This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
[{'content': 'Organism which has specific affinity for growing around prosthesis - \nSelect and explain. \nA. Staplylococcus aureus, B. Staplylococcus epidermidis, C. Streptococcus pyogenes, D. Enterococcus faecalis', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Staphylococcus epidermidis Staphylococcus epidermidis* Most common coagulase negative staph, causing human infections.* It is present on normal human skin (where it is the most abundant bacterial species) as well as in the oropharynx and vagina.* It is a common cause of stitch abscesses.* It has a predilection for growth on the implanted foreign bodies such as artificial heart valves, shunts, intravascular catheters and prosthetic appliances leading to bacteremia.* S. epidermidis is uniquely adopted to colonize these devices by its capacity to elaborate the extracellular poly- saccharide (slime) that facilitates formation of a protective biofilm (slime layer) on the device surface. This biofilm acts as a barrier protecting bacteria from host defence mechanisms as well as from antibiotics.* The surface - associated staphylococcal enzyme autolysin (Atle) may play a role in attachment to prosthetic surfaces, which are often coated with host serum or tissue constituents such as fibrinogen or fibronectin.* It can cause cystitis and endocarditis.* Staphylococcus epidermidis is the most common cause of prosthetic valve endocarditis (early onset, upto 12 months).", 'role': 'assistant'}]