ANALYZING HISTOPATHOLOGY OF MACACA FASCICULARIS KIDNEYS WITH KLEBSIELLA PNEUMONIAE INFECTION

Abstract

This study analysed the histopathological impact of Klebsiella pneumoniae infection on the kidneys of Macaca fascicularis, a critical species in biomedical research. Three naturally infected subjects (IA33900, 190517, and IA3511) were evaluated using hematoxylin-eosin (HE) staining and quantitative metrics. Histopathological scoring revealed distinct renal damage severity: IA33900 exhibited moderate lesions (score 2), while 190517 and IA3511 showed advanced necrosis and haemorrhage (score 3). Common findings included tubular degeneration, vascular congestion, and inflammatory infiltration, consistent with bacterial cytotoxicity and immune-mediated damage. Strain-specific virulence factors, such as hypervirulent K. pneumoniae (hvKp) with LPS and fimbrial adhesins, exacerbated endothelial injury and microthrombi formation. Chronic inflammation driven by Th17/Th2-polarized cytokine cascades promoted interstitial fibrosis and tubular atrophy. Quantitative analysis demonstrated significant tubular dilatation index (TDI) elevation in infected kidneys (P < 0.001), correlating with tubular damage, while glomerular/Bowman’s capsule ratios remained unaffected (P = 0.83). These findings underscore the interplay between bacterial virulence and host immune dysregulation in renal pathology. The study highlights the need for targeted therapies addressing microbial eradication and immune modulation, as well as improved management of K. pneumoniae in SPF primate colonies to safeguard research integrity.