Original Article http://dx.doi.org/10.3349/ymj.2012.53.4.742 pISSN: 0513-5796, eISSN: 1976-2437 Yonsei Med J 53(4):742-747, 2012 Carriage Rates and Serogroups of Neisseria meningitidis among Freshmen in a University Dormitory in Korea Areum Durey,1* Song-Mee Bae, 2 * Hye-Jin Lee,3 So-Yun Nah,1 Mijeong Kim,1 Ji Hyeon Baek, 1 Yeon-Ho Kang,2 Moon-Hyun Chung, 1 and Jin-Soo Lee1 Departments of 1Internal Medicine and 3Infection Control Service, Inha University Hospital, Incheon; 2Division of Bacterial Respiratory Infections, Centers for Infectious Diseases, National Institute of Health, Korea Centers for Disease Control and Prevention, Seoul, Korea. Received: May 18, 2011 Revised: July 25, 2011 Accepted: July 26, 2011 Corresponding author: Dr. Jin-Soo Lee, Department of Internal Medicine, Inha University Hospital, 7-206 Sinheung-dong 3-ga, Jung-gu, Incheon 400-711, Korea. Tel: 82-32-890-3616, Fax: 82-32-882-6578 E-mail: ljinsoo@medimail.co.kr *Areum Durey and Song-Mee Bae contributed equally to this work. ∙ The authors have no financial conflicts of interest. © Copyright: Yonsei University College of Medicine 2012 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non- Commercial License (http://creativecommons.org/ licenses/by-nc/3.0) which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose: Neisseria meningitidis is a leading cause of bacterial meningitis in young adults. University students, especially those living in dormitories, have been known to be at increased risk of meningococcal disease. We performed a longitu- dinal study to determine the carriage rates of N. meningitidis and the changes thereof. Materials and Methods: We recruited Inha University freshmen who were, at that time, admitted to a student dormitory. A pharyngeal swab was taken from all participant who were also asked to complete a questionnaire. This was re- peated four weeks later. Results: A total of 136 students were enrolled at the first culture. After four weeks, 128 students were enrolled, including 106 re-partici- pants. The overall carriage rates changed from 11.8% to 14.1%. In analysis of the 106 re-participants, “visiting to pubs” was associated with carriage of N. meningi- tis for both the first (p=0.047) and second cultures (p=0.026). Serogroup C was found to be the most frequent serogroup (5 isolates), while 3 isolates were found from serogroup B. The most prevalent PorA types were P1.22,14-6 (4 isolates) and P1.19,15 (3 isolates). The DNA sequences of PorA VR2 were changed in 2 students during prolonged carriage. Conclusion: The meningococcal carriage rate among first year university students who resided in a dormitory did not significant- ly increase over 4-week interval between cultures, which is markedly different from those reported in Western studies. Close social contact appeared to be related with carriage. Our data also revealed diversity in PorA types, suggesting the possi- bility of rapid mutation of the PorA gene during the 4-week interval. Key Words: Neisseria meningitidis, meningococcus, carriage, serogroup, PorA INTRODUCTION Neisseria meningitidis is a leading cause of bacterial meningitis in young adults.1 It has been known that bringing together groups of young adults, such as military recruits, is associated with epidemic meningococcal disease. The congregation of students on university campuses, and in particular those living in university dormi- tories, may share some of the same characteristics of concern with meningococcal 742 Yonsei Med J http://www.eymj.org Volume 53 Number 4 July 2012