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. 2019 Jan 8;19(1):29.
doi: 10.1186/s12879-018-3598-3.

Carriage rates and risk factors during an outbreak of invasive meningococcal disease due to Neisseria meningitidis serogroup C ST-11 (cc11) in Tuscany, Italy: a cross-sectional study

Alessandro Miglietta  1   2   3 , Francesco Innocenti  4 , Patrizio Pezzotti  5 , Eleonora Riccobono  6 , Maria Moriondo  7 , Patrizia Pecile  8 , Francesco Nieddu  7 , Gian Maria Rossolini  6   8 , Chiara Azzari  7 ; Meningococcal Carriage Study Group; Emanuela Balocchini  9 , Giovanni Rezza  5 , Fabio Voller  4 , Paola Stefanelli  5
Collaborators, Affiliations

Carriage rates and risk factors during an outbreak of invasive meningococcal disease due to Neisseria meningitidis serogroup C ST-11 (cc11) in Tuscany, Italy: a cross-sectional study

Alessandro Miglietta et al. BMC Infect Dis. .

Abstract

Background: During 2015-2016 an outbreak of invasive meningococcal disease due to N. meningitidis serogroup C ST-11 (cc11) occurred in Tuscany, Italy. The outbreak affected mainly the age group 20-30 years, men who have sex with men, and the area located between the cities of Firenze, Prato and Empoli, with discos and gay-venues associated-clusters. A cross-sectional-survey was conducted to assess the prevalence and risk factors for meningococcal-carriage, in order to address public health interventions.

Methods: A convenience sample of people aged 11-45 years provided oropharyngeal swab specimens and completed questionnaires on risk factors for meningococcal carriage during a 3 months study-period, conducted either in the outbreak-area and in a control-area not affected by the outbreak (cities of Grosseto and Siena). Isolates were tested by culture plus polymerase chain reaction. Serogroup C meningococcal isolates were further characterized using multilocus sequence typing. Univariate and multivariate analyses were performed to estimate adjusted odds ratios (AORs) for meningococcal carriage.

Results: A total of 2285 oropharyngeal samples were collected. Overall, meningococcal carriage prevalence was 4.8% (n = 110), with nonencapsulated meningococci most prevalent (2.3%; n = 52). Among encapsulated meningococci, serogroup B was the most prevalent (1.8%; n = 41), followed by serogroup Y (0.5%; n = 11) and serogroup C (0.2%; n = 4); one carrier of serogroup E and one of serogroup Z, were also found (0.04%). Three individuals from the city of Empoli were found to carry the outbreak strain, C:ST-11 (cc11); this city also had the highest serogroup C carriage prevalence (0.5%). At the multivariate analyses, risk factors for meningococcal carriage were: illicit-drugs consumption (AOR 6.30; p < 0.01), active smoking (AOR 2.78; p = 0.01), disco/clubs/parties attendance (AOR 2.06; p = 0.04), being aged 20-30 years (AOR 3.08; p < 0.01), and have had same-sex intercourses (AOR 6.69; p < 0.01).

Conclusions: A low prevalence of meningococcal serogroup C carriage in an area affected by an outbreak due to the hypervirulent N. meningitidis serogroup C ST-11 (cc11) strain was found. The city of Empoli had the highest attack-rate during the outbreak and also the highest meningococcal serogroup C carriage-prevalence due to the outbreak-strain. Multivariate analyses underlined a convergence of risk factors, which partially confirmed those observed among meningococcal outbreak-cases, and that should be considered in targeted immunization campaigns.

Keywords: Carrier state; Cross-sectional studies; Disease outbreaks; Neisseria meninigitidis.

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Conflict of interest statement

Ethics approval and consent to participate

The study was approved by the Regional Ethic Committee of Tuscany. Participants signed a written informed consent for participation that was also obtained from parents/legal guardians of subject aged less than 18 years.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

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Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

    1. Trotter CL, Gay NJ, Edmunds WJ. The natural history of meningococcal carriage and disease. Epidemiol Infect. 2006;134:556–566. doi: 10.1017/S0950268805005339. - DOI - PMC - PubMed
    1. Soriano-Gabarró M, Wolter J, Hogea C, Vyse A. Carriage of Neisseria meningitidis in Europe: a review of studies undertaken in the region. Expert Rev Anti-Infect Ther. 2011;9:761–774. doi: 10.1586/eri.11.89. - DOI - PubMed
    1. Christensen H, May M, Bowen L, Hickman M, Trotter CL. Meningococcal carriage by age: a systematic review and meta-analysis. Lancet Infect Dis. 2010;10:853–861. doi: 10.1016/S1473-3099(10)70251-6. - DOI - PubMed
    1. Caugant DA, Tzanakaki G, Kriz P. Lessons from meningococcal carriage studies. FEMS Microbiol Rev. 2007;31:52–63. doi: 10.1111/j.1574-6976.2006.00052.x. - DOI - PubMed
    1. European Centre for Disease Prevention and Control. Annual Epidemiological Report 2016. Invasive meningococcal disease. 2016. https://ecdc.europa.eu/en/publications-data/invasive-meningococcal-disea....

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