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Womens College of Pharmacy, Peth Vadgaon, Maharashtra, India
One of the biggest risks to global public health in the twenty-first century is antibiotic resistance. It happens when bacteria, fungi, viruses, and parasites become resistant to antimicrobial agents that used to be effective against them. The emergence of resistant microbes has been driven by the extensive abuse and misuse of antibiotics in human medicine, veterinary care, agriculture, and aquaculture. Antibiotic resistance increases mortality, lengthens illness, raises healthcare costs, and decreases the efficacy of conventional treatments. The history, mechanisms, causes, transmission, clinical impact, diagnosis, prevention, and therapy of antibiotic resistance are all covered in this overview. The review also emphasises how governments, the pharmaceutical industry, healthcare providers, and the general public should all help fight antibiotic resistance. Additionally covered are cutting-edge treatment approaches such as combination therapy, antimicrobial peptides, nanotechnology, vaccinations, and bacteriophage therapy. Reducing the burden of resistant pathogens requires the creation of antibiotic stewardship programs and stringent infection control regulations.
One of the most significant medical breakthroughs in history is the development of antibiotics. These are chemicals that are used to either eradicate or stop the growth of microorganisms, particularly bacteria. Antibiotics have significantly decreased the mortality and morbidity linked to infectious diseases since Alexander Fleming discovered penicillin in 1928. By making previously lethal illnesses manageable and enabling cutting-edge medical operations like organ transplantation, chemotherapy, surgery, and intensive care treatment, the discovery of antibiotics transformed healthcare.
Antibiotics are frequently used to prevent and cure bacterial infections in human medicine, veterinary care, agriculture, and aquaculture. Antibiotics are an efficient treatment for common bacterial disorders such pneumonia, TB, urinary tract infections, septicaemia, meningitis, and skin infections. Global life expectancy and quality of life have greatly increased as a result of their widespread use.
However, as antibiotic resistance develops, the efficacy of antibiotics is progressively decreasing. When bacteria learn to withstand exposure to antibiotics that were once effective against them, this is known as antibiotic resistance. Even when therapeutic doses of antibiotics are present, resistant microorganisms continue to proliferate and thrive, making the treatment of illnesses challenging or even impossible.
Antibiotic overuse and abuse have sped up the natural evolutionary development of antibiotic resistance. The evolution of resistance bacteria is greatly aided by the overprescription of antibiotics, self-medication, improper dosage, unfinished treatment courses, inadequate infection control procedures, and the extensive use of antibiotics in livestock production. The issue is made worse by the widespread availability of antibiotics without a prescription in many nations.
Through a variety of processes, including enzymatic antibiotic degradation, alteration of antibiotic target sites, decreased drug permeability, efflux pump systems, and biofilm development, microorganisms acquire resistance. Through horizontal gene transfer processes like conjugation, transformation, and transduction, resistance genes can spread quickly among bacteria. Multidrug-resistant organisms are consequently becoming more commonplace globally.
A significant global public health concern that affects both industrialised and developing nations is antibiotic resistance. Antimicrobial resistance is one of the top ten worldwide public health risks that humanity faces, according to the World Health Organization. Due to the decreased efficacy of currently available antibiotics, common diseases that were formerly easily cured are becoming more challenging to treat. Methicillin-Resistant Staphylococcus aureus (MRSA), Vancomycin-Resistant Enterococci (VRE), Multidrug-Resistant Tuberculosis (MDR-TB), and Carbapenem-Resistant Enterobacteriaceae (CRE) are examples of resistant pathogens that are linked to higher mortality, longer hospital stays, and higher medical expenses.
Antibiotic resistance has an effect outside of medical facilities. Contaminated food, water, animals, and the environment can all harbour resistant bacteria, which can have an impact on entire communities. Alternative treatments for infections brought on by resistant organisms are costly, hazardous, and may have serious side effects. Furthermore, there are significant worries about how infectious diseases will be managed in the future due to the absence of new antibiotic research.
Numerous advances in contemporary medicine are at risk due to the rise of antibiotic resistance. Effective antibiotics are essential for preventing and treating infections during surgical procedures, cancer treatments, newborn care, and organ transplantation. These procedures become more dangerous and potentially fatal in the absence of appropriate antibacterial drugs.
Coordinated international efforts including medical professionals, researchers, governments, the pharmaceutical industry, the agriculture sector, and the general public are needed to combat antibiotic resistance. Essential tactics for preventing the spread of resistance include the prudent use of antibiotics, stringent infection control procedures, antimicrobial stewardship programs, surveillance systems, public awareness campaigns, and research into novel therapeutic techniques.
