Nasopharyngeal bacterial and fungal microbiota in normal horses and horses with nasopharyngeal cicatrix syndrome

Abstract

Background The nasopharyngeal bacterial and fungal microbiota of normal horses and those with nasopharyngeal cicatrix syndrome (NCS) are unknown. Hypotheses/Objectives To describe the microbiota from nasopharyngeal washes of healthy horses and of horses acutely affected with NCS. Animals Twenty‐six horses acutely affected with NCS horses and 14 unaffected horses. Methods Prospective, observational cohort study. Horses were recruited by investigators through personal communications in central Texas. Bacterial (16s RNA) and fungal (internal transcribed spacer) microbiota from nasopharyngeal washes were evaluated. Polymerase chain reaction for detection of Pythium insidiosum was performed. Results Results indicated that 6 fungal genera (Alternaria, Bipolaris, Microascus, Spegazzinia, Paraconiothyrium, Claviceps) and 1 bacterial genera (Staphylococcus) were significantly different between affected and unaffected horses. The fungal genus Bipolaris had increased abundance in NCS affected horses and on NCS affected farms. Pythium insidiosum was absent in the nasopharyngeal wash of all horses, irrespective of health status. Conclusion and Clinical Importance Significant differences were identified in the fungal microbiota in horses affected with NCS and farms affected with NCS compared to those unaffected. Therefore, Bipolaris warrants further investigation.

Topography of the respiratory, oral, and guttural pouch bacterial and fungal microbiotas in horses

“…Limited information is available regarding the topography of the respiratory tract microbiota of horses 8,9,14,15 . A recent culture‐based study investigated the prevalence of fungi in respiratory samples of horses diagnosed with mild asthma and found that the presence of fungi in tracheal wash cytology doubled the likelihood of a horse having mild asthma 16 .…”

“…Limited information is available regarding the topography of the respiratory tract microbiota of horses. 8 , 9 , 14 , 15 A recent culture‐based study investigated the prevalence of fungi in respiratory samples of horses diagnosed with mild asthma and found that the presence of fungi in tracheal wash cytology doubled the likelihood of a horse having mild asthma. 16 Given that the overall bacterial composition of the respiratory tract contributes to various disease states, it is logical to question the role of the respiratory fungal microbiota in the healthy horse.…”

Standing surgical procedure for treatment of otitis media in a horse

“…The lack of sterile sampling method may be considered a limitation to this study. Pseudomonas was part of nasopharyngeal flora in 13 out of the 14 horses but was not included in the most prevalent genera found in the nasopharynx of healthy horses (Rodriguez et al, 2021). It is therefore possible that the Pseudomonas aeruginosa cultured from the fluid sample may have been a contaminant; however, the likelihood of this is considered low due to the pure growth rather than a mixed growth including other, more prevalent, microflora genera in the nasopharynx.…”