Dr. Brad Spellberg, LA BioMed (IMAGE) LA BioMed Caption Dr. Brad Spellberg, LA BioMed infectious disease specialist, says dramatic differences in the incidence and rate of change in the number of MRSA and MSSA infections indicate ongoing, fundamental changes in bacterial ecology. Credit LA BioMed Usage Restrictions None 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.