Antibiotic resistance's history, mechanisms, causes, clinical impact, diagnosis, prevention, management techniques, and future prospects are all included in this review. Developing successful strategies to maintain the effectiveness of currently available medicines and safeguard global public health requires an understanding of antibiotic resistance.
History of Antibiotics and Resistance :-
Alexander Fleming's 1928 discovery of penicillin marked the beginning of the history of antibiotics. Fleming found that bacterial growth was hindered by the fungus Penicillium notatum. Millions of lives were saved by penicillin, which became readily accessible during World War II.
Following penicillin, several antibiotics were discovered:-
Between 1940 and 1960, a number of novel antibiotics were created during the "golden age of antibiotics."
Antibiotic resistance, however, appeared shortly after the introduction of antibiotics. Within a few years of using penicillin, reports of penicillin-resistant Staphylococcus aureus were made. The 1960s saw the emergence of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), multidrug-resistant tuberculosis (MDR-TB), and carbapenem-resistant Enterobacteriaceae (CRE).
Because of bacterial evolution and the selective pressure brought on by antibiotic exposure, resistance has persisted.
Clinical Examples
Methicillin-resistant Staphylococcus aureus (MRSA)
A major antibiotic-resistant bacteria linked to a number of clinical diseases, such as pneumonia, sepsis, and skin and soft tissue infections, is methicillin-resistant Staphylococcus aureus (MRSA). The primary cause of MRSA's methicillin resistance is the mecA gene, which alters penicillin-binding proteins (PBPs) when activated. In the end, this change helps bacteria avoid the effects of antibiotics, which helps them survive and persist in clinical settings. Due to the organism's resistance to traditional treatments, acquiring methicillin-resistant Staphylococcus aureus (MRSA) in both inpatient and outpatient settings poses serious difficulties. In order to successfully treat infections in such circumstances, medical professionals may turn to the usage of both newer medications like linezolid and last-resort antibiotics like vancomycin.
Vancomycin-Resistant Enterococcus (VRE)
When it comes to infections linked to healthcare, especially in individuals with impaired immune systems, vancomycin-resistant enterococci (VREs) pose a serious threat. Vancomycin, a last-resort antibiotic, can cause Enterococci, which are usually found in the gastrointestinal tract, to become resistant to it. Bacteremia, endocarditis, and urinary tract infections are among the difficult-to-treat illnesses that arise from this resistance. Vancomycin is unable to bind to and block the formation of cell walls in vancomycin-resistant enterococci (VREs) due to a mechanism of resistance involving the alteration of cell wall precursors. As a result, only alternative antibiotics like daptomycin and linezolid are available for treating VRE infections. Nevertheless, compared to vancomycin, these substitutes often have a higher toxicity profile and lower effectiveness.
Multidrug-Resistant Mycobacterium tuberculosis (MDR-TB)
Drug-resistant forms of Mycobacterium tuberculosis, which cause tuberculosis (TB), pose a serious threat to public health, especially in areas where the disease is more common.30. Resistance to isoniazid and rifampicin, the two most effective first-line antitubercular drugs, is the hallmark of multidrug resistant tuberculosis (MDR-TB). This illness poses a serious obstacle to the treatment of tuberculosis. Treatment options for MDR TB may include second-line medications, which are frequently more toxic even when they are not much more effective. In clinical practice, the use of these second-line medications in addition to MDR-TB treatment is still crucial31. Drug-resistant tuberculosis (TB) poses a major issue because to its resistance to two or more second-line drugs, in contrast to drug-susceptible TB, which can be efficiently controlled with shorter and safer treatment regimens. To improve antibacterial efficacy, this calls for the application of thorough medication combination techniques. In order to create more efficient treatment plans, researchers and medical professionals must pay more attention to the dynamics of antibiotic resistance in this setting.
Carbapenem-Resistant (CRE)
the best antibiotics for treating gram-negative infections as a last resort. The production of carbapenemase enzymes is primarily responsible for the resistance of Enterobacteriaceae Carbapenem-resistant Enterobacteriaceae (CRE), which include strains of Escherichia coli and Klebsiella pneumoniae, to carbapenems. One important enzyme that aids in the hydrolysis of a variety of carbapenems is Klebsiella pneumoniae carbapenemase (KPC). The effectiveness of these essential beta-lactam antibiotics is compromised by this enzymatic activity, which presents a significant problem in clinical settings35. Treatment strategies for infections brought on by Enterobacteriaceae that are resistant to carbapenem (CRE) are linked to noticeably higher death rates. The lack of viable pharmacological combinations in the treatment landscape frequently necessitates the employment of older, more toxic medicines like polymyxins.
