Bacterial resistance to Antibiotics
1. Introduction:
1.1 What is Antibiotic:
An antibiotic is a drug which prevent the advancement of bacteria or kills it. The word antibiotic comes from the Greek anti , that means “against” and bios means
“life”.Other Way, Antibiotics are also known as antibacterials which
are used to treat infections compel by bacteria. [1]
Antibiotics
are one clan of "antimicrobials", a colossal group which also comprise
anti-viral, anti-fungal, and anti-parasitic drugs. They are almost
harmless to the host, and also can be used to treat infection. The term
originally described only those conception acquired from living
organisms, but is now adapted also to synthetic antimicrobials, as like
as the sulfonamides.
1.2 How Antibiotics affect Bacteria:
There are a few number of various types of antibiotic which are work in one of two ways:
- The bacteria are killed by a bactericidal antibiotic. Penicillin is one kind of bactericidal. A bactericidal frequently either prevent the formation of the bacterium's cell wall or the particles of cell.
- A bacteriostatic usually stops bacteria from generate.
There
are various type of classes of antibiotics have been discovered and are
use in fighting bacterial infections. Every class of antibiotics has
its own mode of action or MOA. Basically the mode of action is how the
drug works to damage or kill bacteria.
- Penicillins: correlated to a class of antibiotics which is called B-lactams, the class of drugs impede with peptidoglycan cell wall structure. Human cells have no cells walls or peptidoglycan, for that case these are not harmed by Beta-lactam drugs.
- Tetracyclines: Extensive spectrum antibiotics which can disable bacteria by intercede with the cell’s capacity to make proteins. Therefore human cells besides produce proteins, the protein-making amoebic machinery is changed from eukaryotic cells, so it is not damaged by Tetracycline.
- Quinolones: This class of antibiotics conflict with the bacterial cell’s capacity to copy its DNA; before a cell can separate and multiply something need to be done. The eukaryotic DNA of human cells is wrapped distinctively, so its replication is not attenuate by Quinolones.
1.3 How Bacteria become resistant to Antibiotics:
Bacterial
resistant to antibiotics occur mainly by the misuse of antibiotics. For
example, if a patient is prescribed by physician for antibiotic with 10
days course, say penicillin, for 10 days, many people may stop taking
the penicillin after they feel good, and would instead stockpile the
antibiotic, expecting to preserve it for later use. In general an
antibiotic does not destroy all bacteria at a time, and it does not
destroy bacteria randomly. The bacteria removed first are those which
are most subject to the antibiotic, making those which are more proof,
and which bring level of resistance genetics.
Additionally,
genetic material which provides for bacterial resistance can be spread
among different types of bacteria in its lifecycle through a process
known as conjugation. In this re-developed where bacteria form plasmids
through enzyme, basically capsules consists of genetic material, which
are transferred from one to many bacteria.
Bacteria can achieve resistance against antibiotic by two primary ways:
a. By Mutation:
One
of the antibiotic working mechanism is inactivating an essential part
of bacterial protein. Organic change can be removed that protein. Again mutations in
the active part can prevent the antibiotic from binding or if it does
bind, prevent it from inactivating the target portion of bacteria.
Additionally, bacteria can produce an antibiotic-inactivating enzyme. As well, they may change the construction of its cell membrane or grow organic wall to the antibiotic.
b. Transfer of Antibiotic-resistant genes:
This is another way to gain resistance for bacteria. This mechanism transfers an existing antibiotic-resistant gene from
one bacterium to another bacterium. Famous microbiologist Dr. John
Turnidge, says they directly borrow their resistance genes from neighboring bacterium. "They are the simple but original life forms
almost, so for the millions of years they’ve had a chance to work out
ways to survive and one of those is to borrow genes from other bacteria
to survive." [3]
Fig: Bacterial resistance against Antibiotic [4]
2. Discussion:
Improper
use of antibiotic drugs have turned out to be the main health risk for
public and it is blamed that very soon, common infections are unlikely
to cure for treatment with antibiotic drugs no more. As a result of such
extreme use as well as abuse of antibiotics, we have actually ignored
the truth that nature offers its own ways of attacking back and
producing multi-resistant bacterial strains.
2.1 What is it:
Antibiotic
resistance in human body is a growing threat for public health in now a
days. It appears due to strains of bacteria in the human body become
resistant against antibiotics due to excess and misuse of antibiotics.
2.2 How many people affect:
With
growing of infectious disease on human health, now 190 million of
antibiotics courses are applied each day in hospitals. Additionally for
non-hospitalized patients, more than 133 million courses of antibiotics
are advised by physicians each year. It is approximated that 50 percent
of these latter solutions are needless since they are being recommended
for the common cold, coughs and other attacks. [5]
2.3 Common reasons:
It
is common practice for patients to assume or ask their doctors to
prescribe antibiotics in their sickness or in common disease like catch
cold. Patients are not conscious about infection either it is viral or
bacterial but antibiotics are used to treat bacterial infections and by
nature common cold is a viral infection. The only true way to know if
any cold, cough and fever or sickness is a bacterial infection and
possible chance of treating with antibiotics is to test it advised by
physician. If that test results come positive for bacterial infection,
then antibiotics can be prescribed to cure the disease. There is no
definite way of identifying whether a cold or sickness is a bacterial
infection or not without pathological test.
