Neisseria meningitidis: analysis of pili and LPS in emerging Brazilian strains

Abstract

Background: Neisseria meningitidis is the main cause of bacterial meningitis in Brazil, where the main serogroups isolated are B and C; however, the serogroup W has recently emerged. LPS and type IV pili are important virulence factors that increase meningococci pathogenicity. Methods: The characterization of Lipopolysaccharide (LPS) and type IV pili in 19 meningococci strains of serogroup B, 21 of serogroup C, 45 of serogroup W and 28 of serogroup Y, isolated in Brazil between 2011 and 2017, was conducted using the Enzyme-linked Immunosorbent Assay (Dot- ELISA) technique and monoclonal antibodies. Results: We would like to emphasize the importance of characterizing relevant antigens, such as pili and LPS, the use of monoclonal antibodies to support it, and how such studies improve vaccine development and monitoring. Most of the strains studied presented L3,7,9 LPS and type IV pili; both antigens are associated with the capacity to cause invasive disease. Conclusion: Due to the impact of meningococcal disease, it is important to maintain and improve vaccine studies. Epitopes characterization provides data about the virulence of circulating strains. The use of monoclonal antibodies and serological techniques are relevant and support vaccine development.

A Rare Cause of a Rare Disorder: E. coli-Induced Purpura Fulminans Secondary to Urinary Tract Infection

“…Rat models in vivo have also isolated one specific Meningococcus strain containing type IV pili that adheres to the endothelium with subsequent colony formation and microvascular thrombosis due to excessive protein C activation and a consumptive coagulopathy [ 6 ]. Type IV pili are found in 5 serotypes of Neisseria meningitidis A, B, C, W135, and Y, which may in part explain the petechial rash commonly observed [ 7 ]. Rare cases associated with measles virus, Rickettsia spp., and Haemophilus influenzae have also been reported in the medical literature [ 8 ].…”

New strategy to select cross-reactivity Meningococci strains: immunization with Outer membrane vesicles of serogroup C and cationic lipid as adjuvant

“…In Brazil, the epidemiology of IMD has been changing, with the increase of serogroup W in the South region, which accompanies the widespread of W:2a:P1.5,2 clone in South America and Europe [1,14]. Once again, it is important to maintain epidemiologic surveillance to follow these changes and adequate the immunization programs [1,12]. Our laboratory followed this strategy of cross-reactive immunization using OMV of C:2a:P1.5 strains against both C and W serogroups.…”

“…However, outbreaks and epidemics are often caused by specific meningococci clones that presents little heterogeneity and can be controlled by OMV vaccines [10,11]. It is interesting for countries that consider their adoption to keep epidemiological surveillance and phenotypical characterization of circulating meningococci strains, to maintain the conformity between the antigens expressed by the strains and the vaccine antigens [12]. In Brazil, the main isolates of N. meningitidis belong to serogroups C and B and the last epidemic occurred in the '80s, in São Paulo, because of a B:4:P1.15 strain [13].…”