Molecular Characterization of Two Phenotypes of Mixta calida Isolated from Post-Liver Transplant Drainage Fluid

We reported the isolation of Mixta calida strains and their genomic characteristics from the drainage fluid of a patient with hepatitis B-related cirrhosis following liver transplantation. Two distinct morphotypes were identified: a mucoid type (mixA) and a dry type (mixB). Whole-genome sequencing revealed high structural similarity between the genomes, with a total length of approximately 4.13 Mb and a GC content of 56.91%. The nucleotide sequence homogeneity between the two strains was 99.99%, with comparable metabolic pathways, annotated genes, and potential virulence factors. Comparative genomic analysis highlighted unique genetic features related to transposases in both strains, suggesting adaptive advantages. Notably, mixA exhibited a greater abundance of glycoside hydrolases and carbohydrate-active enzymes, indicating its potential for carbohydrate degradation and utilization. Transcriptomic analysis revealed significant differences in gene expression, with mixA upregulating genes associated with stress response and carbohydrate metabolism, suggesting enhanced environmental adaptability and stability. This study underscores the clinical significance of Mixta calida in post-operative infections and provides insights into its genomic and transcriptomic profiles.