Coagulase-negative staphylococci (CoNS) are among the most frequently recovered bacteria
in routine clinical care. Their incidence has steadily increased over the past decades in parallel to
the advancement in medicine, especially in regard to the utilization of foreign body devices. Many
new species have been described within the past years, while clinical information to most of those
species is still sparse. In addition, interspecies differences that render some species more virulent
than others have to be taken into account. The distinct populations in which CoNS infections play a
prominent role are preterm neonates, patients with implanted medical devices, immunodeficient
patients, and those with other relevant comorbidities. Due to the property of CoNS to colonize the
human skin, contamination of blood cultures or other samples occurs frequently. Hence, the main
diagnostic hurdle is to correctly identify the cases in which CoNS are causative agents rather than
contaminants. However, neither phenotypic nor genetic tools have been able to provide a satisfying
solution to this problem. Another dilemma of CoNS in clinical practice pertains to their extensive
antimicrobial resistance profile, especially in healthcare settings. Therefore, true infections caused by
CoNS most often necessitate the use of second-line antimicrobial drugs