<prompt> A post operative patient developed septicemia and was empirically started on combination chemotherapy by a new resident doctor. However, when the patient did not respond even after 10 days of antibiotics treatment, the review of the charts was done. It was found that the resident doctor had started the combination of antibiotics which was mutually antagonistic in action. Which of the following is the most likely combination that was given?Vancomycin and amikacinCephalexin and gentamicinAmpicillin and chloramphenicolCiprofloxacin and piperacillin  <response>: Ans. C Ampicillin and chloramphenicol See belowRef: KDT 8e p749Combination of a bactericidal ampicillin and a bacteriostatic drug chloramphenicol is usually antagonistic in nature. This is because cidal drugs are usually acting on a fast multiplying organisms whereas static drugs decrease this multiplication. 