Oral Presentation 25th International Pathogenic Neisseria Conference 2026

Neisseria bergeri unmasked in meningococcal carriage surveys among asymptomatic individuals in Northern Ghana (2023-2024) (140508)

Felix E Nenyewodey 1 2 , Brenda Kwambana 3 4 , Patrick O Ansah 1 , Rito Mikhari-Chauke 5 , Cecilia S Bugbillah 1 , Ebenezer A Bonney 1 , Emmanuel Broni 1 , Jeremiah K Ganyo 1 , Dineo Magale 5 , Rivionia Nero 5 , Linda de Gouveia 5 , Keabetswe Motsepe 5 , Comfort Brown 4 , Franklin Asiedu-Bekoe 6 , Sally O Ohene 7 , Jason Mwenda 8 , Deborah K Narwortey 1 , Francis Broni 1 , Victor Asoala 1 , Lucas N Amenga-Etego 9 , Migno du du Plessis 2 5 , Anne von Gottberg 2 5
  1. Biomedical Science Department, Navrongo Health Research Centre, Navrongo, Upper East Region, Ghana
  2. Clinical Microbiology and Infectious Disease, University of the Witwatersrand, Johannesburg, South Africa.
  3. Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
  4. Malawi Liverpool Wellcome Research Programme, Blantyre, Malawi
  5. Centre for Respiratory Disease and Meningitis , National Institute for Communicable Diseases , Johannesburg, South Africa
  6. Ghana Health Service, Accra, Ghana
  7. World Health Organization Country Office, Accra, Ghana
  8. World Health Organization Regional office for Africa, Brazzaville, Republic of Congo
  9. Department of Biochemistry Cell and Molecular Biology, West African Center for Cell Biology of Infectious Pathogens , Accra, Ghana

Background

Northern Ghana, in the African meningitis belt, frequently experiences meningitis outbreaks caused by meningococcus and pneumococcus. After the 2012 rollout of the MenA vaccine, meningococcal serogroup A disease decreased, but other serogroups have emerged, highlighting the need for ongoing genomic surveillance to monitor circulating strains. This study characterized N. meningitidis isolates circulating in northern Ghana among asymptomatic individuals.

 

Methodology

In 2023, a cross-sectional carriage survey (survey 1) of 2932 individuals (all ages), was conducted in the Upper East region to monitor vaccine-preventable meningitis. In 2024, a similar survey (survey 2) of 1,045 school children and adults was carried out in response to a meningitis outbreak in the Upper West region. Oropharyngeal swabs were cultured for meningococci using standard microbiological methods. Putative meningococcal isolates, identified by MALDI-TOF (Bruker Biotyper RUO) and sodC PCR, were sequenced using Illumina. Serogroup and antimicrobial susceptibility testing were performed. De novo-assembled genomes were analyzed (https://pubmlst.org/organisms/neisseria-spp) to determine genogroup, MLST, and penA alleles.

 

Results

Of 63 presumptive meningococcal isolates from both surveys, whole-genome sequence (WGS) analysis revealed that 38%(24/63) were N. bergeri, distributed across eight different sequence types. Additionally, 5%(3/63) isolates were identified as non-meningococcal Neisseria spp., and 10%(6/63) isolates had insufficient read quality for species identification. For the confirmed meningococcal isolates (n=30), the carriage prevalence was 0.4%(13/2932) in survey 1 and 1.6%(17/1045) in survey 2. Capsule-null meningococci accounted for 20%(6/30), and 73%(22/30) were non-genogroupable. Serogroups B and C (n=1 each) were in survey 1, belonging to cc41/44 and cc10217 lineages, respectively. Phenotypic resistance to sulfamethoxazole was 93%(29/30) of isolates, while 67%(20/30) exhibited multidrug resistance (resistant to ≥ 3 antibiotic classes) across both study populations. Penicillin non-susceptibility was 90% (27/30). Among the 30 isolates, six penA alleles were identified, with 20/30 having allele 662. BlaTEM-1 was found in 7% (2/30) of isolates.

 

Conclusion

Following WGS, a substantial proportion of isolates identified as N. meningitidis by MALDI-TOF and PCR were identified as N. bergeri (a new species closely related to N. polysaccharea). MenB and MenC meningococcal hypervirulent lineages, previously associated with disease outbreaks, indicates a potential outbreak risk.