Information about becoming certified in Infection Control can be found at the Certification Board of Infection Control and Epidemiology, Inc. web site www.cbic.org
Having a CIC is a certification in infection control does not authorize practice as a CNS. A CNS is a registered nurse who has completed a master's degree program that is accredited to include clinical nurse specialist components (education and clinical practicum) in the curriculum. There may be a master's program with a CNS focus in infection control out there somewhere.
Hope this helps answer your question.