Cytolethal distending toxin (CDT) of the Haemophilus parasuis SC096 strain contributes to serum resistance and adherence to and invasion of PK-15 and PUVEC cells.
Cytolethal distending toxin (CDT) is proposed to be an important virulence determinant of many pathogens. Although two cdt gene cluster loci have been identified in Haemophilus parasuis strain SH0165, the characteristics of CDTs associated with pathogenesis remain unclear. In this study, three CDT-deficient mutants, cdt-1, cdt-2 and the double-knockout cdt-1cdt-2 (Δcdt-1, Δcdt-2 and Δcdt-1Δcdt-2, respectively), were obtained in the H. parasuis serovar 4 clinical strain SC096 using a natural transformation method. Compared to the wild-type SC096 strain, the Δcdt-1, Δcdt-2 and Δcdt-1Δcdt-2 mutants showed subtle growth defects and clearly exhibited an increased sensitivity to the bactericidal action of porcine and rabbit sera. Additionally, these mutants had a significantly reduced ability to adhere to and invade porcine umbilicus vein endothelial cells (PUVEC) and porcine kidney epithelial cells (PK-15). These findings suggest that both CDTs in the H. parasuis SC096 strain are involved in serum resistance and adherence and invasion of host cells.
Key Laboratory of Veterinary Vaccine Innovation of Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China.
Bin
B
Zhang
Yanbing
Y
He
Chenggang
C
Xu
Lina
L
Xu
Saixiang
S
Feng
Ming
M
Liao
Tao
T
Ren
D000818:Animals; D001422:Bacterial Adhesion; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D001770:Blood Bactericidal Activity; D002460:Cell Line; D042783:Endothelial Cells / Q000382:microbiology; D004847:Epithelial Cells / Q000382:microbiology; D055786:Gene Knockout Techniques; D006192:Haemophilus Infections / Q000382:microbiology / Q000662:veterinary*; D044137:Haemophilus parasuis / Q000235:genetics / Q000472:pathogenicity*; D011817:Rabbits; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology; D014774:Virulence
D001427:Bacterial Toxins; C067044:cytolethal distending toxin