Chlamydia muridarum lung infection in infants alters hematopoietic cells to promote allergic airway disease in mice

Background Viral and bacterial respiratory tract infections in early-life are linked to the development of allergic airway inflammation and asthma. However, the mechanisms involved are not well understood. We have previously shown that neonatal and infant, but not adult, chlamydial lung infections in mice permanently alter inflammatory phenotype and physiology to increase the severity of allergic airway disease by increasing lung interleukin (IL)-13 expression, mucus hyper-secretion and airway hyper-responsiveness. This occurred through different mechanisms with infection at different ages. Neonatal infection suppressed inflammatory responses but enhanced systemic dendritic cell:T-cell IL-13 release and induced permanent alterations in lung structure (i.e., increased the size of alveoli). Infant infection enhanced inflammatory responses but had no effect on lung structure. Here we investigated the role of hematopoietic cells in these processes using bone marrow chimera studies. Methodology/Principal Findings Neonatal (<24-hours-old), infant (3-weeks-old) and adult (6-weeks-old) mice were infected with C. muridarum. Nine weeks after infection bone marrow was collected and transferred into recipient age-matched irradiated naïve mice. Allergic airway disease was induced (8 weeks after adoptive transfer) by sensitization and challenge with ovalbumin. Reconstitution of irradiated naïve mice with bone marrow from mice infected as neonates resulted in the suppression of the hallmark features of allergic airway disease including mucus hyper-secretion and airway hyper-responsiveness, which was associated with decreased IL-13 levels in the lung. In stark contrast, reconstitution with bone marrow from mice infected as infants increased the severity of allergic airway disease by increasing T helper type-2 cell cytokine release (IL-5 and IL-13), mucus hyper-secretion, airway hyper-responsiveness and IL-13 levels in the lung. Reconstitution with bone marrow from infected adult mice had no effects. Conclusions These results suggest that an infant chlamydial lung infection results in long lasting alterations in hematopoietic cells that increases the severity of allergic airway disease in later-life.

Ureaplasma parvum serovar 3 multiple banded antigen size variation after chronic intra-amniotic infection/colonization

Ureaplasma species are the microorganisms most frequently associated with adverse pregnancy outcomes. The multiple banded antigen (MBA), a surface-exposed lipoprotein, is a key virulence factor of ureaplasmas. The MBA demonstrates size variation, which we have shown previously to be correlated with the severity of chorioamnion inflammation. We aimed to investigate U. parvum serovar 3 pathogenesis in vivo, using a sheep model, by investigating: MBA variation after long term (chronic) and short term (acute) durations of in utero ureaplasma infections, and the severity of chorioamnionitis and inflammation in other fetal tissues. Inocula of 2x107 colony-forming-units (CFU) of U. parvum serovar 3 (Up) or media controls (C) were injected intra-amniotically into pregnant ewes at one of three time points: day 55 (69d Up, n=8; C69, n=4); day 117 (7d Up, n=8; C7, n=2); and day 121 (3d Up, n=8; C3, n=2) of gestation (term=145-150d). At day 124, preterm fetuses were delivered surgically. Samples of chorioamnion, fetal lung, and umbilical cord were: (i) snap frozen for subsequent ureaplasma culture, and (ii) fixed, embedded, sectioned and stained by haematoxylin and eosin stain for histological analysis. Selected fetal lung clinical ureaplasma isolates were cloned and filtered to obtain cultures from a single CFU. Passage 1 and clone 2 ureaplasma cultures were tested by western blot to demonstrate MBA variation. In acute durations of ureaplasma infection no MBA variants (3d Up) or very few MBA variants (7d Up) were present when compared to the original inoculum. However, numerous MBA size variants were generated in vivo (alike within contiguous tissues, amniotic fluid and fetal lung, but different variants were present within chorioamnion), during chronic, 69d exposure to ureaplasma infection. For the first time we have shown that the degree of ureaplasma MBA variation in vivo increased with the duration of gestation.

Mid-gestation intra-amniotic infection with Ureaplasma parvum is resolved within spiny mice (Acomys cahirinus) by term delivery: but caused chronic infection of fetal lungs and placentae

