RESUMO
Nontypeable Haemophilus influenzae (NTHi) exclusively colonize and infect humans and are critical to the pathogenesis of chronic obstructive pulmonary disease (COPD). In vitro and animal models do not accurately capture the complex environments encountered by NTHi during human infection. We conducted whole-genome sequencing of 269 longitudinally collected cleared and persistent NTHi from a 15-y prospective study of adults with COPD. Genome sequences were used to elucidate the phylogeny of NTHi isolates, identify genomic changes that occur with persistence in the human airways, and evaluate the effect of selective pressure on 12 candidate vaccine antigens. Strains persisted in individuals with COPD for as long as 1,422 d. Slipped-strand mispairing, mediated by changes in simple sequence repeats in multiple genes during persistence, regulates expression of critical virulence functions, including adherence, nutrient uptake, and modification of surface molecules, and is a major mechanism for survival in the hostile environment of the human airways. A subset of strains underwent a large 400-kb inversion during persistence. NTHi does not undergo significant gene gain or loss during persistence, in contrast to other persistent respiratory tract pathogens. Amino acid sequence changes occurred in 8 of 12 candidate vaccine antigens during persistence, an observation with important implications for vaccine development. These results indicate that NTHi alters its genome during persistence by regulation of critical virulence functions primarily by slipped-strand mispairing, advancing our understanding of how a bacterial pathogen that plays a critical role in COPD adapts to survival in the human respiratory tract.
Assuntos
Evolução Molecular , Genoma Viral , Infecções por Haemophilus/epidemiologia , Haemophilus influenzae/genética , Doença Pulmonar Obstrutiva Crônica/complicações , Vacinas Virais/genética , Virulência/genética , Adulto , Sequência de Aminoácidos , Infecções por Haemophilus/virologia , Haemophilus influenzae/isolamento & purificação , Humanos , Mutação , Filogenia , Estudos Prospectivos , Sistema Respiratório/microbiologia , Vacinas Virais/imunologiaRESUMO
This study examined the phylogenetic structure of serotype a Haemophilus influenzae (Hia) isolates recovered from patients in Canada. Hia isolates from 490 separate patients and an American Type Culture Collection (ATCC) strain were analyzed by multilocus sequence typing (MLST), with 18 different sequence types (STs) identified. Most (85.7%) Hia patient isolates were typed as ST-23 and another 12.7% belonged to 14 different STs with 6, 5, or 4 MLST gene loci related to ST-23 (ST-23 complex). Core genome single-nucleotide variation phylogeny (SNVPhyl) on whole genome sequence (WGS) data of 121 Hia patient isolates representing all identified STs and the ATCC strain revealed 2 phylogenetic populations, with all the ST-23 complex isolates within 1 population. The other phylogenetic population contained only the ATCC strain and 3 patient isolates. Concatenated hitABC sequences retrieved from WGS data and analyzed by MEGA (Molecular Evolutionary Genetic Analysis) alignment confirmed the phylogeny obtained by SNVPhyl. The sodC gene was found only in isolates in the minor phylogenetic population. The 2 phylogenetic populations of the Canadian Hia isolates are similar to the 2 clonal divisions described for serotype b H. influenzae. Combining MLST, core SNVPhyl, and hitABC gene sequence alignment showed that most (99.4%) Canadian Hia patient isolates belonged to 1 major phylogenetic population.
Assuntos
Infecções por Haemophilus/virologia , Haemophilus influenzae/genética , Sequenciamento Completo do Genoma , Canadá/epidemiologia , Pré-Escolar , Evolução Molecular , Feminino , Infecções por Haemophilus/epidemiologia , Haemophilus influenzae/imunologia , Humanos , Lactente , Masculino , Tipagem de Sequências Multilocus , Filogenia , Alinhamento de Sequência , SorogrupoRESUMO
BACKGROUND: Identification and characterization of non-typeable Haemophilus influenzae (NTHi) with reduced susceptibility to ß-lactam antibiotics due to mutations in penicillin binding protein 3 (PBP3) is a clinical challenge. We analyzed a blood isolate, NTHi93-57485, that was categorized as aminopenicillin resistant but lacked key amino acid substitutions in PBP3 that have previously been associated with reduced aminopenicillin susceptibility. The significance of an alternative amino acid substitution (Y528H) in this isolate was examined. RESULTS: Site-directed mutagenesis of a ß-lactam susceptible H. influenzae (NTHi3655) was performed to introduce the Y528H substitution into wild-type ftsI (encoding for PBP3). Disc diffusion screening and broth microdilution determination of MICs for ß-lactam agents were done with the NTHi3655-PBP3Y528H mutant and were compared with the NTHi3655 wild-type as well as the original clinical isolate NTHi93-57485. Introduction of the Y528H substitution in NTHi3655 resulted in positive screening for ß-lactam resistance. MICs for aminopenicillins were increased in the mutant compared to the wild-type. However, the mutant remained susceptible to aminopenicillins according to EUCAST clinical breakpoints (assuming intravenous treatment) and the introduction of Y528H alone did not increase the resistance to the same level as NTHi93-57485. None of the isolates had frame shift insertions in the acrR gene regulating the AcrAB efflux pump. CONCLUSIONS: In parallel to the previously well-described PBP3-substitutions R517H and N526K, we demonstrate that Y528H confers reduced aminopenicillin susceptibility.
