I’m not a dog lover. Far from it in fact, however a new paper in the Journal of Hospital Infection caught my eye today. Yesterday I was sitting in the Longitude Prize Advisory Committee meeting bemoaning the lack of ‘left field’ ideas coming forward. Harrison himself, winner of the original prize was such a person. He came at the problem of solving the longitude issue from a completely different direction when all of the respected science at the time was convinced that astrology was the answer. Problem: cloud, and not much of a silver lining. So we are looking for a new way to diagnose infection rapidly, distinguishing between those caused by viruses and bacteria in the hope of turning the increasing tide of resistance. So what does Fido (or Nimbus in this case) have to do with this?
A dog’s nose is very sensitive and it can distinguish between Volatile Organic Compounds (VOC). Previous studies have shown that MRSA and MSSA can be differentiated based solely on their VOC profiles (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4443899/) and in this study the authors decided to test this with dogs that had been trained for 3 months to detect the difference and following this a chosen animal was able to distinguish CMRSA from MSSA, MRSE (presented alone and in combination) with high sensitivity (97%) and specificity (92%). As the authors point out, compounds expressed from a pure culture in a microbiology laboratory may differ from a clinical setting, where for example there would be multiple organisms present in a wound. However the proof of concept is emerging. I cannot see dogs strolling around hospital wards looking for antibiotic-resistant organisms however they could be useful in agricultural or low-resource settings. Other studies have also shown the utility of VOC detection, as in the C. difficile sniffing dog and in a previous blog, the UTI detection dog. Development of a small, hand held device that could detect the presence of an organism likely to be causing an infection may be useful, particularly if resistant organisms could be the target, although colonisation would still be an issue. IS anyone out there working on this area and would they need any help in developing it? I’m sure that the Longitude Prize organisers would be only too delighted to hear from them and there are a variety of support mechanisms available, including the Discovery Awards.