A Narrative Review of the Molecular Epidemiology and Laboratory Surveillance of Vaccine Preventable Bacterial Meningitis Agents: Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae and Streptococcus agalactiae

Abstract

This narrative review describes the public health importance of four most common bacterial meningitis agents, Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae, and S. agalactiae (group B Streptococcus). Three of them are strict human pathogens that normally colonize the nasopharynx and may invade the blood stream to cause systemic infections and meningitis. S. agalactiae colonizes the genito-gastrointestinal tract and is an important meningitis agent in newborns, but also causes invasive infections in infants or adults. These four bacteria have polysaccharide capsules that protect them against the host complement defense. Currently licensed conjugate vaccines (against S. pneumoniae, H. influenza, and N. meningitidis only but not S. agalactiae) can induce protective serum antibodies in infants as young as two months old offering protection to the most vulnerable groups, and the ability to eliminate carriage of homologous serotype strains in vaccinated subjects lending further protection to those not vaccinated through herd immunity. However, the serotype-specific nature of these vaccines have driven the bacteria to adapt by mechanisms that affect the capsule antigens through either capsule switching or capsule replacement in addition to the possibility of unmasking of strains or serotypes not covered by the vaccines. The post-vaccine molecular epidemiology of vaccine-preventable bacterial meningitis is discussed based on findings obtained with newer genomic laboratory surveillance methods.

Gamma-Irradiated Non-Capsule Group B Streptococcus Promotes T-Cell Dependent Immunity and Provides a Cross-Protective Reaction

“…However, immune pressure and selection against these pathogens can be expected to change their natural habitat and serogroups in the post-vaccine period. Thus, the ecology of GBS may make the effects of polysaccharide-conjugate vaccines on epidemiology challenging to predict [ 64 ]. In this study, our findings suggested that Rad-GBS could activate sufficient adaptive immune responses, likely CD4 + T cell-dependent and humoral immunity.…”

Evaluation of the World Health Organization Global Invasive Bacterial Vaccine-Preventable Disease (IB-VPD) Surveillance Network’s Laboratory External Quality Assessment Programme, 2014–2019

“…It is anticipated that, in time, resources will improve for these laboratories and they can submit a higher proportion of completely correct results, to increase their value to surveillance. This is an important aspiration, as NTHi and serotype a, e and f Hi strains and Nm serogroup W and Y strains do cause a significant amount of invasive disease [27][28][29][30]. Serotype replacement following Sp vaccination will also increase the need to broaden Sp serotyping [31].…”

Investigation of Upper Respiratory Carriage of Bacterial Pathogens among University Students in Kampar, Malaysia

“…Streptococcus pneumoniae , Haemophilus influenzae , Neisseria meningitidis , Staphylococcus aureus , Klebsiella pneumoniae and Pseudomonas aeruginosa are among the bacterial pathogens that colonize the human upper respiratory tract (URT) [ 1 , 2 , 3 ]. Their pathogenicity is mediated by some major virulence factors involved in host cell adherence and invasion, tissue damage and immune evasion [ 4 , 5 , 6 , 7 ]. Despite being pathogenic, most individuals do not show any symptoms when these bacteria colonize the URT.…”