Assuntos
Substituição de Aminoácidos , Infecções por Haemophilus/virologia , Haemophilus influenzae/isolamento & purificação , Proteínas de Ligação às Penicilinas/genética , Haemophilus influenzae/efeitos dos fármacos , Haemophilus influenzae/genética , Humanos , Testes de Sensibilidade Microbiana , Mutagênese Sítio-Dirigida , Penicilinas , Proteínas Virais/genética , Resistência beta-LactâmicaRESUMO
BACKGROUND: Postweaning multisystemic wasting syndrome (PMWS) is an emerging disease in swine. Pigs with PMWS are often infected with a variety of other pathogens, including bacteria, viruses and mycoplasm, in addition to porcine circovirus type 2 (PCV2). PCV2 and Haemophilus parasuis serovar 4 (HPS4) coinfection remain epidemic in China. METHODS: Here we report construction of a three-week-old naturally farrowed, colostrum-deprived (NFCD) piglet's infection model and demonstrate that PCV2-infected piglets with the HPS4 coinfection increased the virulence of PCV2 and these pathogens interact acquired PMWS. RESULTS: All the single infected piglets were transiently bacteremic or viremic. All the PCV2/HPS4 coinfected piglets developed PMWS, characterized by dyspnea, anorexia, prostration and lose weight severely. Co-infection with PCV2 and HPS4 resulted in an increased amount of virus in serum and tissues, presented a slower generation and lower levels of antibodies against PCV2. Co-infection with PCV2 and HPS4 resulted in further reductions in total and differential peripheral blood leukocyte counts. Meantime, PCV2/ HPS4 coinfection potentiated the severity of lung and lymphoid lesions by PCV2-associated, increased the virulence of PCV2-antigen and enhanced the incidence of PMWS in piglets. CONCLUSION: Co-infection with PCV2 and HPS4 induce the exacerbation of system injuries and enhance the pathogenicity of PCV2 in piglets.
Assuntos
Circovirus/patogenicidade , Coinfecção/veterinária , Infecções por Haemophilus/veterinária , Haemophilus parasuis/fisiologia , Síndrome Definhante Multissistêmico de Suínos Desmamados/microbiologia , Síndrome Definhante Multissistêmico de Suínos Desmamados/virologia , Virulência/fisiologia , Animais , Anticorpos Antivirais/sangue , China , Coinfecção/microbiologia , Coinfecção/patologia , Coinfecção/virologia , DNA Viral/sangue , Infecções por Haemophilus/patologia , Infecções por Haemophilus/virologia , Contagem de Leucócitos/veterinária , Reação em Cadeia da Polimerase/veterinária , Síndrome Definhante Multissistêmico de Suínos Desmamados/patologia , SuínosRESUMO
Porcine reproductive and respiratory syndrome (PRRS) is one of the most significant and economically important infectious diseases affecting swine worldwide and can predispose pigs to secondary bacterial infections caused by, e.g. Haemophilus parasuis. The aim of the presented study was to compare susceptibility of two different types of macrophages which could be in contact with both pathogens during infection with PRRS virus (PRRSV) and in co-infection with H. parasuis. Alveolar macrophages (PAMs) as resident cells provide one of the first lines of defence against microbes invading lung tissue. On the other hand, monocyte derived macrophages (MDMs) represent inflammatory cells accumulating at the site of inflammation. While PAMs were relatively resistant to cytopathogenic effect caused by PRRSV, MDMs were much more sensitive to PRRSV infection. MDMs infected with PRRSV increased expression of pro-apoptotic Bad, Bax and p53 mRNA. Increased mortality of MDMs may be also related to a higher intensity of ROS production after infection with PRRSV. In addition, MDMs (but not PAMs) infected with H. parasuis alone formed multinucleated giant cells (MGC); these cells were not observed in MDMs infected with both pathogens. Higher sensitivity of MDMs to PRRSV infection, which is associated with limited MDMs survival and restriction of MGC formation, could contribute to the development of multifactorial respiratory disease of swine.
