Prevalence of invasive meningococcal subtypes in Bilbao after immunization

Abstract number: P1364

Unzaga M.J., Ezpeleta C., Alava J.A., Gerediaga I., Sanchez M., Cisterna R.

Objectives: In 1990 an increasing number of serogroup C meningococcal strains were observed in Basque Country. These strains were characterized as C:2b: P1.2,5. As results a mass immunization campaign was conducted in 1997. The aim of our study was to determine the serotypes of invasive meningococcal disease nowadays, years after establishing vaccination.

Methods: The strains isolated from blood a cerebrospinal fluid in our hospital in 2008 and 2009 were sent to the Spanish Reference Laboratory for serotyping with monoclonal antibodies.

Results: The results of 18 meningococcal strains were analyzed. One strain was C serogroup C:2a:P1.5 and 17 strains were B serogroup. Completely serosubtypable were 10 strains: [seven: B:1:P1.14, one: B 4:P1.2,5 one B:2a:P1.5, one B:15:P1.15], Partially serosubtypable were five strains: [three, B 1:NT, and one respectively B:4:NT, and B:NT:P1.14] and B non-serosubtypable two strains. The outcome of invasive disease was not death whatever the serogroup involved.

The most prevalent strain B:1:P1.14 was not involved in complex diseases in either case. The C serogroup was isolated from a male 39 y-old and B:2a: P1.5 from another male 33 y-old. The disease was severe in both cases with complications as pericardial and pleural fluid, internal malleolus abscess in C serogroup strain and arthritis in B serogroup strain. The only strain B: 15: P1.15 was involved in the development of a more severe disease with multiple organ failure. The two strains caused by B non-serosubtypable also developed complications such as arthritis and leg edema. The patients were an adult and a child respectively.

No strain was resistant to penicillin, while 11 of them showed intermediate sensitivity: 4 strains B:1:P1.14, the three strains B 1:NT, the two strains B non serosubtypable, B:15:P1.15 and the B 4:P1.2,5 strain. All of isolates were susceptible to cefotaxime, rifampin and ciprofloxacin.

Conclusions: The most prevalent meningococcal subtypes in our hospital is B:1:P1.14. The disease is not severe. The isolation of B:2a:P1.5 and C:2a:P1.5 strains from sporadic cases coincide with meningococcal C vaccination as in other regions and suggest that strong immunological pressure might be selecting these types of strains that evade the immune response produced by the vaccine. These strains behave more aggressive than other serotypes.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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