Days after delivering a call to defeat superbugs, Mr Cameron was urged not to wait for the outcome of a two-year review addressing the problem.
Steps had to be taken now to ensure antibiotics were no longer given to people and animals inappropriately, said the Science and Technology Committee.
There was also a need for more Government-funded research, better training of doctors, public awareness campaigns, and "rapid and accurate diagnostic tests", the committee found.
A report from the MPs said: "The unnecessary prescription of antibiotics has contributed to the acceleration of antibiotic resistance."
Last week Mr Cameron announced the appointment of former Goldman Sachs chief economist Jim O'Neill as head of an expert group conducting the new review, which will focus on the global problem of drug resistance.
The report stressed policy on antibiotics had to be evidence-based, adding: "There is a lack of data on the post-prescription behaviour of patients, and we suggest the Government develops a system for monitoring this.
"Furthermore, there is a lack of information and evidence on the link between resistance in animal pathogens, the environment, and resistance in human pathogens.
"The Government cannot rely on the notion that curiosity-driven research will provide the information it needs and must plan to fund necessary research directly."