Bugs, drugs and death

Various E. Coli looking harmless

Would you eat animal excrement if the flavour was right? Mayu Yamamoto of the International Medical Center of Japan thinks you might, and won the 2007 Ig Nobel for chemistry for developing a way to extract vanilla fragrance from cow dung.

The Japanese team were looking for ways to tackle a major environmental problem in the country. Livestock produce 50 million tons of excrement each year, and almost all farms are located close to residential areas in Japan, increasing the dangers of pollution – bacteria like E. coli are one of the most widely used indicators of faecal contamination of water.

The case in Germany is only the latest in a long list of deadly outbreaks. However, although it is a particularly nasty variant, there are no signs that E. o104 (the present strain of E. coli) is the mutant superbug epidemiologists have nightmares about.

It is though a warning about drug resistance.

Microbes resistant to penicillin appeared within a few years of the drug’s introduction, and since then medical science has been fighting an increasingly serious battle against microbial resistance to cheap and effective first-choice, or “first-line” drugs.

Bacterial infections which contribute most to human disease are also the most resistant: diarrhoeal diseases, respiratory tract infections, meningitis, sexually transmitted infections, and hospital-acquired infections.

Resistance is becoming more serious due to a number of trends.

Urbanisation facilitates the spread of typhoid, tuberculosis, respiratory infections, and pneumonia.

Pollution, environmental degradation, and changing weather patterns affect incidence and distribution, especially those spread by insects and other vectors.

A growing proportion of elderly people need hospital care and thus are at risk of exposure to highly resistant pathogens found in hospitals.

AIDS has enlarged the population of  patients at risk from many previously rare infections.

The resurgence of diseases such as malaria and tuberculosis plus greater global mobility increases the speed and facility with which diseases and resistant micro-organisms can spread.

Irrational use of antibiotics is also promoting resistance. This is due to their being prescribed when not needed or in self-medication, or because patients do not complete courses for financial or other reasons.

Antibiotics use in agriculture is another factor. In North America and Europe, half of all antimicrobial production by weight is used in farm animals and poultry, notably as regular supplements for prophylaxis or growth promotion, exposing even healthy animals to antimicrobials.

As ever, the impacts are worse in poorer countries. In South Asia, one newborn baby dies every two minutes due to treatment failure caused by antibiotic resistance. Treating multidrug-resistant tuberculosis in South Africa costs around $4300, compared with $35 if first-choice or “first-line” drugs are effective.

It’s a problem in rich countries too. As Harvey Rubin recalls in his paper on pandemics for the OECD Future Global Shocks Project, the direct costs to the US healthcare system from antibiotic resistant infections runs into the tens of billions of dollars. He quotes a study by the Infectious Diseases Society of America which found that more than 70% of the 90,000 deaths from bacterial infections were attributable to antibiotic resistant strains, and that “For many patients, there simply are no drugs that work…”.

Moreover, the pipeline of new treatments is practically empty, with only two new classes of antibiotics brought to the market in the past 30 years.  Rubin argues that major pharmaceutical companies have stopped developing new agents because antibiotics are not as profitable as drugs that treat chronic (long-term) conditions and lifestyle issues.

Useful links

OECD Efficacy Workshop On Antimicrobial Biocides

OECD work on health