Detection of Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia akari in Skin Biopsy Specimens Using a Multiplex Real-Time PCR Assay

Detection of Rickettsia rickettsii, Rickettsia parkeri, and Rickettsia akari in Skin Biopsy Specimens Using a Multiplex Real-Time PCR Assay

1. Amy M. Denison1,a, 
2. Bijal D. Amin3, 
3. William L. Nicholson2, and
4. Christopher D. Paddock1,b

+Author Affiliations

1. ¹Division of High-Consequence Pathogens and Pathology, Infectious Diseases Pathology Branch
2. ²Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
3. ³Department of Pathology, Division of Surgical Pathology, Montefiore Medical Center, Bronx, NY, 10467

1. ↵aCorresponding author. Address: 1600 Clifton Rd. NE, MS G-32, Atlanta, GA 30333. Phone: (404) 639-1758. Fax: 404-639-3043. E-mail: crk6@cdc.gov

1. ↵b Alternate corresponding author. Address: 1600 Clifton Rd. NE, MS G-32, Atlanta, GA 30333. Phone: (404) 639-1309. Fax: 404-639-3043. E-mail: cdp9@cdc.gov

Abstract

Background. Rickettsia rickettsii, R. parkeri, and R. akari are the most common causes of spotted fever group rickettsioses indigenous to the United States. Infected patients characteristically present with a maculopapular rash, often accompanied by an inoculation eschar. Skin biopsy specimens are often obtained from these lesions for diagnostic evaluation. However, a species-specific diagnosis is achieved infrequently from pathologic specimens because immunohistochemical stains do not differentiate among the causative agents of spotted fever group rickettsiae, and existing PCR assays generally target large gene segments that may be difficult or impossible to obtain from formalin-fixed tissues.

Methods. This work describes the development and evaluation of a multiplex real-time PCR assay for the detection of these three Rickettsiaspecies from formalin-fixed, paraffin-embedded (FFPE) skin biopsy specimens.

Results. The multiplex PCR assay was specific at discriminating each species from FFPE controls of unrelated bacterial, viral, protozoan, and fungal pathogens that cause skin lesions, as well other closely related spotted fever group Rickettsia species.

Conclusions. This multiplex real-time PCR demonstrates greater sensitivity than nested PCR assays in FFPE tissues and provides an effective method to specifically identify cases of Rocky Mountain spotted fever, rickettsialpox, and R. parkeri rickettsiosis by using skin biopsy specimens.

• Received March 14, 2014.
• Accepted May 5, 2014.

• Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.