<s>[INST] hello , i am durgesh My Esr level in blood is increseing every year and dure to that my left knee ge swelled. any doc i refered they given many medicine  even 2-3 times they took puss from the knee and 1 time i went for Arthroscopy operation. What is the cause of this?? [/INST] Hi and welcome to Chat Doctor. Thank you for your query. I am Chat Doctor, I understand your concerns and I will try to help you as much as I can. This is caused by bacterial infection, usually staphylococcus aureus which may be resistant in your case, and you need more powerful antibiotics and so-called flow Chat Doctor. I hope I have answered you query. If you have any further questions you can contact us in every time. Kindly regards. Wish you a good health. </s>