Tarai Bansidhar, Sen Poornima, Kanaujia Rimjhim, Kaur Jasleen, Biswal Manisha, Das Poonam
Max Hospital, New Delhi, India.
Max Hospital, New Delhi, India.
Indian J Med Microbiol. 2022 Oct-Dec;40(4):552-556. doi: 10.1016/j.ijmmb.2022.07.008. Epub 2022 Aug 8.
Scrub typhus (ST) is a zoonotic disease, caused by O. tsutsugamushi is a major cause of acute febrile illness (AFI) in India. There is a need to study the prevalence and risk factors in various regions of India.
A study to estimate the prevalence and study the risk factors of ST in patients presenting with acute febrile illness (AFI) was performed. All patients underwent serology for IgM antibodies to Orientia tsutsugamushi (In Bios International Inc, Seattle, WA) as per the manufacturers' protocol. Following this, Polymerase Chain reaction (PCR) (real time SYBR green based targeting groEL gene and conventional PCR targeting 56 kDa type specific antigen gene) was performed from stored serum samples.
During the study period, 473 patients were admitted. Of these 56 (11.8%) patients were ST positive by IgM serology. The conventional PCR targeting 56 kDa type specific antigen gene of O. tsutsugamushi was positive in six patients while Ot groEL SYBR green based PCR) was positive in five. PCR was positive in patients who had demonstrated a higher OD value in ELISA. Conventional PCR positive amplicons were sent for Sanger sequencing and confirmed to be O. tsutsugamushi. The mean age of the patients was 49 ± 18.3 years and males constituted a higher number of patients (67.9%, n = 38). The pathognomonic eschar was present in 7 (12.5%) patients. Phylogenetic analysis revealed that sequences clustered close to Kato-like Hualein-20 strain and Karp-like Linh DT strains. All patients were administered doxycycline in our study. Mortality was recorded in 8.9% of the patients.
In patients presenting with acute febrile illness, ST should be considered as a differential diagnosis, especially in post-monsoon season. Along with serology, serum can also be used as sample for PCR in an intracellular bacterium like O. tsutsugamushi.
恙虫病是一种人畜共患病，由恙虫病东方体引起，是印度急性发热性疾病（AFI）的主要病因。有必要研究印度各地区的患病率及危险因素。
开展一项研究，以估计急性发热性疾病（AFI）患者中恙虫病的患病率并研究其危险因素。所有患者均按照制造商的方案接受针对恙虫病东方体IgM抗体的血清学检测（In Bios International Inc，西雅图，华盛顿州）。在此之后，对储存的血清样本进行聚合酶链反应（PCR）（基于实时SYBR绿靶向groEL基因以及靶向56 kDa型特异性抗原基因的常规PCR）。
在研究期间，收治了473例患者。其中，56例（11.8%）患者IgM血清学检测恙虫病呈阳性。靶向恙虫病东方体56 kDa型特异性抗原基因的常规PCR在6例患者中呈阳性，而基于Ot groEL SYBR绿的PCR在5例患者中呈阳性。在ELISA中OD值较高的患者PCR呈阳性。常规PCR阳性扩增子送去进行桑格测序，证实为恙虫病东方体。患者的平均年龄为49±18.3岁，男性患者数量较多（67.9%，n = 38）。7例（12.5%）患者出现了特征性焦痂。系统发育分析显示，序列聚集在接近Kato样Hualein - 20菌株和Karp样Linh DT菌株的位置。在我们的研究中，所有患者均接受了多西环素治疗。8.9%的患者有死亡记录。
对于出现急性发热性疾病的患者，应将恙虫病视为鉴别诊断疾病，尤其是在季风季节之后。除血清学检测外，血清也可作为针对恙虫病东方体这种细胞内细菌进行PCR检测的样本。
