Abstract
Purpose :
The ability to acquire and use a diverse array of nutrient substrates (metabolism) correlates with an organism’s ability to adapt and establish disease. Host response and niche environment play important roles in preventing and modulating infection and or pathology. Pseudomonas aeruginosa adapts and utilizes a wide variety of nutritional cues (carbon and nitrogen sources for growth, invasion and social signaling. communities.
To document the impact of niche and host environment on the catabolic and molecular fingerprints of Pseudomonas aeruginosa ocular isolates.
Methods :
We used a combination of the Vitek2 gram negative identification card (GNI) containing 47 carbon, nitrogen and antibiotic resistance substrates, PCR (ExoS, ExoU) and shotgun metagenomics to characterize Pseudomonas aeruginosa metabolic phenotypes and molecular fingerprint from cornea (n=120), contact lens (n=21), intraocular fluids (n=11)and middle ear (n=52).
Results :
Metabolic diversity index (MDI)/profiles for the external and internal ocular environments were distinct. The most diverse and aggressive (pyocyanin and ExoS toxin production) were associated with cornea isolates (MDI=46.8%, N=22 substrates). Reduced metabolic efficiency was documented for intraocular isolates (MDI=42.5%, n=20), but with increased upregulation of biofilm associated substrates (proline, arginine). Contact lens isolates were more diverse, MDI:51.1% (n=24 substrates) than matched cornea isolates and were associated with signaling molecules. Although different, the MDIs for P. aeruginosa invasive strains (ExoS, n=36) and cytotoxic strains (ExoU, n=28) were similar, 48.9% (n=23) and 46.8%, (n=22). Metabolic profiles for otitis media isolates was MDI:50%, (n=26).
Conclusions :
The metabolic phenotype may offer clues to molecular diversity, gene expression and pathology of ocular Pseudomonas aeruginosa isolates. Metabolic diversity and pathology are modulated by the ocular environment.
This is a 2020 ARVO Annual Meeting abstract.