Resistance stems from misguided efforts to try to sterilise our environment

Bacterial resistance to multiple antibiotics characterises the present decade. Finding organisms insensitive to over 10 different antibiotics is not unusual. Although most of the hardier organisms are present in hospitals, strains of multidrug resistant bacteria, such as Streptococcus pneumoniae, Mycobacterium tuberculosis, and Escherichia coli, also cause serious community acquired infections. Moreover, resistant bacteria from hospitals can be introduced into the community via the estimated 5% of patients discharged for continued treatment at home — taking with them multidrug resistant Staphylococcus aureus and vancomycin resistant enterococci. Since about half of antibiotic usage in the developed world (and perhaps more in the developing world) is inappropriate, there is a certain optimism that we can reverse the resistance problem if we improve use and thus return to an environment populated with susceptible strains.

To understand resistance, imagine being a bacterium in a world bombarded with antimicrobials. Living in a human, you would face antibiotics being taken for routine infections and for non-threatening conditions like acne. As a susceptible strain you have to acquire a survival mechanism. This is not too difficult, as your resistant counterparts, though less common, are very …