Leuconostoc 균혈증이 확인된 성인 환자의 임상적 특징과 치료 결과: 단일 3차 의료기관 연구 = Clinical characteristics and outcomes of adult patients with Leuconostoc species bacteremia: a study in a tertiary care hospital

다국어 초록 (Multilingual Abstract)

Introduction: Leuconostoc species are lactic acid-producing, Gram-positive coccobacilli that exhibit intrinsic resistance to glycopeptides. Clinical data on these rare opportunistic pathogens remain limited and largely anecdotal.

Methods: This retrospective study reviewed all adult patients diagnosed with Leuconostoc bacteremia at a 2,700-bed tertiary care hospital between January 1997 and December 2024. Clinical data were extracted from electronic medical records, including demographic profiles, underlying morbidities, prior exposure to antimicrobial agents, laboratory findings, clinical course and mortality. Concomitant bloodstream pathogen and antimicrobial susceptibility test results were collected from the microbiology database. The presence of systemic inflammatory response syndrome (SIRS), sepsis, and septic shock was assessed. Risk factors for thirty-day mortality were analyzed using multivariate regression analysis.

Results: I analyzed 129 cases of adult patients with Leuconostoc bacteremia. The median age was 63 years and 57.4% (74/129) were male. Of the total cohort, 51.2% (66/129) had solid tumors, and abdominal-origin cancers constituted 42.6% (55/129) of the overall cases. One- third (43/129) of the patients were immunocompromised. Hospital-acquired infections accounted for 75.2% (97/129) of cases, and over 40% (55/127) had been exposed to glycopeptides in the past three months. All tested isolates exhibited resistance to glycopeptides. Susceptibility was observed in 28.2% (22/78) of isolates to ceftriaxone and 79.4% (27/34) to ciprofloxacin, whereas all isolates remained susceptible to erythromycin and clindamycin (102/102, 110/110, respectively). Monomicrobial bacteremia was 53.5% (69/129) and polymicrobial bacteremia was 46.5% (60/129). Enterococcus species and Candida species were the most common co-pathogens. Primary portal of entry was the abdomen (49.6%), followed by unknown primary sources (41.9%) and catheter-related infections (7.8%). One patient had infective endocarditis. SIRS, sepsis (Sepsis-3), and septic shock were observed in 80.6% (104/129), 31.8% (41/129), and 10.9% (14/129) patients, respectively. Patients who had at least two sets of positive blood cultures and satisfied SIRS criteria were significantly less observed in monomicrobial bacteremia group (21.7% vs. 50%, p < 0.001). The 30-day mortality was 21.7% (28/129). Polymicrobial bacteremia was the only independent predictor of 30-day mortality (adjusted OR, 3.14; 95% CI, 1.25-7.88, P=0.015). In the 69 patients (53.5%) with monomicrobial bacteremia, only one death (1/69) was directly linked to Leuconostoc infection.

Conclusion: While Leuconostoc species are primarily hospital-acquired pathogens that frequently invade the bloodstream via abdomen in immunocompromised patients, Leuconostoc bacteremia generally shows low intrinsic virulence, and contamination seems to be common. Mortality was mainly associated with concomitant infection.

목차 (Table of Contents)

• Summary i
• List of tables iv
• List of figures v
• Introduction 1
• Methods 3
• Results 6
• Discussion 23
• Conclusion 28
• References 29
• Korean summary 34