Antibiotic Resistance: An Overview

Introduction

Antibiotic resistance is the ability of a microbe to resist the antibiotic. The term Antibiotic resistance is very common these days. In this article I will give you an overview of Antibiotic resistance.

Infections are very common in our daily life and responsible for a large number of diseases. Disease-causing microorganisms are termed as “Pathogens”. Most of the diseases are caused by bacteria. To treat such diseases antibiotics are used.

After the discovery of antibiotics in the 20th century, these have always been considered as one of the wonder discoveries. Over a period of time, various classes of antibiotics were introduced in the market. Besides that bacteria become resistant to certain antibiotics over the period of time. This resistance is termed as Antibiotic resistance. There are several factors that are responsible for antibiotic resistance.

History of antibiotics

The first antibiotic, penicillin, was discovered in 1929 by Sir Alexander Fleming. He observed inhibition of staphylococci on an agar plate contaminated by a Penicillium mold.

Fleming was searching for potential antibacterial compounds. He noticed that a patch of the mold Penicillium notatum had grown on a plate. The plate containing the bacterium Staphylococcus and that around the mold there was a zone where no Staphylococcus could grow.

After more research, he was able to show that the culture broth of the mold prevented the growth of the Staphylococcus. This growth is prevented even though diluted up to 800 times. He named the active substance penicillin but was unable to isolate it.

Several years later, in 1939, Ernst Chain and Howard Florey developed a way to isolate penicillin. It was used to treat bacterial infections during the Second World War. The new drug came into clinical usage in 1946 and made a huge impact on public health.

While Fleming was working on penicillin, Gerhard Domagk, a German doctor, announced the discovery of a synthetic molecule with antibacterial properties. He named the compound Prontosil, and it became the first of a long series of synthetic antibiotics called sulfonamides or sulfa drugs.

In the late 1940s and early 1950s, new antibiotics were introduced. These include streptomycin, chloramphenicol, and tetracycline. The age of antibiotic chemotherapy came into full being.

Antibiotic Resistance

Antibiotics are drugs used for treating infections caused by bacteria. Also known as antimicrobial drugs, antibiotics have saved countless lives.

Misuse and overuse of these drugs, however, have contributed to a phenomenon known as antibiotic resistance. This resistance develops when potentially harmful bacteria change in a way that reduces or eliminates the effectiveness of antibiotics.

According to CDC Each year in the United States, at least 2 million people become infected with bacteria that are resistant to antibiotics and at least 23,000 people die each year as a direct result of these infections.

Multiple drug-resistant organisms

Multiple drug-resistant organisms are resistant to treatment with several, often unrelated, antimicrobial agents as described above in Shigella. Some of the most important types of multiple drug-resistant organisms that have been encountered include:

MRSA – methicillin/oxacillin-resistant Staphylococcus aureus

VRE – vancomycin-resistant enterococci

ESBLs – extended-spectrum beta-lactamases (which are resistant to cephalosporins and monobactams)

PRSP – penicillin-resistant Streptococcus pneumoniae

MRSA and VRE are the most commonly encountered multiple drug-resistant organisms in patients residing in non-hospital healthcare facilities, such as nursing homes and other long-term care facilities.

PRSP is more common in patients seeking care in outpatient settings such as physicians’ offices and clinics, especially in pediatric settings. ESBLs are most often encountered in the hospital (intensive care) setting, but MRSA and VRE also have significant nosocomial ecology.

Antibiotic	Method of resistance
Chloramphenicol	reduced uptake into cell
Tetracycline	active efflux from the cell
β-lactams, Erythromycin, Lincomycin	eliminates or reduces binding of antibiotic to cell target
β-lactams, Aminoglycosides, Chloramphenicol	enzymatic cleavage or modification to inactivate antibiotic molecule
Sulfonamides, Trimethoprim	metabolic bypass of inhibited reaction

Causes

Antibiotic resistance occurs when bacteria change in some way that reduces or eliminates the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The bacteria survive and continue to multiply causing more harm. Bacteria can do this through several mechanisms. Some bacteria develop the ability to neutralize the antibiotic before it can do harm, others can rapidly pump the antibiotic out, and still, others can change the antibiotic attack site so it cannot affect the function of the bacteria.

