High-Grade Staphylococcus lugdunensis Bacteremia in a Patient on Home Hemodialysis
Background: Staphylococcus lugdunensis (S lugdunensis) is a species of coagulase-negative Staphylococcus and a constituent of human skin flora. S lugdunensis has gained notoriety for its virulence, which resembles Staphylococcus aureus (S aureus). S lugdunensis is now recognized as an important nosocomial pathogen and cause of prosthetic device infections, including vascular catheter infections.
Case Presentation: A 60-year-old man with a history of uncontrolled type 2 diabetes mellitus and end-stage renal disease on home hemodialysis via arteriovenous fistula (AVF) presented to the emergency department for evaluation of subacute progressive low back pain. Initial laboratory tests were notable for elevated inflammatory markers. Magnetic resonance imaging with contrast of the thoracic and lumbar spine revealed abnormal marrow edema in the T11-T12 vertebrae with abnormal fluid signal in the T11-T12 disc space. Cultures grew methicillin-sensitive S lugdunensis. The patient’s antibiotic regimen was narrowed to IV oxacillin. He was transitioned to IV cefazolin dosed 3 times weekly after hemodialysis and an outpatient dialysis center.
Conclusions: Treatment of bacteremia caused by S lugdunensis or S aureus should be managed with prompt initiation of IV antistaphylococcal therapy, a thorough evaluation for the source of bacteremia as well as metastatic complications, and consultation with an infectious disease specialist. This case highlights AVF as a potential source for infection even without localized signs of infection. The buttonhole method of AVF cannulation was thought to be a major contributor to the development and persistence of our patient’s bacteremia. This risk should be discussed with patients using a shared decision-making approach when developing a dialysis treatment plan.
Due to their virulence, bloodstream infections caused by S aureus and S lugdunensis often require more than timely antimicrobial treatment to ensure eradication. Consultation with an infectious disease specialist to manage patients with S aureus bacteremia has been proven to reduce mortality.25 A similar mortality benefit is seen when infectious disease specialists are consulted for S lugdunensis bacteremia.26 This mortality benefit is likely explained by S lugdunensis’ propensity to cause aggressive, metastatic infections. In such cases, infectious disease consultants may recommend additional imaging (eg, transthoracic echocardiogram) to evaluate for occult sources of infection, advocate for appropriate source control, and guide the selection of an appropriate antibiotic course to ensure resolution of the bacteremia.
Conclusions
S lugdunensis is an increasingly recognized cause of nosocomial bloodstream infections. Given the commonalities in virulence that S lugdunensis shares with S aureus, treatment of bacteremia caused by either species should follow similar management principles: prompt initiation of IV antistaphylococcal therapy, a thorough evaluation for the source(s) of bacteremia as well as metastatic complications, and consultation with an infectious disease specialist. This case report also highlights the importance of considering a patient’s AVF as a potential source for infection even in the absence of localized signs of infection. The buttonhole method of AVF cannulation was thought to be a major contributor to the development and persistence of our patient’s bacteremia. This risk should be discussed with patients using a shared decision-making approach when developing a dialysis treatment plan.