Classification of Antibiotics :-
Antibiotics can be categorised according to their range of activity, chemical structure, and mode of action.
1 Based on Mechanism of Action
A. Cell Wall Synthesis Inhibitors :-
B. Protein Synthesis Inhibitors :-
C. Nucleic Acid Synthesis Inhibitors
D. Metabolic Pathway Inhibitors :-
E. Cell Membrane Disruptors
2. Based on Spectrum :-
1. Broad Spectrum Antibiotics :-
These act against both Gram-positive and Gram-negative bacteria. Examples:
2. Narrow Spectrum Antibiotics :-
These act against a limited group of bacteria. Examples:
Mechanism of antibiotics :-
Fig no 1 :- Mechanism of antibiotics
Causes of Antibiotic Resistance :-
1. Overuse of Antibiotics :-
Overuse of antibiotics puts bacteria under more selective pressure.
2. Inappropriate Prescription :-
For viral infections, antibiotics are frequently provided needlessly.
3. Self-Medication :-
Many people use antibiotics without consulting a doctor.
4. Incomplete Course of Treatment :-
Early antibiotic cessation promotes the survival of resistant microorganisms.
5. Agricultural Use :-
In livestock, antibiotics are used to prevent illness and encourage growth.
6. Poor Infection Control ;-
The transmission of resistant microorganisms is facilitated by poor sanitation and hygiene.
7. Lack of New Antibiotics :-
The exorbitant expense of research is preventing the development of many new antibiotics.
Types of Antibiotic Resistance :-
1. Intrinsic Resistance :-
Natural resistance present in bacteria. Example:
Gram-negative bacteria resistant to vancomycin.
2. Acquired Resistance :-
Resistance developed through mutation or gene transfer.
3. Cross Resistance :-
Resistance to one antibiotic causes resistance to similar antibiotics.
4. Multidrug Resistance :-
Resistance to multiple antibiotics.
5. Extensive Drug Resistance :-
Resistance to almost all available drug
Major antibiotics resistance pathogens:-
Fig no2 :- Major antibiotics resistant pathogens
Transmission of Resistant Bacteria :-
Resistant bacteria spread through:
Clinical Impact of Antibiotic Resistance :-
Antibiotic resistance has severe consequences
1. Increased Mortality :-
Untreatable infections increase death rates.
2. Longer Hospital Stay :-
Patients require prolonged hospitalization.
3. Increased Healthcare Costs :-
Expensive antibiotics and intensive care increase treatment costs.
4. Failure of Medical Procedures :-
Surgeries, chemotherapy, and organ transplantation become risky.
5. Increased Disease Burden :-
Communities face outbreaks of resistant infections.
Antibiotic Resistance in Hospitals :-
Hospitals are major centers for resistant infections due to:
Common hospital-acquired resistant infections include:
Hospital infection control measures include:
Diagnosis of Resistant Infections :-
Laboratory diagnosis is important for selecting effective therapy.
1. Culture and Sensitivity Testing :-
Determines bacterial susceptibility to antibiotics.
2. Molecular Methods :-
PCR identifies resistance genes.
3. Automated Systems:-
Rapid identification and susceptibility testing.
4. Whole Genome Sequencing
Used for surveillance and outbreak investigation.
Challenges in Combating Antibiotic Resistance:-
Several challenges hinder control efforts.
1. Lack of Awareness
Many people misuse antibiotics.
2. Limited Development of New Drugs
Pharmaceutical companies face financial challenges.
3. Poor Regulation
Over-the-counter antibiotic sales contribute to misuse.
4. Global Travel
International travel spreads resistant bacteria.
5. Inadequate Surveillance
Many countries lack proper monitoring systems.