Assuntos
Coinfecção/veterinária , Células Gigantes/virologia , Infecções por Haemophilus/veterinária , Haemophilus parasuis , Macrófagos/virologia , Síndrome Respiratória e Reprodutiva Suína/virologia , Vírus da Síndrome Respiratória e Reprodutiva Suína , Animais , Coinfecção/metabolismo , Coinfecção/patologia , Células Gigantes/metabolismo , Células Gigantes/patologia , Infecções por Haemophilus/complicações , Infecções por Haemophilus/patologia , Infecções por Haemophilus/virologia , Macrófagos/metabolismo , Macrófagos/patologia , Síndrome Respiratória e Reprodutiva Suína/metabolismo , Síndrome Respiratória e Reprodutiva Suína/patologia , Pirimidinas , Espécies Reativas de Oxigênio/metabolismo , Sulfonamidas , SuínosRESUMO
BACKGROUND: Coinfections by Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi) are frequently implicated in complex otitis media. Whereas upper respiratory tract carriage precedes disease for both pathogens, interactions between species in cocolonized hosts are poorly understood. We compared colonization densities and the diversity and fitness of pneumococcal serotypes in single-species and mixed-species colonization. METHODS: We analyzed nasopharyngeal pneumococcal carriage and nasopharyngeal and oropharyngeal NTHi carriage in 13 541 samples collected over 6909 study visits from 769 children 2-30 months old in a 7-valent pneumococcal conjugate vaccine dosing trial. We measured density associations between the species and compared pneumococcal serotype diversity during and in the absence of NTHi colonization. We used logistic regression to quantify associations between NTHi colonization and previously published pneumococcal serotype factors related to fitness. RESULTS: Densities of the 2 species were positively associated when they co-occur in the nasopharynx. NTHi colonization was associated with reduced pneumococcal serotype diversity among children 2-18 months old and was more prevalent among children carrying pneumococcal serotypes with greater capsular thickness, neutrophil resistance, and metabolic efficiency. CONCLUSIONS: Pneumococcal-NTHi cocolonization is associated with an elevated density of both species and with reduced diversity and increased fitness of pneumococcal serotypes. NTHi colonization may create a selective environment favoring pneumococci with immune-evasive phenotypes.
Assuntos
Coinfecção/microbiologia , Coinfecção/virologia , Haemophilus influenzae/crescimento & desenvolvimento , Infecções Respiratórias/microbiologia , Infecções Respiratórias/virologia , Streptococcus pneumoniae/crescimento & desenvolvimento , Portador Sadio/imunologia , Portador Sadio/microbiologia , Portador Sadio/virologia , Pré-Escolar , Coinfecção/imunologia , Feminino , Infecções por Haemophilus/imunologia , Infecções por Haemophilus/microbiologia , Infecções por Haemophilus/virologia , Haemophilus influenzae/imunologia , Humanos , Lactente , Masculino , Nasofaringe/imunologia , Nasofaringe/microbiologia , Nasofaringe/virologia , Orofaringe/imunologia , Orofaringe/microbiologia , Orofaringe/virologia , Otite Média/imunologia , Otite Média/microbiologia , Otite Média/virologia , Infecções Pneumocócicas/imunologia , Infecções Pneumocócicas/microbiologia , Infecções Pneumocócicas/virologia , Vacinas Pneumocócicas/imunologia , Infecções Respiratórias/imunologia , Sorogrupo , Streptococcus pneumoniae/imunologia , Vacinas Conjugadas/imunologiaRESUMO
Phosphorylcholine (ChoP) decoration of lipopolysaccharides is an important virulence strategy adopted by Haemophilus influenzae to establish a niche on the mucosal surface and to promote adherence to the host cells. The incorporation of ChoP on the LPS surface involves the lic1 operon, which consists of the licA, licB, licC, and licD genes. Among which, licB is a choline transporter gene required for acquisition of choline from environmental sources. In this study, we investigated the pathogenesis of the licB gene in an aged mice infection model. Due to immediate clearance of H. influenzae upon infection in mice, we employed influenza A virus and H. influenzae co-infection model. Our data showed that in the co-infection model, the secondary bacterial infection with a very low H. influenzae concentration of 100 colony forming unit is lethal to the aged mice. Although we did not observe any differences in weight loss between parent and licB mutant strains during the course of infection, a significant reduction of lung tissue damage was observed in the licB mutant infected aged mice. These results suggest that the licB gene is a virulence factor during H. influenzae infection in the lung in aged mice, possibly due to the increased binding to the host cell receptor via ChoP expression on the bacterial surface. In addition, when aged mice and mature mice were compared in the challenge experiments, we did not observe any protective immunity in the co-infection model suggesting the detrimental effects of the secondary bacterial infection on the aged mice in contrast to obvious immune-protections observed in the mature mice. The results of our experiments also implied that the co-infection model with influenza A virus and H. influenzae may be employed as a model system to study H. influenzae pathogenesis in vivo in aged mice.