In addition, bacteria that were at one time susceptible to an antibiotic can acquire resistance through mutation of their genetic material or by acquiring pieces of DNA that code for the resistance properties from other bacteria. The DNA that codes for resistance can be grouped in a single easily transferable package. This means that bacteria can become resistant to many antimicrobial agents because of the transfer of one piece of DNA.

Prevention

Antibiotics designed for bacterial infections are not useful for viral infections such as a cold, cough, or the flu. Some useful tips to remember are:

1. Talk with your healthcare provider about antibiotic resistance:
   • Ask whether an antibiotic is likely to be beneficial for your illness
   • Ask what else you can do to feel better sooner
2. Do not take an antibiotic for a viral infection like a cold or the flu.
3. Do not save some of your antibiotics for the next time you get sick. Discard any leftover medication once you have completed your prescribed course of treatment.
4. Take an antibiotic exactly as the healthcare provider tells you. Do not skip doses. Complete the prescribed course of treatment even if you are feeling better. If treatment stops too soon, some bacteria may survive and re-infect.
5. Do not take antibiotics prescribed for someone else. The antibiotic may not be appropriate for your illness. Taking the wrong medicine may delay correct treatment and allow bacteria to multiply.
6. If your healthcare provider determines that you do not have a bacterial infection, ask about ways to help relieve your symptoms. Do not pressure your provider to prescribe an antibiotic.

Additional Precautions

Additional precautions are used when caring for patients who are known or suspected to be infected or colonized with highly infectious pathogens (micro-organisms that cause disease). Micro-organisms may be classed as ‘high risk’ if:

• Their transmission route makes them more contagious – they may be spread through contact or droplets or maybe airborne
• They are caused by antibiotic-resistant bacteria
• They are resistant to standard sterilization procedures.

Additional precautions are tailored to the particular pathogen and route of transmission. Additional precautions may include:

• use of a single room with unsuited facilities or a dedicated toilet
• dedicated patient care equipment
• restricted movement of patient and healthcare workers.

Transmission in the community

Antibiotic-resistant bacteria can be passed from person to person within the community. This is becoming more common.

Ways to prevent transmission of all organisms, including antibiotic-resistant bacteria, are:

• Wash hands before and after food handling, going to the toilet and changing nappies.
• Cover your nose and mouth when coughing and sneezing.
• Use tissues to blow or wipe your nose.
• Dispose of tissues properly.
• Do not spit.
• Stay at home if you are unwell and cannot manage your normal requirements of the day.
• Do not send children to childcare, crèche or school if they are unwell.
• If you are feeling better even then take the entire course of antibiotics.
• If you continue to feel unwell, go back to the doctor.
• Avoid the use of products that advertise they contain antibiotics, antibacterial and antimicrobial without your doctors advise.

Things to remember

• Antibiotic resistance is a serious public health problem.
• Some bacteria that are capable of causing serious disease are becoming resistant to most commonly available antibiotics.
• Antibiotic-resistant bacteria can spread from person to person in the community or from patient to patient in the hospital.
• Careful infection control procedures will minimize the spread of these bacteria in hospitals.
• Good personal hygiene will minimize the spread of these bacteria in the community.
• Careful prescribing of antibiotics will minimize the development of more antibiotic-resistant strains of bacteria.

Conclusion

In the past 60 years, antibiotics have been critical in the fight against infectious diseases caused by bacteria and other microbes. Antimicrobial chemotherapy has been a leading cause for the dramatic rise of average life expectancy in the Twentieth Century. Disease-causing microbes that have become resistant to antibiotic drug therapy are an increasing public health problem. Wound infections, gonorrhea, tuberculosis, pneumonia, septicemia and childhood ear infections are just a few of the diseases that have become hard to treat with antibiotics.

One part of the problem is that bacteria and other microbes that cause infections are remarkably resilient and have developed several ways to resist antibiotics and other antimicrobial drugs. Another part of the problem is due to increasing use, and misuse, of existing antibiotics in humans.