Coagulase-Negative Staphylococci (CoNS): An Emerging Threat, Antimicrobial Resistance, and Health Concern

Coagulase-negative staphylococci (CoNS) have evolved from a harmless commensal group to an alarming threat to patient, environmental, and population health due to their challenging treatment and their impact on health outcomes. The widespread presence of CoNS in these environments poses a public health concern due to various virulence factors, biofilm formation, and toxin production, which contribute to pathogenicity and antimicrobial resistance (AMR). Major clinical manifestations include device-related infections, bloodstream infections, and neonatal sepsis. Nonclinical reservoirs, such as soil, water, animals, and food-processing environments, are considered critical sources of resistance gene flow. The mechanisms of resistance include the mecA gene and a variety of SCCmec elements, as well as horizontal gene transfer via plasmids and transposons, and tolerance via biofilm formation. This review summarizes current findings on the epidemiology, AMR mechanisms, biofilm-linked pathogenicity, diagnostic advances, and One Health implementations of CoNS across nonclinical and clinical contexts, while recognizing priorities for therapeutic and surveillance development. Here, the reviewed literature suggests considerable variation in drug resistant CoNS and distribution landscapes across nonclinical and clinical contexts, with MGEs, biofilm establishment, and environmental repertoires reflecting imperative determinants in the dissemination and persistence of AMR. An analysis of the existing literature indicates that genetic links between clinical and environmental isolates remain insufficiently established and that surveillance data are lacking; accordingly, future research should focus on these gaps. Addressing the threat of CoNS requires enhanced surveillance, improved diagnostic precision, and the development of novel antimicrobial and antibiofilm strategies. Future research should focus on epidemiological surveillance, innovation in therapy, and systems-based approaches, which consider the interrelationship of human, animal, and environmental health.