Clinical characteristics of infections due to Staphylococcus lugdunensis compared to other staphylococcal infections

Staphylococcus lugdunensis is a coagulase-negative staphylococcal species with virulence characteristics resembling those of Staphylococcus aureus. Despite its increasing recognition as a clinically significant pathogen, data comparing its clinical outcomes with other staphylococcal infections remain limited. This study aimed to compare the clinical characteristics, outcomes, and factors associated with unfavorable clinical outcomes among patients with S. lugdunensis, S. aureus, and Staphylococcus epidermidis infections.

We conducted a retrospective cohort study at the American University of Beirut Medical Center between January 2019 and December 2023. Adult patients with S. lugdunensis infections were identified and matched by site of infection to patients with S. aureus and S. epidermidis infections. Demographic, clinical, microbiological, treatment, and outcome data were collected. Bivariable analyses and multivariable logistic regression were performed to identify factors independently associated with unfavorable clinical outcome, defined as a composite of in-hospital mortality and major infection-related complications.

A total of 301 patients were included: 101 with S. lugdunensis, 103 with S. aureus, and 97 with S. epidermidis infections. Skin and soft tissue infections were the most common presentation of S. lugdunensis (72%), followed by urinary tract infections (16%), bacteremia (8%), and respiratory infections (4%). Compared with S. aureus, S. lugdunensis infections were associated with lower rates of persistent bacteremia (0% vs. 4.9%, p = 0.025) and higher rates of acute renal failure (8.9% vs. 1.9%, p = 0.028). No significant outcome differences were observed between S. lugdunensis and S. epidermidis infections. Overall in-hospital mortality rates were 7.9%, 5.8%, and 7.2% for S. lugdunensis, S. aureus, and S. epidermidis, respectively. In multivariable analysis, S. aureus infection was associated with lower odds of unfavorable clinical outcome than S. lugdunensis (aOR 0.31, 95% CI 0.13-0.75), whereas no significant difference was observed between S. lugdunensis and S. epidermidis. Diabetes mellitus (aOR 2.71, 95% CI 1.27-5.82) and hospitalization within the previous 30 days (aOR 1.97, 95% CI 1.26-3.06) were independently associated with unfavorable clinical outcome.

S. lugdunensis demonstrates clinical characteristics and outcomes overlapping those of S. aureus and S. epidermidis. Prompt recognition and appropriate management remain essential to optimize clinical outcomes.