Antibiotic Resistance: Why Medications Stop Working and What to Do?

Antibiotics have revolutionized medicine, saving millions of lives from infectious diseases. However, today we face a growing problem: many bacteria are becoming resistant to these vital drugs. This phenomenon, known as antibiotic resistance, threatens treatment effectiveness and complicates the fight against infections worldwide.

The Global Threat of Antibiotic Resistance

Despite significant progress in the development of new antibiotics, millions of people still die from infections every year [3]. The mortality rate from certain serious conditions, such as bacteremia caused by Staphylococcus aureus (SAB), remains unacceptably high and has improved only slightly over recent decades [1]. A particularly challenging task is the treatment of infections caused by methicillin-resistant strains of Staphylococcus aureus (MRSA) [1].

This problem is not limited to hospital-acquired infections. For example, the effectiveness of empiric treatment regimens for Helicobacter pylori infection, especially those containing clarithromycin, is declining due to increasing antimicrobial resistance [5, 6]. H. pylori causes chronic gastritis, peptic ulcer disease, gastric lymphoma, and gastric cancer, and its successful eradication is critical [6].

Why Antibiotics Stop Working: Mechanisms of Resistance

The main reason for the decline in antibiotic effectiveness is the ability of bacteria to develop resistance to them. This process is accelerated by the inappropriate and excessive use of antibiotics. Bacteria can acquire resistance through various pathways:

• Mutations: Changes in bacterial DNA that make them unresponsive to the drug's action.
• Acquisition of resistance genes: Bacteria can exchange genetic material, passing resistance-encoding genes to one another.
• Defense mechanisms: Bacteria can produce enzymes that destroy the antibiotic (e.g., beta-lactamases), alter the drug's target sites, or actively pump it out of the cell.

Examples of such resistance include the resistance of H. pylori to clarithromycin, metronidazole, and levofloxacin, which has significantly reduced the effectiveness of older empiric treatment regimens [6].

When Antibiotics Fail: Factors Beyond Resistance

Surprisingly, the ineffectiveness of antimicrobial therapy is not always explained by genetically determined resistance [3]. There are other critical factors that can hinder successful treatment:

• Biofilm formation: Bacteria often form protective communities called biofilms, making them less vulnerable to antibiotics and the body's immune system [3].
• Sepsis: In severe systemic infections such as sepsis, the complexity of pathophysiological processes and the patient's condition can affect antibiotic efficacy, even if the bacteria are sensitive to them [3].
• Microbiome: The interaction between the pathogen, the antibiotic, and the patient's own microbiome can play a role in treatment outcomes [3].
• Inappropriate choice of empiric therapy: In a hospital setting, empiric therapy for patients with sepsis is challenging. If the initial treatment does not account for the prevalence of multi-resistant organisms in a given facility, it may be ineffective [2].
• Patient characteristics: Age, comorbidities (e.g., chronic renal failure, hypothyroidism), and immune system status can affect the metabolism and efficacy of antibiotics, as well as the risk of side effects [8].

Strategies to Combat Resistance and Optimize Treatment

To effectively combat antibiotic resistance and improve treatment success, a multifaceted approach is required:

Antibiotic Stewardship

This strategy aims to optimize antibiotic use and minimize the development of resistance [2]. Physicians should:

• Avoid over-treating colonizing organisms in the respiratory tract and urinary catheters [2].
• Account for the prevalence of multi-resistant organisms in the hospital environment when choosing empiric therapy [2].
• Choose an antibiotic with a low resistance potential, administer it at the highest possible dose without toxicity, and for the shortest duration necessary to eliminate the infection [2].

Targeted and Personalized Therapy

Instead of empiric prescriptions, an approach based on precise data is increasingly used:

• Resistance monitoring: Local surveillance of resistance and identification of clinical predictors of resistance are critical for selecting treatment strategies [5, 7].
• Mechanism-driven therapy: In the case of H. pylori, management is shifting from empiric eradication to therapy matching the mechanisms of action and biology of the microbe. This includes the use of potassium-competitive acid blockers (P-CABs) and molecular resistance testing [6].
• Updating guidelines: Regular review and updating of guidelines, such as WHO recommendations for treating sepsis in newborns and children, are necessary to account for changing resistance patterns, costs, and side effect risks [4].

New Antibiotics and Approaches

The development of new drugs continues. For example, new antistaphylococcal drugs are available for treating MRSA infections, and their role as alternatives to standard therapy is being actively investigated [1]. Therapeutic strategies beyond traditional antibiotics are also being actively studied, including novel anti-infective drugs or approaches aimed at enhancing the host immune response [3].

Side Effects of Antibiotics: An Important Aspect of Treatment

In addition to resistance, antibiotic side effects can also complicate treatment. For example, carbapenems—broad-spectrum antibiotics used to treat infections caused by multi-resistant organisms—are associated with neurotoxicity, especially in high-risk groups. These include the elderly, patients with pre-existing neurological diseases, renal impairment, and hypoalbuminemia [8].

In one case, a 92-year-old female patient with chronic kidney disease, dementia, and stable epilepsy developed a focal seizure with impaired consciousness on the third day of ertapenem treatment, despite previous tolerance to the drug. This case highlights that ertapenem can be a potential trigger for neurotoxicity in patients with multiple comorbidities, even with a stable course of chronic conditions [8]. This demonstrates the need for careful risk-benefit assessment when prescribing antibiotics.

Conclusion: The Future of Fighting Infections

Combating antibiotic resistance and ensuring the effectiveness of infection treatment requires a comprehensive, multidisciplinary approach [1]. This includes responsible antibiotic prescribing, continuous resistance monitoring, the development of new drugs and therapeutic strategies, and a deep understanding of all factors affecting treatment success. Only through joint efforts can we keep antibiotics effective for future generations.

Sources

1. 1. Pharmacotherapeutic treatment options for Staphylococcus aureus bacteremia. (Expert opinion on pharmacotherapy, 2017)
2. 2. Antibiotic stewardship: strategies to minimize antibiotic resistance while maximizing antibiotic effectiveness. (The Medical clinics of North America, 2018)
3. 3. Antibiotic failure: Beyond antimicrobial resistance. (Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy, 2023)
4. 4. Overview of WHO guidelines on antibiotic use for sepsis in newborns and children. (Paediatrics and international child health, 2018)
5. 5. Antimicrobial resistance patterns and predictors in Helicobacter pylori infection: a real-world cohort study. (Microorganisms, 2026)
6. 6. Mechanism-driven treatment of Helicobacter pylori in the era of potassium-competitive acid blockers. (Frontiers in medicine, 2026)
7. 7. Antimicrobial resistance patterns and determinants of Helicobacter pylori culture success: A prospective study. (Antibiotics (Basel, Switzerland), 2025)
8. 8. Ertapenem-associated neurotoxicity in a patient with chronic kidney disease and hypothyroidism: A case report. (Cureus, 2026)

The information provided in the article is for reference purposes only and does not replace consultation with a qualified specialist. Always consult a physician for diagnosis and treatment.