Implementation of microbiota analysis in clinical trials for cystic fibrosis lung infection: Experience from the OligoG phase 2b clinical trials

The fungal diversity in the lungs of children with cystic fibrosis captured by sputum-induction and bronchoalveolar lavage

BACKGROUND

The prevalence of fungi in cystic fibrosis (CF) lung infections is poorly understood and studies have focused on adult patients. We investigated the fungal diversity in children with CF using bronchoalveolar lavage (BAL) and induced sputum (IS) samples to capture multiple lung niches.

METHODS

Sequencing of the fungal ITS2 region and molecular mycobiota diversity analysis was performed on 25 matched sets of BAL-IS samples from 23 children collected as part of the CF-SpIT study (UKCRN14615; ISRCTNR12473810).

RESULTS

Aspergillus and Candida were detected in all samples and were the most abundant and prevalent genera, followed by Dipodascus, Lecanicillium and Simplicillium. The presumptive CF pathogens Exophiala, Lomentospora and Scedosporium were identified at variable abundances in 100 %, 64 %, and 24 % of sample sets, respectively. Fungal pathogens observed at high relative abundance (≥40 %) were not accurately diagnosed by routine culture microbiology in over 50 % of the cohort. The fungal communities captured by BAL and IS samples were similar in diversity and composition, with exception to C. albicans being significantly increased in IS samples. The respiratory mycobiota varied greatly between individuals, with only 13 of 25 sample sets containing a dominant fungal taxon. In 11/25 BAL sample sets, airway compartmentalisation was observed with diverse mycobiota detected from different lobes of the lung.

CONCLUSIONS

The paediatric mycobiota is diverse, complex and inadequately diagnosed by conventional microbiology. Overlapping fungal communities were identified in BAL and IS samples, showing that IS can capture fungal genera associated with the lower airway. Compartmentalisation of the lower airway presents difficulties for consistent mycobiota sampling.

Alginate oligosaccharides: The structure-function relationships and the directional preparation for application

Alginate oligosaccharides (AOS) are degradation products of alginate extracted from brown algae. With low molecular weight, high water solubility, and good biological activity, AOS present anti-inflammatory, antimicrobial, antioxidant, and antitumor properties. They also exert growth-promoting effects in animals and plants. Three types of AOS, mannuronate oligosaccharides (MAOS), guluronate oligosaccharides (GAOS), and heterozygous mannuronate and guluronate oligosaccharides (HAOS), can be produced from alginate by enzymatic hydrolysis. Thus far, most studies on the applications and biological activities of AOS have been based mainly on a hybrid form of HAOS. To improve the directional production of AOS for practical applications, systematic studies on the structures and related biological activities of AOS are needed. This review provides a summary of current understanding of structure-function relationships and advances in the production of AOS. The current challenges and opportunities in the application of AOS is suggested to guide the precise application of AOS in practice.

Combination and nanotechnology based pharmaceutical strategies for combating respiratory bacterial biofilm infections

Respiratory infections are one of the major global health problems. Among them, chronic respiratory infections caused by biofilm formation are difficult to treat because of both drug tolerance and poor drug penetration into the complex biofilm structure. A major part of the current research on combating respiratory biofilm infections have been focused on destroying the matrix of extracellular polymeric substance and eDNA of the biofilm or promoting the penetration of antibiotics through the extracellular polymeric substance via delivery technologies in order to kill the bacteria inside. There are also experimental data showing that certain inhaled antibiotics with simple formulations can effectively penetrate EPS to kill surficially located bacteria and centrally located dormant bacteria or persisters. This article aims to review recent advances in the pharmaceutical strategies for combating respiratory biofilm infections with a focus on nanotechnology-based drug delivery approaches. The formation and characteristics of bacterial biofilm infections in the airway mucus are presented, which is followed by a brief review on the current clinical approaches to treat respiratory biofilm infections by surgical removal and antimicrobial therapy, and also the emerging clinical treatment approaches. The current combination of antibiotics and non-antibiotic adjuvants to combat respiratory biofilm infections are also discussed.