It is one of those studies where you know the outcome before you start. Doctors at the Northwestern Memorial Hospital in Chicago analysed data in the Nationwide Inpatient Sample in the US and concluded that the number of infections of the bacterium Staphylococcus aureus is rising by 7 per cent each year. The cost of treating infections has been increasing by 12 per cent, although the mortality rate showed a downward trend possibly owing to early treatment. The data, from 1998 to 2003, showed that the cost of treating staph infections had risen from $8.7 billion in 1998 to $14.5 billion in 2003.

The study, the results of which have been published in the journal Clinical Infectious Diseases, is only one of the many recent ones that show the increasing economic burden of bacterial infections. It looked at records pertaining to seven million hospital stays, and was thus one of the largest studies done anywhere recently. The reason for the increased number of infections is not hard to determine: increasing antibiotic resistance.

The news is consistently grim anywhere in the world. For instance, the Health Protection Agency in the UK found that antibiotic resistant Escherichia coli is spreading in the country and now infects 30,000 people annually.

Antibiotic resistance is a problem in India as well, but large countrywide studies are not available to support the obvious. Doctors and researchers in India have shown that bacteria that cause diseases like pneumonia, typhoid, malaria and several others are acquiring drug resistance.

Increasing antibiotic resistance is one of the reasons large pharmaceutical companies like Eli Lilly and Wyeth are abandoning projects to develop antibiotics. It costs several hundred million dollars and seven years to develop a drug, but bacteria can develop resistance within a year. “It is a difficult war to win,” says R. Ramachandran, former director of the Astra Zeneca R&D Centre in Bangalore and now founder CEO of Gangagen Biotechnologies, California. But that does not mean we are losing the battle, because many small companies are trying out novel approaches.

Gangagen itself is a new company that looks at a different way of fighting drug resistant bacteria, by drafting in their natural enemies. Considering the speed with which bacteria evolve, they would have taken control of the planet long ago. However, they are kept in check by another kind of microorganism — called phages — which are, in fact, the most abundant organisms on earth. A specific type of phage attacks only specific bacteria, and is harmless to even other kinds of bacteria, not to speak of humans.

Some other companies are betting on different kinds of antibiotics. Two small companies — Sweden’s Innate Pharmaceuticals and France’s Mutabilis — are trying out a new strategy: do not kill the bacteria, but stop it from causing disease. Innate is relying on a mechanism that is common to many bacteria: a pump that injects toxins into the host cells. These toxins disable the immune system of the host and help the bacteria to spread. Says Innate CEO Sune Rosell: “When you take away the injection system, you take away its ability to attack the immune system.” Innate has developed molecules to block this mechanism, and is doing animal trials now.

The advantage of this approach is obvious: it does not harm useful bacteria, unlike conventional antibiotics. Since this approach does not kill the bacteria directly (it is the immune system that cleans them up), it is not easy for them to develop resistance. There are several such approaches being developed, and some drugs using them are about to enter clinical trials.

Scientists in universities are also working on drug molecules that can fight resistance. At the University of Illinois in the US, Gerard Wong discovered the possible mechanism of a class of antibiotics called antimicrobial peptides. He also found that these peptides can be made active, partially active or highly active by altering their lengths in a specific way. These peptides attack and punch holes in bacterial walls, but leave the cells of higher organisms intact, because bacterial cell walls contains larger amounts of a molecule called DOPE. “It is difficult for bacteria to evolve resistance to this,” says Wong, “because a change in composition of the wall is lethal to the bacteria.”

While all these methods promise to counteract drug resistant bacteria, doctors say infection control is one the primary ways of reducing antibiotic resistance. “Antibiotic resistance is getting worse everywhere except in Holland, Denmark and Belgium,” says William Jarvis, a public health expert who retired recently from the Centers for Disease Control and Prevention in Atlanta. “These countries have brought down the infection of multidrug resistant staph to around 1 per cent simply by isolating infected people.” A lesson, perhaps, for all other countries.