Antibiotic resistance

Antibiotics

Antibiotics are powerful drugs, but they are not the cure for all the diseases. Antibiotics are drugs that fight infections caused by bacteria. They are not effective against viral infections like the common cold, most sore throats, and the flu.

Antibiotic resistance

Antibiotic resistance is the ability of a microorganism to withstand the effects of an antibiotic. Bacteria, not humans, become antibiotic resistant. These bacteria may then infect humans and are harder to treat than non-resistant bacteria.

Today, almost all important bacterial infection in the India and throughout the world are becoming resistant to antibiotics. Antibiotic resistance has been called one of the world’s most pressing public health concerns. Irrational use of antimicrobials is widespread throughout the world. This is harmful in terms of increased cost of therapy, unnecessary adverse drug reactions, therapeutic failure, reduced quality of care and worst of it is Anitimicrobial resistance (AMR). A growing list of infections—such as pneumonia, tuberculosis, blood poisoning and gonorrhoea—are becoming harder, and sometimes impossible, to treat as antibiotics become less effective.

Difference between antibiotic and antimicrobial resistance

Antibiotic resistance refers specifically to the resistance to antibiotics that occurs in common bacteria that cause infections. Antimicrobial resistance is a broader term, encompassing resistance to drugs to treat infections caused by other microbes as well, such as parasites (e.g. malaria), viruses (e.g. HIV) and fungi (e.g. Candida).

Causes contributing to antibiotic /antimicrobial resistance

• Development and spread of antimicrobial resistance (AMR) is commonly due to overuse, misuse, and indiscriminate use of antimicrobials by doctors, nurses and pharmacists, non - compliance and self medication by patients and use in animal husbandry and agriculture.
• It is estimated that 70 - 80% of prescriptions for antimicrobials are probably advised unnecessarily by the health professionals. In spite of the fact that most common colds and diarrheal episodes are viral in origin, yet, antimicrobials are used indiscriminately. Reasons for over prescribing are often lack of confidence, peer pressure, patient pressure and pharmaceutical company pressure.
• Another common cause of developing resistance is improper diagnosis. In many instances dearth of an adequately equipped diagnostic laboratory in the vicinity compels the physician to prescribe antibiotics empirically, thus, increasing the likelihood of the patient receiving a wrong antibiotic.
• Furthermore, ready availability of antibiotics over - the - counter and sales promotion schemes by the pharmaceutical manufacturers also leads to the promotion of indiscriminate use, thus, increasing the likelihood of development of resistance.
• Counterfeit drugs are also a problem contributing to development of resistance. These contain either the wrong ingredient, or lesser amount of the active ingredient. In some instances, the medication poisons are capable of causing disability or even death.
• The impact of the media has also contributed to the development of resistance. Patients often demand antibiotics for their ailment on the basis of advertisements read or seen.
• Unwitting use of more active drugs at sub therapeutic doses leads directly to the development of multi drug resistance.

Established mechanisms of AMR

For an antibiotic to be effective, it must reach the target site in an active form, bind to the target, and interfere with its function. Thus, bacterial resistance to an antimicrobial agent can occur due to three general mechanisms:

• The drug does not reach its target : In Gram negative bacteria, many antibiotics enter the cell through protein channels called porins. Mutations or loss of these channels can prevent/slow the rate of antibiotic entry into a cell, effectively reducing drug concentration at the target site. If the drug target is intracellular and the drug requires active transport across the cell membrane, a mutation that interferes with the transport mechanism can confer resistance e.g. aminoglycosides. Bacteria can also transport antimicrobial drugs out of the cell through efflux pumps. Resistance to numerous drugs, including fluoroquinolones, macrolides, tetracyclines and beta lactam antibiotics, is mediated by this mechanism.
• The drug is inactivated : Bacterial resistance to aminoglycosides can be due to a plasmid encoded aminoglycoside-modifying enzymes. Similarly, β-lactamase production is the most common mechanism of resistance to penicillins and other β-lactam drugs. Many hundreds of different β-lactamases have now been identified. A variation of this mechanism is failure of the bacterial cell to activate a prodrug e.g. loss of ability of M. tuberculosis to activate isoniazid (INH).
• The target site is altered : This may be due to mutations in drug binding region of target enzyme e.g. fluoroquinolones, target modification e.g. ribosomal protection type of resistance to macrolides and acquirement of a resistant form of the susceptible target e.g., methicillin resistance in Staphylococcus Spp. due to production of a low-affinity penicillin-binding protein (PBP).

Prevention and control

Antibiotic resistance is accelerated by the misuse and overuse of antibiotics, as well as poor infection prevention and control. Steps can be taken at all levels of society to reduce the impact and limit the spread of resistance.

The general public can help by:

• Preventing infections by regularly washing hands, practicing good food hygiene, avoiding close contact with sick people and keeping vaccinations up to date
• Only using antibiotics when prescribed by a certified health professional
• Always taking the full prescription
• Never using left-over antibiotics
• Never sharing antibiotics with others.

• Preventing infections by ensuring hands, instruments and environment are clean
• Keeping patients’ vaccinations up to date
• When a bacterial infection is suspected, perform bacterial cultures and testing to confirm
• Only prescribing and dispensing antibiotics when they are truly needed
• Prescribing and dispensing the right antibiotic at the right dose for the right duration.

• Having a robust national action plan to tackle antibiotic resistance
• Improving surveillance of antibiotic-resistant infections
• Strengthening infection prevention and control measures
• Regulating and promoting the appropriate use of quality medicines
• Making information on the impact of antibiotic resistance available
• Rewarding the development of new treatment options, vaccines and diagnostics.

• Ensure that antibiotics given to animals - including food-producing and companion animals - are only used to treat infectious diseases and under veterinary supervision.
• Vaccinate animals to reduce the need for antibiotics and develop alternatives to the use of antibiotics in plants.
• Promote and apply good practices at all steps of production and processing of foods from animal and plant sources.
• Adopt sustainable systems with improved hygiene, biosecurity and stress-free handling of animals.
• Implement international standards for the responsible use of antibiotics, set out by OIE, FAO and WHO.

• Investing in new antibiotics, vaccines, and diagnostics.

Global action plan to antimicrobial resistance

A global action plan on antimicrobial resistance, including antibiotic resistance, was endorsed at the World Health Assembly in May 2015. The global action plan aims to ensure that the prevention and treatment of infectious diseases with safe and effective medicines continues. The global action plan has 5 strategic objectives:

• To improve awareness and understanding of antimicrobial resistance
• To strengthen surveillance and research
• To reduce the incidence of infection
• To optimize the use of antimicrobial medicines
• To ensure sustainable investment in countering antimicrobial resistance.

Sources :

1. General Information on antibiotics and antibiotic resistance by Central Drugs Standard Control Organization (CDSCO)
2. Antibiotic resistance - Fact sheet - November 2017
3. National policy for containment of Antimicrobial resistance