Unexpected clinical case of Pasteurella multocida infectious endocarditis in a patient with iv drug abuse: why epidemiological history matters

Abstract

Right-sided lesions caused by staphylococci are the most common clinical entity of infectious endocarditis (IE) among iv drug abusers. But some aspects of the epidemiological history are critical in terms of early detection of uncommon pathogens. We describe a clinical observation of native aortic valve IE caused by Pasteurella multocida in a 37-year-old female with a history of heroin addiction, alcohol abuse and liver cirrhosis.She presented herself at our hospital with acute fever, chills, subconjunctival petechial hemorrhages, traces of scratches on the hands, splenomegaly, peripheral edema, elevated WBC and inflammatory serum markers. Initial transthoracic echocardiography was negative, but the patient was put on oxacillin for suspected right-sided IE. The transesophageal echocardiography revealed vegetation on noncoronary leaflet of aortic valve. Blood culture was positive with the growth of P. multocida in 4/4 samples.On detailed questioning, a close domestic contact with cats was revealed. Oxacillin was switched to meropenem and tigecycline with a prompt clinical response. The P. multocida isolate was found to be susceptible to penicillins, so the patient was discharged after 3 weeks with recommendations to take amoxicillin for up to 4 weeks. At 3 and 6 months follow-up there were no signs of IE relapse revealed. P. multocida is a rare causative agent of IE. In our case, this pathogen was identified in a patient with injection drug use, where such etiology is not usually assumed. The close contact with cats was not taken into account, which caused late diagnosis and delayed therapy.