When wonder drugs fail
By Radhakrishna Rao

NOT long back, hailed as wonder drugs for a wide range of disorders and diseases, antibiotics are now rapidly losing their punch and potency. What’s more, many antibiotics are rapidly becoming counter-productive by accentuating the diseases they are supposed to fight. Antibiotics, a majority of which are produced by making use of micro-organisms like fungi, actinomycetes and bacteria are routinely prescribed by physicians for fever, respiratory disorders as well as gastro-intestinal and genito-urinary infections.

But over the last two decades, many of the once powerful antibiotics have been ineffective in the face of growing resistance shown by micro-organism. Resistance of bacteria to antibiotics is due to the enzyme beta lactamose. This particular enzyme breaks down the beta lactum antibodies and renders antibiotics ineffective in the process. Penicillin, once considered a wonder drug, is no more a panacea for a number of diseases. For instance the resistance of the micro-organism streptococcus pneumonita to penicillin varies greatly with the age of the patient, implying that resistance is higher in children than adults and is more common in hospitals than in a community.

"Antibiotics never did work against viruses but we used to be able to count on them for most of infections", says Dr Gail Cassell, professor of microbiology at the University of Alabama in Birmingham, "Now, whether it is tuberculosis bacterial pneumonia or staph infection the chances that they will respond to antibiotics grow slimmer almost by the day. Every antibiotic, sooner or later, will become the victim of its own success".

According to WHO, one-third of the world’s population is already infected with tuberculosis causing bacillus and more than 50 million people are infected with drug-resistant strains of TB bacteria. The poor compliance with drug regimen by patients as well as biochemical abnormalities has rendered the existing antibiotics such as isoniazid, rifampicin and chlorabutol ineffective. This has resulted in the emergence of multi-drug resistant strains of TB bacteria.

Antibiotic resistance in micro-organisms can be adaptive or genetic. Virtually, the whole cellular population undergoes some changes in its surface structure and becomes tolerant to the antibiotic. The resistance is transient and will last till there are no antibiotics in the environment of the organims.

Significantly, resistance develops more rapidly in some antibiotics such as methicillin and streptomycin. Cases of MRSA (Methicillin Resistant Staphylococous Aures) have been reported from Malaysia and other Third World countries. According to WHO, the problem is global and is the result of widespread and indiscriminate use of antibiotics.

A report published in the US Journal of Medical Microbiology points out that in the hospitals surveyed, up to 27 per cent of the bacteria in sewage was resistant to at least one form of antibodies. And nearly 43 per cent of the resistant bacteria carried the so-called "R" factor, implying it had the potential for multiple drug resistance. It is surmised that antibodies change the genetic trait in such a way as to hasten the process of drug resistance to the antibiotics.

Because antibiotics are quick acting, they are prescribed by physicians to the patients keen on "instant cure". Each of the antibiotics has a well defined area of action. The tendency therefore is to combine these antibiotics as a "gun shot" therapy.

Though antibiotics are to be sold only on prescription, they are handed over across the counter without any questions being asked. This easy availability has led to self-medication and quackery.

It is now well established that diarrhoeal infection could be aggravated by the irritative effect of the antibiotic tetracycline, when administered orally.