Isolation and whole-genome characterization of Coxiella burnetii from an acute Q fever patient in Korea.

Coxiella burnetii is an environmentally stable intracellular bacterium responsible for severe global outbreaks of the zoonotic disease, Q fever. Q fever is transmitted by the inhalation of aerosols contaminated with the birth products and excretions of infected animals, mainly of sheep and goats. A 28-year-old cattle raiser presented with headache and fever without a significant medical history, although his cattle herd had previously been diagnosed with brucellosis. He spent time outdoors but reported no tick bites or eschar. Initial evaluation revealed mild thrombocytopenia and elevated aspartate aminotransferase, alanine aminotransferase, and C-reactive protein levels. On day 2 after disease onset, his blood tested positive for the IS1111 gene of C. burnetii by nested PCR. After amplifying C. burnetii in severe combined immunodeficient mice, the pathogen was isolated using a cell culture system. The isolated CH12 strain was confirmed via PCR, nucleotide sequence analysis, and whole-genome sequencing. This study reports a case of acute Q fever in Korea, in which C. burnetii was isolated and characterized using whole-genome sequencing.