Neisseria meningitidis serogroup X sequence type 2888, Italy.
Article Type: Case study
Subject: Genetic variation (Research)
Meningitis, Cerebrospinal (Causes of)
Meningitis, Cerebrospinal (Diagnosis)
Meningitis, Cerebrospinal (Care and treatment)
Meningitis, Cerebrospinal (Patient outcomes)
Meningitis, Cerebrospinal (Case studies)
Neisseria meningitidis (Health aspects)
Neisseria meningitidis (Genetic aspects)
Authors: Fazio, Cecilia
Starnino, Stefania
Dal Solda, Marina
Sofia, Tonino
Neri, Arianna
Mastrantonio, Paola
Stefanelli, Paola
Pub Date: 02/01/2010
Publication: Name: Emerging Infectious Diseases Publisher: U.S. National Center for Infectious Diseases Audience: Academic; Professional Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2010 U.S. National Center for Infectious Diseases ISSN: 1080-6040
Issue: Date: Feb, 2010 Source Volume: 16 Source Issue: 2
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: Italy Geographic Code: 4EUIT Italy
Accession Number: 221918684
Full Text: To the Editor: Neisseria meningitidis serogroup X was first described in the 1960s and has been found to be responsible of rare cases of invasive meningococcal diseases, in particular, meningitis, in North America, Europe, Australia, Africa, and the People's Republic of China (1-3). This serogroup has recently emerged in Africa as an increasing cause of meningitis; unfortunately, it is not covered by current vaccine programs. Serogroup X outbreaks have been reported in Niger, Ghana, and Kenya (4-6). In particular, in Niger during January-June 2006, N. meningitidis serogroup X represented 51% of confirmed cases of meningitis (4).

To investigate the population structure of serogroup X meningococci isolated during recent decades in Africa, Europe, and North America, Gagneux et al. (1) compared the molecular characteristics among them. That study highlighted a low genetic variability between African serogroup X strains, which contrasts with higher genetic variability among isolates from Europe and the United States (1).

We describe a case of invasive meningococcal disease caused by a serogroup X N. meningitidis strain isolated in Italy. The patient was a 55-year-old Italian woman with no immune deficiency. The onset of disease started quickly with high fever (39[degrees]C) on June 1, 2009. No contacts with persons coming from abroad were reported. This case was diagnosed on the basis of clinical signs and symptoms and results of laboratory confirmatory tests, including blood culture. The patient received ceftriaxone (2 g/day) for 7 days with a favorable outcome.

The strain was susceptible to penicillin G, rifampin, ciprofloxacin, and ceftriaxone, as determined by Etest method (bioMerieux, Florence, Italy). The breakpoints were those recommended by the Clinical and Laboratory Standards Institute (7). Serogroup was determined by serum agglutination, and serotype/subtype, NT:P1.15, 19 were determined by standard whole-cell ELISA with monoclonal antibodies (obtained from the National Institute for Biological Standards and Control, South Mimms, UK) (8).

PorA variable regions, FetA, and multilocus sequence typing analyses were performed according to standard procedures from the Neisseria Multi Locus Sequence Typing Web site (http://pubmlst.org/neisseria). The isolate from Italy had the pattern PorA VR1-19, VR2-15, and VR3-36; F5-5 and sequence type (ST)-2888. The same ST was already described in Greece in 2002 but in a noninvasive strain (http://pubmlst.org/neisseria).

The pattern obtained by pulsed-field gel electrophoresis (9), using the rare-cutting enzyme NheI, (data not shown), was identical to patterns found among meningococci X strains isolated in United Kingdom and belonging to ST-750, clonal group X-II (1). In particular, ST-2888 resembles, except for gdh gene sequence, ST-2317, which was found among the X meningococci isolated in the United Kingdom in 2002 with phenotype X:4:P1.7 (http://pubmlst.org/neisseria).

Our data document a rare case of invasive meningococcal meningitis in Italy, caused by N. meningitidis serogroup X ST-2888. Future surveillance data may be able to determine epidemiologic influences, likely emanating from nearby countries, on the spread of such a strain into Italy.

DOI: 10.3201/eid1602.091553

Acknowledgments

We thank Anna Pavan, Maria Gramegna, and Luigi Macchi for the collaboration in the Italian Surveillance System for Invasive Bacterial Diseases.

This work was partially funded by the Ministry of Health-CCM Project 116 "Surveillance of invasive bacterial diseases," 2007-2009.

References

(1.) Gagneux S, Wirth T, Hodgson A, Ehrhard I, Morelli G, Kriz P, et al. Clonal groupings in serogroup X Neisseria meningi tidis. Emerg Infect Dis. 2002;8:462-6.

(2.) del Castillo CM, Vazquez JA, Romero J, Pascual A. Infections by Neisseria meningitidis serogroup X in Spain. Clin Microbiol Infect. 2003;9:964-5. DOI: 10.1046/ j.1469-0691.2003.00685.x

(3.) Chen C, Zhang TG, Wu J, Chen LJ, Liu JF, Pang XH, et al. A first meningococcal meningitis case caused by serogroup X Neisseria meningitidis strains in China. Chin Med J. 2008;127:664-6.

(4.) Boisier P, Nicolas P, Djibo S, Taha M-K, Jeanne I, Mainassara HB, et al. Meningococcal meningitis: unprecedented incidence of serogroup X-related cases in 2006 in Niger. Clin Infect Dis. 2007;44:657-63. DOI: 10.1086/511646

(5.) Gagneux SP, Hodgson A, Smith TA, Wirth T, Ehrhard I, Morelli G, et al. Prospective study of a serogroup X Neisseria meningitidis outbreak in northern Ghana. J Infect Dis. 2002;185:618-26. DOI: 10.1086/339010

(6.) Mutonga DM, Pimentel G, Muindi J, Nzioka C, Mutiso J, Klena JD, et al. Epidemiology and risk factors for serogroup X meningococcal meningitis during an outbreak in western Kenya. Am J Trop Med Hyg. 2009;80:619-24.

(7.) Clinical and Laboratory Standard Institute. Performance standards for antimicrobial susceptibility testing, 18th informational supplement. M100-S18. Wayne (PA): The Institute; 2008.

(8.) Abdillahi H, Poolman JT. Whole-cell ELISA for typing Neisseria meningitidis with monoclonal antibodies. FEMS Microbiol Lett. 1987;48:367-71. DOI: 10.1111/j.1574-6968.1987.tb02626.x

(9.) Hartstein A, Phelps C, Lemonte A. Typing of sequential bacterial isolates by pulsed-field gel electrophoresis. Diagn Microbiol Infect Dis. 1995;22:309-14. DOI: 10.1016/0732-8893(95)00139-8

Author affiliations: Istituto Superiore di Sanita, Rome, Italy (C. Fazio, S. Starnino, T. Sofia, A. Neri, P. Mastrantonio, P. Stefanelli); and Azienda Sanitaria, Locale, Cremona, Italy (M. Dal Solda)

Address for correspondence: Paola Mastrantonio, Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanita, Viale Regina Elena, 299, 00161, Rome, Italy; email: paola.mastrantonio@iss.it
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