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Antimicrobial resistance of ocular microbes and the role of antimicrobial peptides
Shyam Sunder Tummanapalli1, Mark Dp Willcox1
1School of Optometry and Vision Science, The University of New South Wales, Sydney, Australia.
Abstract:
Isolation of antimicrobial-resistant microbes from ocular infections may be becoming more frequent. Infections caused by these microbes can be difficult to treat and lead to poor outcomes. However, new therapies are being developed which may help improve clinical outcomes. This review examines recent reports on the isolation of antibiotic-resistant microbes from ocular infections. In addition, an overview of the development of some new antibiotic therapies is given. The recent literature regarding antibiotic use and resistance, isolation of antibiotic-resistant microbes from ocular infections and the development of potential new antibiotics that can be used to treat these infections was reviewed. Ocular microbial infections are a global public health issue as they can result in vision loss which compromises quality of life. Approximately 70 per cent of ocular infections are caused by bacteria including Chlamydia trachomatis, Staphylococcus aureus, and Pseudomonas aeruginosa and fungi such as Candida albicans, Aspergillus spp. and Fusarium spp. Resistance to first-line antibiotics such as fluoroquinolones and azoles has increased, with resistance of S. aureus isolates from the USA to fluoroquinolones reaching 32 per cent of isolates and 35 per cent being methicillin-resistant (MRSA). Lower levels of MRSA (seven per cent) were isolated by an Australian study. Antimicrobial peptides, which are broad-spectrum alternatives to antibiotics, have been tested as possible new drugs. Several have shown promise in animal models of keratitis, especially treating P. aeruginosa, S. aureus or C. albicans infections. Reports of increasing resistance of ocular isolates to mainstay antibiotics are a concern, and there is evidence that for ocular surface disease this resistance translates into worse clinical outcomes. New antibiotics are being developed, but not by large pharmaceutical companies and mostly in university research laboratories and smaller biotech companies. Antimicrobial peptides show promise in treating keratitis.
Insights
Antimicrobial resistance in ocular infections is rising, leading to difficult-to-treat conditions. New therapies, like antimicrobial peptides, show promise for improving outcomes in eye infections caused by resistant bacteria and fungi.
Area of Science:
- Ophthalmology
- Microbiology
- Infectious Diseases
Background:
- Ocular microbial infections pose a significant global health challenge, potentially causing vision loss.
- Bacteria like Staphylococcus aureus and Pseudomonas aeruginosa, and fungi such as Candida albicans, are common causes of eye infections.
- Increasing resistance to first-line antibiotics (fluoroquinolones, azoles) in ocular pathogens is a growing concern.
Purpose of the Study:
- To review recent findings on antibiotic-resistant microbes in ocular infections.
- To provide an overview of emerging antibiotic therapies for these infections.
- To highlight the clinical implications of antimicrobial resistance in ophthalmology.
Main Methods:
- Comprehensive review of recent scientific literature.
- Analysis of data on antibiotic resistance patterns in ocular isolates.
- Examination of preclinical and clinical development of new antimicrobial agents.
Main Results:
- Significant isolation rates of antimicrobial-resistant microbes, including methicillin-resistant Staphylococcus aureus (MRSA), from ocular infections.
- Fluoroquinolone resistance in Staphylococcus aureus isolates reaching concerning levels (e.g., 32% in the USA).
- Antimicrobial peptides demonstrate potential efficacy in animal models for keratitis, particularly against Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans.
Conclusions:
- Rising antimicrobial resistance in ocular infections is linked to poorer clinical outcomes.
- Development of novel antibiotics is primarily driven by academic research and smaller biotech firms, not large pharmaceutical companies.
- Antimicrobial peptides represent a promising therapeutic avenue for treating resistant ocular infections like keratitis.
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