The primary hypothesis is that the efficacy of all the antibiotics will not significantly different. The expected success rates (infection resolution rates) are 83%, 87%, and 78% for cefotaxime, ceftriaxone, and ciprofloxacin. This is non-inferiority trial. The level of significance is 5%. The power of this stuy is 80%. Non-inferiority margin is 15%. Therefore 87 patients for each group are needed.