Transmission of Bordetella holmesii during Pertussis Outbreak, Japan

Hajime Kamiya, Nao Otsuka, Yuka Ando, Fumito Odaira, Shuji Yoshino, Kimiko Kawano, Hirokazu Takahashi, Toshihide Nishida, Yoshio Hidaka, Hiromi Toyoizumi-Ajisaka, Keigo Shibayama, Kazunari Kamachi

, Tomimasa Sunagawa, Kiyosu Taniguchi, and Nobuhiko Okabe

Author affiliations: National Institute of Infectious Diseases, Tokyo, Japan (H. Kamiya, N. Otsuka, Y. Ando, F. Odaira, H. Toyoizumi-Ajisaka, K. Shibayama, K. Kamachi, T. Sunagawa, K. Taniguchi, N. Okabe); Miyazaki Prefectural Institute for Public Health and Environment, Miyazaki, Japan (S. Yoshino, K. Kawano); Takahashi Clinic, Miyazaki (H. Takahashi); and Nobeoka Public Health Center, Miyazaki (T. Nishida, Y. Hidaka)

Abstract

We describe the epidemiology of a pertussis outbreak in Japan in 2010–2011 and Bordetella holmesii transmission. Six patients were infected; 4 patients were students and a teacher at the same junior high school. Epidemiologic links were found between 5 patients. B. holmesii may have been transmitted from person to person.

Bordetella holmesii, a small gram-negative coccoid bacillus that was first reported in 1995 (1), was originally identified as a member of the Centers for Disease Control and Prevention nonoxidizer group 2. The organism is associated with bacteremia, endocarditis, and pneumonia, usually in patients with underlying disorders such as asplenia or sickle cell anemia, and has been isolated from blood and sputum samples (1–5). B. holmesii may also be responsible for causing symptoms similar to those of pertussis (whooping cough) in otherwise healthy patients (6). Large surveillance studies in the United States and Canada have shown that the organism was detected in nasopharyngeal swab (NPS) specimens of patients with pertussis-like symptoms (7,8). Although humans may be infected with B. holmesii, transmission of B. holmesii between humans has not yet been fully elucidated.

Pertussis is a highly contagious disease caused by the bacterium B. pertussis. The organism is known to be transmitted from person to person by airborne droplets (9). During a recent pertussis outbreak, we conducted a laboratory-based active surveillance study and detected 76 suspected cases of pertussis. Among these cases, we identified not only B. pertussis infection but also B. holmesii infection. The purpose of this study was to describe the epidemiology of the pertussis outbreak and to determine the epidemiologic relatedness of B. holmesii transmission.