Prevalence and abundance of Staphylococcus aureus in the middle meatus of patients with chronic rhinosinusitis, nasal polyps, and asthma

Department of Otolaryngology-Head and Neck Surgery, University of Colorado, Aurora, CO.
International Forum of Allergy and Rhinology (Impact Factor: 2.37). 04/2013; 3(4). DOI: 10.1002/alr.21101
Source: PubMed

ABSTRACT BACKGROUND: Chronic rhinosinusitis (CRS) is an idiosyncratic and multifactorial disease process. Bacteria play a role in some patients, by infection or stimulation of inflammation. Staphylococcus aureus (SA) appears to be implicated in a number of infectious and inflammatory mechanisms, and may be particularly relevant in CRS patients with nasal polyps and asthma. METHODS: Middle meatus swabs from control and CRS patients collected during endoscopic sinus surgery were analyzed by quantitative polymerase chain reaction (QPCR). Total bacterial count, SA prevalence, and SA abundance were examined with respect to patient demographics and disease characteristics. RESULTS: Total bacteria, as measured by QPCR, was not statistically different between controls, CRS without nasal polyps (CRSsNP), CRS with nasal polyps (CRSwNP), or CRS with asthma groups (p < 0.09). Total bacterial counts did not correlate with disease severity as measured by Lund-Mackay computed tomography (CT) scores (p = 0.65). The prevalence of SA was similar between groups (15-25%); however, the abundance increased in CRS patients with allergic rhinitis, nasal polyps, and asthma. CONCLUSION: The paranasal sinuses are not sterile. SA is implicated in a subset of CRS patients with nasal polyps and/or asthma. Further study is required to predict this subset of patients, and to define the mechanisms of SA pathogenesis.

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    ABSTRACT: Chronic rhinosinusitis (CRS) affects approximately 5% of the adult population in Western societies and severely reduces the patient's quality of life. The role of bacteria in the pathogenesis of this condition has not yet been established with certainty. However, recent reports of bacterial and fungal biofilms in CRS highlight a potential role for these microorganisms. In this study, 16S rRNA gene-targeted amplicon pyrosequencing and qPCR were used to determine the composition and abundance, respectively, of the sinus microbiota within 9 patients with CRS and 6 healthy individuals. Within-patient variability was also investigated by sampling from anterior nares, inferior turbinate, and middle meatus on each side of the sinuses. Our results indicate that more of the variation in bacterial composition can be explained by inter-personal differences, rather than sampling location or even disease status. In addition, bacterial community diversity was significantly lower in CRS samples compared to those from healthy subjects, whereas bacterial load was not associated with disease status. Although members of the genera Corynebacterium and Staphylococcus were prevalent in the majority of samples (including healthy subjects), the large amount of variation observed between individuals, particularly within the CRS cohort, suggests that an imbalance or dysbiosis in community structure could be the driving force behind the disease. Ultimately, understanding the causes of variation within the sinus microbiota may lead to more personalized treatment options for CRS.
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    ABSTRACT: Background Chronic rhinosinusitis (CRS) is an inflammatory disorder of the paranasal sinuses in which bacteria are implicated. Culture-based assays are commonly used in clinical and research practice; however, culture conditions may not accurately detect the full range of microorganisms present in a sample. The objective of this study was to determine the accuracy of clinical culture of CRS specimens compared with DNA-based molecular techniques.Methods Ethmoid samples from 54 CRS patients collected during endoscopic sinus surgery were analyzed by both clinical culture and 16S ribosomal RNA (rRNA) gene sequencing. The association between 16S relative abundance and detection by culture was determined using logistic regression.ResultsEach subject had an average of 3 isolates identified by bacterial culture and 21.5 ± 12.5 species identified by 16S sequencing. On average, 1.6 dominant taxa (>10% abundance) per subject were identified using molecular techniques, but only 47.7% of these taxa were identified by culture. Low abundance taxa (abundance <1%) were detected in only 4.5% of cultures. The odds that any organism would be detected by culture were 2.3 times higher with each 10% increase in relative abundance (p < 0.01). Conversely, only 29.5% of isolates identified by culture represented the dominant species, whereas 40% accounted for species with 1% to 10% abundance. Interestingly, 12% of isolates detected by culture were not identified by 16S pyrosequencing.Conclusion Standard clinical culture is a poor representation of resident microbiota. The incorporation of modern culture-independent techniques into clinical and research practices provides additional information that may be relevant for CRS.
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