Antibiotics Vs Resistant Bacteria : A Big Fight

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Department of General Medicine

Antibiotics or antibacterials, are types of medications that destroy or slow down the growth of bacteria. They plays a major role in human health.Many diseases that killed the people can now be treated effectively with antibiotics.  Although, some bacteria become resistant to commonly used antibiotics.

Antibiotic resistance is the capacity or ability of a microorganism to withstand the effects of an antibiotic.

Antibiotic resistance occurs when an antibiotic lost its capacity to effectively control or kill the bacterial growth; or the bacteria are "resistant" and continue to multiply in the presence of therapeutic levels of an antibiotic. Antibiotic resistant bacteria are  not controlled or killed by antibiotics. They are able to survive and multiply in the presence of an antibiotic.Bacteria that are resistant to so many antibiotics are known as multi-resistant organisms.

Some bacteria are naturally resistant to some other  antibiotics. For example, benzyl penicillin has very little effect on most organisms present in the human digestive system (gut).

Causes of Antibiotic resistance

Antibiotic or Antibacterial  resistance is a natural phenomenon. When an antibiotic is taken, bacteria that can resist that antibiotic have a chance of survival than those that are "susceptible." Susceptible bacteria destroy or inhibited by an antibiotic,  forms  a selective pressure for the survival of resistant strains of bacteria.

Mechanism of Antibiotic resistance

An antibiotic to be potent ,it must reach the target site in an active form, bind to the target, and  obstruct  with its function. Thus, bacterial resistance to an antibiotic agent can takes place  in two ways:

1) By a genetic mutation

2) By acquiring resistance from another bacterium.

• By a genetic mutation : Mutations are rare spontaneous changes of the bacteria's genetic material, which are thought to hapen in about one in one million to one in ten million cells. Different genetic mutations produce  different types of resistance. Some mutations allow the bacteria to produce effective chemicals (enzymes) that inactivate antibiotics, while other mutations remove the cell target that the antibiotic attacks. Still others close the entry ports that permit antibiotics into the cell, and others manufacture pumping mechanisms that export the antibiotic back outside so it never reaches its target.

• By acquiring resistance from another bacterium : Bacteria can obtain antibiotic resistance genes from other bacteria by various methods. By undergoing a simple mating process called "conjugation," bacteria can convey genetic material,including genes encoding resistance to antibiotics from one bacterium to another. Any bacteria that earn resistance genes, whether by spontaneous mutation or genetic exchange with other bacteria, have the capacity to withstand one or more antibiotics. Because bacteria can gather multiple resistancefeature over time, they can become resistant to different families of antibiotics.

Spreading of Antibiotic resistance

Genetically,antibiotic resistance spreads along bacteria populations both "vertically" and "horizontally" Horizontal gene exchange can even happen between different bacterial species.Environmentally, antibiotic resistance spreads by moving from one place to other place; bacteria can travel via airplane, water and wind. People can spread the resistant bacteria to other peoples by coughing or contact with unwashed hands etc.

Ways to prevent antibiotic resistance

The major ways to prevent antibiotic resistance are:

•        Complete the full course of any prescribed antibiotic so that it can be fully effective and not propagate resistance.

•        Reduce unwanted  prescribing and over prescribing of antibiotics. This happen when people expect doctors to prescribe antibiotics for a viral illness (antibiotics do not act against viruses) or when antibiotics are prescribed for unnecessary case.

•        Practise good hygiene and use appropriate and correct  infection control procedures.

Reference

• Antibiotic Resistance by LauraLe Dyner MD ; Pediatric Infectious Disease Fellow June 2009.

• Antimicrobial resistance ; Medi centre.

• General Background: About Antibiotic Resistance ; Alliance for the prudent use of Antibiotics.

• Antimicrobial resistance ; European Centere for Disease Prevention and control.

• Antibiotic resistant bacteria ;from Better Health.

• Bacterial Resistance to AntibioticsTodar’s Online book of Bacteriology  byKenneth Todar, PhD