Group A Streptococci (IMAGE) Georgia Institute of Technology Caption Group A Streptococci, colored yellow, are the most common culprits in bacterial upper respiratory infections. The Georgia Tech researchers suggest finding alternatives to broader spectrum antibiotics to take care of such ailments in order to preserve antibiotic effectiveness longer for more extreme infections. Credit National Institute of Allergy and Infectious Diseases of the NIH Usage Restrictions Press handout from NIAID for appropriate use. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.