Objective: To investigate the differences between the sequences of papA and papG of UPEC4030 strain and the related genes, to better understand the genetic variation of UPEC4030 papA and its combination forms with papG so as to identify if it was a new genotype.
Methods: Cloning and sequencing methods were used to analyze the sequences of papG and papA of UPEC4030 strain and to compare their related sequences.
Results: Through sequence analysis of papA, it was revealed that there was a 722 bp gene, encoding 192 amino acid polypeptide. The overall homology of the papA genes between UPEC4030 and the standard strains of ten F types were 36.11% - 77.95% and 22.20% - 78.34% at nucleotide and deduced amino acid levels. Homology between the sequences of reverse primers and the corresponding sequence of UPEC4030 papA was 10.00% - 66.67%. The results confirmed that UPEC4030 strain contained a novel papA variant. Through sequence analysis of UPEC4030 papG, we revealed a 1100 bp gene, encoding 337 amino acid polypeptide. The homology of the papG genes between UPEC4030 and UPEC IA2, the standard strain, was 99.00% at nucleotide level and 99.11% at deduced amino acid and UPEC4030 strain carried class II genotype of papG.
Conclusion: UPEC4030 strain contained an unknown papA variant or the new genotype and carried class II genotype of papG. The pathogenic mechanism and epidemiology call for further study.