A Case Series of Staphylococcus lugdunensis Infection in Cancer Patients at an Academic Cancer Institute in the United States

Staphylococcus lugdunensis as Cause of Septic Pericarditis

Staphylococcus lugdunensis (S. lugdunensis) is a coagulase-negative gram-positive bacterium, considered part of skin flora, which can simultaneously cause human diseases. S. lugdunensis has been reported in the literature as one of the causative agents for infective endocarditis.1 Although one of the coagulasenegative staphylococci, S. lugdunensis shares many virulent characteristics with Staphylococcus aureus (S. aureus), including biofilm formation. It has been associated with various foreign body-related infections such as prosthetic joint infections,2 in addition to bacteremia, osteomyelitis, septic arthritis, central nervous system, urinary tract infections, peritonitis, infective endocarditis and others. Given the association with severe and aggressive infections, it is important to treat S. lugdunensis as true infection rather than a contaminant, particularly in a suspect clinical context.3-6 Currently, there are no reported cases in the literature on pericarditis secondary to S. lugdunensis. We present a case of a 69-year-old woman with pericarditis, sepsis and disseminated intravascular coagulopathy (DIC) due to S. lugdunensis.

Infectious diseases specialist consultation in Staphylococcus lugdunensis bacteremia

Background

Commensal coagulase negative Staphylococcus lugdunensis may cause severe bacteremia (SLB) and complications. Treatment of SLB is not fully established and we wanted to evaluate if infectious diseases specialist consultation (IDSC) would improve management and prognosis.

Methods

Multicenter retrospective study of SLB patients followed for 1 year. Patients were stratified according to bedside (formal), telephone (informal) or lack of IDSC within 7 days of SLB diagnosis.

Results

Altogether, 104 SLB patients were identified: 24% received formal bedside and 52% informal telephone IDSC whereas 24% were managed without any IDSC. No differences in demographics, underlying conditions or severity of illness were observed between the groups. Patients with bedside IDSC, compared to telephone IDSC or lack of IDSC, had transthoracic echocardiography more often performed (odds ratio [OR] 4.00; 95% confidence interval [CI] 1.31–12.2; p = 0.012) and (OR 16.0; 95% CI, 4.00–63.9; P<0.001). Bedside IDSC was associated with more deep infections diagnosed compared to telephone IDSC (OR, 7.44; 95% CI, 2.58–21.4; p<0.001) or lack of IDSC (OR, 9.56; 95% CI, 2.43–37.7; p = 0.001). The overall mortality was 7%, 10% and 17% at 28 days, 90 days and 1 year, respectively. Considering all prognostic parameters, patients with IDSC, compared to lack of IDSC, had lower 90 days and 1 year mortality (OR, 0.11; 95% CI, 0.02–0.51; p = 0.005) and (OR, 0.22; 95% CI, 0.07–0.67; p = 0.007).

Conclusion

IDSC may improve management and outcome of Staphylococcus lugdunensis bacteremia.

Efficacy of chelerythrine against dual-species biofilms of Staphylococcus aureus and Staphylococcus lugdunensis

Staphylococcus aureus and Staphylococcus lugdunensis are often associated with pathogenic biofilms ranging from superficial mucosal to life-threatening systemic infections. Recent studies have reported that chelerythrine (CHE) displays antimicrobial activities against a few microorganisms, but its effects on dual-species biofilms of S. aureus and S. lugdunensis have never been reported. The purpose of this study was to investigate how dual-species biofilms of S. aureus and S. lugdunensis respond when challenged with CHE. Minimum inhibitory concentration (MIC) of CHE against planktic cells in dual-species culture was 8 μg/mL. CHE also suppressed dual-species biofilm formation at minimal biofilm inhibitory concentration (MBIC₉₀, 4 μg/mL). Further, confocal laser scanning microscope (CLSM) using five fluorescent dyes revealed the dose-dependent reduction of the levels of three key biofilm matrix components, and reduced tolerance to gatifloxacin, of biofilms exposed to CHE. Moreover, CHE efficiently eradicated preformed dual-species biofilms at minimal biofilm eradication concentration (MBEC, 256 μg/mL). Hence, CHE has the potential to address biofilm infections of clinical course and other biofilm-related diseases caused by S. aureus and S. lugdunensis.