The
improper use and abuse of antibiotics increase the chance of the
development of antibiotic resistance. The most common abuse are:
- Physicians prescribing antibiotics for viral infections
- Take incomplete dosage of the antibiotic. When an antibiotic course is not finished fully, it leaves some bacteria alive and those resistant against antibiotic.
2.4 Bacterial mechanisms of Antibiotic resistance:
Various mechanisms
have developed in bacteria which allow them with antibiotic resistance.
These mechanisms can whatever organic change the antibiotic, deliver it
inactive through physical removal from the cell, or modify active part
so that it is not committed by the antibiotic.
The
most common mode is organic inactivation of the antibiotic. An existing
cell enzyme is reproduced to respond with the antibiotic in such a way
that it has minimal effects for the microorganism. An alternative action
applied by many bacteria is the differences of the antibiotic active
portion. These mechanisms are shown in the the figure below.
Bacteria
employ several devices to stave off antibiotic attack. Some antibiotics
must accumulate inside the bacteria to be effective, and bacteria have
pumps on the cell membrane to expel the drug before it has a chance to
reach its intracellular targets. If a mutation allows a bacterial cell
to overproduce membrane pumps, it will eject the drug faster than it can
diffuse in. The drug concentration inside the cell will remain low, and
the bacterium will survive.
The
best way to slow down antibiotic resistance is to couple different dose
of drugs in a course of treatment. The bacterial strain randomly
converting an immunity to one antibiotic medicine is low, but
considering the millions of cells in a single infection and thus
different types infections that may appear after long time in human
body. Applying different level of multiple drugs simultaneously, require
that survival strain to be developed multiple resistances. It results
in dramatically lower than the possibility of a strain growing
resistance to a single drug. Thus survive all these antibacterial
treatments may become less effective against the immune system of
bacteria.
Both
doctor and patients must have cooperation to perform in reducing the
misuse of antibiotics. Antibiotics should only be prescribed in
bacterial infection present at human body and it can be assured by
pathological test. Antibiotics are not applied against viral infection.
On the contrary, patients can ask about their infection to their
physicians and thus prevent unnecessary prescribing antibiotics when
they are not needed. Taking antibiotics when patient have a viral
infection not only waste time and money, but also do harm for health and
increase the chance of antibiotic resistance.[6]
3. Conclusion:
The
increased use and in some cases abuse of antibiotic has effected in
bacterial resistance in human health. Although research for newer and
more effective antibiotics are going on, necessary steps must be taken
to reverse the practices that increase antibiotic resistance in
bacteria. The World Health Organisation (WHO) has concerned on it and
directed Antimicrobial Resistance Monitoring program which conceal the
spread of antibiotic-resistant bacteria.
Patients
should ask their doctor about infection whether it is viral or
bacterial disease. Physicians should also change their prescribing
practices. They can reduce misuse of antibiotic drugs and only prescribe
antibiotics for bacterial infection. [7]
Antibiotic
resistance is a crucial community health problem.Some bacteria that are
able to produce serious human disease are becoming immune to most
generally available antibiotics. Generally antibiotic resistant bacteria
can expand from individual to individual in the society or from patient
to others in hospital. Careful infection control procedures will reduce
propagate of these bacteria in hospitals. Good personal hygiene and
practice of being clean will lower the risk of spreading of these
bacteria in the community. Accurate prescribing of antibiotics will minimize the development chance of more antibiotic resistant strains of
bacteria.[8]
References:
1. What Are Antibiotics? website: http://www.medicalnewstoday.com/articles/10278.php
2. Bacterial Resistance to Antibiotics. © 2009 Kenneth Todar PhD .
3. Antibiotic-resistant genes. website: http://www.abc.net.au/science/slab/antibiotics/resistance.htm
4. ANTIBIOTIC RESISTANCE. website: http://orbit.dtu.dk/fedora/objects/orbit:55386/datastreams/file_3687727/content
5.
Bacteriophages as potential new therapeutics to replace or supplement
antibiotics by by Mzia Kutateladze, Revaz
Adamia
6. Antibiotic Resistance.
7. ASM Task Force on Antibiotic Resistance. 1995. Report of the ASM Task Force
on Antibiotic Resistance. Antimicrob Agents Chemother 1995; ther 1992;30(suppl A):9–14.
39(suppl):2–23.
8. Antibiotic resistant bacteria. website: http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Antibiotic_resistant_bacteria
