## 3 Results
### The Role of Microbiomes
Various environmental factors influence the production of neurons during the development process in the central nervous system. The intestinal microbiome plays a pivotal role in regulating and directing the neural development of the central nervous system [47]. Some IBS symptoms, such as visceral hypersensitivity, the influence of gut microbes on the host immune response and intestinal barrier integrity, and aspects of the brain-gut axis, could be accounted for by these changes. The preservation of the intestinal barrier is largely attributed to a well-established interaction among the gut microbiome, mucosal lining, host cells, immune defence system, and intestinal vascular barrier. This relationship involves a complex network of bidirectional interactions and regulation of inflammatory processes [48]. Bacterial overgrowth in the small intestine is characterised by an unusual increase in bacterial counts there; this phenomenon is seen as a significant positive indicator for patients with IBS [49]. For intestinal health and overall well-being, a healthy and diverse microbiome is essential. Healthy individuals typically possess a varied microbial composition, featuring beneficial bacteria like _Lactobacillus_ spp. and _Bifidobacterium_ spp. [50]. The gut microbiota mainly consists of four phyla: _Actinobacteria_, _Bacteroidetes_ (_Bacteroidota_), _Frimicutes_ (_Bacilota_), and _Proteobacteria_ spp., which are all crucial for metabolic processes and immune function [51]. Patients with IBS usually exhibit changes in their gut microbiota, such as a reduction in _Bifidobacterium_ spp. and an increase in _Bacteroides_ spp. [52]. However, the reasons behind these changes and their stability are still under investigation [53]. Antibiotic exposure, on the other hand, is a risk factor for IBS [54]. Nonetheless, there is a lack of direct evidence showing that exposure to antibiotics during motherhood can cause IBS to develop in adulthood. Infants' gut microbiota is very sensitive to the impact of antibiotics. Human health can be significantly impacted by alterations in microbiota composition and microbial colonisation [55]. After antibiotic treatment, a notable alteration in the gut microbiota is the proliferation of three genera--_Bacteroides_ spp., _Peptostreptococcus_ spp., and _Enterobacter_ spp.--while the abundance of the _Bacteroidetes_ (_Bacteroidota_) phylum diminishes [56]. Research from a European infants study found that maternal antibiotic use during the perinatal and breastfeeding periods may reduce _Bacteroides_ spp. counts, while antibiotic treatment in newborns can alter microbiota composition by raising _Enterobacteriaceae_ spp. levels [57], which is associated with IBS patients. The aforementioned alterations in gut flora can elevate the risk of intestinal disorders, such as IBS, through the modulation of the intestinal microbiota. To examine the link between antibiotic exposure in early life and IBS incidence, it is still necessary to conduct long-term evaluations of the impact of antibiotics on gut flora as well as large-scale retrospective studies. Antibiotics have been connected with the development of IBS and alter the gut microbiota [58]. Although small intestine bacterial overgrowth has been associated [59], its significance is mostly because of the limits of the diagnostic procedures, such as the culture of jejun aspirates and breath tests [60]. Live bacteria called probiotics can change the nature of the gut microbiota when they are ingested as part of a diet. There are more and more probiotics available on the market. Probiotics are generally thought to be harmless, although they can have negative effects on people with impaired immune systems. Daily doses of these bacteria range from \(10^{6}\) to \(10^{10}\) CFU, and they are beneficial to health. It is crucial to remember that probiotics might differ in their composition and effects; they are not all the same [61]. The type of probiotics and the conditions for which they are used determine their effectiveness.