Abstract
Purpose :
Pseudomonas aeruginosa and Acanthamoeba species are leading causes of corneal morbidity and vision loss. Dynamics of their complex social interactions and resultant outcomes in mixed microbial communities is not fully understood. Which emerges as the dominant victor or pathogen in this rock-scissor-paper game of competition, cooperation and or peaceful coexistence is just beginning to be deciphered.
Methods :
We used a combination of culture, routine PCR and metagenomics to identify and confirm the prevelance,community biodiversity and corneal pathogen outcome for matched cornea and contact lens pairs where both Acanthamobea and Pseudomonas aeruginosa were present in the contact lens storage case and or Acanthamoeba host over a 20 year period (1990-2014)
Results :
Results: Pseudomonas aeruginosa was the most frequent cornea pathogens during the 20-year period. It was recovered in 25% (n=1902/7450) of culture positive corneal cultures and 48% (987/2087) of cultured contact lens cases. Acanthamoeba was an infrequent cornea pathogen, constituting 3% (224/7450) of all positive cornea cultures. It was recovered from 2.4% (n=50) from contact lenses cultures. Among the 138 matched pairs, where contact lens/cases contained P. aeruginosa (71%, n=98), Acanthamoeba species (15.9%, n=22) and or both (13.0%, n=18), P. aeruginosa emerged as the dominant pathogen in 66.3% (n=65) of the P. aeruginosa cases and Acanthamoeba species, 90.9% (n=20) of acanthamoeba cases. Among the cases with both acanthamoeba and P. aeruginosa, acanthamoeba out competed P. aeruginosa in 10/18 or 55.5% or the cases. P. aeruginosa was the pathogen in a third (n=6/18, 33.3%) of the cases. Mixed P. aeruginosa and Acanthamoeba was documented in 11.1% (n=2/18) of cases. Relative abundance and biodiversity (acanthamoeba vs P. aeruginosa, community mixed) in these cases averaged 2-5:1. and were more likely to include S. maltophilia (7:1).
Conclusions :
Coinfection with both Pseudomonas aeruginosa and Acanthamoeba species in contact-associated microbial keratitis may be more frequent than reported. Relative abundance, biodiversity and the presence of species such as Stenotrophomonas maltophilia may modulate interspecies outcomes and cornea pathogen selection in the rock, scissors game dynamics occurring in contact lens communities.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.