Streptococcus pyogenes: An overlooked cause of meningitis

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Streptococcus pyogenes - illustration for sticker
I catch what some don't look for: S. pyogenes
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Clinical case

An unexpected cause of meningitis detected with syndromic testing

Based on a real clinical case provided by Katie Hardy, Consultant Clinical Scientist Infection Control Doctor, University Hospitals of Derby and Burton and Katie Harrod, Trainee Clinical Scientist, NHS.

A 72 year-old woman arrived at the ER with ear pain and discharge, vomiting, dizziness and delirium.

The medical team learned that the woman had recovered from a case of Streptococcus pneumoniae meningitis just ten months earlier. Could these new symptoms be a recurrence?

Initial labs showed high inflammatory markers, while a CT scan revealed mastoid opacification and signs of meningitis. The team immediately started her on ceftriaxone, amoxicillin, acyclovir and dexamethasone.

By morning, her blood cultures revealed gram-positive cocci in chains – once again pointing to S. pneumoniae.

But a QIAstat-Dx Meningitis/Encephalitis Panel revealed the true identity of the cocci chains: Streptococcus pyogenes.

With this information, and their other clinical findings, the team chose to stop the unnecessary antimicrobials but continue IV ceftriaxone. They also quickly initiated appropriate infection control measures and contact tracing for what they now knew was an invasive Group A infection.

In this case, initial tests pointed toward S. pneumoniae meningitis, but a fast QIAstat‑Dx panel revealed S. pyogenes as the true cause. Without that specific target on the syndromic panel, the case could have been misdiagnosed.

S. pyogenes should be on your radar

S. pyogenes, commonly known for causing strep throat and skin infections, is often overlooked as a cause of meningitis. But it should be included in your routine meningitis/encephalitis testing.

  • The cause of invasive group A streptococcal (iGAS) infections: Including bloodstream infections, sepsis and central nervous system (CNS) infections.
  • High risk of complications: iGAS infections can result in long-term sequelae and even death (1,2).
  • A rare but serious cause of meningitis: iGAS isn’t common in bacterial meningitis but should always be considered in childhood cases.
A person in a pink outfit comforts a child with a bandaged hand. 🌸🤝🩹
Monthly distribution of invasive Group A Streptococcal (iGAS) disease in children in Spain between 2019 and 2022
Monthly distribution of iGAS disease in children in Spain between 2019 and 2022, adapted from (3).

The latest on S. pyogenes epidemiology

  • Rising iGAS case rates: Since 2022, iGAS infections have been on the rise worldwide (3). Children and older adults are at the highest risk (4).
  • Consider iGAS during flu season: Symptoms can overlap with influenza, making diagnosis more difficult (1).
  • S. pyogenes is showing up in suspected CNS infections: Our QIAsphere surveillance data from 2024 shows that S. pyogenes was detected in 2.8% of suspected cases tested with QIAstat-Dx Meningitis/Encephalitis Panel (5).

Early detection supports early treatment

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References

1. Lucas MJ, Brouwer MC, Bovenkerk S, Man WK, van der Ende A, van de Beek D. Group A Streptococcal meningitis in adults. J Infect. 2015;71(1):37-42. doi:10.1016/j.jinf.2015.01.008

2. Castro C, Warren E. Streptococcus pyogenes: A devastating cause of meningitis in a young adult. Chest. 2018;154(4 Suppl):319A. doi:10.1016/j.chest.2018.08.292

3. Cobo-Vázquez E, Aguilera-Alonso D, Carrasco-Colom J, Calvo C, Saavedra-Lozano J; PedGAS-net Working Group. Increasing incidence and severity of invasive Group A streptococcal disease in Spanish children in 2019-2022. Lancet Reg Health Eur. 2023;27:100597. doi:10.1016/j.lanepe.2023.100597

4. Valcarcel Salamanca B, Cyr PR, Bentdal YE, et al. Increase in invasive group A streptococcal infections (iGAS) in children and older adults, Norway, 2022 to 2024. Euro Surveill. 2024;29(20):2400242. doi:10.2807/1560-7917.ES.2024.29.20.2400242

5. From QIAstat-Dx Meningitis/Encephalitis Panel (Cat. No. 691611) epidemiology dashboard in QIAsphere Insights, January – December 2024 for EMEA. This specific version of the panel is not available in the U.S.


In some cases, data cited pertains to the use of a device from another manufacturer.

For up-to-date licensing information and product-specific disclaimers, see the respective QIAGEN kit instructions for use or user manual. QIAGEN instructions for use and user manuals are available at www.qiagen.com or can be requested from QIAGEN Technical Services (or your local distributor).