Background: Ureaplasma species in amniotic fluid at the time of second-trimester amniocentesis increases the risk of preterm birth, but most affected pregnancies continue to term (Gerber et al. J Infect Dis 2003). We aimed to model intra-amniotic (IA) ureaplasma infection in spiny mice, a species with a relatively long gestation (39 days) that allows investigation of the disposition and possible clearance of ureaplasmas in the feto-placental compartment. Method: Pregnant spiny mice received IA injections of U. parvum serovar 6 (10µL, 1x104 colony-forming-units in PBS) or 10B media (10µL; control) at 20 days (d) of gestation (term=39d). At 37d fetuses (n=3 ureaplasma, n=4 control) were surgically delivered and tissues were collected for; bacterial culture, ureaplasma mba and urease gene expression by PCR, tissue WBC counts and indirect fluorescent antibody (IFA) staining using anti-ureaplasma serovar 6 (rabbit) antiserum. Maternal and fetal plasma IgG was measured by Western blot. Results: Ureaplasmas were not detected by culture or PCR in fetal or maternal tissues but were visualized by IFA within placental and fetal lung tissues, in association with inflammatory changes and elevated WBC counts (p<0.0001). Anti-ureaplasma IgG was detected in maternal (2/2 tested) and fetal (1/2 tested) plasma but not in controls (0/3). Conclusions: IA injection of ureaplasmas in mid-gestation spiny mice caused persistent fetal lung and placental infection even though ureaplasmas were undetectable using standard culture or PCR techniques. This is consistent with resolution of IA infection, which may occur in human pregnancies that continue to term despite detection of ureaplasmas in mid-gestation.

Comparison of intranasal and transcutaneous immunization for induction of protective immunity against chlamydia muridarum respiratory tract infection

Chlamydia pneumoniae causes a range of respiratory infections including bronchitis, pharyngitis and pneumonia. Infection has also been implicated in exacerbation/initiation of asthma and chronic obstructive pulmonary disease (COPD) and may play a role in atherosclerosis and Alzheimer's disease. We have used a mouse model of Chlamydia respiratory infection to determine the effectiveness of intranasal (IN) and transcutaneous immunization (TCI) to prevent Chlamydia lung infection. Female BALB/c mice were immunized with chlamydial major outer membrane protein (MOMP) mixed with cholera toxin and CpG oligodeoxynucleotide adjuvants by either the IN or TCI routes. Serum and bronchoalveolar lavage (BAL) were collected for antibody analysis. Mononuclear cells from lung-draining lymph nodes were stimulated in vitro with MOMP and cytokine mRNA production determined by real time PCR. Animals were challenged with live Chlamydia and weighed daily following challenge. At day 10 (the peak of infection) animals were sacrificed and the numbers of recoverable Chlamydia in lungs determined by real time PCR. MOMP-specific antibody-secreting cells in lung tissues were also determined at day 10 post-infection. Both IN and TCI protected animals against weight loss compared to non-immunized controls with both immunized groups gaining weight by day 10-post challenge while controls had lost 6% of body weight. Both immunization protocols induced MOMP-specific IgG in serum and BAL while only IN immunization induced MOMP-specific IgA in BAL. Both immunization routes resulted in high numbers of MOMP-specific antibody-secreting cells in lung tissues (IN > TCI). Following in vitro re-stimulation of lung-draining lymph node cells with MOMP; IFNγ mRNA increased 20-fold in cells from IN immunized animals (compared to non-immunized controls) while IFNγ levels increased 6- to 7-fold in TCI animals. Ten days post challenge non-immunized animals had >7000 IFU in their lungs, IN immunized animals <50 IFU and TCI immunized animals <1500 IFU. Thus, both intranasal and transcutaneous immunization protected mice against respiratory challenge with Chlamydia. The best protection was obtained following IN immunization and correlated with IFNγ production by mononuclear cells in lung-draining LN and MOMP-specific IgA in BAL.

The role of inflammation in the pathogenesis of non-small cell lung cancer

The link between chronic immune activation and tumorigenesis is well established. Compelling evidence has accumulated that histologic assessment of infiltration patterns of different host immune response components in non-small cell lung cancer specimens helps identify different prognostic patient subgroups. This review provides an overview of recent insights gained in the understanding of the role played by chronic inflammation in lung carcinogenesis. The usefulness of quantification of different populations of lymphocytes, natural killer cells, macrophages, and mast cells within the tumor microenvironment in non-small cell lung cancer is also discussed. In particular, the importance of assessment of inflammatory cell microlocalization within both the tumor islet and surrounding stromal components is emphasized. Copyright © 2010 by the International Association for the Study of Lung Cancer.