Assuntos
Coinfecção/microbiologia , Infecções por Haemophilus/microbiologia , Haemophilus influenzae/genética , Vírus da Influenza A/isolamento & purificação , Pulmão/patologia , Proteínas de Membrana Transportadoras/genética , Infecções por Orthomyxoviridae/microbiologia , Fatores Etários , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/metabolismo , Colina/metabolismo , Coinfecção/metabolismo , Coinfecção/patologia , Coinfecção/virologia , Modelos Animais de Doenças , Infecções por Haemophilus/metabolismo , Infecções por Haemophilus/virologia , Haemophilus influenzae/metabolismo , Haemophilus influenzae/patogenicidade , Vírus da Influenza A/genética , Vírus da Influenza A/patogenicidade , Lipopolissacarídeos/metabolismo , Pulmão/microbiologia , Pulmão/virologia , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Mutação , Infecções por Orthomyxoviridae/metabolismo , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/virologia , Fosforilcolina/metabolismo , Fator de Transcrição CHOP/metabolismo , VirulênciaRESUMO
Nontypeable Haemophilus influenzae (NTHI) strains are responsible for respiratory-related infections which cause a significant burden of disease in Australian children. We previously identified a disparity in NTHI culture-defined carriage rates between Aboriginal and non-Aboriginal children (42% versus 11%). The aim of this study was to use molecular techniques to accurately determine the true NTHI carriage rates (excluding other culture-identical Haemophilus spp.) and assess whether the NTHI strain diversity correlates with the disparity in NTHI carriage rates. NTHI isolates were cultured from 595 nasopharyngeal aspirates collected longitudinally from asymptomatic Aboriginal (n=81) and non-Aboriginal (n=76) children aged 0 to 2 years living in the Kalgoorlie-Boulder region, Western Australia. NTHI-specific 16S rRNA gene PCR and PCR ribotyping were conducted on these isolates. Confirmation of NTHI by 16S rRNA gene PCR corrected the NTHI carriage rates from 42% to 36% in Aboriginal children and from 11% to 9% in non-Aboriginal children. A total of 75 different NTHI ribotypes were identified, with 51% unique to Aboriginal children and 13% unique to non-Aboriginal children (P<0.0001). The strain richness (proportion of different NTHI ribotypes) was similar for Aboriginal (19%, 65/346) and non-Aboriginal children (19%, 37/192) (P=0.909). Persistent carriage of the same ribotype was rare in the two groups, but colonization with multiple NTHI strains was more common in Aboriginal children than in non-Aboriginal children. True NTHI carriage was less than that estimated by culture. The Aboriginal children were more likely to carry unique and multiple NTHI strains, which may contribute to the chronicity of NTHI colonization and subsequent disease.
Assuntos
Infecções por Haemophilus/virologia , Haemophilus influenzae/genética , Pré-Escolar , Humanos , Lactente , Recém-Nascido , Nasofaringe/virologia , Reação em Cadeia da Polimerase/métodos , RNA Ribossômico 16S/genética , Infecções Respiratórias/virologia , Austrália OcidentalRESUMO
BACKGROUND: Recently, necrotizing fasciitis has been reported in patients treated with bevacizumab, usually secondary to wound healing complications, gastrointestinal perforations, or fistula formation. The risk of invasive Haemophilus influenzae type b infection is significantly increased in immunocompromised hosts. However, necrotizing fasciitis due to Haemophilus influenzae type b in a patient treated with combined bevacizumab and chemotherapy has not been previously reported. CASE PRESENTATION: A 59-year-old woman was admitted to the intensive care unit after sudden onset of fever, chills, and right thigh pain. She received chemotherapy with fluorouracil, irinotecan, and bevacizumab for colon cancer 10 days prior to admission. The advancing erythematous margin and her worsening clinical condition prompted us to suspect necrotizing fasciitis and consult the orthopedics department for a fascia biopsy and debridement. Surgical exploration revealed a murky dishwater-colored pus exudate from the incision site and the lack of a shiny appearance of the fascia that also suggested necrotizing fasciitis. After 2 days, the final results of the blood and exudate cultures confirmed the presence of Haemophilus influenzae type b. A diagnosis of necrotizing fasciitis due to Haemophilus influenzae type b was made. The patient required recurrent surgical debridement and drainage, but she recovered from the septic shock. CONCLUSIONS: We report a case of necrotizing fasciitis due to Haemophilus influenzae type b in a patient without injury and with rectal cancer treated with combined bevacizumab and chemotherapy. Physicians should consider invasive Haemophilus influenzae type b disease in the presence of necrotizing fasciitis in patients treated with this combined treatment modality.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Fasciite Necrosante/virologia , Infecções por Haemophilus/virologia , Haemophilus influenzae tipo b/isolamento & purificação , Neoplasias Retais/tratamento farmacológico , Neoplasias Retais/virologia , Anticorpos Monoclonais Humanizados/administração & dosagem , Bevacizumab , Feminino , Humanos , Pessoa de Meia-Idade , Choque Séptico/virologiaRESUMO
Gammaherpesviruses are ubiquitous, lifelong pathogens associated with multiple cancers that infect over 95% of the adult population. Increases in viral reactivation, due to stress and other unknown factors impacting the immune response, frequently precedes lymphomagenesis. One potential stressor that could promote viral reactivation and increase viral latency would be the myriad of infections from bacterial and viral pathogens that we experience throughout our lives. Using murine gammaherpesvirus 68 (MHV68), a mouse model of gammaherpesvirus infection, we examined the impact of bacterial challenge on gammaherpesvirus infection. We challenged MHV68 infected mice during the establishment of latency with nontypeable Haemophilus influenzae (NTHi) to determine the impact of bacterial infection on viral reactivation and latency. Mice infected with MHV68 and then challenged with NTHi, saw increases in viral reactivation and viral latency. These data support the hypothesis that bacterial challenge can promote gammaherpesvirus reactivation and latency establishment, with possible consequences for viral lymphomagenesis.
