Diagnosis of Septic Body Cavity Effusion in Dogs and Cats: Cytology vs. Bacterial Culture.

Simple Summary: Septic exudates in the body cavities of dogs and cats are considered a critical clinical condition. The current elective diagnostic tools for detecting septic effusion are bacterial culture and fluid cytology. Although culture is considered the gold standard, clinicians may not have access to the results for several days. This may result in a delayed diagnosis of septic effusion, which may have adverse effects on patient outcomes. This study compared the performances of cytology and bacterial culture in the identification of septic exudative body cavity effusions in dogs and cats. The results of our investigation indicated moderate agreement between cytology and microbiology. Cytology and bacterial culture results for exudative body cavity effusions in dogs and cats can be misleading when conducted individually. To improve diagnostic accuracy, these two methodologies should be integrated. The elective test for the determination of the effusions etiopathogenesis is represented by physico-chemical analysis and cytology. Nevertheless, the bacterial culture and antibiotic sensitivity tests are crucial for setting therapy and for the outcome. This study compared cytology with microbiology in the etiologic diagnosis of exudative body cavity effusions in dogs and cats collected from October 2018 to October 2022. All samples underwent aerobic and anaerobic culture and cytology examination. Bacterial identifications were confirmed using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry, whereas cytological samples were blindly evaluated either in May Grunwald-Giemsa (MGG) or Gram-stained samples by two board-certified clinical pathologists. A moderate agreement (κ = 0.454) between cytology and bacterial culture was revealed. The sensitivity of the cytological evaluation in our study ranged from 38.5% to 67.9%, and the specificity ranged from 88.9% to 100%, depending on the type of the effusion, so cytology may not be representative of the etiopathogenesis, whereas bacterial culture can misidentify or fail to isolate the correct pathogen for difficult in vitro growing due to the presence of inhibitory substances or contamination. Cytology and bacterial culture results for exudative body cavity effusions in dogs and cats can be misleading if conducted separately, so these two tests should be performed together to increase diagnostic accuracy. [ABSTRACT FROM AUTHOR]