Abstract
BackgroundWith the upcoming licensure of Outer Membrane Protein-based vaccines against meningococcal disease, data on disease incidence and molecular characteristic of circulating N. meningitidis strains in Latin American countries is needed. Chile is, to date, one of the few countries in the region that has performed this type of work in a comprehensive collection of disease-associated strains from two consecutive years, 2010–2011.MethodsA total of 119 N. meningitidis strains isolated from patients with invasive disease in Chile in 2010–2011 were characterized by the National Reference Laboratory. Serogroup determination, MLST and porA typing were performed.ResultsSerogroup B was predominant in both study years, but W135 experienced a noticeable increase in 2011 compared to 2010. ST-11 complex, ST-41/44 complex ST-32 complex were the most prevalent among the isolates, and were strongly associated with serogroups W135 (ST-11 Complex) and B (ST-41/44 and ST-32 complexes). Likewise, the major porA types detected were strongly associated with these three clonal complexes: P1.5,2 was found exclusively among W135:ST-11 isolates, whereas P1.7, 2–3 was only detected in C:ST-11. ST-41/44 isolates mainly had P1.10-8, and ST-32 complex were associated with a P1.18-8 porA.ConclusionsOur data show disease-associated N. meningitidis circulating in Chile are similar to those found in other parts of the world. The increase on W135:ST-11 isolates observed in 2011 foretold the unusual epidemiological situation experienced in the country in 2012, and MLST data show that this strain is indistinguishable from the one linked to the global Hajj 2000-related outbreak that occurred in 2001. Finally, this work demonstrates the importance of maintaining a strong national surveillance program integrating clinical, epidemiological and laboratory data and incorporating gold standard diagnostic and characterization techniques that allow the data to be compared all over the world.
Highlights
Neisseria meningitidis, the meningococcus, is an exclusively human Gram negative pathogen that is carried asymptomatically by 8– 20% of the population and can cause invasive disease in the form of meningitis and septicemia [1]
This study presents a comprehensive analysis of Invasive meningococcal disease (IMD) causing strains in Chile during a two-year period, from 2010 to 2011, combining traditional microbiological characterization with molecular typing of strains, and will provide an insight into the characteristics of circulating meningococcal strains in the country, as well as allow data to be compared to that from other parts of the world
This study represents, to the author’s knowledge, the first comprehensive investigation combining microbiological and molecular data on a collection of meningococcal strains from Chile for a two-year period. These isolates are fully representative of the epidemiology of the country in 2010–11, as meningococcal disease is of compulsory notification and the country has a very efficient epidemiological surveillance system that is well coordinated with the national reference laboratory in the Instituto de Salud Publica (ISP) [17]
Summary
The meningococcus, is an exclusively human Gram negative pathogen that is carried asymptomatically by 8– 20% of the population and can cause invasive disease in the form of meningitis and septicemia [1]. Disease epidemiology varies among continents and countries, and maintaining a well-established and coordinated clinical and laboratory-based surveillance system is crucial for identifying disease trends and timely identification of outbreaks, as well as evaluating the impact of preventive measures, including vaccination strategies [5]. Phenotypic characterization of N. meningitidis includes serogroup determination and is usually complemented by antigen typing, which is based on the variable regions of outer membrane proteins (OMP) and determines the serotype (porB) and serosubtype (porA). With the upcoming licensure of Outer Membrane Protein-based vaccines against meningococcal disease, data on disease incidence and molecular characteristic of circulating N. meningitidis strains in Latin American countries is needed. To date, one of the few countries in the region that has performed this type of work in a comprehensive collection of disease-associated strains from two consecutive years, 2010–2011
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