Optimization of antibiotic therapy in the treatment of acute respiratory infections in children

The use of antibiotics without indications, as is known, increases the risk of selecting resistant microbial strains and the risk of side effects from antibacterial therapy, including allergic and toxic reactions, hematological disorders, and dyspeptic phenomena. Furthermore, antibiotics suppress not only pathogenic but also normal microflora, causing a qualitative and quantitative imbalance of microbial populations (primarily in the gastrointestinal tract) [3, 8]. The manifestations of dysbiosis are highly diverse: from an asymptomatic course to clearly defined, severe clinical forms such as antibiotic-associated diarrhea (AAD). According to the modern definition, AAD is three or more episodes of unformed stool over two or more consecutive days, developing during antibacterial therapy and up to 4 weeks after antibiotic discontinuation [9]. AAD occurs in 5–25% of patients receiving antibiotics [10–12].

Side reactions are the reason for discontinuing therapy in 50% of patients and require additional treatment in 30% of cases [13]. In recent years, significant attention in correcting intestinal microbial ecology has been given to prebiotics, which selectively affect the indigenous microflora without enhancing the growth and proliferation of toxin-producing clostridia, toxigenic strains of E. coli, and bacteroides [1].

One of the most studied and well-established prebiotics is lactulose.

Lactulose is a disaccharide consisting of galactose and fructose molecules, a synthetic stereoisomer of milk sugar produced industrially. It is not found in nature. Lactulose is not absorbed in the human intestine because humans lack the enzymes capable of hydrolyzing lactulose. Reaching the large intestine unchanged, lactulose is captured and metabolized by colonic bacteria capable of utilizing it. The products of bacterial metabolism of lactulose shift the pH of the environment in the large intestine to the acidic side, thereby inhibiting the growth and reproduction of pathogenic microorganisms and creating a more favorable environment for the reproduction of "beneficial" saprophytic bacteria. In the presence of lactulose, candidiasis does not occur, and it prevents the proliferation of Clostridium difficile. These effects of lactulose are widely used in the treatment of intestinal dysbiosis.

Ingestion of a prebiotic dose of lactulose does not lead to a change in stool frequency but, on the contrary, can have an anti-diarrheal effect, which in this case is realized through the same mechanisms as the action of probiotics: the growth of saccharolytic microflora promotes competitive inhibition of proteolytic microflora growth, which reduces the production of entero- and cytotoxins. Thus, low doses of lactulose ensure the normalization of intestinal microflora without a laxative effect, allowing preparations containing it to be used as a pathogenetic means for correcting intestinal dysbiosis [14].