Different groups of antibiotics use different mechanisms to prevent bacterial growth and multiplication. Each antibiotic has a certain spectrum of activity and, if chosen adequately, is effective in treating bacterial infections. Besides their impact on bacteria, antibiotics also influence the human body in a way that can be desired (immunomodulatory effect) or undesired (various side effects).
Gastrointestinal side effects are the most common adverse effect and all antibiotics influence the suppression of certain components of intestinal microflora, depending on the activity spectrum, dosage, duration of therapy and method of administration. By destroying pathogenic microorganisms, an antibiotic simultaneously changes the microbiological diversity of intestinal microflora, thereby reducing the physiological defences of the organism.
Intestinal microflora has an influence on a range of physiological and pathophysiological mechanisms, it is a part of the process of digestion, development of immunity and protection from pathogen microorganisms. Its natural balance is of particular significance to health because intestinal microflora represents the first line of defence from external antigens that enter the body through the digestive system.
It has been shown that after the administration of antibiotics, there is a change in the type and number of bacteria in the stool. The amount of bacteria of the normal physiological flora, of the Bifidobacterium, Streptococcus and Lactobacillus genus, was decreasing, while, for example, the amount of Klebsielle and yeast increased.
Side effects associated with the use of antibiotics range from nausea, vomiting and mild diarrhoea to severe and life-threatening pseudomembranous colitis.
Antibiotic-related diarrhoea occurs in nearly 40% of children treated with broad spectrum antibiotics and in 15% of adults.
Side effects are a common consequence of non-compliance with doctor’s instructions on taking the drug and premature discontinuation of antibiotic treatment. One of the more important causes (with irrational prescribing of antibiotic treatment) for the development of bacterial resistance to antibiotics has been mentioned.
Colonizing the intestinal microflora with probiotics prevents the growth of pathogenic bacteria and thus reduces the side effects, but also gives enough time to restore the intestinal microflora after antibiotic use.
One of the mechanisms of probiotic activity is the creation of a medium in which the growth of pathogenic bacteria has been prevented. Probiotics produce antibacterial substances that lower pH and inhibit the growth of most pathogenic bacteria.
Administration of probiotics can improve the antibiotic treatment and patient cooperation in the following way:
- improving tolerability of antibiotic treatment by reducing side effects;
- more regular administration of drugs;
- reducing the development of bacterial resistance (indirectly due to regular drug administration);
- reducing the risk of superinfections induced by antibiotics;
- regulating the immunological response of the intestinal mucosa.