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Shenandoa Toote, Jorge Maestre-Mesa, Darlene Miller; Prevalence and Diversity of Antibiotic Resistant Determinants (Genes) in Acanthamoeba Hosts and Contact Lens Associated Microbial Communities. Invest. Ophthalmol. Vis. Sci. 2018;59(9):3670. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Antibiotic resistance is an increasing public health concern among isolates recovered from corneal ulcers. Contact lens wear is a leading risk factor for microbial keratitis. Prevalence of environmental and pathogen specific antibiotic resistant genes and their interaction in contact lens cases or at the ocular surface is unknown. Our purpose was to document the frequency and diversity of antibiotic resistant genes among Acanthamoeba hosts and contact lens case associated microbial communities (CLAMC) recovered from patients with microbial keratitis.
We utilized whole genome sequencing and metagenomics to survey and document the presence of antibiotic resistant genes among amebic microbiomes (n=4), mixed CLAMC with (ACLAMC, n=4) and without Acanthamoeba species (NACLAMC, n=7).
A total of 172 unique antibiotic resistant determinants (genes) were documented among the 3 groups conveying resistance to 14 individual and multiple drug classes. No significant difference was documented between the average number of antibiotic resistant genes in ACLAMC or NACLAMC contact lens communities (n=38/266, n=39/156, p=0.8386) respectively. Frequency of antibiotic genes among amebic hosts (n=20) with average of 5 was 8X lower than in contact lens cases. No overlap of genes was found in Acanthamoeba hosts versus contact lens communities.Antibiotic resistant genes to commonly dispensed ocular antimicrobials classes included: aminoglycosides (n=24, 13.9%), beta lactams (n= 33, 19.2%), quinolones/fluoroquinolones (n=2, 1.2%), glycopeptides (n=2, 1.2%), tetracyclines (n=7, 4.1%), macrolides (n=11, 6.4%), sulfonamides (n=4, 2.3%), and polypeptides (n=8, 4.6%). Multidrug resistance genes due to the presence of efflux pumps were harbored by 39.5% of gene determinants.Resistant determinants were most frequently detected in gram negative organisms (n=14/22, 64% vs n=8/22, 36% for gram positives). P. aeruginosa was associated with 65% of all samples and 81% of all CLAMC. S. aureus was linked to 78% of host samples and 16% of NACLAMC compared to 2% of ACLAMC samples.
Antibiotic resistant genes may be a frequent occurrence among Acanthamoeba hosts and contact lens associated microbial communities. Contact lens cases may serve as a unique niche for recovery, exchange, and dispersal of multidrug resistant genes to the ocular surface and/or environment.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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