Genotypic Characterization of Invasive Neisseria meningitidis serogroup B (MenB) in Argentina 2006.

SORHOUET PEREIRA C; REGUEIRA M; TAHA M; MOLLERACH M

Rotterdam, Holanda

Congreso; 16th International Pathogenic Neisseria Conference 2008; 2008

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Introduction: The annual incidence of meningococcal disease has been estimated to be around 0.6 - 2.9 cases per 100,000 inhabitants in the last fourteen years in Argentina (39 million inhabitants). An active laboratory-based surveillance system for invasive meningococcal infections has been established at the Instituto Nacional de Enfermedades Infecciosas - ANLIS “Dr Carlos G. Malbrán”. Isolates are collected from the participating laboratories that are geographically dispersed among the 23 provinces of the country. We report data on the genetic structure of the invasive meningococcal isolates collected during 2006. Methods: The study was performed on 46/49 serogroup B isolates (MenB) collected during 2006. The relatedness among isolates was evaluated by multilocus sequence typing (MLST) and by sequencing porA gene fragments encoding VR1 and VR2 regions (geno-subtyping). Results: MenB Isolates were most prevalent and represented 72% of all N. meningitidis isolates in 2006. The 46 MenB isolates were clustered in several clonal complexes but 95.6% of the isolates were associated with 4 clonal complexes. The isolated were further grouped into 17 different geno-subtypes on the basis of porA sequencing. The most prevalent geno-subtype was P1.21,16-36 (30.4%), followed by P1.22-1,14 (21.7%), and P1.7,16 (10.9%). The other subtypes were represented by 1-2 isolates each. All of the P1.21,16-36  isolates  belonged to the clonal complex ST-865 and 13/14 showed the sequence type ST-3327 of this clonal complex. The P1.22-1,14 isolates belonged to the clonal complex S-T35. The clonal complex ST41/44/Lineage 3  was represented by 10 isolates with very heterogeneous geno-subtypes. Conclusions: This study represents the best available resource for obtaining information about clonal distribution and PorA types of MenB strains in Argentina and provides valuable information for considering a probable PorA-based vaccine. However, an Outer Membrane Vesicle (OMV) vaccine should include several PorA types in order to cover most of the current circulating isolates