The point prevalence of respiratory syncytial virus in hospital and community-based studies in children from Northern Australia:studies in a 'high-risk' population

Introduction: Respiratory syncytial virus (RSV) is the leading viral cause of acute lower respiratory infections globally, accounting for high morbidity and mortality burden among children aged less than 5 years. As candidate RSV vaccine trials in pregnant women and infants are underway a greater understanding of RSV epidemiology is now needed, especially in paediatric populations with high rates of acute and chronic respiratory disease. The objective was to identify RSV prevalence in children living in northern Australia, a region with a high respiratory disease burden. Methods: Data were sourced from 11 prospective studies (four hospital and seven community-based) of infants and children with acute and chronic respiratory illnesses, as well as otitis media, conducted between 1996 and 2017 inclusive. The data from northern Australian children in these trials were extracted and, where available and consented, their nasopharyngeal swabs (biobanked at -80°C) were tested by polymerase chain reaction assays for RSV-A and B, 16 other viruses and atypical respiratory bacterial pathogens. Results: Overall, 1127 children were included. Their median age was 1.8 years (interquartile range 0.5-4.9); 58% were male and 90% Indigenous, with 81% from remote communities. After human rhinoviruses (HRV), RSV was the second most prevalent virus (15%, 95% confidence interval (CI) 13-18). RSV prevalence was greatest amongst children aged less than 2 years hospitalised with bronchiolitis (47%, 95%CI 41.4-52.4), with more than two-thirds with RSV aged less than 6 months. In contrast, the prevalence of RSV was only 1-3.5% in other age groups and settings. In onethird of RSV cases, another respiratory virus was also detected. Individual viruses other than RSV and HRV were uncommon (0-9%). Conclusion: Combined data from 11 hospital and communitybased studies of children aged less than 18 years who lived in communities with a high burden of acute and chronic respiratory illness showed that RSV was second only to HRV as the most prevalent virus detected across all settings. RSV was the most frequently detected virus in infants hospitalised with bronchiolitis, including those aged less than 6 months. In contrast, RSV was uncommonly detected in children in community settings. In northern Australia, effective maternal and infant RSV vaccines could substantially reduce RSV bronchiolitis-related hospitalisations, including admissions of Indigenous infants from remote communities.</p

Method for culturing Candidatus Ornithobacterium hominis.

Candidatus Ornithobacterium hominis has been detected in nasopharyngeal microbiota sequence data from around the world. This report provides the first description of culture conditions for isolating this bacterium. The availability of an easily reproducible culture method is expected to facilitate deeper understanding of the clinical significance of this species

Diversity of Nontypeable Haemophilus influenzae Strains Colonizing Australian Aboriginal and Non-Aboriginal Children

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 &lt; 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 diseas