Clinical significance of Mycobacterium asiaticum isolates in Queensland, Australia

Mycobacterium asiaticum was first reported as a cause of human disease in 1982, with only a few cases in the literature to date. This study aims to review the clinical significance of M. asiaticum isolates in Queensland, Australia. A retrospective review (1989 to 2008) of patients with M. asiaticum isolates was conducted. Data were collected through the Queensland TB Control Centre database. Disease was defined in accordance with the American Thoracic Society criteria. Twenty-four patients (13 female) had a positive culture of M. asiaticum, many residing around the Tropic of Capricorn. M. asiaticum was responsible for pulmonary disease (n = 2), childhood lymphadenitis (n = 1), olecranon bursitis (n = 1), 6 cases of possible pulmonary disease, and 2 possible wound infections. Chronic lung disease was a risk factor for pulmonary infection, and wounds/lacerations were a risk factor for extrapulmonary disease. Extrapulmonary disease responded to local measures. Pulmonary disease responded to ethambutol-isoniazid-rifampin plus pyrazinamide for the first 2 months in one patient, and amikacin-azithromycin-minocycline in another patient. While M. asiaticum is rare in Queensland, there appears to be an environmental niche. Although often a colonizer, it can be a cause of pulmonary and extrapulmonary disease. Treatment of pulmonary disease remains challenging. Extrapulmonary disease does not mandate specific nontuberculous mycobacterium (NTM) treatment.

The severity of chorioamnionitis in pregnant sheep is associated with in vivo variation of the surface-exposed multiple-banded antigen/gene of ureaplasma parvum

Ureaplasma species are the bacteria most frequently isolated from human amniotic fluid in asymptomatic pregnancies and placental infections. Ureaplasma parvum serovars 3 and 6 are the most prevalent serovars isolated from men and women. We hypothesized that the effects on the fetus and chorioamnion of chronic ureaplasma infection in amniotic fluid are dependent on the serovar, dose, and variation of the ureaplasma multiple banded antigen (MBA) and mba gene. We injected high- or low dose U. parvum serovar 3, serovar 6, or vehicle intra-amniotically into pregnant ewes at 55 days of gestation (term = 150 days) and examined the chorioamnion, amniotic fluid, and fetal lung tissue of animals delivered by cesarean section at 125 days of gestation. Variation of the multiple banded antigen/mba generated by serovar 3 and serovar 6 ureaplasmas in vivo were compared by PCR assay and Western blot. Ureaplasma inoculums demonstrated only one (serovar 3) or two (serovar 6) MBA variants in vitro, but numerous antigenic variants were generated in vivo: serovar 6 passage 1 amniotic fluid cultures contained more MBA size variants than serovar 3 (P = 0.005),and ureaplasma titers were inversely related to the number of variants (P = 0.025). The severity of chorioamnionitis varied between animals. Low numbers of mba size variants (five or fewer) within amniotic fluid were associated with severe inflammation, whereas the chorioamnion from animals with nine or more mba variants showed little or no inflammation. These differences in chorioamnion inflammation may explain why not all women with in utero Ureaplasma spp. experience adverse pregnancy outcomes.

Interleukin-13 promotes susceptibility to chlamydial infection of the respiratory and genital tracts

Chlamydiae are intracellular bacteria that commonly cause infections of the respiratory and genital tracts, which are major clinical problems. Infections are also linked to the aetiology of diseases such as asthma, emphysema and heart disease. The clinical management of infection is problematic and antibiotic resistance is emerging. Increased understanding of immune processes that are involved in both clearance and immunopathology of chlamydial infection is critical for the development of improved treatment strategies. Here, we show that IL-13 was produced in the lungs of mice rapidly after Chlamydia muridarum (Cmu) infection and promoted susceptibility to infection. Wild-type (WT) mice had increased disease severity, bacterial load and associated inflammation compared to IL-13 deficient (−/−) mice as early as 3 days post infection (p.i.). Intratracheal instillation of IL-13 enhanced bacterial load in IL-13−/− mice. There were no differences in early IFN-g and IL-10 expression between WT and IL-13−/− mice and depletion of CD4+ T cells did not affect infection in IL-13−/− mice. Collectively, these data demonstrate a lack of CD4+ T cell involvement and a novel role for IL-13 in innate responses to infection. We also showed that IL-13 deficiency increased macrophage uptake of Cmu in vitro and in vivo. Moreover, the depletion of IL-13 during infection of lung epithelial cells in vitro decreased the percentage of infected cells and reduced bacterial growth. Our results suggest that enhanced IL-13 responses in the airways, such as that found in asthmatics, may promote susceptibility to chlamydial lung infection. Importantly the role of IL-13 in regulating infection was not limited to the lung as we showed that IL-13 also promoted susceptibility to Cmu genital tract infection. Collectively our findings demonstrate that innate IL-13 release promotes infection that results in enhanced inflammation and have broad implications for the treatment of chlamydial infections and IL-13-associated diseases.

