Cytological Findings in Bronchoalveolar Lavage Fluid of Foals With Pneumonia Caused by Rhodococcus equi and Other Bacteria

Abstract

The distinction between lower respiratory tract infections caused by Rhodococcus equi and those caused by other pathogens is difficult. The aim of this retrospective study was to describe cytological findings in bronchoalveolar lavage fluid (BALF) of foals with pneumonia caused by R. equi or other bacteria. Nineteen foals aged from 3 weeks to 6 months with evidence of respiratory disease between 2015 and 2016 were selected from the database of the Veterinary Teaching Hospital "Mario Modenato" of the University of Pisa. Eight foals out of 19 (42.1%) had R. equi pneumonia while eleven out of 19 (57.9%) had another bacterial pneumonia. R. equi positive foals had statistically significant higher TNCC (P=0.02) and neutrophils percentage (P=0.002) than R. equi negative ones. Macrophages proportion (P=0.01) was lower in R. equi positive than in R. equi negative foals. BAL is a quite easy procedure that can be performed in the field with minimal equipment required. Here we reported significant differences in the cellular composition of BALF that can be used to differentiate foals with R. equi bronchopneumonia from those with other bacterial pneumonias, while waiting for culture results.

Agents isolated from horses with respiratory system infection signs

“…Respiratory diseases have been reported to be among the most common diseases in horse breeding in countries around the world (Sharma et al 2017;Kasap et al 2018;Vitale et al 2019). In particular, unsuitable shelter conditions, crowded environments and unfavorable climatic conditions increase the exposure of horses to different respiratory pathogens (Wood et al 2005).…”

“…Materials such as straw and straw naturally contain an important native mi-croflora that can grow further when stored or used as feed or bedding (Carvallo et al 2017). In addition, respiratory system infections are an important cause of death in foals (Vitale et al 2019). Generally, viral and bacterial upper respiratory tract infections occur in foals aged 1, inflammatory respiratory tract disease and pleuropneumonia occur in race horses aged 2 or more.…”

Protective immune responses against Rhodococcus equi : an innate immunity-focused review

“…R. equi pneumonia in foals is characterized by recruiting neutrophils to the lungs resulting in a higher proportion of neutrophils in BAL fluid than in pneumonia caused by other bacteria. 183 Neutrophils from neonates and adults are functionally and phenotypically different because of the considerable differences between fetal and adult physiology. 112 Neutrophil adaptations to fetal and neonatal physiology, which include preventing pro-inflammatory responses in the hypoxic uterus and allowing the colonization of a healthy microbiome in the postpartum period, are vital during the perinatal period.…”

Survival rate of donkey foals: Status quo and improvement methods

“…Furthermore, the analysis of BALF cellular components is instantaneous and does not require a specific laboratory. By examining the cells in the bronchoalveolar lavage fluid of donkey foals with pneumonia caused by other bacteria, possible differences can be identified and detected to help veterinarians in clinical settings to achieve an early diagnosis (Cowell and Tyler, 2002;Hostetter et al, 2017;Vitale et al, 2019). Donkey foals born in winter and spring have an extremely high risk of pneumonia.…”