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Cocos Gram-positivos

Staphylococcus lugdunensis

Gram-positive cocci in clusters

Identification & Growth

Identification

  • Tube coagulase-negative, but clumping factor (latex test) frequently positive
  • Ornithine decarboxylase and PYR positive

Growth Conditions

  • Blood agar: colonies with mild hemolysis, characteristic odour, 24 h at 35 °C

Clinical Significance

  • Aggressive endocarditis, skin and prosthetic-device infection — behaves like S. aureus

Intrinsic Resistance

  • Aztreonam, colistin and nalidixic acid have no activity

Bench Alerts

  • Should never be dismissed as a contaminant
  • Interpret oxacillin/cefoxitin using S. aureus criteria, not coagulase-negative staphylococci criteria

Clinical Notes

Clinical presentations

  • Behaves clinically more aggressively than other coagulase-negative staphylococci, resembling S. aureus.
  • Causes native and prosthetic valve endocarditis with a fulminant course and rapid valvular destruction.
  • Associated with skin and soft tissue infections, osteomyelitis, and orthopedic device infections.

Specimens and collection

  • Serial blood cultures are essential when endocarditis is suspected, given the rapid clinical evolution.
  • Bone or joint tissue specimens should be surgically obtained and sent without delay to maximize recovery.

Epidemiology and at-risk populations

  • Colonizes the perineal and inguinal region, unlike S. epidermidis, which predominates in upper body regions.
  • Patients with valve or joint prostheses are particularly vulnerable to severe infections by this organism.

Resistance and therapeutic implications

  • Most isolates are methicillin/oxacillin-susceptible, unlike the predominantly resistant pattern of other hospital CoNS.
  • Due to its aggressive clinical behavior, it should be treated with the same therapeutic rigor as S. aureus, despite being a CoNS.

Bench and reporting notes

  • May be mistaken for S. aureus because it produces a clumping factor that yields false-positive latex coagulase results.
  • The DNase test is typically negative, helping differentiate it from S. aureus when the latex test is ambiguous.
  • The report should clinically flag the organism's invasive behavior, even though it is identified as coagulase-negative.

Sources

Educational decision-support content. It does not replace laboratory validation, current guidelines or review by the responsible professional.

FAQ: Frequently Asked Questions

How to identify Staphylococcus lugdunensis in the lab?

Staphylococcus lugdunensis is identified through tube coagulase-negative, but clumping factor (latex test) frequently positive, ornithine decarboxylase and pyr positive.

What are the intrinsic resistances of Staphylococcus lugdunensis?

This organism is naturally resistant to aztreonam, colistin and nalidixic acid have no activity. These drugs should not be reported as susceptible.

Where is Staphylococcus lugdunensis commonly found?

It is typically associated with aggressive endocarditis, skin and prosthetic-device infection — behaves like s. aureus.

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