Dysbiosis of the cervical lymph node microbiome associated with lymphadenitis in guinea pigs (Cavia porcellus)

Cervical lymphadenitis is a significant infectious disease in guinea pig ( Cavia porcellus ) production, however, little is known about the microbiota associated with cervical lymph nodes in healthy and infected animals. This study compared the microbiota of cervical lymph nodes from healthy guinea pigs and those with lymphadenitis using 16S rRNA gene sequencing, bioinformatics analysis, and molecular validation by PCR. The results showed that healthy lymph nodes harbor diverse bacterial communities, while infected lymph nodes exhibit a marked reduction in microbial diversity and an increased relative abundance of Streptococcus equi subsp. zooepidemicus . Furthermore, a subset of samples revealed an alternative etiology characterized by the dominance of the genus Caviibacter , suggesting etiological heterogeneity of the disease in this study. Taken together, these findings suggest that cervical lymphadenitis in guinea pigs is associated with dysbiosis of the lymph node microbiome and support the use of metagenomic approaches for etiological characterization.