A narrative review of coagulase-negative staphylococci in diabetic foot infections

SUMMARY Coagulase-negative staphylococci (CoNS) are a group of bacteria commonly found on human skin and mucous membranes. Traditionally regarded as low-virulence microorganisms, they have gained recognition as significant pathogens in healthcare-associated infections, particularly among immunocompromised individuals and patients with indwelling medical devices. In diabetic foot infections (DFIs), CoNS can play a substantial role, particularly following previous antibiotic treatments or in the presence of indwelling devices. DFIs are usually polymicrobial, involving a mixture of aerobic and anaerobic bacteria. Although Staphylococcus aureus is recognized as the major pathogen, especially in Western countries, CoNS are increasingly emerging as significant pathogens in DFIs, including osteomyelitis. Their presence may complicate treatment by increasing the microbial burden and harboring antibiotic resistance mechanisms. The treatment of DFIs involving CoNS often requires a combination of antibiotics targeting both gram-positive and gram-negative bacteria, selected according to the severity of the infection and results of antibiotic susceptibility testing. This review aims to highlight the growing importance of CoNS in DFIs, discussing their pathogenic mechanisms, clinical implications, and the necessity for healthcare providers to consider their involvement in order to ensure effective treatment and successful patient outcomes. This narrative review aims to underscore the growing clinical relevance of CoNS in DFIs by exploring their pathogenic mechanisms, diagnostic challenges, and therapeutic implications. It emphasizes the need for clinicians to recognize CoNS as potential pathogens rather than mere contaminants and highlights the ongoing difficulty in distinguishing true infection from colonization. This distinction is critical for accurate diagnosis, appropriate antimicrobial stewardship, and the development of improved treatment strategies.