Microbial Keratitis in Malawi

Microbial Keratitis in Malawi: A Microbiological Pilot Study

Microbial Keratitis (MK) is an infection of the cornea (the transparent front part of the eye) that may lead to ulcers, scarring and loss of sight. The risk factors and organisms that cause MK are unknown in Malawi meaning that treatment is limited and outcomes are poor. One of the barriers to identifying the organisms has been the difficulty in collecting samples from the cornea which has depended on the use of sharp instruments and specialist equipment, which are not available in resource-deprived settings like in Malawi. In 2015, BCPB supported a project led by Dr Tobi Somerville of The University of Liverpool to develop a new method to obtain corneal samples which required the use of corneal impression membranes (CIM), like a small piece of filter paper, to be placed on the corneal ulcer before being transported to the laboratory. This technique is simple to perform and is less invasive than scraping methods that are normally used at the moment. The aim of the study was to assess how well this new method, which does not require specialist equipment, can be used to identify organisms that are causing MK in Malawi.

Dr Somerville and her team collected corneal samples from 71 patients with MK in Malawi using the CIM. They found organisms likely to be causing infection in 80.3% of participants which is much higher than that seen with traditional corneal scraping methods. The most commonly found type of organism was grampositive bacteria, which is similar to what we see in the UK. As the method is not invasive and there have been no adverse events or reactions, the team are now extending this study by collecting samples from the participants’ other eye. This will help them to work out which of the organisms they find are likely to be really causing MK and which are only found as they naturally live on the front surface of the eye without causing infection. This new methodology means that samples can be transported long distances from remote areas without loss of information. The project has helped us to understand which organisms cause MK in Malawi and will help find ways of improving subsequent treatment and outcomes.

An update about this work will be added soon