Weissella confusa (Basonym: Lactobacillus confusus ) Bacteremia: a Case Report

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Abstract
Infection with Lactobacillus is rare, and only a handful of species have been identified as being clinically significant: Lactobacillus casei, Lactobacillus rhamnosus, and Lactobacillus leichmannii. The literature contains one case report of bacteremia caused by Weissella confusa(basonym: Lactobacillus confusus), but the clinical significance of the infection was unclear. We describe a case ofW. confusa bacteremia in a 46-year-old man with a history of abdominal aortic dissection and repair. This procedure was complicated by gut ischemia, which necessitated massive small bowel resection. He subsequently developed short-bowel syndrome, which required him to have total parenteral nutrition. He later developed anEnterococcus faecalis aortic valve endocarditis that required a coronary artery bypass graft and aortic root replacement with homograft and 6 weeks of intravenous ampicillin and gentamicin. Three months prior to his most recent admission, he was diagnosed withKlebsiella pneumoniae bacteremia and candidemia. At the present admission, he had fever (T max, 39.5°C) and chills of 2 days' duration and was admitted to the intensive care unit because of hemodynamic instability. Blood cultures grew K. pneumoniae and W. confusa in four of four blood culture bottles (both aerobe and anaerobe bottles). Imaging studies failed to find any foci of infection. A transesophageal echocardiogram revealed no vegetations. A culture of the patient's Hickman catheter tip was negative. The patient was treated with piperacillin-tazobactam and gentamicin. His condition improved, and he was discharged home, where he completed 4 weeks of piperacillin-tazobactam therapy. Lactobacillemia seldom results in mortality; however, it may be a marker of a serious underlying disease. It is usually seen in patients who have a complex medical history or in patients who receive multiple antibiotics. Lactobacillusspp. are generally associated with polymicrobial infections, and when isolated from the blood, they need to be considered possible pathogens. The presence of a vancomycin-resistant, gram-positive coccobacilli on a blood culture should alert clinicians to the possibility of bacteremia caused by W. confusa or other small gram-positive rods.