The Killers Within: The Deadly Rise of Drug Resistant Bacteria by Michael Shnayerson and Mark Plotkin

The lethal microbes no 'magic bullet' can defeat

There are two ways to launch a biological assault on the human race. Nature has been adept at both. The first is to evolve a lethal bacterium or virus against which we have no defence. Aids, Ebola and now Sars are examples, caused by toxic organisms which have cut a swath through humanity and spread fear and panic.

Less feared but just as deadly are organisms which have found a way around our defences by evolving protection against the antibiotic drugs we use to destroy them. In evading destruction, they survive to multiply, infect and ultimately overwhelm us. It is their indestructibility, rather than toxicity, that makes them lethal.

The collective blindness the world has shown to the growth of these drug-resistant bacteria is a matter of immense concern. In Britain we have seen the consequences in outbreaks of MRSA (Methicillin-Resistant Staphylococcus Aureus), which has closed hospital wards and dispatched thousands of patients. Last year the first American cases emerged of organisms fully resistant to vancomycin, the last line of defence in our antibiotic arsenal. If these organisms get a firm foothold, the outlook is grim.

Those in the know have long warned that we are heading for a public health disaster. This book makes a valiant attempt to bring it to public consciousness. Written with verve and pace, it focuses on the human casualties already falling in this war against nature. As Joshua Lederberg, the Nobel laureate and expert on antibiotic resistance, says: "The odds of Ebola breaking out are quite low, but the stakes are very high. With antibiotic resistance the odds are certain and the stakes are just as high. It is happening right under our noses."

How does antibiotic resistance arise? The answer is evolution. Bacteria, like all living organisms, are programmed to survive. Chance mutations that confer advantage against a threat such as antibiotic drugs are naturally selected. Bacteria resistant to the drugs grow and multiply. The more widely the drugs are used, the greater opportunities for resistance to develop. Thus the overuse of antibiotics around the world is not merely wasteful: it places the lives of millions at risk.

Antibiotics are now used so indiscriminately that the planet is bathed in a dilute solution of them. Among the worst culprits is the agricultural industry, where antibiotics are added routinely to food as growth promoters. The result has been the emergence of bacteria resistant to antibiotic drugs before those drugs have even been launched on the market for humans. Resistance is acquired from the use of similar drugs in animals. Belatedly, the European Union banned the use of all growth promoters associated with human medicine in 1998.

The antibiotic era which began with the discovery of penicillin almost conquered infectious disease. Almost, but not quite. The emergence of multi-drug resistance has demonstrated that "no antibiotic would be a magic bullet for long". The bugs will always find a mechanism to resist them. Overuse of antibiotics over the past 60 years has created a microbiological threat to our world. Unless we find a way to deal with it, the microbes will win.