Are Antibiotic-Resistant Diseases Mother Nature’s Revenge?
The methicillin-impervious infection Staphylococcus aureus is the most common post-surgery illness.
June 18, 2013 - 9:00 am
Resistance to antibiotics is often described by neo-pagans as Mother Nature’s vengeance on Man for having had the temerity to interfere in her natural biological processes. According to the neo-pagans, this vengeance has left Man (deservedly) worse off than if he had never discovered antibiotics at all. I do not see the logic of this.
There is no doubt, however, that bacterial resistance to antibiotics is a serious problem worldwide. It is particularly serious in hospitals, where patients may pick up infections that they never had before admission. Many patients die from these infections, which may be of epidemic proportions.
The most important such infection is MRSA, methicillin-resistant Staphylococcus aureus. (Methicillin is a semi-artificial penicillin that was developed when the Staphylococcus first became resistant to ordinary penicillin, and soon met with resistance itself.) MRSA accounts for most post-surgical infections; the proportion of patients infected by it is often taken in research as a measure of a hospital’s hygiene.
An important paper in a recent edition of the New England Journal of Medicine compares various strategies for reducing the spread of MRSA in intensive care units, a common place for patients to become infected.
The method of control usually employed is to screen patients for MRSA on admission to the ICU and to institute special precautions such as isolation and barrier nursing if they test positive. The authors compared this method with attempts by means of antibacterial products at “decolonization” of those who tested positive, and similar “decolonization” practiced on every patient admitted to an ICU irrespective of whether or not he tested positive for MRSA.
The authors then compared the overall rate of blood-borne infections with MRSA between the groups. They found universal decolonization – the prophylactic use of antibacterials regardless of whether or not patients were initially infected – was by far the most effective, with decolonization of those initially infected next best, and the method most widely used around the world — isolation and special nursing precautions — the least effective.
One of the reasons for the superior efficacy of universal decolonization might have been that those who were infected with MRSA on admission were disinfected straight away rather than after a delay while laboratory results were awaited, and thus the offending organism had no opportunity to spread in the meantime.
The authors estimated that 54 patients under the scheme of universal decolonization had to be treated in order to prevent one blood-borne infection. The cost of universal decolonization was $40 a head: that is to say, one blood-borne infection was prevented at a cost of $2160. If, as seems likely (though the authors are hesitant on the point), such an infection involves the extra expenditure of more than $2160 per patient, then universal decolonization would lead to economic savings as well as – presumably – to less suffering. (Additional savings would be made by the need for fewer initial laboratory tests.) The trial was not large enough, however, to determine whether any lives would be saved by universal decolonization and if so, how many. It seems to me likely, though, that lives would be saved.
The neo-pagans, however, could take some comfort from a caveat issued by the authors. If universal decolonization were instituted, as seems to be the logical practical consequence of the experiment, the bacteria might develop resistance to the products (chlorhexidine and mupirocin) used to disinfect. Indeed, there is already some evidence that this is happening. Thus victory over bacterial infection is only temporary, not final and probably never to be final, given the genetic flexibility of bacteria; medicine is thus an aspect of Man’s Promethean bargain. But temporary victory is to be preferred to perpetual defeat.