Assuntos
Infecções por Haemophilus , Haemophilus influenzae , Infecções por Herpesviridae , Ativação Viral , Latência Viral , Animais , Haemophilus influenzae/fisiologia , Camundongos , Infecções por Herpesviridae/virologia , Infecções por Haemophilus/microbiologia , Infecções por Haemophilus/virologia , Gammaherpesvirinae/fisiologia , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , Rhadinovirus/fisiologia , FemininoRESUMO
BACKGROUND: The introduction of the Haemophilus influenzae serotype b (Hib) conjugate vaccine into national immunization has led to rapid and sustained declines in invasive Hib disease incidence across all age groups. In industrialized countries with established Hib vaccination programs, however, little is known about individuals who develop invasive Hib disease. This study describes the epidemiology of invasive Hib disease in England and Wales during 2000-2012 and the clinical characteristics of laboratory-confirmed Hib cases diagnosed during 2009-2012. METHODS: Public Health England (PHE) conducts enhanced national surveillance of invasive Hib disease in England and Wales. Detailed clinical information was obtained for all laboratory-confirmed Hib cases diagnosed during 2009-2012. RESULTS: Invasive Hib disease in England and Wales has been declining since 2002, reaching its lowest incidence of 0.02 per 100 000 (14 cases) in 2012. In children aged <5 years of age, Hib incidence was 0.06 per 100 000 (2 cases), compared with 35.5 per 100 000 prior to routine Hib vaccination. Follow-up of all 106 case patients over the 4-year period revealed that most cases occurred in adults (73%) who often had preexisting medical conditions (77%) and presented with pneumonia (56%). The Hib-associated case fatality rate was 9.4% (10/106 cases). CONCLUSIONS: Control of Hib disease in England and Wales is currently the best that has been achieved since the introduction of routine Hib vaccination in 1992. Invasive Hib disease is no longer a major cause of acute bacterial meningitis in children but, instead, cases are more likely to present as pneumonia in older adults with comorbidities, similar to the less virulent nonencapsulated H. influenzae.
Assuntos
Infecções por Haemophilus/epidemiologia , Vacinas Anti-Haemophilus/administração & dosagem , Haemophilus influenzae tipo b/isolamento & purificação , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Inglaterra/epidemiologia , Feminino , Infecções por Haemophilus/prevenção & controle , Infecções por Haemophilus/virologia , Haemophilus influenzae tipo b/imunologia , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Vigilância em Saúde Pública , País de Gales/epidemiologia , Adulto JovemRESUMO
The introduction of the Haemophilus influenzae type b vaccine in the immunization programs of many countries has greatly reduced this invasive disease and the carriage caused by this serotype, also increasing other capsular types and non-capsular isolations. There were 313 isolations of H. influenzae under study, which were recovered from a sterile site coming from pediatric and adult patients carrying the invasive disease. Patients were treated at 90 different hospitals belonging to the Red Nacional de Laboratorios para Meningitis e Infecciones Respiratorias Agudas Bacterianas (National Lab Network for Meningitis and Acute Bacterial Respiratory Infections) from 2005 to 2010 for the following disorders: pneumonia, 40.3% (n=126), meningitis, 30.0% (n=94) and bacteremia, 26.5% (n=83). In pediatric patients (n=279), the highest frequency of isolations corresponded to children under the age of 2 years, 74.5% (n=208). Regarding type distribution, 61.3% corresponded to non-capsular H. influenzae (n=192), 20.1% to type b (n=63), 11.2% to type a (n=35), 4.8% to type f, and 2.6% to other types. Capsular H. influenzae was predominant in meningitis whereas non-capsular H. influenzae in pneumonia and bacteremia. The biotype was determined in 306 isolations. The totality (100%) of type a (n=35) was biotype II whereas 66.7% of type b (n=63) was biotype I. Slide agglutination and PCR tests were used in 220 isolations. There was a match of 0.982 (IC: 0.92-1.00) between them. During the last year, there was a great increase in type b, showing the importance of clinical and laboratory-based surveillance of the invasive disease caused by H. influenzae.
