Molecular Characterization of Invasive Neisseria meningitidis Strains Isolated in Chile during 2010–2011

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.

Neisseria meningitidisinfection: who, when and where?

“…Currently, these serogroup C clones, and especially cc103, constitute the main cause of endemic meningococcal disease in Brazil [109]. As for Chile, during 2010-2011, Barra et al [84] did not observe changes in serogroup C incidence, reporting an average of 11.5%.…”

“…A study conducted on 6955 isolates collected in Latin America and the Caribbean region, and especially from Brazil and Chile, reported that 69% of the isolates belonged to serogroup B [83]. A recent investigation reported a slight lower percentage for serogroup B distribution: 63.6% in 2010 and 51.6% in 2011, upon a characterization conducted on a total of 119 N. meningitidis strains isolated in Chile [84]. Among the other countries of Latin America, serogroup B has been predominant in Argentina [85] since 2001 and especially during the periods 1993-1995 and 2002-2005, causing about two-third of cases of infections [86], and in Colombia as resulted by the analysis performed on 434 isolates collected between 1994 and 2006 [87].…”

Outbreaks of meningococcal B infection and the 4CMenB vaccine: historical and future perspectives

“…The emergence of CC11 strains associated with serogroup W in Africa represents an example of expansion of a successful clone. The epidemic with phenotype W:2a:P1.5,2 was identified in 2001 as being associated with the Hajj pilgrimage, with disease emerging throughout Europe, and, in the last few years, in Argentina and other countries in Latin America [65,175,176]. CC8 complex (formerly cluster A4), genetically related to CC11, was also mainly associated with serogroup C disease [122], was first identified in the Netherlands in 1961 [44] and has been a common cause of disease since 1970s [24,177,178], although in the last years strains belonging to CC8 have decreased worldwide (source: EU-IBIS).…”

“…CC41/44 has also been recognized as one of the most common causes of serogroup B meningococcal disease in several European countries, including the Czech Republic, Greece, Norway [38] and France [63], the USA [12,64] and Latin American countries, such as Chile [65]. From 2001 to 2006, meningococcal strains with antigenic profile B:P1.7-2,4:F1-5 caused an outbreak in the German city of Aachen and in three neighboring counties [66].…”

Enfermedad meningocóccica invasora por serogrupo B en dos niños chilenos vacunados contra serogrupos ACWY

“…A pesar de los avances obtenidos en el manejo del paciente crítico, la EMI continua siendo un problema de salud pública, dado su amplia distribución, perfil epidémico y alta tasa de secuelas y letalidad asociada 3 . Dentro de las teorías que explican esta situación se considera la aparición y predominio del serogrupo W observada en Chile desde 2012, con una cepa del linaje hipervirulento W:P1.5,2:ST-11, la cual contiene el alelo ID 22 para el gen fHbp, que le daría la propiedad de ser hiperinvasor 4 . Este cambio epidemiológico motivó una campaña masiva de vacunación, con vacunas conjugadas tetravalentes ACWY, acorde a las aprobaciones vigentes para ese momento, la cual se enfocó en niños entre nueve meses y cuatro años de edad, desde octubre de 2012.…”