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.
2 thoughts on “Dogs can be useful – Woof of concept obtained”
Hello Martin, there has been (and continues to be) work on VOC detection by dogs in cancer research. Alexandra Horowitz gives a good description of one such study in her book ‘Being a dog – following the dog into a world of smell’. Seems that training is essential and some dogs are better than others – neither of these are surprising – and I imagine the same holds true for VOC detection in bacteria (or whatever it is they can smell – seems to be more VOCs out there than you can poke a stick at).
I am reminded of nurses who swore they could smell the causative organism in diarrhoea or wounds or urine. Funny how they always picked the most usual causative organisms. Never seemed to be able to detect the less obvious ones.
Anyway, I guess the takeaway message is that the research shows promise but a bit too early to let Mr Fluffy diagnose your infection (or cancer).
Hi Fiona. Yes, I was just wondering that if we can sequence a whole genome surely it must be possible to develop a small sniffing machine that would be able to reliably detect VOCs. Agree about a nurses nose – I also remember my staff being able to tell me who the C. difficile positive result was on as I entered the ward door, as per https://academic.oup.com/cid/article/44/8/1142/299003/Does-the-Nose-Know-The-Odiferous-Diagnosis-o f. However other studies have shown the reverse of course https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3571629/. Still, hope springs eternal