Assuntos
Infecções por Haemophilus/prevenção & controle , Infecções por Haemophilus/virologia , Vacinas Anti-Haemophilus , Haemophilus influenzae tipo b/classificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Argentina , Criança , Pré-Escolar , Monitoramento Epidemiológico , Feminino , Haemophilus influenzae tipo b/isolamento & purificação , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Sorotipagem , Fatores de Tempo , Vacinas Conjugadas , Adulto JovemRESUMO
Secondary bacterial infections that follow infection with influenza virus result in considerable morbidity and mortality in young children, the elderly, and immunocompromised individuals and may also significantly increase mortality in normal healthy adults during influenza pandemics. We herein describe a mouse model for investigating the interaction between influenza virus and the bacterium Haemophilus influenzae. Sequential infection with sublethal doses of influenza and H. influenzae resulted in synergy between the two pathogens and caused mortality in immunocompetent adult wild-type mice. Lethality was dependent on the interval between administration of the bacteria and virus, and bacterial growth was prolonged in the lungs of dual-infected mice, although influenza virus titers were unaffected. Dual infection induced severe damage to the airway epithelium and confluent pneumonia, similar to that observed in victims of the 1918 global influenza pandemic. Increased bronchial epithelial cell death was observed as early as 1 day after bacterial inoculation in the dual-infected mice. Studies using knockout mice indicated that lethality occurs via a mechanism that is not dependent on Fas, CCR2, CXCR3, interleukin-6, tumor necrosis factor, or Toll-like receptor-4 and does not require T or B cells. This model suggests that infection with virulent strains of influenza may predispose even immunocompetent individuals to severe illness on secondary infection with H. influenzae by a mechanism that involves innate immunity, but does not require tumor necrosis factor, interleukin-6, or signaling via Toll-like receptor-4.
Assuntos
Modelos Animais de Doenças , Infecções por Haemophilus/mortalidade , Haemophilus influenzae/fisiologia , Vírus da Influenza A/fisiologia , Infecções por Orthomyxoviridae/mortalidade , Imunidade Adaptativa/fisiologia , Animais , Células Cultivadas , Cães , Infecções por Haemophilus/complicações , Infecções por Haemophilus/patologia , Infecções por Haemophilus/virologia , Humanos , Pulmão/patologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Infecções por Orthomyxoviridae/complicações , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/virologia , Superinfecção/imunologia , Superinfecção/mortalidade , Superinfecção/patologia , Superinfecção/virologia , Carga ViralRESUMO
Bacterial coinfection occurs in pediatric bronchopulmonary infections caused by respiratory syncytial virus (RSV), but the incidence is uncertain. Our subjects are 188 pediatric inpatients having RSV bronchopulmonary infection in two hospitals in Chiba Prefecture between 2005 and 2007. On admission, antigen detection kits using nasopharyngeal aspirate were performed to detect RSV infection and washed sputum bacterial culture was performed to detect bacterial infection. Of the 188 pediatric inpatients with RSV bronchopulmonary infection, 95 (50.5%) patients were aged less than 1 year, 57 (30.3%) were aged 1-2 years, and 36 (19.1%) were aged 2 years or more. Thirty-six (19.1%) patients were associated with bronchial asthma attacks. Pathogenic bacteria were predominantly isolated from 43.6% of the patients. The three most frequently isolated bacteria were Haemophilus influenzae (43.9%), Streptococcus pneumoniae (36.6%), and Moraxella catarrhalis (29.3%). We found that 38.9% of H. influenzae strains were ß-lactamase-nonproducing ampicillin-resistant strains. All S. pneumoniae strains were penicillin G (PcG) sensitive. However, 21.9% of S. pneumoniae strains showed PcG minimum inhibitory concentration values of 2 µg/ml. RSV bronchopulmonary infections in hospitalized children are often associated with antimicrobial-resistant bacterial infection in their lower airways. These results indicate that we should be aware of bacterial coinfections in the management of pediatric inpatients with RSV bronchopulmonary infection.
