When we look back at the history of medicine to decide what ‘improvements’ led to an ever increasing life span in humans, three major things stand out. First interestingly enough was the improvement in the management of pregnancy and especially the period around the delivery of the child. This improved ‘maternal and infant’ mortality. The second major development was understanding the importance of micronutrients including vitamins in diet. And third was the discovery of antibiotics. Of these the first two improvements are well established and require only fine tuning but antibiotics are becoming problematic.
Antibiotics are designed to kill organisms that can kill humans. So in a sense antibiotics and related medicines are a form of offensive warfare against other life forms. These primitive life forms include primarily bacteria but also include viruses and parasites. It is however important to understand that humans are surrounded by bacteria and there are literally billions of bacteria living inside our bodies many of whom are beneficial to our body processes. So, not all bacteria are harmful to humans but some are. The first line of defence against harmful bacteria is the body’s immune system. Antibiotics are needed when the body cannot fight against the bacteria by itself.
Medical science has developed stronger and better antibiotics to overcome bacterial resistance but the microbes kept developing resistance to even the newer and the more powerful antibiotics. So far science has been able to produce more effective antibiotics but we are reaching a state of diminishing returns. Newer antibiotics besides being more expensive also have detrimental side effects on the human organism itself.
There are three factors that have been blamed for this new medical threat. It is quite possible that with the emergence of antibiotic resistance bacteria, infections will again become a major source of morbidity and mortality among people in general but especially among the sick and the very old and the very young. The factors are first widespread and often inappropriate use of antibiotics in patients. Second, the routine use of antibiotics in farm animals even in the absence of any infection and third an aging population that is less able to fight against infections and needs to be treated more often.
Considering the inappropriate use of antibiotics in humans, estimates of antibiotics that are prescribed unnecessarily are quite large even in the United States (US) where antibiotics are only dispensed with a prescription from a registered physician. Why do physicians prescribe too many antibiotics is an interesting question for which there are many possible answers.
First is the most common one, namely it is easier to be cautious and prescribe an antibiotic for a sore throat or an upset stomach rather than order appropriate cultures (tests) to determine the real nature of the infection and then choose an appropriate antibiotic. These tests can take days to provide the answer while the patients want something done immediately. Doing the ‘right thing’ is often more time consuming and more expensive.
The second problem is that the prescription is correct but the patient feels better in a couple of days and decides to stop taking the antibiotics. This allows incomplete eradication of the infection and the surviving bacteria can develop resistance to that antibiotic. Worse, patients keep the unused antibiotics and use it another time if they have the same problem thus increasing the chance of producing resistance. The obvious question the patient asks is if all the bacteria are not dead then why am I better. Well, the body can also kill bacteria and once the number is lower, a healthy body can keep these bacteria in check.
In Pakistan, though the problem is often quite different. Physicians do prescribe antibiotics more than they should but they are not the only culprits. Almost all antibiotics are available ‘over the counter’ without a prescription. Patients can walk in and buy these antibiotics based on personal preference, a friend’s advice or on the advice of the pharmacy employee who in all probability has no formal medicine related training. There have been times when standing at a pharmacy counter I have seen people walk in and buy two or three antibiotic pills.
Feeding small doses of antibiotics to farm animals is very common especially in the US where most of the antibiotics used are fed to healthy animals being bred for human consumption. For whatever reason, these antibiotics fed animals are larger and healthier. Why these animals are larger and healthier is not really known. However this indiscriminate use of antibiotics is responsible for producing resistant bacteria that can transfer to humans and then produce infections that are difficult to control. There is a push to decrease the use of antibiotics in healthy animals.
As our populations get older and sicker, they develop weakness of their immune systems that naturally fight infections. These people then become more susceptible to getting infections and therefore need frequent antibiotics. Frequent use of antibiotics tends to produce resistant bacteria. Since many of these sick patients are in hospitals when they are treated these resistant bacteria start living in the hospital environment. Even under the most stringent cleaning techniques some of these bacteria persist and can infect other patients especially those that undergo major operations or need ‘tubes and lines’ reaching into the body. This type of infection acquired while in a hospital is called a nosocomial infection and is becoming a major problem in the hospital setting. These bacteria living in hospital environment are frequently resistant to most antibiotics.
Why bacteria develop resistance is a complicated question. The most probable cause is that the bacteria receive sub-lethal doses of antibiotics and survive but at the same time develop a mechanism for withstanding the effects of that antibiotic in the future through genetic mutations. The other fact is that most antibiotics have existed in nature in plants and fungi even before discovery by science and bacteria coming in contact with them developed resistance as an evolutionary defence mechanism. Whatever the reasons for antibiotic resistance, it is fast becoming a major health problem almost all the world over.
In a country like Pakistan, the most common reason for the increased development of antibiotic resistance is ‘off prescription’ use of these medicines. Clearly antibiotics should only be taken after being prescribed by a proper healthcare professional. Equally important is that antibiotics like all medicines should be taken as prescribed and for as long as they are prescribed for. In Pakistan another factor is also of importance. That is the unsupervised and often inappropriate production of medicines including antibiotics. It would be interesting to see how many of the antibiotics manufactured and being sold in the market place contain less than the advertised amount of the antibiotic.
Finally as I mentioned above antibiotics are designed to kill bacteria. Bacteria as living organisms have built in evolutionary mechanisms designed to survive adverse environmental factors including antibiotics. Eventually science will have to develop vaccination like mechanisms to prevent bacterial infections. Preventing infections eventually will be more effective than fighting infections by killing the invading bacteria. This is how we managed to control diseases like small pox and polio.