01:28pm Monday 11 December 2017

In the blood

Photo by VI Levi/ iStockphoto

Photo by VI Levi/ iStockphoto

The elite world of taxonomic microbiologists – the people who get to decide what we call our microscopic friends – is divided into the “lumpers” and the “splitters.” The lumpers try to minimise the number of families and genuses that bacteria, viruses and other pathogens can scientifically be classified into, while the splitters rejoice in discovering subtle and minor differences between micro-organisms, and love to distinguish them as new species or occasionally to create a new genus. Even as a practising infectious diseases specialist I have trouble keeping up with the names of bugs: every month or so our laboratory sends me a report which names a pathogen that I have never heard of. At the time of writing this, the most recent was Nesterenkonia halobia. I had to ask a colleague what it was.

“Used to be a micrococcus,” she said. “At least I could spell that.”

There is a degree of hypocrisy in this complaint, for I myself belong to a research group that changed the name of a bug. In my defence, however, we showed that our germ belonged to an established genus, one whose properties – and spelling – were well known to the mainstream microbiological world. We brought our little charge in from the obscurity and loneliness of an unpronounceable genus – it was the sole species of the genus Calymmatobacter – and added it to a warm and loving family, the Klebsiellae.

But my pedantic taxonomic colleagues seem to delight in taking a relatively well-known bug and, through a process reminiscent of Winston Smith’s work in George Orwell’s novel Nineteen Eighty-Four, depriving it of identity with the stroke of a pen. A paper is published and you wake the next day to find that what you knew before you went to bed isn’t so today. Yesterday’s Branhamella is today’s Moraxella – or was it the other way round?

The taxonomy of some bugs, however, is so established that reclassifying and renaming them would be unthinkable, and perhaps the best example of this is Staphylococcus aureus. Although doctors will abbreviate the name to Staph aureus, most likely you will know it under another name – golden staph. An aureus was a Roman gold coin and staphylococcus is from the Greek “staphyle” (a bunch of grapes) and “coccus” (granule). The Greco-Roman name beautifully describes the appearance of the bacteria in the laboratory – they really do look like a bunch of grapes under the microscope, and the colonies that grow on an agar plate are yellow.

I took very little notice of Staph aureus as a student and junior doctor. It was, to my mind, a pedestrian sort of bug. There was little romance associated with it – everybody had it on their skin, up their nose or in their groin. It caused tedious things like skin infections and abscesses and it had no international allure. Its main claim to fame was that some strains had developed a special characteristic that made them stand out in a crowd – resistance. The most famous strain is known mainly by its acronym, MRSA (Methicillin-resistant Staphylococcus aureus).

Antibiotic resistance is a fashionable subject in the early twenty-first century. Some authorities believe that we may be in the last decades of the Antibiotic Age, that soon the bacteria will win and we will be back to the 1930s, before the advent of sulphur drugs and penicillin. It is hard to pick up a medical journal without reading about the appearance of a germ that has mutated so that it is resistant to most antibiotics. There is no better way to frighten patients than to inform them that they have an infection caused by a resistant organism. “Oh my god, that’s a superbug isn’t it?” they usually say, and you can see family members trying to hide the fact that they have taken a small step back from the bedside. Often the patient’s perception is that MRSA has flesh-eating capabilities and they will be banished to an isolation ward in the basement of the hospital, somewhere between the incinerator and the morgue.

Read the rest of the article at Inside Story

This is an edited extract from Frank Bowden’s latest book, Gone Viral: The Germs that Share Our Lives, launched at ANU today. Professor Bowden is an infectious diseases physician who works for ACT Health and teaches at ANU. Inside Story is edited at the Institute for Social Research at Swinburne University of Technology in association with ANU. Selected articles appear in the Forum section of The Canberra Times.


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