The cytology and microbiology of persistent paranasal sinus secretions after endoscopic sinus surgery: a controlled study

Cytological Examination of Secretions From the Paranasal Sinuses in Horses

The objective of this study was to determine whether the assessment of cytological features of secretions from the paranasal sinuses represents a useful diagnostic tool in equine sinusitis to distinguish between different etiologies. Secretion samples from 50 horses with sinusitis and 10 healthy horses were taken transendoscopically from the drainage angle of the nasomaxillary aperture using a Swing Tip catheter. An additional direct sample from the caudal maxillary sinus was taken from all healthy horses after trephination. A direct sample was obtained from the affected sinus in 19 diseased horses after osteotomy. Samples were smeared on microscope slides and dyed using "Pappenheim stain" for cytological evaluation. Smears from horses with sinusitis (primary n = 14, dental n = 28, cyst n = 2, progressive ethmoidal hematoma [PEH] n = 2, traumatic n = 2, malignant neoplasia n = 2) were dominated by moderate to high numbers of neutrophilic granulocytes and moderate numbers of different epithelial cells, whereas samples from healthy sinuses revealed almost exclusively epithelial cells. Smears in dental-related sinusitis tended to contain more lytic cellular material than in other conditions. Horses with dental sinusitis also showed a higher intracellular and extracellular bacterial burden than horses with other underlying etiologies and healthy horses. The absence of bacteria in light microscopy did not exclude the evidence of pathogenic bacteria from bacterial culture in every case. Case numbers were too small to evaluate the diagnostic value for neoplastic conditions or PEH. In conclusion, cytological examination of secretions from the paranasal sinuses can provide an additional but limited ancillary diagnostic value in equine sinusitis.

Evaluation of bacterial transmission to the paranasal sinuses through sinus irrigation

BACKGROUND

Saline nasal irrigation is effective in the treatment of sinonasal disorders, including chronic rhinosinusitis (CRS). Despite bacterial contamination in rinse bottles and reports of infections from contaminated irrigation water, tap water is still used by ∼50% of irrigation users, raising a potential public health concern. This study aimed to determine whether bacteria from the water supply used in sinus irrigations colonizes the paranasal sinuses.

METHODS

Samples were taken from the: (1) water used for irrigation, (2) faucet or container the water originated from, (3) rinse bottle, and (4) postoperative ethmoid cavity from 13 subjects with CRS. Microbiota were characterized using quantitative polymerase chain reaction (qPCR) and 16S ribosomal RNA (rRNA) gene sequencing. The Morisita-Horn beta-diversity index (M-H) was used to assess similarity in microbiota between samples, and genomic analysis was performed to assess clonality of cultured bacteria.

RESULTS

Of 13 subjects, 6 used distilled water, 6 used tap water, and 1 used well water in this institutional review board (IRB)-approved observational study. Well-water had markedly more bacteria than tap or distilled water. There was a trend toward tap having more bacteria than distilled water. The sinus samples were notably dissimilar to the bottle, faucet, and irrigant (M-H 0.15, 0.09, and 0.18, respectively). There was no difference in postoperative microbiotas between distilled and tap water users.

CONCLUSION

The current study suggests that irrigation plays little role in establishing the sinus microbiome. Although rinsing with tap water may never be formally recommended, these data are useful to counsel patients who prefer to do so in non-endemic areas if the municipal water supply is appropriately treated.