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.

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?

SUBMITTER: Miglietta A 

PROVIDER: S-EPMC6323866 | biostudies-other | 2019 Jan

REPOSITORIES: biostudies-other