Neisseria meningitidisSequence Type and Risk for Death, Iceland

Magnús Gottfreðsson,Helga Erlendsdóttir,Hjördís Harðardóttir,David I Lawrie,Stuart C Clarke,Karl G Kristinsson,Mathew A Diggle

doi:10.3201/eid1207.051624

Abstract

Invasive meningococcal infections are hyperendemic in Iceland, a relatively isolated country in the mid-Atlantic. We performed a nationwide study on all viable meningococcal strains (N = 362) from 1977 to 2004. We analyzed the association of patient's age and sex, meningococcal serogroups, and sequence types (STs) with outcomes. Overall, 59 different STs were identified, 19 of which were unique to Iceland. The most common STs were 32 (24.6%), 11 (19.9%), and 10 (10.2%). The unique ST-3492 ranked fourth (7.7%). The most common serogroups were B (56.4%), C (39.8%), and A (2.2%). Age (p<0.001) and infection with a unique ST (p = 0.011) were independently associated with increased death rates, whereas isolation of meningococci from cerebrospinal fluid only was associated with lower death rates (p = 0.046). This study shows evolutionary trends of meningococcal isolates in a relatively isolated community and highlights an association between unique STs and poor outcome.

Highlights

Invasive meningococcal infections are hyperendemic in Iceland, a relatively isolated country in the mid-Atlantic
The average incidence of invasive meningococcal disease during this 28-year period was 7.1 cases/100,000 population/year, but if the epidemic year of 1977 is excluded, it drops to 6.4 cases/100,000 population/year
Sequence Typing of Meningococcal Isolates Multilocus sequence typing (MLST) was performed on all 362 viable strains, which were responsible for 72.7% of all documented cases of invasive meningococcal disease in the country during the study period

Summary

Introduction

Invasive meningococcal infections are hyperendemic in Iceland, a relatively isolated country in the mid-Atlantic. We analyzed the association of patient’s age and sex, meningococcal serogroups, and sequence types (STs) with outcomes. This study shows evolutionary trends of meningococcal isolates in a relatively isolated community and highlights an association between unique STs and poor outcome. We used MLST to study the evolutionary dynamics of invasive meningococcal infections in Iceland during a 28-year period, 1977–2004. The purpose of this long-term, nationwide study was 2-fold: 1) compare Icelandic strains with those circulating globally and 2) study the association between patient demographics, sequence types (STs), serogroups, and outcomes

Methods

Results

Conclusion