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Phenotypic and genotypic characterization of meningococcal carriage and disease isolates in Burkina Faso after mass vaccination with a serogroup a conjugate vaccine.

Kristiansen PA, Ba AK, Sanou I, Ouédraogo AS, Ouédraogo R, Sangaré L, Diomandé F, Kandolo D, Thomas JD, Clark TA, Laforce M, Caugant DA - BMC Infect. Dis. (2013)

Bottom Line: All the invasive isolates and 817 carriage isolates were characterized by serogroup, multilocus sequence typing and porA-fetA sequencing.Serogroup X carriage and disease prevalence increased before vaccine introduction, due to the expansion of ST-181, which comprised 48.5% of all the characterized carriage isolates.Successive clonal waves of ST-181 and ST-11 may explain the changing epidemiology in Burkina Faso after the virtual disappearance of NmA disease and carriage.

View Article: PubMed Central - HTML - PubMed

Affiliation: Norwegian Institute of Public Health, Oslo, Norway. paul.kristiansen@fhi.no

ABSTRACT

Background: The conjugate vaccine against serogroup A Neisseria meningitidis (NmA), MenAfriVac, was first introduced in mass vaccination campaigns of the 1-29-year-olds in Burkina Faso in 2010. The aim of this study was to genetically characterize meningococcal isolates circulating in Burkina Faso before and up to 13 months after MenAfriVac mass vaccination.

Methods: A total of 1,659 meningococcal carriage isolates were collected in a repeated cross-sectional carriage study of the 1-29-year-olds in three districts of Burkina Faso in 2010 and 2011, before and up to 13 months after mass vaccination. Forty-two invasive isolates were collected through the national surveillance in Burkina Faso in the same period. All the invasive isolates and 817 carriage isolates were characterized by serogroup, multilocus sequence typing and porA-fetA sequencing.

Results: Seven serogroup A isolates were identified, six in 2010, before vaccination (4 from carriers and 2 from patients), and one in 2011 from an unvaccinated patient; all were assigned to sequence type (ST)-2859 of the ST-5 clonal complex. No NmA carriage isolate and no ST-2859 isolate with another capsule were identified after vaccination. Serogroup X carriage and disease prevalence increased before vaccine introduction, due to the expansion of ST-181, which comprised 48.5% of all the characterized carriage isolates. The hypervirulent serogroup W ST-11 clone that was responsible for most of meningococcal disease in 2011 and 2012 was not observed in 2010; it appeared during the epidemic season of 2011, when it represented 40.6% of the serogroup W carriage isolates.

Conclusions: Successive clonal waves of ST-181 and ST-11 may explain the changing epidemiology in Burkina Faso after the virtual disappearance of NmA disease and carriage. No ST-2859 strain of any serogroup was found after vaccination, suggesting that capsule switching of ST-2859 did not occur, at least not during the first 13 months after vaccination.

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Carriage prevalence of Neisseria meningitidis serogroup X ST-181 and serogroup W ST-11 and ST-2881 in three Districts of Burkina Faso during the sampling campaigns S1-S9, 2009–2011. Data from S1 to S4 are from a previously published study [34]. Black lines with boxes, serogroup X ST-181. Dotted lines with triangle, serogroup W ST-2881. Dotted lines with cross, serogroup W ST-11.
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Figure 2: Carriage prevalence of Neisseria meningitidis serogroup X ST-181 and serogroup W ST-11 and ST-2881 in three Districts of Burkina Faso during the sampling campaigns S1-S9, 2009–2011. Data from S1 to S4 are from a previously published study [34]. Black lines with boxes, serogroup X ST-181. Dotted lines with triangle, serogroup W ST-2881. Dotted lines with cross, serogroup W ST-11.

Mentions: ST-2859, expressing a serogroup A capsule, was present in the non-vaccinated district of Dandé in October-November 2010, but was not seen after introduction of MenAfriVac (Figure 1). The other two genotypes known to cause outbreaks in sub-Saharan Africa, ST-181 and ST-11, were present in carriers after vaccine introduction. However, NmX ST-181 was circulating already since 2009 [34], while NmW ST-11 was detected only after vaccine introduction (Figure 1). The NmW ST-11 clone was first detected in the district of Dandé from S6 and then in Bogodogo from S7 (Figure 2). A non-groupable ST-11; P1.5-2; F1-1 isolate was also detected in Bogodogo during sampling S6.


