Staphylococcus lugdunensis

Published 28.9.21

Bacteria

Staph lugdunensis is a coagulase-negative Staphylococcus (CoNS) but capable of causing aggressive diseases like Staph aureus.

  • It is a Gram-positive cocci in cluster formation, which produces non-pigmented/ yellow/ golden colony and could be beta-haemolytic on blood agar. It tends to show colony polymorphism.

  • It has a characteristic odour (hypochlorite bleach like smell) similar to Eikenella. (Note: smelling/wafting the bacteria on the plate in the laboratory is NOT recommended)

  • It is catalase-positive, coagulase neg., non-motile, facultative anaerobe.

  • Upto 65% of isolates may produces clamping factor (bound Coagulase) giving a positive result in the slide coagulase test.

  • Use tube Coagulase, which tests for free Coagulase, to differentiate Staph aureus (tube coagulase +ve) from Staph lugdunensis )tube coagulase-negative).

  • Identification can be done using MALDI-ToF.

Staph lugdunensis tends to be more susceptible to antibiotics compared to other CoNS.

Vancomycin tolerance – could be present, i.e. the ability of bacteria to survive in the presence of an antibiotic, even if MIC testing has deemed that it should be susceptible. Check MBC: MIC ratio (more likely if >32).

Coagulase-negative Staphylococcus that gives positive result in slide coagulase test – S. lugdunensis, S. schleiferi, and S. sciuri

Coagulase-negative Staphylococcus that gives positive result in tube-coagulase test – S. pseudointermedius, S. intermedius, S. hyicus, S. delphini, S. schleiferi and S. lutrae

Pathogenesis/virulence factors

  • Biofilm – Protein biofilm (unlike other bacteria – polysaccharide). Biofilm makes the bacteria highly resistant to antibiotics. Biofilm formation decreases in presence of linezolid and tetracycline.

  • Moxifloxacin is the only abx which is active against biofilm S lugdunensis.

  • Other virulence factors:

– Adherence factors, vWF and fibronectin binding protein (endothelial adhesion),
– Delta toxin like haemolytic peptide, DNAse, Lipase,

Similar virulence factors noted in S schleiferi as well but it mostly causes animal disease

Clinical feature

  • Skin and soft tissue infection– Staph lugdunensis tend to colonize below the waist esp. perineum. Infection can occur secondary to an invasive procedure in the groin. Infective endocarditis (IE) has been reported to be associated with prostate cancer/ perineal procedures or lesions.

  • Most common soft tissue infection above the waist is breast abscess.


  • Endocarditis: Community-acquired, usually involve the native valve. It is an aggressive disease with a high rate of complication and mortality (>40%). Complications – heart failure, periannuler abscess, embolism.

  • Prosthetic valve endocarditis – late-onset, with a high rate of periannuler abscess (>60%).

  • Bacteraemia: Often associated with foreign body, healthcare-associated. Prognosis is good if it is not associated with IE.

  • Other infections – prosthetic device (joint/shunt) infection, arthritis, OM, psoas abscess, UTI, peritonitis.

Treatment

Treatment should be guided by susceptibility testing.

Flucloxacillin can be used

SSTI – treat for 1-2 weeks, non IE bacteraemia – 1 week, endocarditis – follow guideline.