Assuntos
Infecções por Haemophilus/epidemiologia , Pneumopatias/epidemiologia , Infecções Pneumocócicas/epidemiologia , Infecções por Vírus Respiratório Sincicial/epidemiologia , Antibacterianos/farmacologia , Pré-Escolar , Estudos de Coortes , Infecções por Haemophilus/microbiologia , Infecções por Haemophilus/virologia , Haemophilus influenzae/efeitos dos fármacos , Humanos , Lactente , Recém-Nascido , Japão/epidemiologia , Pneumopatias/microbiologia , Pneumopatias/virologia , Testes de Sensibilidade Microbiana , Infecções Pneumocócicas/microbiologia , Infecções Pneumocócicas/virologia , Infecções por Vírus Respiratório Sincicial/complicações , Infecções por Vírus Respiratório Sincicial/microbiologia , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano , Escarro/microbiologia , Escarro/virologia , Streptococcus pneumoniaeAssuntos
Educação Médica Continuada , Vacinas Anti-Haemophilus/uso terapêutico , Haemophilus influenzae/patogenicidade , Estudos Transversais , Infecções por Haemophilus/imunologia , Infecções por Haemophilus/patologia , Infecções por Haemophilus/virologia , Vacinas Anti-Haemophilus/imunologia , Haemophilus influenzae/imunologia , Haemophilus influenzae/virologia , HumanosRESUMO
Haemophilus parasuis is the etiological agent of Glässer's disease in swine, which associates with severe economic losses in the swine industry worldwide. A real-time recombinase polymerase amplification assay (real-time RPA) was developed for direct and rapid detection of H. parasuis basing on the translation-initiation factor IF2 (infB) gene. The assay was performed successfully at 39°C for 20 min in Genie III, which is portable and chargeable by battery. The developed assay was highly specific for H. parasuis, and the limit of detection of the assay was 6.0 × 103 fg of H. parasuis genomic DNA, which was the same as that of a real-time PCR developed previously. The assay was further evaluated on 68 pig tissue samples, and 18 (26.5%), 20 (29.4%), and 8 (11.8%) samples were positive for H. parasuis by the real-time RPA, real-time PCR and bacterial isolation, respectively. With the bacteria isolation as the reference method, the real-time RPA showed a diagnostic specificity of 83.33% and a diagnostic sensitivity of 100%. The above data demonstrated the well-potentiality and usefulness of the developed real-time RPA assay in reliable diagnosis of swine Glässer's disease, especially in resource limited settings.
Assuntos
Infecções por Haemophilus/veterinária , Haemophilus parasuis/isolamento & purificação , Técnicas de Amplificação de Ácido Nucleico/veterinária , Doenças dos Suínos/diagnóstico , Animais , Infecções por Haemophilus/diagnóstico , Infecções por Haemophilus/virologia , Haemophilus parasuis/enzimologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Recombinases/análise , Sus scrofa , Suínos , Doenças dos Suínos/virologiaRESUMO
In 2017, the Turlock branch of the California Animal Health & Food Safety laboratory system received a significant increase in infectious coryza (IC) necropsy cases, with a total of 54 submissions originating from commercial broilers (n = 40), commercial layers (n = 11), and backyard chickens (n = 3). Layer flocks positive for IC were distributed within the adjacent counties of Merced and Stanislaus, while broiler flocks were concentrated within Merced County. The backyard flocks were located in Alameda and Sacramento counties. The clinical and pathologic presentation was consistent with IC, although septicemic lesions were also noticed. Avibacterium paragallinarum was isolated and identified by PCR from the respiratory tract as well as from extrarespiratory sites. Polymicrobial infections involving other viral (infectious bronchitis virus, infectious bursal disease virus) and bacterial (Mycoplasma spp., Escherichia coli, Ornithobacterium rhinotracheale, Gallibacterium anatis biovar haemolytica) agents were commonly reported. Thirteen selected Av. paragallinarum isolates were successfully characterized as serovar C (Page scheme) and serovar C2 (Kume scheme). They shared a unique enterobacterial repetitive intergenic consensus (ERIC) PCR, differing from the four reference strains, and showed consistent high minimum inhibitory concentration values for tetracycline, suggesting a common origin from a single clone. Based on these results, high biosecurity standards and proper immunization of susceptible, multi-age flocks should always be implemented and adjusted as needed. The importance of backyard flocks should not be underestimated due to their unique epidemiologic role.
Caracterización de un brote de coriza infecciosa (Avibacterium paragallinarum) en pollos comerciales en la parte central de California. En el año 2017, la sede en Turlock del Sistema de Laboratorios de Salud Animal y Seguridad Alimentaria de California recibió un aumento significativo en el número de casos de necropsia por coriza infecciosa, con un total de 54 casos, incluyendo casos provenientes de pollos de engorde comerciales (n = 40), gallinas de postura comerciales (n = 11) y aves de traspatio (n = 3). Las parvadas de gallinas de postura positivas para coriza infecciosa se distribuyeron en los condados adyacentes de Merced y Stanislaus, mientras que las parvadas de pollos de engorde se concentraron en el condado de Merced. Las parvadas de traspatio estaban ubicadas en los condados de Alameda y Sacramento. La presentación clínica y patológica fue consistente con coriza infecciosa, aunque también se observaron lesiones septicémicas. Se aisló Avibacterium paragallinarum y se identificó mediante PCR en el tracto respiratorio y también de sitios extrarespiratorios. Las infecciones polimicrobianas relacionadas con otros virus (virus de la bronquitis infecciosa, virus de la enfermedad infecciosa de la bolsa) y bacterias (Mycoplasma spp., Escherichia coli, Ornithobacterium rhinotracheale, Gallibacterium anatis biovar haemolytica) fueron reportadas comúnmente. Trece aislamientos seleccionados de A. paragalinarum se caracterizaron con éxito como serovar C (esquema de Page) y serovar C2 (esquema de Kume). Estos aislamientos Compartieron por PCR un consenso intergénico repetitivo enterobacterial (ERIC) único, que difiere de las cuatro cepas de referencia y mostraron valores constantes de concentración mínima inhibitoria alta para tetraciclina, lo que sugiere un origen común de un solo clon. Con base en estos resultados, siempre se deben implementar y ajustar estándares de bioseguridad altos y la inmunización adecuada de parvadas susceptibles de edades múltiples, según sea necesario. La importancia de las parvadas de traspatio no debe subestimarse debido a su función epidemiológica especial.
