Group A Streptococcal Meningitis in Children: The Importance of Microbiologic Case Definitions

To the Editors: We read with interest the article published in the Pediatric Infectious Disease Journal by Jansen et al,1 describing a cohort of pediatric Group A streptococcal (GAS) meningitis over the 2015–2024 period. The authors highlight both the rarity and the severity of this condition, reporting 27 cases, including 13 with complete data available. GAS meningitis cases were identified both retrospectively and prospectively from a cohort of invasive GAS infections (IGAS). However, it remains unclear how the diagnosis of meningitis was established, given that lumbar puncture appears to have been performed in only 61% (8/13) of patients, of which 38% (5/13) at presentation, as reported in the Results section. We know that performing a lumbar puncture during the acute phase of shock may not always be feasible or safe, and that some children may therefore not have undergone this procedure initially. However, in the context of a research study, it would be important to ensure that the diagnosis is supported by evidence. Ideally, the series labeled as meningitis should, in our view, include only children who had a positive lumbar puncture, based on cerebrospinal fluid (CSF) pleocytosis and/or bacteriology and/or molecular testing, such as polymerase chain reaction or a positive blood culture or other sterile-site samples in the presence of CSF pleocytosis.2 The inclusion criteria in the article seem relatively broad, and it is likely that a substantial proportion of this cohort corresponds to IGAS infections presenting with clinical features suggestive of meningitis, rather than confirmed meningitis. Consequently, this cohort does not consist exclusively of patients with confirmed CSF involvement. This represents an important limitation that was not explicitly acknowledged by the authors. Maintaining strict inclusion criteria remains essential to ensure diagnostic accuracy, validity of analyses, and comparability across studies.2 Since 2001, our research group (GPIP-ACTIV) has been conducting a nationwide surveillance of pediatric bacterial meningitis in France.3–5 Among 8720 cases of bacterial meningitis identified from 2001 to 2025, 71 were attributable to GAS, representing 0.8%. In our surveillance system, we apply stringent inclusion criteria requiring microbiologic confirmation for all cases.3–5 Accordingly, all children in our cohort underwent lumbar puncture, and microbiologic confirmation was achieved in 100% of cases.3–5 CSF cultures were positive in 80.3% (57/71); when CSF cultures were negative, diagnosis relied on positive blood cultures or other sterile-site samples in the presence of CSF pleocytosis (8/71, 11.3%), or on positive CSF polymerase chain reaction (6/71, 8.5%). During the surge in invasive GAS infections observed in Europe in September 2022, we conducted the ISAI study on IGAS, which included 402 cases, among which 7 cases of meningitis were identified, representing 1.7% of all IGAS cases, with no deaths reported among affected children.6 By analyzing our cases of GAS meningitis between 2015 and 2024, as in the Jansen et al1 article, and despite discrepancies in case definitions, we observe similarities among the 33 cases, but our cases seem less severe. Admission to the intensive care unit was required for 36.4% of children in our cohort versus 55.5% in their study, and 9.1% of children died (9.1%) compared with 14.8% (Table 1). Our findings, including those reported during the surge of IGAS infections, suggest that GAS meningitis may be associated with a less severe clinical outcome than other forms of IGAS infections. Variations in diagnostic criteria may substantially impact the interpretation of clinical severity, outcomes and epidemiologic patterns across studies. TABLE 1. - Comparison of the Severity and the Characteristics of Pediatric Group A Streptococcal Meningitis in the Netherlands and in France From 2015 to 2024 The Netherlands, N (%) France, N (%) Number of centers 20 23 Number of cases 27 33 Number of lumbar punctures 8/13 (61) 33/33 (100) Number of meningitis proven by lumbar puncture 4/8 (50) 33/33 (100) Cases occurring during the first quarter of the year 13/27 (48.1) 16/33 (48.5) Age <5 yr 11/27 (40.7) 19/33 (57.6) Median Age (yr) 5.6 4.3 Male 6/13 (46.2) 20/33 (60.6) Predisposing condition 14/27 (51.9) 19/33 (57.6) Median C-reactive protein at presentation (mg/dL) 223* 120† Intensive care unit 15/27 (55.5) 12/33 (36.4) Complications 7/12 (58.3) 9/33 (32.1) Death 4/27 (14.8) 3/33 (9.1) emm-typing emm-1 5/9 (55.6) 16/24 (66.7) emm-4 2/9 (22.2) emm-6 2/24 (8.3) emm-12 1/9 (11.1) 2/24 (8.3) emm-3.93 1/9 (11.1) emm-89 2/24 (8.3) emm-28 1 (4.2) emm44 1 (4.2) *Available data for 9 patients.†Available data for 28 patients.