Diabetic hyperglycaemia leads to increased [glucose] in the airway surface liquid (ASL). This has been shown to be associated with an increased risk of developing a pulmonary infection in patients in the intensive care unit and in patients who have diabetes and chronic lung disease1. It was recently discovered that the lung is inhabited by resident bacteria and that it possesses its own unique microbiome. Chronic lung conditions, such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) shown induced changes to the resident lung microbiota. The effect of high ASL [glucose] on the lung microbiome was examined using 16S ribosomal RNA amplification. Also compared was the effect of phenotype and environment on the lung microbiome. Preliminary studies used db/db and GK+/- diabetic mice (models of Type 2 and Type 1 diabetes). Animals were subjected to Schedule 1 terminal anaesthesia (i.p. injection of 0.2 mL pentobarbital (60 mg/ml) diluted 1:1 with saline) at 12 weeks. Samples were collected using bronchoalveolar lavage (BAL) technique. Cannulas were inserted via the trachea and lungs were washed using 1ml of sterile PBS. The lung microbiome was analysed using the Illumina MiSeq platform. Two sets of db/db mice and one set of GK+/- mice were used. One set of each genotype of mice was raised and culled in AstraZeneca’s Gothenburg facility, the remaining db/db mice were raised and culled in St George’s, London. Mice were kept under similar conditions and were fed a standard rodent chow. The core lung microbiome remained consistent irrespective of the genotype, hyperglycaemia or the housing location. Bacterial orders (o.) such as Actinomycetales, Bacillales (namely family of Staphylococcaceae), Rhizobiales and Burkholderiales dominated lung microbiomes of both diabetic and non-diabetic mice. Bacteria of o. Lactobacillales, o. Sphingomonadales and o. Pseudomonadales have been observed in db/db mice housed in Sweden and the UK, while either absent or in low abundance in GK+/- animals. In contrast, bacterial o. Clostridiales and o. Enterobacteriales represented a major component of GK+/- mice lung microbiome; were absent in the lungs of db/db mice. Hyperglycaemia was seen to affect the lung’s microbiome diversity and species abundance. However, these effects were inconsistent between phenotypes and housing conditions. I.e. there was an abundance of Staphylococcaceae in lungs of diabetic db/db mice housed in Sweden compared to non-diabetic littermates, the opposite trend was observed in db/db mice housed in the UK. Interestingly, increase of abundance in the bacteria of o. Pasteurellales and o. Rhizobiales were observed in both db/db mice housed in Sweden and the UK compared to non-diabetic littermates, while no changes in the abundance of these species were observed in GK+/- mice. To date, we have demonstrated both hyperglycaemic, genetic and environmental changes to the lung microbiome of mice.