Old Singaporean MRSA Isolates (1980’s and 1990’s)
A major highlight of working on the Singapore MRSA evolution and competition study was obtaining the very old MRSA isolates from the 1980’s and 1990’s. One of the biggest issues in the Singapore clinical microbiology scene – to me – is the loss of historical isolates (and the lack of any attempts to correct this to date). Because of the lack of physical space in our local hospital microbiology laboratories, the vast majority of all clinical microbes (i.e. obtained from patients) are discarded. Even for bacterial isolates from blood cultures, the majority are discarded after a certain period of time. This represents a tremendous loss of data and – in some ways – historical points to track the evolution of bacteria as well as the appearance of new and unique mechanisms of resistance or virulence in these bacteria (usually not picked up during the initial evaluation by laboratory staff) in Singapore.
Prof. Warren Grubb (currently emeritus professor at Curtin University, Perth, Australia) is one of a handful of great Staphylococcus aureus researchers whose work from the 1970’s to 2000’s have helped us understand much about the epidemiology and resistance mechanisms of this bug. He was one of the first to understand the threat posed by MRSA and had been instrumental in persuading the Western Australian government of that early period to take its control seriously (unlike, say, Singapore or most of the Asian countries). Even a casual student of infection control and MRSA epidemiology will realise that Western Australia’s MRSA control practices resemble that of northern Europe’s (i.e. search and destroy policy), with similar very low (think <1%) healthcare-associated MRSA (HA-MRSA) rates in its hospitals. This is in stark contrast to MRSA control practices (and HA-MRSA rates) in the rest of the country and Asia. He was also one of the first to recognise and chart the rise of the phenomenon of community-associated MRSA (CA-MRSA) (at a time when most Western microbiologists and clinicians did not believe there were actually distinct CA-MRSA as opposed to “feral” or “escaped” HA-MRSA), identifying them in aboriginal Australians living in Western Australia.
Rather fortuitously, he had developed a working relationship with several of the older (now retired) microbiologists from the Singapore General Hospital (SGH), and Dr. Tay Leng had sent him several MRSA isolates in the 1980’s for typing. This collaboration did result in an academic publication, and I had documented it in an earlier post, along with the actual paper itself. Another stroke of luck occurred in the late 1990’s. One of the laboratory technologists working at SGH, whom I shall not name, decided to do a PhD at the Curtin University under the guidance of Prof. Grubb. This intrepid technologist had persuaded the clinical microbiologists at SGH and the National University Hospital (NUH) to let her work on a collection of MRSA isolates (from 1996 and 1997) from these hospitals, and she brought them up with her to Perth! Prof. Grubb had kept all these isolates at the Gram-Positive Typing and Research Laboratory (which he had founded – although by 1997 it had been renamed as the Australian Collaborating Centre for Enterococcus and Staphylococcus) in Perth, and he was kind enough to freely ship these isolates back to Singapore when we were looking for historical MRSA isolates for our study.
On a personal note, I have found Prof. Grubb to be one of those rare scientists who are passionate and extremely knowledgeable about their work, and also extremely generous with their time and expertise. I had written an email to him (he didn’t know me from Adam at that time) in 2004 for reasons I no longer remember, describing this unique MRSA clone that had been increasing in prevalence in local hospitals, and he replied promptly, recognising the clone as the pandemic UK-EMRSA-15 clone, and even provided the simple biochemical test (urease activity) that would clinch the identity. This was really quite astounding for a (then) young ID physician, since not a single local microbiologist could tell me anything about the MRSA clones that were circulating in our hospitals during that time. When I visited his laboratory later that year, he was kind enough to show me around for 3 days, and have his staff share with me their various protocols for typing S. aureus and other bacteria. I believe that without this generous encounter (and another experience in Lyon, which I may share in a later post about CA-MRSA in Singapore), it would have been impossible for me to have performed all my current research on MRSA.