The term “antibiosis”, meaning “against life”, was introduced by the French bacteriologist Jean Paul Vuillemin as a descriptive name of the phenomenon exhibited by early antibacterial drugs.
The term “antibiotic” was first used in 1942 by Selman Waksman and his collaborators in journal articles to describe any substance produced by a microorganism that is antagonistic to the growth of other microorganisms in high dilution.
This definition excluded substances that kill bacteria, but that are not produced by microorganisms (such as gastric juices and hydrogen peroxide).
It also excluded synthetic antibacterial compounds such as the sulphonamides.
In current usage, the term “antibiotic” is applied to any medication that kills bacteria or inhibits their growth, regardless of whether that medication is produced by a microorganism or not.
The ancient Egyptians, Chinese and Native Americans all used moulds to treat infected wounds.
However, they did not understand the connection between the antibacterial properties of mould and the treatment of diseases.
The search for antibiotics began in the late 1800s, with the growing acceptance of the germ theory of disease.
This is a theory that links bacteria and other microbes to the causation of a variety of ailments.
As a result, scientists began to devote time to searching for drugs that would kill these disease-causing bacteria.
Dangerously high levels
Antimicrobial resistance (AMR) is the ability of microorganisms to resist the effects of medication that could once successfully treat them.
The term “antibiotic resistance” is a subset of AMR, as it applies only to bacteria becoming resistant to antibiotics.
Resistant bacteria are more difficult to treat, requiring alternative medications or higher doses of antibiotics.
These approaches may be more expensive, more toxic or both.
Bacteria, not humans or animals, become antibiotic-resistant.
These bacteria can infect humans and animals, causing infections that are tougher to treat as they can resist the effects of certain antibiotics to kill them.
Today, antibiotic resistance is one of the biggest threats to global health, food security and economic development.
It is rising to dangerously high levels in all parts of the world.
Antibiotic resistance can affect anyone, of any age, in any country.
It occurs naturally, but misuse of antibiotics in humans and animals is accelerating the process.
A growing number of infections – such as pneumonia, tuberculosis, gonorrhoea and salmonellosis – are becoming harder to treat as the antibiotics used to treat them have become less effective.
Antibiotic resistance leads to a longer hospital stay, higher medical costs and increased rates of death.
Newer resistance mechanisms are emerging and spreading globally, threatening our ability to treat common infectious diseases.
Leading the resistance
The causes of antibiotic resistance include:
- Lack of target
Antibiotics normally bind onto specific proteins on the bacteria’s cell wall.
Some bacteria have no cell wall, giving the antibiotic no place to latch onto and rendering it useless.
This gives these bacteria an innate resistance to penicillin.
- Lack of entry
After binding to the cell wall proteins, the antibiotic normally enters the bacterial cells via porin channels in the cell wall.
The loss of these specific porin channels or the creation of new porin channels in the bacterial cell wall block antibiotics from entering the cells.
- Blocked entry or increased excretion
This means that the drug is either blocked from entering the cell or there is a mechanism that causes the drug to be excreted from the cell too quickly to be of much use.
For example, some gram negative bacteria inhibit the plasmid-mediated synthesis of porin channels, which obstructs the influx of penicillin.
- Enzyme inactivation
Certain enzymes can either destroy antibiotics or prevent them from binding to target sites.
- Altered target
The specific binding proteins on the bacterial cell surface can be altered due to genetic mutations as the cells replicate, resulting in the antibiotic being unable to bind to them any more.
- Alternative pathway
An alternative pathway that bypasses the reaction inhibited by the antibiotic allows for the bacteria to avoid the antibiotic’s harmful effect.
- Genetic mutations
This refers to the random change in the DNA structure of genes, which occurs at a frequency of one per ten million cells.
Mutations can randomly confer the ability to resist antibiotics on bacteria through a few methods, including those listed above.
Plasmids are extra chromosomal genetic elements that can replicate independently and freely in a cell’s cytoplasm.
When a plasmid develops a mutation that enables it to resist the harmful effects of an antibiotic, it can easily pass this mutation on to another plasmid or to a cell’s chromosome.
Plasmids that carry resistant genes (r-genes) are called R-plasmids.
Much of the drug resistance encountered in clinical practice is plasmid-mediated.
The human factor
However, antibiotic resistance is not solely propagated by the biological causes above.
Us humans also act in various ways to help promote antibiotic resistance.
- Forgetting to take medication.
- Stopping their medication when they begin to feel better.
- Unable to afford the full course of medication and only taking part of the course.
- Misuse of antibiotics.
- Self-medication, which may be unnecessary or taken in the wrong doses.
- Overprescribing broad spectrum drugs when a narrow spectrum drug is appropriate.
- Giving the wrong prescription.
- Giving unnecessary prescriptions.
- Inadequate survelliance and susceptibility testing, leading to use of broad-spectrum drugs, rather than a narrow spectrum one.
- Poor infection control practices like inadequate handwashing, not changing gloves between patients, etc, which can lead to highly-resistant bacterial pathogens that cause hospital-acquired infections in patients.
- Circulating and using expired and counterfeit antibiotics.
- Lack of quality compliance and monitoring.
- Used for growth and disease control in poultry, cattle, pigs, etc. Humans are indirectly taking these antibiotics when eating the meat.
- Residents of developing countries often carry antibiotic-resistant faecal commensal organisms due to close living quarters.
- Visitors to developing countries passively acquire antibiotic-resistant E. coli.
We’re all involved
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 of antibiotic resistance and limit its spread, including by individuals, policymakers, healthcare professionals, and both the healthcare and agriculture industries.
These steps include developing prescription guidelines, emphasising public awareness and quality compliance, monitoring the manufacture and dispensation of antibiotics and public sanitation, and improving hospital infection control.
The emergence and spread of antibiotic resistance is made worse when antibiotics can be bought for human or animal use without a prescription.
Similarly, in countries without standard treatment guidelines, antibiotics are often overprescribed by health workers and veterinarians, and overused by the public.
The world urgently needs to change the way it prescribes and uses antibiotics.
Even if new medicines are developed, without behaviour change, antibiotic resistance will remain a major threat.
Behaviour changes must include actions to reduce the spread of infections through vaccination, handwashing, safer sex and good food hygiene.
Without urgent action, we are heading for a post-antibiotic era in which common infections and minor injuries can once again kill.
Dr Mohammad Nazmul Hasan Maziz is deputy dean and associate professor in medical microbiology at the Perdana University Graduate School of Medicine. This article is courtesy of Perdana University. For more information, email firstname.lastname@example.org. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
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