The development of chronic cough in children following presentation to a tertiary paediatric emergency department with acute respiratory illness : study protocol for a prospective cohort study

Background Acute respiratory illness, a leading cause of cough in children, accounts for a substantial proportion of childhood morbidity and mortality worldwide. In some children acute cough progresses to chronic cough (> 4 weeks duration), impacting on morbidity and decreasing quality of life. Despite the importance of chronic cough as a cause of substantial childhood morbidity and associated economic, family and social costs, data on the prevalence, predictors, aetiology and natural history of the symptom are scarce. This study aims to comprehensively describe the epidemiology, aetiology and outcomes of cough during and after acute respiratory illness in children presenting to a tertiary paediatric emergency department. Methods/design A prospective cohort study of children aged <15 years attending the Royal Children's Hospital Emergency Department, Brisbane, for a respiratory illness that includes parent reported cough (wet or dry) as a symptom. The primary objective is to determine the prevalence and predictors of chronic cough (>= 4 weeks duration) post presentation with acute respiratory illness. Demographic, epidemiological, risk factor, microbiological and clinical data are completed at enrolment. Subjects complete daily cough dairies and weekly follow-up contacts for 28(+/-3) days to ascertain cough persistence. Children who continue to cough for 28 days post enrolment are referred to a paediatric respiratory physician for review. Primary analysis will be the proportion of children with persistent cough at day 28(+/-3). Multivariate analyses will be performed to evaluate variables independently associated with chronic cough at day 28(+/-3). Discussion Our protocol will be the first to comprehensively describe the natural history, epidemiology, aetiology and outcomes of cough during and after acute respiratory illness in children. The results will contribute to studies leading to the development of evidence-based clinical guidelines to improve the early detection and management of chronic cough in children during and after acute respiratory illness.

Lung health care for Aboriginal and Torres Strait Islander Queenslanders : breathing easy is not so easy

Objectives In Aboriginal and Torres Strait Islander peoples in Queensland, to (a) determine the disease burden of common chronic lung diseases and (b) identify areas of need with respect to lung health services. Methods Literature reviews and analyses of hospitalisation and mortality data were used to describe disease epidemiology and available programs and services. Key stakeholder interviews and an online survey of health professionals were used to evaluate lung health services across the state and to identify services, needs and gaps. Results Morbidity and mortality from respiratory diseases in the Indigenous population is substantially higher than the non-Indigenous population across all age groups and regions. There are inadequate clinical services and resources to address disease prevention, detection, intervention and management in an evidence-based and culturally acceptable fashion. There is a lack of culturally appropriate educational resources and management programs, insufficient access to appropriately engaged Indigenous health professionals, a lack of multi-disciplinary specialist outreach teams, fragmented information systems and inadequate coordination of care. Conclusions Major initiatives are required at all levels of the healthcare system to adequately address service provision for Indigenous Queenslanders with lung diseases, including high quality research to investigate the causes for poor lung health, which are likely to be multifactorial.

Lung recruitment manoeuvres for reducing respiratory morbidity in mechanically ventilated neonates

This is the protocol for a review and there is no abstract. The objectives are as follows: To determine the evidence supporting the use of recruitment manoeuvres in mechanically ventilated neonates and identify the optimal method of lung recruitment. To determine the effects of lung recruitment manoeuvres in neonates receiving ventilatory support on neonatal mortality and development of chronic lung disease when compared to no recruitment. If data are available, subgroup analyses will include: chronological age, gestational age, lung pathophysiology and pre-existing lung disease, mode and length of ventilation, timing and frequency of recruitment techniques.

Host-pathogen checkpoints and population bottlenecks in persistent and intracellular uropathogenic Escherichia coli bladder infection

Bladder infections affect millions of people yearly, and recurrent symptomatic infections (cystitis) are very common. The rapid increase in infections caused by multidrug-resistant uropathogens threatens to make recurrent cystitis an increasingly troubling public health concern. Uropathogenic Escherichia coli (UPEC) cause the vast majority of bladder infections. Upon entry into the lower urinary tract, UPEC face obstacles to colonization that constitute population bottlenecks, reducing diversity, and selecting for fit clones. A critical mucosal barrier to bladder infection is the epithelium (urothelium). UPEC bypass this barrier when they invade urothelial cells and form intracellular bacterial communities (IBCs), a process which requires type 1 pili. IBCs are transient in nature, occurring primarily during acute infection. Chronic bladder infection is common and can be either latent, in the form of the quiescent intracellular reservoir (QIR), or active, in the form of asymptomatic bacteriuria (ASB/ABU) or chronic cystitis. In mice, the fate of bladder infection, QIR, ASB, or chronic cystitis, is determined within the first 24 h of infection and constitutes a putative host–pathogen mucosal checkpoint that contributes to susceptibility to recurrent cystitis. Knowledge of these checkpoints and bottlenecks is critical for our understanding of bladder infection and efforts to devise novel therapeutic strategies.