ADS 31 - Reflex Testing for Group a Streptococci Is an Attributing Factor of Outbreak in a Long-term Care Facility

Background: Group A streptococci (GAS) infections frequently manifest as a mild illness in immunocompetent individuals; however, they can be life-threatening in elderly populations and/or residents of long-term care facilities (LTCFs). In July 2022, a rural LTCF partnered with the Arkansas Department of Health (ADH) to investigate increased GAS pharyngitis reports among residents.

Methods: The ADH investigated according to the Association for Professionals in Infection Control and Epidemiology (APIC) outbreak investigation model, which included multiple onsite observations and interviews.A retrospective review identified all cases prior to July 2022 to establish that an outbreak occurred. All further antigen-positive GAS reports were to be confirmed for the presence of GAS by culture. Finally, a multidisciplinary team visited the facility to observe practices and environmental factors. During onsite visits, the team observed specimen collection and laboratory processing methods. A single, asymptomatic volunteer was tested by antigen, culture, and polymerase chain reaction (PCR) to evaluate consistency between methods

Results: The retrospective review identified 37 cases, 17 of which had documented symptoms consistent with GAS. All 37 cases identified by rapid antigen test received antibiotic treatment, regardless of clinical presentation. The single validation test resulted in a positive antigen test, negative culture, and negative PCR. On-site inquiries revealed a facility practice to reflex rapid antigen test for GAS when there was a change in the resident condition and a negative COVID antigen test. In addition, observations of specimen collection indicated variations in sample collection techniques among clinicians.

Conclusions: The lack of correlation of laboratory findings with the clinical assessment provided conflicting interpretations of resident outcomes. Testing residents with symptoms not consistent with GAS pharyngitis may potentially misidentify infection when not present and potentially expose residents to unnecessary antibiotics.