Researchers from Hyderabad-based Centre for Cellular and Molecular Biology (CCMB) and the LV Prasad Eye Institute (LVPEI), in a collaborative study, uncovered alarming levels of antimicrobial resistance (AMR) in bacteria causing eye infections.
The study, published in Communications Biology, represents one of the most comprehensive genomic analyses of eye pathogens from India to date. The CCMB researchers led the genomic and bioinformatics analyses, and LVPEI researchers contributed clinical expertise, patient samples, and microbiological characterisation.
The team isolated bacteria from the patient samples and tested them with known antibiotics and found more than 45 per cent of isolates were multidrug-resistant, and included both Gram-positive and Gram-negative bacterial pathogens.
“We found samples with vancomycin-resistant Staphylococcus aureus and extensively-drug resistant (XDR)-Klebsiella pneumoniae strains involved in eye infections. These findings are worrying because they can spread their AMR genes to other bacteria, too. Also, these pathogens can infect other parts of our bodies,” Dr Karthik Bharadwaj, clinician-scientist at CCMB, in a press release said.
The high prevalence of AMR challenges the continued reliance on antibiotics for treatment, the CCMB researchers said, adding that their study found that all the eye pathogens were also resistant to Fluroquinolones, a frequently used class of antibiotics for eye ailments.
“To understand and solve a problem like AMR, it is essential for clinicians and scientists to come together and contribute through their expertise. This is not a problem to be solved with model organisms but rather with real patient samples,” says Dr Vinay K Nandicoori, Director, CSIR-CCMB.
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The authors of the study include Karthik Bharadwaj and Divya Tej Sowpati from CCMB and Dr Joveeta Joseph from LVPEI.
Through whole genome sequencing, researchers have identified new AMR-associated bacterial mechanisms and mutations in this study.
From a clinical standpoint, the study underscores the urgent need to re-evaluate current treatment practices. It is common that a clinician starts treatment based on their best judgments before laboratory results are available. Since identifying the exact organism can take a few days, treatment is initiated with antibiotics that are most likely to be effective, and later adjusted once the test results are known. This is called empirical therapy.
Fluroquinolones are a frequently used class of antibiotics, and this study reported resistance against these antibiotics in all eye pathogens. This highlights the importance of microbiology-guided diagnosis and treatment approaches, particularly in severe infections such as microbial keratitis and endophthalmitis.
“While genomic tools are not yet part of routine clinical workflows, the insights generated through this study provide a critical foundation for developing region-specific treatment guidelines and strengthening antimicrobial stewardship efforts in ophthalmology,” said Dr Joseph, Head of Microbiology at LVPEI.
Eye infections are not isolated events as they are caused by microbes on our skin as well as in the environment. Thus, these results reflect the larger AMR landscape in our surroundings, and not just pertinent to the eye care sector. “This study positions the eye as a valuable site for AMR surveillance in the environment around us,” said LVPEI, Executive Chair Dr Prashant Garg.
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