Serogroup and Clonal Characterization of Czech Invasive Neisseria meningitidis Strains Isolated from 1971 to 2015

Abstract

Background: This study presents antigenic and genetic characteristics of Neisseria meningitidis strains recovered from invasive meningococcal disease (IMD) in the Czech Republic in 1971-2015.

Material and methods: A total of 1970 isolates from IMD, referred to the National Reference Laboratory for Meningococcal Infections in 1971-2015, were studied. All isolates were identified and characterized by conventional biochemical and serological tests. Most isolates (82.5%) were characterized by multilocus sequence typing method.

Results: In the study period 1971-2015, the leading serogroup was B (52.4%), most often assigned to clonal complexes cc32, cc41/44, cc18, and cc269. A significant percentage of strains were of serogroup C (41.4%), with high clonal homogeneity due to hyperinvasive complex cc11, which played an important role in IMD in the Czech Republic in the mid-1990s. Serogroup Y isolates, mostly assigned to cc23, and isolates of clonally homogeneous serogroup W have also been recovered more often over the last years.

Conclusion: The incidence of IMD and distribution of serogroups and clonal complexes of N. meningitidis in the Czech Republic varied over time, as can be seen from the long-term monitoring, including molecular surveillance data. Data from the conventional and molecular IMD surveillance are helpful in refining the antimeningococcal vaccination strategy in the Czech Republic.

Fig 1. Incidence of invasive meningococcal disease, Czech Republic, 1943–2015.

Blue line is incidence (cases per 100 000 population) and the red line is surveillance since 1993.

Fig 2. Number of isolates of N. meningitidis from invasive meningococcal disease, Czech Republic, 1971–2015, n = 1970.

Fig 3. Annual distribution of serogroups of N. meningitidis from invasive meningococcal disease, Czech republic, 1971–2015, n = 1970 (NG = non groupable, nd = not defined).

Fig 4. Annual distribution of major clonal complexes of N. meningitidis from invasive meningococcal disease, Czech Republic, 1971–2015, n = 1970 (cc = clonal complex, ccUA = unassigned clonal complex, nd = not defined).

Fig 5. Annual distribution of major clonal complexes of N. meningitidis B from invasive meningococcal disease, Czech Republic, 1971–2015, n = 938 (cc = clonal complex, ccUA = unassigned clonal complex, nd = not defined).

Fig 6. Annual distribution of major clonal complexes of N. meningitidis C from invasive meningococcal disease, Czech Republic, 1971–2015, n = 741 (cc = clonal complex, ccUA = unassigned clonal complex, nd = not defined).