hi thanks for using healthcare magic Various reason for low sperm count include Varicoceles, abnormality in seminal fluid, immunological infertility, problems with ductal system, testicular failure, certain drugs, infection etc. Any factor can decrease the sperm count but decrease sperm count to such a low extent would not be due to infection. Second in male the ejaculate isn’t sterile, often testing positive for two organisms. That’s why it’s important to be judicious in treating non-sexually-transmitted organisms found on cultures. U have go for antibiotic course, if it improve with antibiotic then it would due to infection otherwise try to find out the cause by getting him investigated. Thanks