Watch CBS News Videos OnlineIn the first installment of a two-part series, CBS Evening News Anchor Katie Couric investigates the connection between the use of antibiotics in factory farms and the incidence of MRSA in humans. Couric talks to a worker at an Arkansas poultry processing facility who developed MRSA; discusses the use overuse of antibiotics on the farm with Shelley Hearne, managing director of the Pew Health Group at The Pew Charitable Trusts; and tells viewers about a University of Iowa study, which found a new strain of MRSA — in nearly three-quarters of hogs (70%), and nearly two-thirds of the workers (64%) — on several farms in Iowa and Western Illinois. All of them use antibiotics, routinely. On antibiotic-free farms no MRSA was found. Couric also talks with Iowa hog farmer Dave Kronlage who admits he uses antibiotics to accelerate growth and fend off disease. The CBS web site contains the expected statements from the National Pork Producers Council, the National Pork Board, and National Cattlemen’s Beef Association. Tomorrow night CBS Evening News will feature part two of the series, which focuses on Denmark’s ban on antibiotic use.