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Drug resistance is often a problem in malaria, tuberculosis, HIV, sexually transmitted diseases and hospital acquired diseases. Judicious use of antibiotics can control the problem.
Drug resistance is a grave medical problem in today’s world. A person is said to be resistant to a drug if he does not respond to it. This problem is often seen with antimicrobial drugs. Antimicrobials especially antibiotics are prescribed indiscriminately. The physician may prescribe the antimicrobial for a particular number of days, but the patient may stop taking the drug as soon as he is better. Antibiotics are often available over – the – counter in the absence of adequate regulations. In such cases, the patient may take a lower dose than necessary. They are also being freely used in poultry and animal husbandry to improve the growth of farm animals and prevent infections. All these conditions predispose organisms to develop resistance to a drug.
Development of resistance is particularly important in cases of diarrhea, respiratory tract infections, sexually transmitted diseases, hospital – acquired infections, malaria, tuberculosis and HIV. In diseases such as tuberculosis and HIV, a combination of drugs is advised to prevent resistance.
Drug resistance can affect the health of a patient. If the patient is resistant to a commonly used antibiotic, he may have to take a second line drug which could be costlier or have more side effects. Treatment may be for a longer duration, and the patient could suffer from complications and even death. Awareness about drug resistance is extremely important in order to control the problem and maintain efficacy of drugs.
Resistance to one drug may also result in resistance to other similar drugs. This phenomenon is called cross resistance. For example, if an organism is resistant to one sulfonamide, it is usually resistant to all sulfonamides. Some organisms are resistant to multiple drugs and are said to be multi – drug resistant strains. These include methicillin – resistant staphylococcus aureus (MRSA) and vancomycin resistant enterococci.
Methicillin Resistant Staphylococcus aureus (MRSA) is one of the most dreaded drug – resistant strains. Infections due to MRSA vary from cellulitis (infection of the skin and the tissues under it) to endocarditis (infection of the inner lining of the heart), osteomyelitis (bone infection) and sepsis (infection in the blood). These infections are serious and can lead to death. Patients often acquire the MRSA infection when they are admitted to hospitals. Antibiotics like vancomycin and linezolid are effective against this resistant bacterium.
New drug resistant bacteria have been recently discovered in South Asia. These contain a particular gene that helps the bacteria produce an enzyme called New Delhi Metallo – b - lactamase -1 (NMD - 1). This enzyme makes these “superbugs” resistant to multiple drugs including carbapenems. Carbapenems are antibiotics related to penicillin and are used to treat serious infections. These drug resistant bacteria are susceptible to only two antibiotics at present, colistin and tigecycline and may soon develop resistance to these as well. India has strongly objected to the enzyme being named after the national capital since the resistance could have developed anywhere and such bad publicity could have an adverse effect on medical tourism.
The discovery of antibiotics has slowed down with very few new classes available in the last few years. It is extremely important to use the available antibiotics judiciously to prevent resistance.
Though drug resistance mainly refers to resistance to antibiotics and other antimicrobials, people may also be resistant to other drugs as well. Cancer patients may be resistant to some anticancer drugs. Diabetes patients may develop resistance to insulin requiring an increased amount of the hormone. This could occur in conditions of stress or due to formation of antibodies following chronic use.