Biswal Manisha, Krishnamoorthi Sivanantham, Bisht Kamlesh, Sehgal Amit, Kaur Jasleen, Sharma Navneet, Suri Vikas, Sethi Sunil
Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
Department of Microbiology, All India Institute of Medical Sciences, Bathinda, Punjab 151001, India.
Trop Med Infect Dis. 2020 Apr 15;5(2):59. doi: 10.3390/tropicalmed5020059.
Rickettsial diseases (RDs) are major under-diagnosed causes of arthropod borne acute febrile illness (AFI) presenting with a range of symptoms from mild self-limiting fever to fatal sepsis. The spotted fever group (SFG) and typhus group (TG) are major RDs, which are commonly caused by and , respectively. The limited availability and role of serological tests in the acute phase of illness warrants rapid reliable molecular methods for diagnosis and epidemiological studies. Two hundred patients with AFI in whom the routine fever diagnostics were negative, were enrolled over a period of two months (April 2019 to May 2019). DNA was extracted and in-house nested PCR using primers specific for both SPG and TG pathogens was used. The positive amplified products were sequenced for species identification and phylogenetic analysis was performed using MEGA 7.0.14 software (iGEM, Temple University, Philadelphia, PA 19122, USA). The demographic details of the RD cases were documented. The prevalence of RD among AFI cases was 7% (14/200); SFG and TG were identified as the cause in 4% and 3% of AFI cases, respectively. The median age of the RD cases was 22 years (range 2-65). The median duration of fever was 3 days (range 1-12). The RD cases presented with respiratory symptoms or signs (44.44%), jaundice (22.22%), abdominal pain (22.22%), diarrhea (22.22), vesicular rash (11.11%), vomiting (11.11%), loss of appetite (11.11%), headache (11.11%), leukocytosis (88.88% with mean count 22,750/mm), and thrombocytopenia (33.33%). The cases were treated empirically with piperacillin-tazobactam (66.66%), clindamycin (44.44%), cefotaxime (33.33%), meropenem (33.33%), metronidazole (33.33%), doxycycline (22.22%), azithromycin (22.22%), ceftriaxone (11.11%), and amoxicillin-clavulanic acid (11.11%). The mortality among the RD cases was 11.11%. The present pilot study shows that RD is not an uncommon cause of AFI in north India. The febrile episodes are usually transient, not severe and associated with heterogenous clinical presentation without documented history of tick exposure in the hospitalized patients. The transient, non-severe, febrile illness could be due to transient rickettsemia resulting from empirical antimicrobial therapy as the rickettsial organisms are expected to be more susceptible to higher doses of β-lactam antibiotics. The study emphasizes the molecular method as a useful tool to identify rickettsial etiology in AFI.
立克次体病（RDs）是节肢动物传播的急性发热性疾病（AFI）的主要漏诊病因，其症状范围从轻度自限性发热到致命性败血症不等。斑点热群（SFG）和斑疹伤寒群（TG）是主要的立克次体病，分别通常由 和 引起。血清学检测在疾病急性期的可用性有限且作用不大，因此需要快速可靠的分子方法用于诊断和流行病学研究。在两个月的时间里（2019年4月至2019年5月），招募了200例常规发热诊断为阴性的AFI患者。提取DNA，并使用针对SFG和TG病原体的特异性引物进行内部巢式PCR。对阳性扩增产物进行测序以进行物种鉴定，并使用MEGA 7.0.14软件（iGEM，美国宾夕法尼亚州费城坦普尔大学，邮编19122）进行系统发育分析。记录了RD病例的人口统计学细节。AFI病例中RD的患病率为7%（14/200）；SFG和TG分别被确定为4%和3%的AFI病例的病因。RD病例的中位年龄为22岁（范围2 - 65岁）。发热的中位持续时间为3天（范围1 - 12天）。RD病例表现出呼吸道症状或体征（44.44%）、黄疸（22.22%）、腹痛（22.22%）、腹泻（22.22%）、水疱性皮疹（11.11%）、呕吐（11.11%）、食欲不振（11.11%）、头痛（11.11%）、白细胞增多（88.88%，平均计数22,750/mm）和血小板减少（33.33%）。这些病例经验性地使用哌拉西林 - 他唑巴坦（66.66%）、克林霉素（44.44%）、头孢噻肟（33.33%）、美罗培南（33.33%）、甲硝唑（33.33%）、多西环素（22.22%）、阿奇霉素（22.22%）、头孢曲松（11.11%）和阿莫西林 - 克拉维酸（11.11%）进行治疗。RD病例的死亡率为11.11%。目前的初步研究表明，在印度北部，RD是AFI的常见病因。发热发作通常是短暂的，不严重，且临床表现多样，住院患者无蜱暴露的记录病史。这种短暂的、不严重的发热性疾病可能是由于经验性抗菌治疗导致的短暂立克次体血症，因为立克次体生物体预计对高剂量的β - 内酰胺抗生素更敏感。该研究强调分子方法是识别AFI中立克次体病因的有用工具。
