1. Tan Tock Seng Hospital, SingaporeOriginated the study idea; was responsible for study design, data collection, analysis, and interpretation; and wrote the final manuscript.
2. Tan Tock Seng Hospital, SingaporeWas responsible for the meningococcal cultures, serogrouping, and pulsed-field gel electrophoresis (PFGE), and contributed to the manuscript.
3. Tan Tock Seng Hospital, SingaporePerformed PFGE and made other contributions to the manuscript.
4. Tan Tock Seng Hospital, SingaporeWas responsible for data entry and statistical analysis.
5. Tan Tock Seng Hospital, SingaporeContributed to the study design and data interpretation, and co-wrote the final manuscript.