Lactococcus lactis Endocarditis in an Immunocompromised Patient.

Lactococcus lactis infections are rarely reported in the medical literature. L. lactis is a commonly used fermenting agent which may be difficult to identify with common microbiology identification processes. This factor may contribute to its lack of recognition in medical journals. We report a case of an immunosuppressed 80-year-old female with L. lactis bacteremia, subsequently, found to have aortic valve vegetation, who responded clinically to a six-week duration of ceftriaxone therapy. Afterward, a brief updated literature review is presented on L. lactis infections.

An 82-year-old man with a prosthetic aortic valve and multimicrobial bacteremia.

The patient is an 82-year-old male with a past medical history of aortic valve replacement who presented to the emergency department after a fall. He developed atrial fibrillation with a rapid ventricular response and non-ST-segment-elevation myocardial infarction, leading to hospitalization. During hospital admission, the patient complained of midline thoracic back pain, and an extensive evaluation for this complaint revealed discitis and osteomyelitis with epidural abscess near the T7 and T8 vertebrae that did not result in neurological deficits and required no surgical intervention. A total of 2 blood cultures were reported positive for Actinomyces naeslundii, Streptococcus mitis, Streptococcus oralis, and Abiotrophia defectiva. A transesophageal echocardiogram showed a small vegetation on the aortic prosthetic valve with probable small vegetation on the mitral valve. He was prescribed ceftriaxone intravenously for 12 weeks, followed by amoxicillin 2 g orally twice a day for at least 12 months. A. naeslundii is not commonly known to cause infective endocarditis, whereas S. mitis, S. oralis, and A. defectiva have been reported to do so. One previous case of A. naeslundii was reported to cause prosthetic valve endocarditis as a single infectious agent. To our knowledge, this is the first case report for A. naeslundii as part of multimicrobial bacteremia leading to endocarditis, discitis, and osteomyelitis.

Duration of colonization with vancomycin-resistant Enterococcus.

OBJECTIVE: To determine the duration of colonization with vancomycin-resistant Enterococcus (VRE) and the adequacy of 3 consecutive negative cultures to determine clearance. DESIGN: Retrospective cohort study. SETTING: A university hospital. POPULATION: Patients identified by perirectal cultures as VRE carriers who had follow-up cultures. METHODS: Follow-up perirectal cultures were collected in inpatient and outpatient settings, at least 1 week apart, when patients were not receiving antibiotics with activity against VRE. The likelihood of culture positivity was analyzed given prior culture results and time from the initial positive culture. RESULTS: A total of 116 patients colonized with VRE had 423 follow-up cultures, a mean of 204 days (range, 4 to 709 days) after their initial isolate. The first follow-up culture, collected a mean of 125 days after the initial positive isolate, was negative in 64%. After 1 negative follow-up culture, the next one was negative in 92% of the patients. After 2 negative cultures, 95% remained culture-negative. After 3 sequential negative cultures, 35 (95%) of 37 patients remained culture-negative. As the interval between the initial and the follow-up isolates increased, the probability that a subsequent culture would be positive decreased (P < .001, chi square for trend). Prolonged hospitalization, intensive care, and antibiotic use each decreased the likelihood of clearing VRE. CONCLUSION: These data support the Centers for Disease Control and Prevention criterion of 3 sequential negative cultures, at least 1 week apart, to remove patients from VRE isolation. Nevertheless, this may reflect a decrease in the quantity of VRE to an undetectable level and these patients should be observed for relapse, especially when re-treated with antibiotics.