Correlation between genotypes of Orientia tsutsugamushi and clinical characteristics of patients with scrub typhus in Guangzhou, China

To explore the correlation between genotypes of Orientia (O.) tsutsugamushi and clinical characteristics of scrub typhus patients. Clinical data of patients with scrub typhus admitted to different types of medical institutions in Guangzhou from September 2012 to December 2016 were collected using medical records. Demographic data, clinical manifestations, as well as hematological and biochemical indicators of patients infected with different genotypes were analyzed and compared. A total of 192 patients were included in this study, including 121 patients with Karp genotype of O. tsutsugamushi infection (63.0%), 36 patients with Gilliam genotype (19.0%), 23 patients with Kato genotype (12.0%), and 12 patients with TA763 genotype (6.0%) infection. The median value of albumin in patients with Karp genotype infection was significantly lower than that of Gilliam-infected patients (P=0.032). Patients with Karp genotype infection had a significantly longer hospital stay (9 days) than those with Gilliam genotype (7 days) (P=0.009) and Kato genotype infection (6 days) (P=0.005). Karp-infected patients also represented for the largest number of patients with complicated organ involvement (88/133, 66.2%). Furthermore, Karp-infected patients had higher risk of developing multiple organ dysfunction syndrome (18.2%) and requiring intensive care unit treatment (15.9%). Besides, patients with Gilliam genotype (8 days) and TA763 genotype infection (7.5 days) had shorter fever duration than those with Karp genotype (9 days) and Kato genotype (9 days) infection, respectively. Genotypes of Orientia tsutsugamushi were associated with varying clinical manifestations, organ involvement, and treatment outcomes, suggesting that genotypes ranged in virulence.