Anatomopathological characterization of pneumonia in guinea pig produced by Streptococcus pneumoniae in intensive breeding

Objective. Characterize macroscopically and microscopically the lesions caused by Streptococcus pneumoniae in samples of guinea pig lung (Cavia porcellus) of intensive breeding in Lima. Materials and methods. The necropsy of 138 guinea pigs with clinical signs of pneumonia was performed, and the sample of the affected lungs was taken. Bacterial isolation was performed for the identification of Streptococcus pneumoniae, using blood agar and biochemical tests; Histopathological processing was performed using the hematoxylin eosin (HE) staining of tissue samples preserved in 10% formalin. Results. Of the total lungs diagnosed with pneumonia at necropsy, 17.4% (24/138) was positive for Streptococcus pneumoniae. Of these, 75% (18/24) showed macroscopic characteristics of interstitial pneumonia and 20.87% (5/24) macroscopic characteristics of suppurative bronchopneumonia and 4.17% (1/24) of fibrinous bronchopneumonia. In the microscopic evaluation it was found that 54.17% presented both interstitial bronchopneumonia, 37.50% interstitial pneumonia, and 8.33% of them correspond to bronchopneumonia. Conclusions. Interstitial bronchopneumonia, interstitial pneumonia and bronchopneumonia with a diagnosis of Streptococcus pneumoniae are lesion patterns found in intensive rearing systems in Lima.