Coagulasenegatiiviset

Coagulasenegatiiviset, often abbreviated as CNS, refers to a group of bacteria that do not produce the enzyme coagulase. This enzyme is significant because it is a key virulence factor for Staphylococcus aureus, the most common coagulase-positive staphylococcus. The inability to produce coagulase helps to distinguish CNS from S. aureus. However, this distinction is not always absolute, and some rare strains of S. aureus may be coagulase-negative.

Coagulase-negative staphylococci are a diverse group of bacteria that are commonly found on the skin and mucous membranes of humans and animals. They are generally considered commensal organisms, meaning they live in symbiosis with their host without causing disease. Despite their commensal nature, CNS can become opportunistic pathogens, particularly in individuals with weakened immune systems or when introduced into normally sterile sites of the body.

Common species within the CNS group include Staphylococcus epidermidis, Staphylococcus saprophyticus, and Staphylococcus haemolyticus. Staphylococcus epidermidis is the most frequently isolated CNS species and is a leading cause of infections associated with indwelling medical devices such as catheters and prosthetic implants. Staphylococcus saprophyticus is a common cause of urinary tract infections, especially in young, sexually active women. Staphylococcus haemolyticus is also associated with bloodstream infections and skin and soft tissue infections.

Diagnosis of CNS infections typically involves culturing samples from affected sites and performing biochemical tests, including the coagulase test, to identify the specific species. Antibiotic susceptibility testing is crucial for guiding treatment, as resistance to multiple antibiotics is a growing concern among CNS.