Assuntos
Galinhas , Surtos de Doenças/veterinária , Infecções por Haemophilus/veterinária , Haemophilus paragallinarum/fisiologia , Doenças das Aves Domésticas/epidemiologia , Animais , Antibacterianos/administração & dosagem , California/epidemiologia , Coinfecção/microbiologia , Coinfecção/veterinária , Infecções por Haemophilus/epidemiologia , Infecções por Haemophilus/virologia , Testes de Sensibilidade Microbiana/veterinária , Doenças das Aves Domésticas/virologiaRESUMO
Haemophilus influenzae is genetically diverse and exists as a near-ubiquitous human commensal or as a pathogen. Invasive type b disease has been almost eliminated in developed countries; however, unencapsulated strains - nontypeable H. influenzae (NTHi) - remain important as causes of respiratory infections. Respiratory tract disease occurs when NTHi adhere to or invade respiratory epithelial cells, initiating one or more of several proinflammatory pathways. Biofilm formation explains many of the observations seen in chronic otitis media and chronic bronchitis. However, NTHi biofilms seem to lack a biofilm-specific polysaccharide in the extracellular matrix, a source of controversy regarding their relevance. Successful commensalism requires dampening of the inflammatory response and evasion of host defenses, accomplished in part through phase variation.
Assuntos
Haemophilus influenzae/crescimento & desenvolvimento , Haemophilus influenzae/patogenicidade , Adesinas Bacterianas/metabolismo , Animais , Aderência Bacteriana , Biofilmes/crescimento & desenvolvimento , Infecções por Haemophilus/virologia , Haemophilus influenzae/classificação , Haemophilus influenzae/genética , Humanos , Inflamação , Camundongos , Camundongos SCID , Sistema Respiratório/citologia , Sistema Respiratório/microbiologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/fisiopatologia , VirulênciaRESUMO
The blood-brain barrier (BBB) is mainly made up of tightly connected microvascular endothelial cells (BMECs), surrounded by pericytes (BMPCs) which regulate BBB tightness by providing soluble factors that control endothelial proliferation. Haemophilus influenzae type a (Hia) is able to reach the BBB, crossing it, thus causing meningitis. In this study, by using an in vitro model of BBB, performed with human BMECs and human BMPCs in co-culture, we demonstrated that, after Hia infection, the number of hBMPCs decreased whereas the number of hBMECs increased in comparison with non-infected cells. SEM and TEM images showed that Hia was able to enter hBMECs and reduce TEER and VE-cadherin expression. When the cells were infected in presence of SCH58261 and PSB603 but not DPCPX, an increase in TEER values was observed thus demonstrating that A2A and A2B adenosine receptors play a key role in BBB dysfunction. These results were confirmed by the use of adenosine receptor agonists CGS21680, CCPA, and NECA. In infected co-cultures cAMP and VEGF increased and TEER reduction was counter-balanced by VEGF-R1 or VEGF-R2 antibodies. Moreover, the phosphorylated CREB and Rho-A significantly increased in infected hBMECs and hBMPCs and the presence of SCH58261 and PSB603 significantly abrogated the phosphorylation. In conclusion, this study demonstrated that the infection stimulated A2A and A2B adenosine receptors in hBMECs and hBMPCs thus inducing the pericytes to release large amounts of VEGF. The latter could be responsible for both, pericyte detachment and endothelial cell proliferation, thus provoking BBB impairment.
Assuntos
Barreira Hematoencefálica/metabolismo , Infecções por Haemophilus/metabolismo , Infecções por Haemophilus/virologia , Haemophilus influenzae/fisiologia , Receptor A2A de Adenosina/metabolismo , Receptor A2B de Adenosina/metabolismo , Barreira Hematoencefálica/patologia , Barreira Hematoencefálica/ultraestrutura , Caderinas/metabolismo , Contagem de Células , Técnicas de Cocultura , AMP Cíclico/biossíntese , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Impedância Elétrica , Células Endoteliais/metabolismo , Células Endoteliais/ultraestrutura , Haemophilus influenzae/ultraestrutura , Humanos , Microvasos/patologia , Pericitos/metabolismo , Fosforilação , Fator A de Crescimento do Endotélio Vascular/metabolismo , Proteínas rho de Ligação ao GTP/metabolismoRESUMO
We determined the genotypes of 95 invasive Haemophilus influenzae type b (Hib) strains collected before and after introduction of widespread Hib vaccination in Italy. No substantial change in genetic diversity was highlighted by pulsed-field gel electrophoresis. However, an upward temporal trend in proportion of strains possessing multiple copies of the capsulation b locus was detected (P = .03).