# The Importance of Gram-Negative Rods in Chronic Rhinosinusitis
## 4 Discussion  
Numerous sinus microbiota studies used new culture-independent techniques [11; 13; 22; 24; 34; 35; 36]. The studies based on a molecular approach to assess sinonasal microbial communities identified more bacterial species per individual than those identified by standard clinical culture methods. Although a greater number of isolates were identified exclusively using molecular methods, several species undetected by molecular techniques were successfully identified through cultivation [37; 38]. Moreover, culture methods remain irreplaceable for practical reasons, including the ability to identify the microorganism at the species level and antimicrobial susceptibility testing for drugs already introduced into treatment and new preparations. In our study, culture-based methods were used, allowing for further analysis. Another important aspect is selecting the appropriate specimen type for microbiological assessment. Several studies suggested that tissue samples may be more optimal for patients with CRS than the middle nasal meatus swabs. The authors reported that tissues provided less variation between samples than swabs, enabling the isolation of bacteria living in the biofilm and penetrating the mucosa cells [26; 39]. Considering the above factors, tissue biopsies were collected from patients in both the CRS and the control groups for our study. The sampling sites for patients with CRS and controls may show niche-specific differences in microbiota, which may be a study limitation. However, we decided to sample the interior turbinate mucosa as a maxillary and ethmoid sinus drainage pathway. Many authors point out the diversity of the sinus microbiome in both health and disease. Moreover, the diversity of bacteria in a healthy state has a protective effect [25; 26; 40; 41]. For example, _Cutiobacterium acnes_, identified in about 80% of healthy people, maintains a physiological bacterial and fungal balance thanks to the bacteriocin it produces and affects the host's immune response [42; 43; 44]. However, it is believed that in contrast to healthy individuals, the sinus microbiota of CRS patients is characterized by significant disturbance, with reduced bacterial diversity and richness [38; 45]. Dysbiosis-alterations in the composition and function of the microbiota- has been suggested as one of the mechanisms engaged in CRS pathogenesis [15; 25; 38; 45]. Figure 3: Classification of the strength of biofilm production. The qualitative composition of microorganisms in patients with CRS is influenced by age, smoking, previous surgery, and prior antibiotic therapy Antibiotic use has a significant impact on the microbiological profile of the sinuses: (1) it reduces the abundance of beneficial or commensal bacteria (e.g., _Corynebacterium_) that play a protective role; (2) it promotes the selection and proliferation of resistant bacterial strains; (3) it facilitates colonization by opportunistic pathogens (e.g., _S. aureus_); and (4) it disrupts microbial homeostasis, which may predispose patients to infection recurrence or progression to chronic forms of the disease [46; 47; 48]. Differences in the quantitative and qualitative composition of the microbiota can also be associated with the severity of CRS, comorbidities, and geographic location. [PERSON] et al. studied the composition of the sinonasal microbiota in healthy individuals and found that the most abundant bacterial phyla were _Firmicutes_, _Proteobacteria_, and _Actinobacteria_. According to some authors, the predominant bacteria at the species level identified in CRS patients include _Staphylococcus epidermidis_, _Staphylococcus aureus_, _Haemophilus influenzae_, _Corynebacterium_ spp., _Streptococcus pneumoniae_, gram-negative bacteria from the _Enterobacterales_ order, as well as anaerobic species, primarily _Cutibacterium_ and _Peptostreptococcus_[49; 46; 47; 50; 51]. [PERSON] et al. proposed three distinct states of the sinonasal microbiota based on their research findings.