# The Importance of Gram-Negative Rods in Chronic Rhinosinusitis
## 3 Results
### Bacterial Microbiota  
Paranasal sinus mucosa tissue samples and nasal concha mucosa tissue samples were collected from patients with CRS (study group) and patients who underwent nasal septoplasty and rhinoplasty (control group), respectively. A total of 125 bacterial species were isolated from patients with CRS (90 from patients with primary CRS, 35 with secondary CRS) and 73 from patients of the control group (Table 2). The distribution of isolated microorganisms in each analyzed group was diverse. More than one dominant microorganism was identified in samples from 50% of patients with primary CRS and 45.5% of those with secondary CRS. In the control group, multiple dominant microorganisms were \begin{table}
\begin{tabular}{c c c c} \hline  & **Control Group** & **Patients with** & **Patients with** \\  & **(n = 47)** & **Primary CRS** & **Secondary CRS** \\  & **(n = 52)** & **(n = 22)** \\ \hline Mean age & 38 & 45 & 43 \\ Male/female & 30/17 & 29/23 & 12/10 \\  & (63.8\%/36.2\%) & (55.8\%/44.2\%) & (54.5\%/45.5\%) \\ Asthma & 4 (8.5\%) & 16 (30.8\%) & 1 (4.5\%) \\ Inhalant allergy & 12 (25.5\%) & 9 (17.3\%) & 8 (35.5\%) \\ Hypertension & 6 (12.8\%) & 8 (15.4\%) & 3 (13.6\%) \\ Cancer & 1 (2.1\%) & 1 (1.9\%) & 0 (0.0\%) \\ Diabetes & 3 (6.4\%) & 1 (1.9\%) & 6 (27.3\%) \\ Steroid use & 6 (12.8\%) & 13 (25\%) & 9 (40.9\%) \\ Smoking & 7 (14.9\%) & 8 (15.4\%) & 4 (18.2\%) \\ Antibiotics & 6 (12.8\%) & 7 (13.5\%) & 3 (13.6\%) \\ Sinus irrigation & 3 (6.4\%) & 10 (19.2\%) & 7 (31.8\%) \\ Contact with & & & \\ chemicals & 17 (36.2\%) & 12 (23.1\%) & 5 (22.7\%) \\ Facial trauma & 6 (12.8\%) & 2 (3.8\%) & 1 (4.5\%) \\ Sinus surgery & 1 (2.1\%) & 16 (30.8\%) & 6 (27.3\%) \\ Nose surgery & 10 (21.3\%) & 7 (13.5\%) & 9 (40.9\%) \\ \hline \end{tabular}
\end{table} 
Table 1: Patients characteristics. found in 17.0% of patients. Among the microorganisms isolated from patients with CRS, Gram-positive cocci of the species _S. epidermidis_ and _S. aureus_ predominated. In the control group, mixed microbiota typical of the nasal flora were isolated in most patients (59.6%). Microbiota dominated by Gram-negative rods were isolated from 27 patients (control group: n = 5, primary CRS: n = 15, secondary CRS: n = 7). Based on the conducted survey, none of these patients had hyperactivity, genetic diseases or syndromes, diabetes, or a history of facial trauma. Compared to the control group, patients with primary and secondary CRS were more likely to have asthma, peptic ulcer disease, hypertension, a history of steroid use, sinus irrigation, and antibiotic use (at least four weeks prior to patients who had used antibiotic agents within four weeks prior to sample collection were excluded from the study). Differences in the prevalence of Gram-negative rods were observed in the studied groups. In patients with CRS, these bacteria were isolated at a rate of approximately 17.6% (across both groups), while in the control group, Gram-negative rods accounted for 6.9% of the isolated bacteria (_p_-value = 0.0341). These organisms were isolated slightly more often from patients with secondary CRS (20%) than from primary CRS (16,7%). The most frequently isolated bacteria from patients with primary CRS were _E. coli_ (n = 7), _Klebsiella oxytoca_ (n = 2), _Morganella morganii_ (n = 2), and _Enterobacter cloace_ (n = 2). Similarly, _E. coli_ (n = 4) was the most commonly isolated species in patients with secondary CRS. In