Mucoid Staphylococcus haemolyticus: an unheeded multidrug-resistant pathogen

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Clinical Pathology

Background:

• Coagulase-negative Staphylococci (CoNS) are significant causes of nosocomial infections, particularly in vulnerable populations.
• Staphylococcus haemolyticus is a common isolate from bloodstream infections, with identification challenges arising from atypical morphology.
• Mucoid variants of S. haemolyticus are increasingly recognized for their enhanced virulence and multidrug resistance.

Observation:

• An uncommon case of multidrug-resistant mucoid Staphylococcus haemolyticus isolated from the blood of a polytrauma patient is presented.
• The patient received empirical therapy including ceftriaxone-sulbactam, gentamicin, and meropenem, followed by intravenous vancomycin.
• Favorable clinical response was observed following vancomycin treatment.

Findings:

• Mucoid S. haemolyticus isolates exhibit increased virulence and multidrug resistance compared to classical morphotypes.
• A systematic review was conducted to assess the prevalence of mucoid S. haemolyticus and linezolid resistance.
• The case highlights the importance of recognizing mucoid phenotypes for accurate identification of Gram-positive cocci.

Implications:

• Accurate identification of mucoid phenotypes is critical for effective clinical management of S. haemolyticus infections.
• Emerging linezolid resistance in S. haemolyticus necessitates stringent antimicrobial stewardship programs and hospital restriction policies.
• Enhanced awareness and diagnostic vigilance are required to combat the growing threat of multidrug-resistant bacteria.