Flagellar length was measured by transmission electron microscopy (TEM) and phospholipase D (PLD) activity was determined by Amplex Red Phospholipase D Assay Kit.<h4>Results</h4>From 327 virulence-associated genes, the VFDB analysis identified significant differences in four virulence factor genes pilA, pldA, algP, and flaG between the exoU and exoS groups (all p < 0.05).When combining PCR and VFDB data from 187 keratitis isolates, pldA (83.6% vs. 31.8%, p < 0.01) and flaG (80% vs. 55.3%, p < 0.01) showed significantly higher prevalence in the exoU than the exoS. The gene discussed is GPLD1; the disease is keratitis.