Summer Buzz

Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Unique Clone of Coxiella burnetii Causing Severe Q Fever, French Guiana

Aba Mahamat¹, Sophie Edouard¹, Magalie Demar, Philippe Abboud, Jean-Yves Patrice, Bernard La Scola, Antoine Okandze, Félix Djossou, and Didier Raoult

Author affiliations: Centre Hospitalier Andree Rosemon, Cayenne, French Guiana (A. Mahamat, M. Demar, P. Abboud, A. Okandze, F. Djossou); Université des Antilles-Guyane, Cayenne (A. Mahamat, M. Demar, P. Abboud, F. Djossou); Aix Marseille Université, Marseille, France (S. Edouard, J.-Y. Patrice, B. La Scola, D. Raoult)

Abstract

Acute Q fever is an emergent and severe disease in French Guiana. We obtained 5 Coxiella burnetii isolates from samples of patients from Cayenne and found an epidemic clone circulating in Cayenne. This clone has caused pneumonia and endocarditis and seems to be more virulent than previously described strains.

Q fever, which is caused by the bacterium Coxiella burnetii, has rapidly emerged in French Guiana since 1996 (1). The incidence of acute Q fever in the capital, Cayenne, is one of the highest in the world. The annual incidence of Q fever was estimated at 37 cases/100,000 persons in 1996 (2) and increased to 150 cases/100,000 persons in 2005 (3). The most common clinical feature of Q fever in Cayenne is pneumonia, and C. burnetii is the causative agent of 24% of all community-acquired pneumonias (4). These forms of acute Q fever are particularly severe (4). Subsequently, we have hypothesized the existence of a specific source of C. burnetii responsible for human infections, which is unidentified to date, and the existence of a different strain of C. burnetii that circulates in Cayenne.
Q fever is diagnosed by serologic analysis in Cayenne. C. burnetii is rarely identified by PCR and has yet to be cultured in Cayenne. In this study, we isolated 5 C. burnetii strains from biologic samples of patients from Cayenne. We compared the strains from Cayenne with other strains and showed that a unique genotype is circulating in Cayenne. This unique genotype might be related to the clinical and epidemiologic features of severe fever in Cayenne.

The Study

As a national reference center for Q fever, our center receives samples from France and other regions for serologic, molecular, histologic, and immunohistochemical analyses as described (5–7). In 2012, we received a cardiac valve sample from a patient in Cayenne with Q fever endocarditis who had undergone surgery in Martinique. In the same year, we collected 4 heparinized blood samples from patients with acute Q fever from Cayenne that were collected before initiation of antimicrobial drug treatment.