In March 2015, a rural urgent-care clinic serving a population of 5,000–7,000 reported a substantial increase in GAS pharyngitis infections since November 2014, with some infections nonresponsive to penicillin and amoxicillin to the Wyoming Department of Health (WDH). By March 2015, the clinic reported diagnosing up to 90 cases of GAS pharyngitis per week. WDH started an investigation to verify this potential GAS pharyngitis outbreak, assess clinic testing and treatment practices, and implement control measures.