças do Recém-Nascido/microbiologia , Complicações na Gravidez/microbiologia , Infecções por Ureaplasma/microbiologia , Ureaplasma , Imunidade Adaptativa , Corioamnionite/microbiologia , Feminino , Humanos , Imunidade Inata , Lactente , Recém-Nascido/imunologia , Doenças do Recém-Nascido/diagnóstico , Doenças do Recém-Nascido/terapia , Gravidez , Complicações na Gravidez/diagnóstico , Complicações na Gravidez/terapia , Nascimento Prematuro/microbiologia , Infecções por Ureaplasma/diagnóstico , Infecções por Ureaplasma/terapia
11.
Viruses ; 13(10)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34696375

RESUMO

Advances in antiretroviral treatment improved the life expectancy of perinatally HIV-infected children. However, growing up with HIV provides challenges in daily functioning. This cross-sectional cohort study investigated the neuropsychological and psychosocial functioning of a group of perinatally HIV-infected children in the Netherlands and compared their outcomes with Dutch normative data and outcomes of a control group of uninfected siblings. The children's functioning was assessed with internationally well-known and standardized questionnaires, using a multi-informant approach, including the perspectives of caregivers, teachers, and school-aged children. In addition, we explored the associations of socio-demographic and medical characteristics of the HIV-infected children with their neuropsychological and psychosocial functioning. Caregivers reported compromised functioning when compared to Dutch normative data for HIV-infected children in the areas of attention, sensory processing, social-emotional functioning, and health-related quality of life. Teachers reported in addition compromised executive functioning for HIV-infected children. A comparison with siblings revealed differences in executive functioning, problems with peers, and general health. The concurrent resemblance between HIV-infected children and siblings regarding problems in other domains implies that social and contextual factors may be of influence. A family-focused approach with special attention to the child's socio-environmental context and additional attention for siblings is recommended.


Assuntos
Infecções por HIV/complicações , Infecções por HIV/psicologia , Transmissão Vertical de Doenças Infecciosas , Testes Neuropsicológicos/estatística & dados numéricos , Funcionamento Psicossocial , Adolescente , Antirretrovirais/uso terapêutico , Cuidadores/estatística & dados numéricos , Criança , Pré-Escolar , Estudos de Coortes , Estudos Transversais , Feminino , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Masculino , Países Baixos , Gravidez , Qualidade de Vida , Inquéritos e Questionários
12.
Pediatr Infect Dis J ; 38(6S Suppl 1): S7-S13, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31205237

RESUMO

Biomarkers have become an integral part of the clinical decision-making process of clinicians dealing with febrile children. C-reactive protein, procalcitonin and white blood cell count are probably the most studied ones. Crucial to using biomarkers is the understanding of how a test result will alter post-test probabilities and then impact on clinical decision making. Improved analytical and computational platforms have enabled the next generation of advanced biomarker discovery studies. Promising combinations of candidate biomarkers for a diverse spectrum of febrile illnesses, such as viral and bacterial infections, have been identified using proteomics, RNA gene expression and metabolomics.


Assuntos
Biomarcadores , Infecções/diagnóstico , Infecções/etiologia , Fatores Etários , Algoritmos , Criança , Pré-Escolar , Testes Diagnósticos de Rotina , Gerenciamento Clínico , Suscetibilidade a Doenças , Interações Hospedeiro-Patógeno , Humanos , Infecções/terapia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
13.
BMJ Case Rep ; 20172017 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-28827297

RESUMO

A 4-month-old female infant presented with a vesicular lesion on her left hand present since 1 day. A few days prior to presentation, she had a similar lesion on the lower lip. Two days after presentation, she returned with new lesions on her thorax and upper eyelid. PCR of the vesicle was positive for herpes simplex virus type 1. The transmission to her chest and face probably resulted from autoinoculation, caused by rubbing of the hand on other parts of the body. Transmission of herpes simplex through skin-to-skin contact is a common route of infection in people engaging in contact sports. Antiviral therapy was started because of the extensiveness and expansion of lesions and risk of developing herpetic keratitis. The patient completely recovered. This case shows that in an otherwise healthy infant, multiple herpetic skin lesions were not due to disseminated infection, but through autoinoculation.