Future Perspectives :-
Future strategies should focus on:
Challenges in addressing AMR
Addressing the rise of AMR poses difficult problems with no easy answers. The extensive integration of antimicrobials into medical care and the economics of food animal production hinders efforts to limit humanity's massive use of these drugs. Modern farming systems rely on the routine administration of antimicrobials to animals for infection prevention and growth promotion, while doctors frequently rely on empirical antibiotic prescribing to protect against bacterial infections due to the lack of quick point-of-care diagnostics.(26) Despite knowledge of the consequences of antibiotic overuse leading to resistance, the implementation of antimicrobial stewardship programs in healthcare and revised animal husbandry policies lags significantly. The pipeline for developing antibiotic drugs is unable to keep up with the ongoing evolution of MDR pathogens, which exacerbates these problems.(26)With few financial incentives, pharmaceutical companies are increasingly giving up on expensive antibiotic research. Furthermore, given the length of phase trials, short-term fixes seem improbable, even though policy expansions funding antibiotic development represent progress.(26)
Despite organizations like the WHO, CDC, and UN acknowledging the borderless threats of AMR, international coordination on surveillance and stewardship protocols is still fragmented, further impeding containment efforts.(26) Novel resistance variables can evolve locally and spread globally due to uneven access to high-quality diagnostics and antibiotic supervision across nations. Localized success may be continuously undermined and negated by patches of poor care. In the end, the distinct "tragedy of the commons" character of antibiotic resistance necessitates fair, collaborative international action and shared accountability.(26) However, geopolitical issues continue to impede agreement on legally binding international laws and financial sources that are necessary to improve antimicrobial stewardship and innovation globally. AMR affects people all over the world and is not limited by geography. Infections that were previously treatable have now become serious health issues.(26) The lack of effective antimicrobial drugs increases the risk of common medical treatments like organ transplants, chemotherapy, and surgery. AMR poses significant financial difficulties for governments, healthcare institutions, and society at large in addition to its detrimental effects on human health. Long hospital stays, increased medical consultations, and the need for expensive drugs as a last resort greatly increase the financial burden of treating resistant illnesses.(26)
Recommendations for research
AMR mitigation requires an all-encompassing approach including numerous sectors and stakeholders. First and foremost, better surveillance methods are required in order to efficiently monitor and track the emergence and spread of resistant diseases. Furthermore, in order to successfully reduce the selective pressure that leads to the development of resistance, it is imperative to stress the significance of using antimicrobials sensibly and ethically. The overuse of antibiotics can be effectively reduced by implementing rules on their use in veterinary medicine and agriculture, as well as by promoting antimicrobial stewardship programs inside healthcare facilities.
To develop and implement effective solutions to minimize antimicrobial resistance (AMR), action-oriented research is essential. Initiatives ought to investigate the complex interrelationships among several components that result in the formation of resistance. Important components of a comprehensive study plan include examining antimicrobial prescription practices, usage trends in agriculture, the role of horizontal gene transfer in the spread of resistance, and sociocultural variables influencing antimicrobial consumption. Developing comprehensive strategies requires an understanding of the dynamics of microbial ecosystems, including the resistome and the impact of environmental factors. To improve our understanding of antimicrobial resistance, interdisciplinary collaboration amongst microbiologists, pharmacologists, epidemiologists, social scientists, and policymakers is essential. Combating antibiotic resistance requires not only surveillance and diagnostic research but also the development of novel antimicrobial medications and alternative treatments. Important developments in this field include discovering new molecular targets, refining existing antibiotics, and exploring unconventional therapeutic approaches like immunomodulation and bacteriophage therapy. Promoting translational research is essential to hastening the adoption of novel interventions by tying laboratory findings to practical applications. For new antimicrobial medications to be discovered, evaluated, and approved more quickly, cooperation between academic institutions, pharmaceutical companies, and regulatory bodies is essential.
Furthermore, research and development efforts must be strengthened in order to find new antibiotics and investigate alternative therapeutic approaches. Governments, pharmaceutical companies, and research institutes must work together to incentivize and expedite the development of novel antimicrobial medicines. Additionally, it should be mentioned that one of the current treatment approaches used to address the problem of AMR may be metal nanoparticles. The problem of high AMR rates may also be resolved by using artificial intelligence. Additionally, it has been suggested that concurrent use of antivirulence medications and antibiotics may provide improved control of harmful germs while reducing the emergence of AMR. Lastly, in order to reduce the dependence on antimicrobial medicines and enable targeted treatment interventions, resources must be directed toward the development of vaccines and diagnostics.
REFERENCES
Sakshi More, Shraddha Lakambare, Dr. Dhanraj Jadge, Review on Antibiotic Resistance, Int. J. of Pharm. Sci., 2026, Vol 4, Issue 6, 1-11. https://doi.org/10.5281/zenodo.20490039
10.5281/zenodo.20490039