Proceedings of The First Current Topic in Infectious Diseases
Serotype Distribution of Invasive and Noninvasive Strains of Pneumococci in Hong Kong
The capsular polysaccharide is a major virulence factor in the pathogenesis of invasive pneumococcal disease. On the basis of the capsular specificity, the pneumococci can be grouped into about 90 serogroups and serotypes (SGTs). While much is known about the SGT distribution of S. pneumoniae isolates in the Western countries, the situation in Asian countries is unclear.16 To determine the coverage of the 7-valent conjugate vaccine for invasive and noninvasive isolates in Hong Kong, the capsular SGT of 721 nonduplicate isolates of S. pneumoniae from diverse sources were determined by the Quellung method.15 Of the 721 isolates, 383 isolates were obtained from the nasopharynx (NP) of children age between two to six years, attending day care centers or kindergartens during a territory-wide surveillance in 2000, 140 isolates were obtained from respiratory tract specimens of hospitalized patients in seven hospitals in 1998, and 199 isolates were obtained from blood (187) or CSF (12) of patients hospitalized in four hospitals between 1996 to 2000. SGT included in the 7-valent pneumococcal conjugate vaccine were 4, 6B, 9V, 14, 18C, 19F and 23F. At all age groups, the most common serotypes were 6B, 19F and 23F. Of the isolates from young children, the 7-valent conjugate vaccine respectively covered 65%, 88% and 88% of the NP, respiratory and invasive isolates. Our data showed that distribution of SGT among invasive and noninvasive isolates among young children in Hong Kong is similar to those reported in the United States. On the basis of the SGT distribution, the recent 7-valent pneumococcal conjugate vaccine could offer protection against many of the invasive pneumococcal infections among children in this locality.
1. Yang Y, Shen X, Jiang Z, et al. Study on Haemophilus influenzae type b diseases in China: the past, present and future. Pediatr Infect Dis J 1998;17:S159-S165.
2. Lau YL, Yung R, Low L, Sung R, Leung CW, Lee WH. Haemophilus influenzae type b infections in Hong Kong. Pediatr Infect Dis J 1998;17:S165-S169.
3. Lau YL. Haemophilus influenzae type b diseases in Asia. Bull.World Health Organ 1999;77:867-8.
4. Levine OS, Schwartz B, Pierce N, Kane M. Development, evaluation and implementation of Haemophilusinfluenzae type b vaccines for young children in developing countries: current status and priority actions. Pediatr Infect Dis J 1998;17:S95-S113.
5. Heath PT. Haemophilus influenzae type b conjugate vaccines: a review of efficacy data. Pediatr Infect Dis J 1998;17:S117-S122.
6. American Academy of Pediatrics. American Academy of Pediatrics. Committee on Infectious Diseases. Policy statement: recommendations for the prevention of pneumococcal infections, including the use of pneumococcal conjugate vaccine (Prevnar), pneumococcal polysaccharide vaccine, and antibiotic prophylaxis. Pediatrics 2000;106: 362-6.
7. Hausdorff WP, Bryant J, Kloek C, Paradiso PR, Siber GR. The contribution of specific pneumococcal serogroups to different disease manifestations: implications for conjugate vaccine formulation and use, part II. Clin Infect Dis 2000;30:122-40.
8. Hausdorff WP, Bryant J, Paradiso PR, Siber GR. Which pneumococcal serogroups cause the most invasive disease: implications for conjugate vaccine formulation and use, part I. Clin Infect Dis 2000;30:100-21.
9. Yang Y, Leng Z, Lu D. Pediatric Haemophilus influenzae type b meninngitis in Hefei city: an epidemiologic study. Chung Hua I. Hsueh Tsa Chih 1998;78:251-3.
10. Levine OS, Liu G, Garman RL, Dowell SF, Yu S, Yang YH. Haemophilus influenzae type b and Streptococcus pneumoniae as causes of pneumonia among children in Beijing, China Emerg Infect Dis 2000;6:165-70.
11. Yang Y, Shen X, Vuori-Holopainen E, et al. Sero-etiology of acute lower respiratory infections among hospitalized children in Beijing. Pediatr Infect Dis J 2001;20:52-8.
12. Lau YL, Low LC, Yung R, et al. Invasive Haemophilus influenzae type b infections in children hospitalized in Hong Kong, 1986-1990. Hong Kong Hib Study Group. Acta Paediatr 1995;84:173-6.
13. Sung RY, Cheng AF, Chan RC, Tam JS, Oppenheimer SJ. Epidemiology and etiology of pneumonia in children in Hong Kong. Clin Infect Dis 1993;17:894-6.
14. Ho PL, Que TL, Tsang DN, Ng TK, Chow KH, Seto WH. Emergence of fluoroquinolone resistance among multiply resistant strains of Streptococcus pneumoniae in Hong Kong. Antimicrob. Agents Chemother 1999;43:1310-3.
15. Ho PL, Yam WC, Cheung TKM, et al. Rapid rise of fluoroquinolone resistance among Streptococcus pneumoniae in Hong Kong linked to acquisition of fluoroquinolone resistance by the locally dominant Spanish 23F clone. Emerg Infect Dis 2001. In press.
16. Luey KY, Kam KM. Vaccine coverage of Streptococcus pneumoniae in Hong Kong with attention to the multiple-antibiotic-resistant strains. Vaccine 1996;14:1573-80.