Assuntos
Face/virologia , Herpes Simples/transmissão , Herpesvirus Humano 1/isolamento & purificação , Tórax/virologia , Aciclovir/administração & dosagem , Aciclovir/uso terapêutico , Administração Intravenosa , Antivirais/uso terapêutico , Diagnóstico Diferencial , Transmissão de Doença Infecciosa , Face/patologia , Feminino , Herpes Simples/tratamento farmacológico , Herpesvirus Humano 1/genética , Humanos , Lactente , Ceratite Herpética/tratamento farmacológico , Ceratite Herpética/prevenção & controle , Lábio/patologia , Lábio/virologia , Tórax/patologia , Resultado do Tratamento
14.
Int J Pediatr Otorhinolaryngol ; 77(4): 488-93, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23369612

RESUMO

OBJECTIVES: Otitis media (OM) is one of the most frequent diseases of childhood, with a minority of children suffering from recurrent acute otitis media (rAOM) or chronic otitis media with effusion (COME), both of which are associated with significant morbidity. We investigated whether the microbiological profiling could be used to differentiate between these two conditions. METHODS: Children up to five years of age, with rAOM (n = 45) or COME (n = 129) and scheduled for tympanostomy tube insertion were enrolled in a prospective study between 2008 and 2009. Middle ear fluids (n = 119) and nasopharyngeal samples (n = 173) were collected during surgery for bacterial culture and PCR analysis to identify Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, and to detect 15 distinct respiratory viruses. RESULTS: The occurrence of bacterial and viral pathogens in middle ear fluids did not significantly differ between patients suffering from rAOM and COME. In both patient cohorts, H. influenzae and rhinovirus were the predominant pathogens in the middle ear and nasopharynx. Nasopharyngeal carriage with two or three bacterial pathogens was associated with the presence of bacteria in middle ear fluid (P = 0.04). The great majority of the bacteria isolated from middle ear fluid were genetically identical to nasopharyngeal isolates from the same patient. CONCLUSIONS: Based on these results, we propose that the common perception that rAOM is associated with recurrent episodes of microbiologically mediated AOM, whereas COME is generally a sterile inflammation, should be reconsidered.


Assuntos
Orelha Média/microbiologia , Nasofaringe/microbiologia , Otite Média com Derrame/microbiologia , Otite Média/microbiologia , Doença Aguda , Pré-Escolar , Doença Crônica , Diagnóstico Diferencial , Feminino , Haemophilus influenzae/genética , Haemophilus influenzae/isolamento & purificação , Humanos , Lactente , Masculino , Moraxella catarrhalis/genética , Moraxella catarrhalis/isolamento & purificação , Países Baixos , Otite Média/epidemiologia , Estudos Prospectivos , Recidiva , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/isolamento & purificação
15.
Pediatr Infect Dis J ; 31(11): 1128-34, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22668804

RESUMO

BACKGROUND: Viral upper respiratory tract infections have been described as an important factor in the development of otitis media (OM), although it is unclear whether they facilitate bacterial OM or can directly cause OM. To clarify the role of viral infections in OM, we compared the relative contribution of viruses and bacteria with the induction of inflammatory cytokine responses in the middle ear of children suffering from OM. METHODS: Children up to 5 years of age, with recurrent or chronic episodes of OM and scheduled for ventilation tube insertion were enrolled in a prospective study. Middle ear fluids (n = 116) were collected during surgery, and quantitative polymerase chain reaction was performed to detect bacterial and viral otopathogens, that is, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and 15 respiratory viruses. Finally, concentrations of the inflammatory mediators interleukin (IL)-1ß, IL-6, IL-8, IL-10, IL-17a and tumor necrosis factor-α were determined. RESULTS: Middle ear fluids were clustered into 4 groups, based on the detection of viruses (28%), bacteria (27%), both bacteria and viruses (27%) or no otopathogens (19%). Bacterial detection was associated with significantly elevated concentrations of cytokines compared with middle ear fluids without bacteria (P < 0.001 for all cytokines tested) in a bacterial load-dependent and species-dependent manner. In contrast, the presence of viruses was not associated with changes in cytokine values, and no synergistic effect between viral-bacterial coinfections was observed. CONCLUSIONS: The presence of bacteria, but not viruses, is associated with an increased inflammatory response in the middle ear of children with recurrent or chronic OM.


Assuntos
Líquidos Corporais/microbiologia , Inflamação/microbiologia , Otite Média/microbiologia , Infecções Bacterianas/microbiologia , Líquidos Corporais/química , Pré-Escolar , Doença Crônica , Citocinas/química , Humanos , Lactente , Otite Média/cirurgia , Recidiva , Viroses/virologia , Vírus/classificação
16.
mBio ; 3(4): e00079-12, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22761391

