# Periorbital infections caused by Group A streptococci: a case series

## TL;DR

This study reports a series of periorbital infections caused by Group A streptococci, mostly involving the M1 clone, with severe outcomes in elderly patients.

## Contribution

The study highlights a cluster of periorbital Group A streptococcal infections, primarily caused by the M1 clone, in elderly patients without clear immunosuppression or trauma.

## Key findings

- Most cases involved the M1 clone of Group A streptococci.
- Patients presented with severe symptoms like septic shock and visual impairment.
- Many patients lacked typical risk factors like immunosuppression or trauma.

## Abstract

A surge in Group A streptococcus (GAS) infections has been described in the post-COVID-19 pandemic period. We reviewed cases with periorbital GAS infections at our institution during a 14-month period, including cases with necrotizing soft tissue infection (NSTI).

A single center retrospective case series was performed at the University Hospital of Copenhagen, Rigshospitalet, during January 2023 to February 2024 including all adult patients referred from secondary centers with a suspicion of periorbital NSTI. All cases were treated for periorbital skin and soft tissue infections with culture-confirmed group A streptococci in an eye swab, a tissue sample or blood cultures.

Eleven cases with a median age of 72 (range 55–84) years with periorbital GAS infection were included. Four patients had diabetes, and one patient had eyelid surgery prior to the infection. Pre-admission symptoms included pain, swelling in the periorbital area, fever and/or a sore throat. Patients presented with fever, nausea, and/or confusion and clinical exams were noticeable for erythema and edema of the periorbital area with the eyelids fully closed on the affected side. Two cases had septic shock. Based on CT scans, six cases were diagnosed with pre-septal cellulitis and five cases were suspected of post-septal NSTI, which was confirmed by surgical debridement. The GAS isolates from tissue samples or blood cultures in these five cases were of type MLST 28 / emm 1.0 (M1 clone). Treatment included meropenem and clindamycin (n = 11), intravenous immunoglobulin (n = 4), surgical debridement (n = 5) and hyperbaric oxygen therapy (n = 3). One patient died in the intensive care unit. Two patients have permanently reduced visual acuity.

We report an accumulation of cases with pre- or post-septal orbital GAS infections in which the majority had no evidence of immunosuppression or a triggering event such as trauma or surgery. All cases of invasive GAS infections were caused by the M1 clone.