Srinivasan Seethalakshmi, Kalaimani Saravanan, Jude Prakash John Antony, Menon Thangam
Department of Microbiology, Dr. AL Mudaliar PG Institute of Basic Medical Sciences, University of Madras, Chennai, Tamil Nadu, India.
Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India.
Indian J Med Microbiol. 2019 Jan-Mar;37(1):50-53. doi: 10.4103/ijmm.IJMM_19_170.
Scrub typhus is a zoonotic infection caused by Orientia tsutsugamushi which is transmitted by Leptotrombidium mites. The disease manifests as a mild-to-severe illness with non-specific clinical symptoms. Rapid diagnosis and prompt treatment are essential for patient management. Both serological and molecular methods are used for the diagnosis of scrub typhus. The present study assessed the usefulness of detection of the gene encoding the 47kDa outer-membrane protein (OMP) for the laboratory diagnosis of scrub typhus.
Nested polymerase chain reaction (nPCR) and real-time PCR targeting 47 kDa OMP antigen gene of O. tsutsugamushi were performed on ethylenediaminetetraacetic acid blood samples.
Six of the 103 (5.8%) patients showed the presence of 47kDa gene by nPCR. Seventy of 103 (67.9%) cases showed the presence of 47kDa gene by qPCR. Among the 70 positive cases, the majority of them were females (40/70, 57.1%). The highest number of positive cases was observed during October-February.
Real-time PCR targeting O. tsutsugamushi-specific 47-kDa gene is more sensitive than nPCR and may be the assay of choice for the detection of the organism in patients with suspected scrub typhus.
恙虫病是由恙虫病东方体引起的一种人畜共患感染，通过恙螨传播。该病表现为从轻度到重度的疾病，伴有非特异性临床症状。快速诊断和及时治疗对患者管理至关重要。血清学和分子方法都用于恙虫病的诊断。本研究评估了检测编码47kDa外膜蛋白（OMP）的基因对恙虫病实验室诊断的有用性。
对乙二胺四乙酸血样进行巢式聚合酶链反应（nPCR）和针对恙虫病东方体47kDa OMP抗原基因的实时PCR。
103例患者中有6例（5.8%）通过nPCR检测到47kDa基因。103例中有70例（67.9%）通过qPCR检测到47kDa基因。在70例阳性病例中，大多数为女性（40/70，57.1%）。10月至2月期间阳性病例数最多。
针对恙虫病东方体特异性47-kDa基因的实时PCR比nPCR更敏感，可能是疑似恙虫病患者病原体检测的首选检测方法。
