Bacterial meningitis in Guinea (2023–2024): regional epidemiology, case mapping, and etiological profile confirmed by multiplex PCR

Bacterial meningitis remains a major medical emergency, associated with high lethality and long-lasting neurological sequelae, especially in resource-limited countries. The main etiological agents are Neisseria meningitidis , Streptococcus pneumoniae , and Haemophilus influenzae , whose distributions vary by age, region, and vaccination coverage. In Guinea, following the introduction of the MenAfriVac ® vaccine, the epidemiological landscape has evolved, but recent data on the regional distribution of cases and circulating agents remain limited. A descriptive, cross-sectional observational study was conducted from January 2023 to June 2024, including 140 patients suspected of bacterial meningitis across six of Guinea’s eight administrative regions. Cases were defined according to the national standardized definition and classified as confirmed, probable, or unconfirmed according to clinical and microbiological criteria. Cerebrospinal fluid (CSF) samples were analyzed by cytology, Gram staining, bacterial culture, and multiplex real-time PCR targeting the main pathogens. Sociodemographic, clinical, and temporal data were collected and analyzed, along with a mapping of the geographical distribution of cases. Of the 140 patients, 60% were boys, with a median age of 12 months; the majority were < 5 years old (60%). The geographical distribution showed a concentration of cases in Conakry and lower numbers in the country’s interior regions. Microbiologically, 48 cases (34.3%) were confirmed, 27 (19.3%) were probable, and 65 (46.4%) were unconfirmed. PCR identified 48 positive cases, mostly S. pneumoniae (85.4%) and H. influenzae (14.6%), while culture yielded an organism in only 4 cases (2.9%), all of which were non-target Gram-negative bacteria. No target pathogen was recovered by culture, supporting the greater sensitivity of real-time PCR for the rapid, specific detection of vaccine-preventable meningitis pathogens. This study provides an updated description of bacterial meningitis cases in post-MenAfriVac ® Guinea, highlighting the predominance of S. pneumoniae and the value of PCR for diagnosis. The geographic and demographic data obtained strengthen integrated surveillance, facilitate early detection of outbreaks, and help guide public health strategies tailored to local contexts.