Isolation of Coxiella burnetii from the blood of a patient with positive Anaplasma phagocytophilum serological results

Division of Medical Microbiology,Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, USAINTRODUCTIONHuman infections caused by bacteria in the familyAnaplasmataceae represent newly emerging tick-borne diseases. At present, Ehrlichia chaffeensis andAnaplasma phagocytophilum are the most importantmembers. The potential for human Anaplasmata-ceae exposure in Portugal justifies routine labora-tory diagnostics used by the Centro de Estudos deVectores e Doenc¸as Infecciosas, Instituto Nacional deSau´de Dr. Ricardo Jorge (CEVDI⁄INSA). Parallel E.chaffeensis and A. phagocytophilum testing, usuallybased on serology, is performed whenever clinicalsuspicion exists. Indirect immunofluorescenceassay (IFA) is the diagnostic gold-standard; how-ever, a potential for serological cross-reactivitywith other pathogens within and out of the genusexists. We present a case of acute Q fever con-firmed by unexpected isolation of Coxiella burnetiifrom an A. phagocytophilum-seropositive patient.CASE REPORTInJune2006,a39-year-old womanwasadmittedtothe Hospital Distrital de Faro, in southern Portu-gal, with 4 days of fever, chills, night sweats,severe headache, vomiting, generalised myalgia,and weight loss. On presentation, the patient alsohad non-productive cough. Her previous medicalhistory was unremarkable. She worked as a housemaid and lived in a rural area of Almancil whereshe reportedly removed ticks from her dogs priorto illness onset. The physical examination revealeda patient with no indicative neurological or cardiacsigns. A petechial rash was observed in the upperlimbs and her palms and soles were erythematous.Wheezes were audible on lung auscultation andthe liver was palpable. Bilateral hilar enlargementwith perihilar interstitial infiltrates was detectedradiographically and abdominal sonographyshowed homogeneous hepatomegaly withoutsplenomegaly. Brain CT scan was normal. Labo-ratory findings showed 3.2 · 10