Anti-Biotic Resistance

Vinoo Jacob, Retd. Clinical Lead Surgeon & Chief of Medical Staff, Believers Church Medical College HospitalBCMCH is a healthcare institution of Believers Church which specializes in Dental, Dermatology, ENT & Head and Neck Surgery, Family Medicine, General Medicine, General Surgery, Ophthalmology, Paediatrics and many more.

An antibiotic is a chemical developed by a microorganism that can either kill or inhibit the growth of another microorganism. An antimicrobial agent is any chemical that does what an antibiotic does. Antimicrobial agents will also include chemicals produced by humans with the intention of acting against microbes, as well as the already mentioned antibiotics.

The term antibiosis was first termed by Jean Paul Vuillemin, a French scientist in 1889, when he used the term to describe a process by which life could be used to destroy life. The term antibiotic was first coined by Selman Abraham Waksman. The development of antibiotics followed the accidental discovery in 1929 by Alexander Fleming that the mould Pencillium could halt the growth of microbes. Florey & Chain were the people who managed to extract the antibiotic from the fungus. Fleming, Florey & Chain shared the Nobel Prize for Medicine in 1945 for their momentous discovery, which was estimated to have saved the lives of over 200 million people.

Following the initial discovery of Pencillin, there was flurry of research activity which resulted in the development of a series of antibiotics and antimicrobials over the next 50 years or so so. However, pharma firms are losing interest in developing newer antibiotics because the returns are poor compared to the heavy outlay in research. This means that in the last few years, no new antibiotic has come on the market. This combined with the fact that most organisms have now developed resistance to even newer powerful antibiotics can eventually lead to a crises of unimaginable prportions.

Antibiotics act on microbes in many different ways. The common methods of action are by inhibition of cell wall or cell membrane synthesis. Cell walls & membranes are the protective layers that cover the bacteria like the skin of the humans. By inhibiting the synthesis of these protective layers, bacteria become vulnerable and will not be able to survive. Other ways that drugs act on bacteria are by interfering in their ability to synthesise protein or nucleic acids, all of which are necessary for bacteria to survive and multiply.

For antimicrobials to act effectively against microbes, they need to achieve certain levels
of concentration within the body of the patient, who is being treated for a particular bacterial infection. Only at these levels of concentration can they be effective in acting against the microbes. To achive these levels of concentration, adequate quantity of the drug has to be given. Moreover, any medication given by any route to the patient is ultimately broken-down and excreted from the body by a variety of means. This means that an effective concentration will only be maintained for a certain period of time, unless the dosing is repeated on time. The time taken for the drug to be broken-down varies from drug-to-drug. Therefore, the frequency of dosing will vary from drug-to-drug. It is, therefore, important to remember these two factors while treating a microbial infection, i.e., giving the correct dose that will provide the effective concentration, as well as repeating the dose at regular intervals so much so that correct levels are maintained.

"Antibiotics act on microbes in many different ways. The common methods of action are by inhibition of cell wall or cell membrane synthesis"

So, what is antibiotic resistance and why is it happening? Antibiotic resistance is the ability of a microorganism to withstand the effects of antibiotics. Microbes can develop resistance in many different ways. First and foremost is inappropriate use of antibiotics. For example, a large number of infections are not caused by bacteria and do not need antibiotic. WHO guidelines have for many years clearly indicated that an uncomplicated diarrhoeal episode does not need any antibiotics. In fact in many cases, patients themselves request that an antibiotic be started. The antibiotic prescribed maybe given in sub-optimal doses or frequency, resulting in inadequate levels of the antibiotic in the body fluids. This means that the bacteria are not killed, but are in contact with the antibiotic, allowing them to develop strategies to resist the antibiotic.

In a large majority of cases, no attempt is made to determine the cause of the apparent infection. Ideally, before a course of antibiotic is started, the doctor should take specimens of relevant body fluids and send them to the lab along with information about the illness, suspected microbial organism and the plan to start a particular antibiotic. By taking a specimen of a suspected body fluid under sterile conditions, and culturing them in the laboratory, bacteria if they are present can be grown, and the Microbiolologist can even find-out which antibiotic they are susceptible to. The doctor can then, using his experience and the symptoms of the patient, start an antibiotic, which he thinks will act against the particular organism that is causing the disease, giving the adequate dose at the correct frequency.

Full reports are usually available in 72 hours, which will indicate which all anti-microbial agents will act against the organism grown. If no organism is grown, then the doctor can stop the course of antibiotic started. If there is a growth and the antibiotic already started is not the suitable one, the doctor can then change it to the most suitable antibiotic.

Unfortunately, most of these relevant precautions or steps would not have been followed. A patient presenting with even a minor ilness would request an antibiotic or he or she may have in fact started themselves on an antibiotic obtained from the chemist. The doctor may start the patient on an antibiotic, which may not be the ideal choice for that particular disease. He may have given a lower dose and the frequency may not be the correct frequency. The doctor may have given the patient a higher wide spectrum antibiotic, when a lower one and more specific antibiotic would have done the trick.

Antibiotic resistance has already reached alarming stages, wherein severe infection causing organisms are already resistent to all known antibiotics. So, how do we prevent the development of further antibiotic resistance? First of all, no antibiotic should be available over the counter, without a prescription. Certain antibiotics, which should only be used in life threatening infections, should only be prescribed by doctors who are dealing with such diseases. This means that the average General Practioner should not be able to access such antibiotics. These antibiotics should only be given-out on the prescription of doctors, who have the reqisite qualification to prescribe such medications. All this needs education of the public, the medical fraternity, as well as adequate legislation and most importantly, watchdog antibiotic stewardship bodies.