Why are some bacteria resistant to penicillin

Antibiotic resistance: causes, consequences and means of limiting

What is the origin of antibiotic resistance?


Resistant bacteria can survive concentrations of antibiotics that others die on.

The main cause of resistance to antibiotics1 is their abuse. As the European Center for Disease Prevention and Control (ECDC) has pointed out, there are three main types of abuse:

  1. The unnecessary prescription of antibiotics for viral infections, against which this drug is ineffective;
  2. The too frequent prescription of "Broadband Antibiotics" instead of a more targeted antibiotic after a more accurate diagnosis;
  3. Improper use by the patient who fails to adhere to either the dosage or the duration of treatment, d. that is, some bacteria can survive and become resistant.

1 Antimicrobial substances are defined as medical devices that kill or stop the growth of living microorganisms. In addition to the "antibacterial" agents, as antibiotics are also called because they work against bacterial infections, microbial agents contain, among other things. also antifungal, antiviral, antifungal and antiparasitic agents.

How does a bacterium develop resistance to antibiotics?

Some bacteria are naturally resistant to certain antibiotics, while others can become resistant by mutating some of their genes when exposed to an antibiotic. This resistance, whether natural or acquired, can spread to other types of bacteria, as bacteria can easily exchange genetic material with one another, even if they are different species.

What are the consequences of antibiotic resistance?

Many of the treatment options available for common bacterial infections are becoming increasingly inefficient. As a result, situations arise in which sick patients can no longer be adequately treated with the available antibiotics. This resistance can delay and prevent treatments, which can lead to complications or even death. In addition, a patient may need more care and may need alternative or more expensive antibiotics that can have serious side effects, or more invasive treatments such as intravenous injections that have to be administered in the hospital.

A recent WHO report clearly showed that resistance to antibiotics in widespread bacteria has reached alarming levels in many parts of the world. In Europe, for example, there is an increase in resistance to the main antibiotics in common bacteria such as, among other things, urinary tract infections, and also Staphylococcus aureus (the MRSA- or methicillin-resistant Staphylococcus aureus), Klebsiella pneumoniae and Pseudomonas aeruginosa.

The WHO sees as a consequence that the progress of modern medicine, which is based on the availability of efficient antibacterial drugs, is in jeopardy. For example:

  • Common infections such as pneumonia, which can often be found in care settings, may no longer respond to available or recommended drugs such as penicillin and put patients' lives at risk;
  • Cystitis, one of the most common of all bacterial infections in women, can become untreatable or require drug injections, which creates additional costs for patients and the health system in general;
  • Antibacterial drugs that are used to prevent infections after surgery or to treat common infections in neonatal and intensive care units may become ineffective or may not work at all.

One problem that the WHO report takes up is that very few antibiotics have been discovered and developed since 1985 that can replace antibiotics that have become ineffective.

Which main infections can no longer be treated because of antibiotic resistance?

Bacteria cause a wide variety of common infections and can become resistant to one or many antibiotics: urinary tract infections, pneumonia, skin infections, diarrhea, bloodstream infections. The high resistance to third generation cephalosporins, as reported in pneumonia from E. coli and K. pneumoniae, for example, means that treatment of severe infections from these bacteria must now rely primarily on another family of antibiotics, which are more expensive and possibly in resource-poor environments is not available. In addition, this can only work as long as these bacteria do not become resistant to this alternative.

For patients in hospitals there is a particular risk of infections caused by resistant and very pathogenic bacteria that can occur in hospitals and clinics, the so-called nosocomial infections, and which are in no way related to the reason for their posting.

What can be done to curb this rising antibiotic resistance?

The first challenge, according to the WHO report, is the significant gap in the monitoring of antibiotic resistance. In 2001 WHO and the Council of the European Community issued global strategies and guidelines to help countries set up systems to monitor antibiotic resistance and implement effective measures, including public awareness campaigns. Today, the most immediate and pressing concerns concern the antibiotic resistance of widespread bacteria. In agreement with the WHO, the ECDC (European Center for Disease Prevention and Control) sees three strategic areas of intervention as urgent, each of which can play an important role:

  1. Careful use of the available antibiotics and, if necessary, prevention of infections through appropriate vaccination;
  2. Hygienic precautions to control cross-transmission of resistant strains from one person to another, including screening resistant strains and isolating carrier patients;
  3. Research and development of antibiotics with a novel mechanism of action.

Does the use of antibiotics in food-producing animals contribute to this problem?

The main cause of antibiotic resistance in humans remains the use of antibiotics in human medicine; the use of antibiotics in food production adds very little to this problem. However, because antibiotics used to treat and prevent bacterial infections in animals belong to the same chemical groups as those used in humans, animals can come into contact with bacteria that are resistant to antibiotics, which are also resistant to human infections come into use.

Credentials:
  1. The ECDC's initiatives on antimicrobial resistance,
    www.ecdc.europa.eu/en/healthtopics/antimicrobial_resistance/pages/,
    www.ecdc.europa.eu/en/publications/Publications/,
    - including the "basic facts": www.ecdc.europa.eu/en/healthtopics/antimicrobial_resistance/basic_facts/Pages/
  2. Antimicrobial Resistance - Global Report on Surveillance - WHO, 2014
    www.who.int/drugresistance/documents/surveillancereport/en/
  3. Global strategy to contain antimicrobial resistance. World Health Organization, 2001.
    www.who.int/drugresistance/WHO_Global_Strategy_English.pdf
  4. 5. The Antibiotic Resistance Threat in the United States 2013 - US Department for Health and Human Services - U.S. Centers for Disease Control and Prevention
    www.cdc.gov/drugresistance/threat-report-2013/pdf/ar-threats-2013-508.pdf
Further references on this topic: