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Evaluation of an in-house PCR for diagnosing scrub typhus along with a preliminary study of genotypic characterization of Orientia tsutshugamushi circulating in Chhattisgarh: A prospective clinico-microbiological study.
Indian J Med Microbiol. 2022 Oct-Dec; 40(4):510-515.IJ

Abstract

PURPOSE

Scrub typhus, caused by Orientia tsutsugamushi (O. tsutsugamushi) present nonspecific clinical features during manifestation of acute undifferentiated febrile illness (AUFI) to render its early diagnosis difficult. Accordingly, this study was undertaken to assess an in-house groEL PCR versus IgM ELISA for the diagnosis of scrub typhus and to genotypically characterise the randomly selected scrub typhus positive cases.

METHODS

Blood samples, collected from two hundred twenty one (221) AUFI cases were subjected to groEL PCR and IgM ELISA for diagnosis of scrub typhus. Eleven randomly selected PCR positive cases were processed for DNA sequencing to determine the genetic diversity of O. tsutsugamushi in Chhattisgarh.

RESULTS

Scrub typhus prevalence of 35.2% were detected among AUFI cases using both in-house groEL PCR and IgM ELISA. PCR alone showed sensitivity, specificity, positive and negative predictive values of 66.6% (CI: 55.08-76.94), 100% (CI: 90 to 100),100% (CI: 93.15 to 100) and 57.37% (CI: 44.05 to 69.96) while for IgM ELISA, these parameters were 62.8% (CI: 51.13-73.50), 100% (CI: 90 to 100), 100% (CI: 92.75 to 100) and 54.68% (CI: 41.75 to 67.18) respectively. PCR and ELISA could detect scrub typhus in 37.2% and 33.3% cases, when tested alone. groEL PCR detected the O. tsutsugamushi throughout the course of infection. Phylogenetic analysis depicted 5 of 11 positive cases belonged to Kuroki, Japan strain of O. tsutsugamushi, followed by Gilliam and Karp strain in 4 and 2 cases respectively.

CONCLUSION

Scrub typhus should be considered in differential diagnosis of AUFI. groEL PCR may aid on to IgM ELISA test for optimum laboratory diagnosis of scrub typhus by its implementation especially in seronegative cases. Predominance of Kuroki-like strain followed by Gillian and Karp strains of O. tsutsugamushi in Chhattisgarh confirm variable geographical distribution of O. tsutsugamushi and provide the baseline epidemiological data which will eventually be used to help the researchers for developing better diagnostic tests and vaccine covering the predominant genotypes.

Authors+Show Affiliations

Department of Microbiology, All India Institute of Medical Sciences (AIIMS), Raipur, India.Department of Microbiology, All India Institute of Medical Sciences (AIIMS), Raipur, India. Electronic address: negidr@aiimsraipur.edu.in.Department of Microbiology, All India Institute of Medical Sciences (AIIMS), Raipur, India.Department of Microbiology, All India Institute of Medical Sciences (AIIMS), Raipur, India.Department of Paediatrics, All India Institute of Medical Sciences (AIIMS), Raipur, India.Department of General Medicine, All India Institute of Medical Sciences (AIIMS), Raipur, India.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

36050139

Citation

Prakash, Rishika, et al. "Evaluation of an In-house PCR for Diagnosing Scrub Typhus Along With a Preliminary Study of Genotypic Characterization of Orientia Tsutshugamushi Circulating in Chhattisgarh: a Prospective Clinico-microbiological Study." Indian Journal of Medical Microbiology, vol. 40, no. 4, 2022, pp. 510-515.
Prakash R, Negi SS, Bhargava A, et al. Evaluation of an in-house PCR for diagnosing scrub typhus along with a preliminary study of genotypic characterization of Orientia tsutshugamushi circulating in Chhattisgarh: A prospective clinico-microbiological study. Indian J Med Microbiol. 2022;40(4):510-515.
Prakash, R., Negi, S. S., Bhargava, A., Sharma, K., Jagzape, T., & Wasnik, P. (2022). Evaluation of an in-house PCR for diagnosing scrub typhus along with a preliminary study of genotypic characterization of Orientia tsutshugamushi circulating in Chhattisgarh: A prospective clinico-microbiological study. Indian Journal of Medical Microbiology, 40(4), 510-515. https://doi.org/10.1016/j.ijmmb.2022.08.005
Prakash R, et al. Evaluation of an In-house PCR for Diagnosing Scrub Typhus Along With a Preliminary Study of Genotypic Characterization of Orientia Tsutshugamushi Circulating in Chhattisgarh: a Prospective Clinico-microbiological Study. Indian J Med Microbiol. 2022 Oct-Dec;40(4):510-515. PubMed PMID: 36050139.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evaluation of an in-house PCR for diagnosing scrub typhus along with a preliminary study of genotypic characterization of Orientia tsutshugamushi circulating in Chhattisgarh: A prospective clinico-microbiological study. AU - Prakash,Rishika, AU - Negi,Sanjay Singh, AU - Bhargava,Anudita, AU - Sharma,Kuldeep, AU - Jagzape,Tushar, AU - Wasnik,Preetam, Y1 - 2022/08/29/ PY - 2022/03/10/received PY - 2022/07/28/revised PY - 2022/08/03/accepted PY - 2022/9/2/pubmed PY - 2022/10/20/medline PY - 2022/9/1/entrez KW - IgM ELISA KW - In-house PCR KW - O.tsutsugamushi KW - Scrub typhus SP - 510 EP - 515 JF - Indian journal of medical microbiology JO - Indian J Med Microbiol VL - 40 IS - 4 N2 - PURPOSE: Scrub typhus, caused by Orientia tsutsugamushi (O. tsutsugamushi) present nonspecific clinical features during manifestation of acute undifferentiated febrile illness (AUFI) to render its early diagnosis difficult. Accordingly, this study was undertaken to assess an in-house groEL PCR versus IgM ELISA for the diagnosis of scrub typhus and to genotypically characterise the randomly selected scrub typhus positive cases. METHODS: Blood samples, collected from two hundred twenty one (221) AUFI cases were subjected to groEL PCR and IgM ELISA for diagnosis of scrub typhus. Eleven randomly selected PCR positive cases were processed for DNA sequencing to determine the genetic diversity of O. tsutsugamushi in Chhattisgarh. RESULTS: Scrub typhus prevalence of 35.2% were detected among AUFI cases using both in-house groEL PCR and IgM ELISA. PCR alone showed sensitivity, specificity, positive and negative predictive values of 66.6% (CI: 55.08-76.94), 100% (CI: 90 to 100),100% (CI: 93.15 to 100) and 57.37% (CI: 44.05 to 69.96) while for IgM ELISA, these parameters were 62.8% (CI: 51.13-73.50), 100% (CI: 90 to 100), 100% (CI: 92.75 to 100) and 54.68% (CI: 41.75 to 67.18) respectively. PCR and ELISA could detect scrub typhus in 37.2% and 33.3% cases, when tested alone. groEL PCR detected the O. tsutsugamushi throughout the course of infection. Phylogenetic analysis depicted 5 of 11 positive cases belonged to Kuroki, Japan strain of O. tsutsugamushi, followed by Gilliam and Karp strain in 4 and 2 cases respectively. CONCLUSION: Scrub typhus should be considered in differential diagnosis of AUFI. groEL PCR may aid on to IgM ELISA test for optimum laboratory diagnosis of scrub typhus by its implementation especially in seronegative cases. Predominance of Kuroki-like strain followed by Gillian and Karp strains of O. tsutsugamushi in Chhattisgarh confirm variable geographical distribution of O. tsutsugamushi and provide the baseline epidemiological data which will eventually be used to help the researchers for developing better diagnostic tests and vaccine covering the predominant genotypes. SN - 1998-3646 UR - https://www.unboundmedicine.com/medline/citation/36050139/Evaluation_of_an_in_house_PCR_for_diagnosing_scrub_typhus_along_with_a_preliminary_study_of_genotypic_characterization_of_Orientia_tsutshugamushi_circulating_in_Chhattisgarh:_A_prospective_clinico_microbiological_study_ DB - PRIME DP - Unbound Medicine ER -