Phenotypic and genotypic characterization of meningococcal carriage and disease isolates in Burkina Faso after mass vaccination with a serogroup a conjugate vaccine.

Kristiansen PA, Ba AK, Sanou I, Ouédraogo AS, Ouédraogo R, Sangaré L, Diomandé F, Kandolo D, Thomas JD, Clark TA, Laforce M, Caugant DA - BMC Infect. Dis. (2013)

Carriage prevalence of Neisseria meningitidis serogroup X ST-181 and serogroup W ST-11 and ST-2881 in three Districts of Burkina Faso during the sampling campaigns S1-S9, 2009–2011. Data from S1 to S4 are from a previously published study [34]. Black lines with boxes, serogroup X ST-181. Dotted lines with triangle, serogroup W ST-2881. Dotted lines with cross, serogroup W ST-11.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750508&req=5

Figure 2: Carriage prevalence of Neisseria meningitidis serogroup X ST-181 and serogroup W ST-11 and ST-2881 in three Districts of Burkina Faso during the sampling campaigns S1-S9, 2009–2011. Data from S1 to S4 are from a previously published study [34]. Black lines with boxes, serogroup X ST-181. Dotted lines with triangle, serogroup W ST-2881. Dotted lines with cross, serogroup W ST-11.
Mentions: ST-2859, expressing a serogroup A capsule, was present in the non-vaccinated district of Dandé in October-November 2010, but was not seen after introduction of MenAfriVac (Figure 1). The other two genotypes known to cause outbreaks in sub-Saharan Africa, ST-181 and ST-11, were present in carriers after vaccine introduction. However, NmX ST-181 was circulating already since 2009 [34], while NmW ST-11 was detected only after vaccine introduction (Figure 1). The NmW ST-11 clone was first detected in the district of Dandé from S6 and then in Bogodogo from S7 (Figure 2). A non-groupable ST-11; P1.5-2; F1-1 isolate was also detected in Bogodogo during sampling S6.

Bottom Line: All the invasive isolates and 817 carriage isolates were characterized by serogroup, multilocus sequence typing and porA-fetA sequencing.Serogroup X carriage and disease prevalence increased before vaccine introduction, due to the expansion of ST-181, which comprised 48.5% of all the characterized carriage isolates.Successive clonal waves of ST-181 and ST-11 may explain the changing epidemiology in Burkina Faso after the virtual disappearance of NmA disease and carriage.

View Article: PubMed Central - HTML - PubMed

Affiliation: Norwegian Institute of Public Health, Oslo, Norway. paul.kristiansen@fhi.no

ABSTRACT

Background: The conjugate vaccine against serogroup A Neisseria meningitidis (NmA), MenAfriVac, was first introduced in mass vaccination campaigns of the 1-29-year-olds in Burkina Faso in 2010. The aim of this study was to genetically characterize meningococcal isolates circulating in Burkina Faso before and up to 13 months after MenAfriVac mass vaccination.

Methods: A total of 1,659 meningococcal carriage isolates were collected in a repeated cross-sectional carriage study of the 1-29-year-olds in three districts of Burkina Faso in 2010 and 2011, before and up to 13 months after mass vaccination. Forty-two invasive isolates were collected through the national surveillance in Burkina Faso in the same period. All the invasive isolates and 817 carriage isolates were characterized by serogroup, multilocus sequence typing and porA-fetA sequencing.

Results: Seven serogroup A isolates were identified, six in 2010, before vaccination (4 from carriers and 2 from patients), and one in 2011 from an unvaccinated patient; all were assigned to sequence type (ST)-2859 of the ST-5 clonal complex. No NmA carriage isolate and no ST-2859 isolate with another capsule were identified after vaccination. Serogroup X carriage and disease prevalence increased before vaccine introduction, due to the expansion of ST-181, which comprised 48.5% of all the characterized carriage isolates. The hypervirulent serogroup W ST-11 clone that was responsible for most of meningococcal disease in 2011 and 2012 was not observed in 2010; it appeared during the epidemic season of 2011, when it represented 40.6% of the serogroup W carriage isolates.

Conclusions: Successive clonal waves of ST-181 and ST-11 may explain the changing epidemiology in Burkina Faso after the virtual disappearance of NmA disease and carriage. No ST-2859 strain of any serogroup was found after vaccination, suggesting that capsule switching of ST-2859 did not occur, at least not during the first 13 months after vaccination.

Show MeSH
Related in: MedlinePlus