High prevalence of Coxiella burnetii coinfection in brucellosis patients: Molecular evidence from an endemic region in Iran

Brucellosis and Q fever are important zoonotic diseases with overlapping clinical manifestations.  Their concurrent occurrence is limited in Iran. This study investigated the prevalence and molecular characteristics of Coxiella burnetii infection among brucellosis patients in Fars province, Southwest Iran. A total of ۱۵۲ blood samples were collected from clinically suspected brucellosis patients (۶۸ men and ۸۴ women) with clinical manifestations of fever, chills, and musculoskeletal pain of less than ۸ weeks’ duration. All patients were confirmed for brucellosis using serological assays and PCR. Subsequently, all samples were evaluated for C. burnetii infection using a species-specific PCR assay. Demographic data and potential risk factors were also analyzed. A remarkably high prevalence of C. burnetii infection (۷۶.۳۱%) was detected among brucellosis patients. Livestock exposure was significantly associated with coinfection (p=۰.۰۳۶). Phylogenetic analysis showed close similarity to internationally reported strains. All patients received combination therapy with doxycycline and streptomycin, resulting in clinical improvement. All patients received combination therapy with doxycycline and streptomycin, resulting in clinical improvement. This study provides compelling molecular evidence of a high rate of brucellosis and Q fever coinfection in an endemic region, highlighting a potentially underrecognized public health concern. The findings emphasize the need to consider Q fever in the differential diagnosis of brucellosis, particularly in high-risk populations with livestock exposure. Incorporating doxycycline into empirical treatment regimens represents a rational and effective strategy to ensure adequate coverage against both Brucella spp. and C. burnetii in endemic settings.

کلیدواژه ها:

Brucellosis Q fever PCR Co ، infection Iran