RESUMO

UNLABELLED: Nontypeable Haemophilus influenzae (NTHi) is a Gram-negative, human-restricted pathogen. Although this bacterium typically colonizes the nasopharynx in the absence of clinical symptoms, it is also one of the major pathogens causing otitis media (OM) in children. Complement represents an important aspect of the host defense against NTHi. In general, NTHi is efficiently killed by complement-mediated killing; however, various resistance mechanisms have also evolved. We measured the complement resistance of NTHi isolates isolated from the nasopharynx and the middle ear fluids of OM patients. Furthermore, we determined the molecular mechanism of NTHi complement resistance. Complement resistance was strongly increased in isolates from the middle ear, which correlated with decreased binding of IgM. We identified a crucial role for the R2866_0112 gene in complement resistance. Deletion of this gene altered the lipooligosaccharide (LOS) composition of the bacterium, which increased IgM binding and complement-mediated lysis. In a novel mouse model of coinfection with influenza virus, we demonstrate decreased virulence for the R2866_0112 deletion mutant. These findings identify a mechanism by which NTHi modifies its LOS structure to prevent recognition by IgM and activation of complement. Importantly, this mechanism plays a crucial role in the ability of NTHi to cause OM. IMPORTANCE: Nontypeable Haemophilus influenzae (NTHi) colonizes the nasopharynx of especially young children without any obvious symptoms. However, NTHi is also a major pathogen in otitis media (OM), one of the most common childhood infections. Although this pathogen is often associated with OM, the mechanism by which this bacterium is able to cause OM is largely unknown. Our study addresses a key biological question that is highly relevant for child health: what is the molecular mechanism that enables NTHi to cause OM? We show that isolates collected from the middle ear fluid exhibit increased complement resistance and that the lipooligosaccharide (LOS) structure determines IgM binding and complement activation. Modification of the LOS structure decreased NTHi virulence in a novel NTHi-influenza A virus coinfection OM mouse model. Our findings may also have important implications for other Gram-negative pathogens harboring LOS, such as Neisseria meningitidis, Moraxella catarrhalis, and Bordetella pertussis.


Assuntos
Proteínas do Sistema Complemento/imunologia , Infecções por Haemophilus/imunologia , Haemophilus influenzae/imunologia , Imunoglobulina M/imunologia , Lipopolissacarídeos/química , Otite Média/imunologia , Animais , Anticorpos Antibacterianos/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Modelos Animais de Doenças , Orelha Média/imunologia , Orelha Média/microbiologia , Feminino , Deleção de Genes , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/química , Haemophilus influenzae/genética , Humanos , Lipopolissacarídeos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Otite Média/microbiologia
17.
Clin Vaccine Immunol ; 19(6): 914-8, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22539468

RESUMO

A prospective clinical cohort study was established to investigate the humoral immune response in middle ear fluids (MEF) and serum against bacterial surface proteins in children suffering from recurrent acute otitis media (rAOM) and chronic otitis media with effusion (COME), using Luminex xMAP technology. The association between the humoral immune response and the presence of Moraxella catarrhalis and Streptococcus pneumoniae in the nasopharynx and middle ear was also studied. The levels of antigen-specific IgG, IgA, and IgM showed extensive interindividual variation. No significant differences in anti-M. catarrhalis and anti-S. pneumoniae serum and MEF median fluorescence intensity (MFI) values (anti-M. catarrhalis and antipneumococcal IgG levels) were observed between the rAOM or COME groups for all antigens tested. No significant differences were observed for M. catarrhalis and S. pneumoniae colonization and serum IgG levels against the Moraxella and pneumococcal antigens. Similar to the antibody response in serum, no significant differences in IgG, IgA, and IgM levels in MEF were observed for all M. catarrhalis and S. pneumoniae antigens between OM M. catarrhalis- or S. pneumoniae-positive and OM M. catarrhalis- or S. pneumonia-negative children suffering from either rAOM or COME. Finally, results indicated a strong correlation between antigen-specific serum and MEF IgG levels. We observed no significant in vivo expressed anti-M. catarrhalis or anti-S. pneumoniae humoral immune responses using a range of putative vaccine candidate proteins. Other factors, such as Eustachian tube dysfunction, viral load, and genetic and environmental factors, may play a more important role in the pathogenesis of OM and in particular in the development of rAOM or COME.


Assuntos
Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/imunologia , Moraxella catarrhalis/imunologia , Infecções por Moraxellaceae/imunologia , Otite Média com Derrame/microbiologia , Infecções Pneumocócicas/imunologia , Streptococcus pneumoniae/imunologia , Antígenos de Superfície/imunologia , Pré-Escolar , Doença Crônica , Estudos de Coortes , Feminino , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Lactente , Recém-Nascido , Masculino , Infecções por Moraxellaceae/microbiologia , Nasofaringe/microbiologia , Otite Média com Derrame/imunologia , Infecções Pneumocócicas/microbiologia , Estudos Prospectivos , Recidiva
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