Significance of Meningococcal Hyperinvasive Clonal Complexes and Their Influence on Vaccines Development

Abstract

Neisseria meningitidis is a commensal of human nasopharynx and humans are the only known reservoir and host of this bacterium. It is also known as a dangerous and devastating pathogen, and infection with N. meningitidis may lead to rapidly progressing septicemia or meningitis. These severe infections, called invasive meningococcal disease (IMD), are one of the major public health threats worldwide. IMD may occur sporadically, but also in outbreaks, epidemics, and pandemics. Most of the IMD cases in the world are caused by isolates of genetically related groups, clonal complexes (CC), including those with special epidemiological significance called hyperinvasive clonal complexes. It is still unknown why some of them may persist for decades, whereas other are quickly replaced and disappear. As a consequence, the epidemiological situation of IMD is variable worldwide and greatly depends on the emergence and widespread of clones belonging to hyperinvasive clonal complexes. Their occurrence has serious implications for health policy, requiring often mass immunization campaigns. Paradoxically, alarming situations caused by hyperinvasive CCs stimulated the development and introduction of new vaccines against meningococci. Despite the unquestionable success of these vaccines, isolates of hyperinvasive clones constitute a permanent public health threat, because they are constantly circulating and able to modify their antigenic profiles to escape the host immune response. Therefore, continuous monitoring of meningococcal isolates including thorough molecular typing is indispensable and fundamental for taking appropriate preventive measures.

Evaluation of Neisseria meningitidis Carriage with the Analysis of Serogroups, Genogroups and Clonal Complexes among Polish Soldiers

“…Stephens (1999) estimated that the risk of developing IMD by people living in closed environments is 1-1.5%. The incidence of specific clonal complexes is associated with the dominance of individual serogroups (Trotter et al 2007;Jandova et al 2016 (Skoczyńska et al 2013;Waśko et al 2015). The present study confirmed that serogroup B was predominant among carriers; it was mostly represented by ST-41/44CC.…”

Diversity of meningococci associated with invasive meningococcal disease in the Republic of Ireland over a 19 year period, 1996-2015

“…Reductions in these STcc were also observed in other countries that introduced the MCC vaccine [20,33,36,50,51,57,58]. However, the recovery of cc11 menC and menW in EY2014/2015 is worthy of monitoring, given the extensive association of this STcc with IMD outbreaks [20,57,59,60] and also especially in view of the recent reports of increasing incidence of menW:cc11 in many European countries [23,27,58,61,62].…”

Circulating Clonal Complexes and Sequence Types of Streptococcus Pneumoniae Serotype 19a Worldwide: The Importance of Multidrug Resistance: A Systematic Literature Review

“…Mass vaccination has a significant influence on the evolution of specific phenotypic features of S. pneumoniae [67]. Isolates of hyperinvasive clones are constantly circulating and are able to modify their phenotypic profile (e.g.…”