Investigation of the role of protein A vand staphylococcal toxins acting as superantigens in the etiology of chronic sinusitis

Investigation of the role of protein A and staphylococcal toxins acting as superantigens in the ethiology of chronic sinusitis. Chronic sinusitis is a symptomatic inflammation of the nasal and paranasal mucosa which lasts more than 12 weeks. Chronic sinusitis is a disease associated with significant reduction of patients quality of life and high costs due to treatment resistance. Despite the real cause of the inflamation developed by chronic sinusitis is not become clear it is thought the bacteria plays the major role. In recent years the hypothesis that has been put forward is the development of chronic sinusitis is reletad with the inflamation resulted from the superantigenes produced by the Staphylococcus aureus colonized in the nasal mucosa. In addition, the protein-A (SpA) increases the release of the histamine in the nasal tissue that results in allergic reactions. Because of its effects, S.aureus is thought to play a major role in the formation of chronic sinusitis. The aim of this study was to investigate the presence of S.aureus and to analyze the presence of staphylococcal exotoxins acting as superantigens and SpA in the strains isolated from the patients with chronic sinusitis and control patients without sinusitis in endoscopic sinus biopsy and nasal swabs samples and to elucidate the role of these parametres in the development of chronic sinusitis. 30 patients diagnosed with chronic sinusitis applied to GUTF hospital Oto Rhino Laryngology (ORL) polyclinic or hospitalized in the ORL service were chosen. Endoscopic surgery were done to these patients and sinus tissue biopsy samples were taken. Nasal septum surgery were performed and tissue biopsy samples were taken from 30 healthy individuals as the control group. Addionally, nasal swabs were also taken from 210 patients diagnosed with chronic sinusitis, and 442 patients without chronic sinusitis who had other disesases and the prevalence of S.aureus in these patients groups were investigated. Presence of toxic-shock syndrome toxin-1 (TSST-1) and enterotoxins A, B, C and D genes were investigated from isolated S.aureus strains by performing real-time PCR. In addition, the toxin production were screened with TECRA Staphylococcal enterotoxin VIA kit (TECRA, New South Wales, Australia) and the SpA were determined with commercial kit Protein-A EIA (Assay Designs-Stressgen, Hines Drive Ann Arbor, Michigan, USA). While S.aureus strains were isolated in 6 of 30 (20%) biopsy specimens taken from the chronic sinusitis patients, no growth were detected in the samples taken from the control group. For the chronic sinusitis patients, S.aureus was detected in 44 of 210 (21%) nasal swab specimens. On the other hand, 50 of 442 (11%) nasal swab specimen cultures obtained from the patients without chronic sinusitis yielded S.aureus. The patient group yielded much more S.aureus than the control group, and this finding was found to be statistically significant. Out of the 50 S.aureus isolates from the chronic sinusitis patients, enterotoxin A gene was found in 27 (54%), enterotoxin B gene was found in 16 (32%), enterotoxin C gene was found in 8 (16%), enterotoxin D gene was found in 8 (16%) of the isolates by real-time PCR method. On the other hand, for the control patients, we found enterotoxin A gene in 23 (46%), enterotoxin B gene in 12 (24%), enterotoxin C gene in 7 (14%), enterotoxin D gene in 7 (14%) of the 50 S.aureus strains. Although the number of the isolates that produce enterotoxin were higher in the patient group than those in the control group, the difference between them was not found to be statistically significant. While 20% of the isolates in the patient group were positive for the TSST-1 toxin gene, 46% were positive in the control group, and this finding was found to be statistically significant. Although 90% of the S.aureus strains in the control group and 88% in the patient group were found to be positive for SpA by enzyme immunoassay method, this was not statistically significant. We found that the supernatants of the S.aureus strains in the patient group yielded an average of 1171 pg/ml SpA, while it was 1248 pg/ml in those of the control group, and this was not statistically significant. In conclusion, we found higher numbers of S.aureus in the endoscopic sinus biopsy samples and nasal swab specimens of the patient group with chronic sinusitis than those of the control group. However, since S.aureus was not isolated in most of the patients, we thougth that this bacterium was only one of the multiple causative agents. It was concluded that the presence of these exotoxins is not an absolute requirement for the development of chronic sinusitis based on the rate of the enterotoxin and TSST-1 genes found in the S.aureus strains isolated from patient and control group. Similarly, it was determined that the levels and proportions of the presence of the SpA in the isolates were not so necessary for the development of chronic sinusitis. It was thought that in the presence of SpA and exotoxins as superantigens, they may lead to exacerbations of the clinical picture with their physiological effects.