Vaccine coverage of Streptococcus pneumoniae in Hong Kong with attention to the multiple-antibiotic-resistant strains.

Two hundred and four isolates of Streptococcus pneumoniae obtained from children and adults in Hong Kong between January 1993 and May 1995 were analysed for serotype and serogroup (SGT) distribution and antibiotic resistance. The predominant serogroups and serotypes (SGTs) were 23, 19, 6 and 3 which accounted for 19.6%, 16.7%, 15.2% and 7.8% of all isolates, respectively. Altogether, 83.8% of all isolates were related to the current 23-valent pneumococcal vaccine. Sixty-six (32.4%) isolates demonstrated multiple antibiotic resistance, defined as resistance to three or more different antibiotics. SGTs 19, 23 and 6 occurred significantly more frequently in this group than in the groups with less antibiotic resistance (97% vs 30%; P < 0.001). Isolates shown to be resistant to all five antibiotics tested (penicillin, chloramphenicol, ceftriaxone, macrolides and tetracycline) were found only in serogroups 6, 19 and 23. The 23-valent vaccine should cover 84.4% (152/180) of SGTs with one or more antibiotic resistance in all age groups, while the proposed 9-valent global pneumococcal conjugate vaccine should cover 85.0% (34/40) of such SGTs in children.

Emergence of multiple-antibiotic-resistant Streptococcus pneumoniae in Hong Kong.

Two hundred four strains of Streptococcus pneumoniae isolated in Hong Kong from January 1993 to May 1995 were analyzed for their antibiotic susceptibilities and epidemiological patterns. The ages of the patients from whom the strains were isolated from 1 month to 93 years (median, 53 years); the male-to-female ratio was 2.8, with a predominance of males in the pediatric group. Fifty-nine (28.9%) strains showed reduced penicillin susceptibility, including 40 (19.6%) with frank penicillin resistance (MIC > 1 microgram/ml). Tetracycline resistance alone was found in 28.4% of strains. Isolates with reduced penicillin susceptibility were more common in children than adults (40 versus 23.9%, P = 0.02), and penicillin resistance rates were significantly higher in hospitalized patients than in outpatients (39.5 versus 12.5%; p < 0.001). Penicillin resistance was significantly associated with resistance to ceftriaxone, erythromycin, and tetracycline (P < 0.01) but not with ofloxacin or vancomycin (P = 0.5). Among eight different patterns of resistance to three or more antibiotics, the commonest one (14.2%) was multiple resistance to penicillin, chloramphenicol, ceftriaxone, erythromycin, and tetracycline. Emergence of multiple-antibiotic-resistant S. pneumoniae reflects changes in the pneumococcus itself and the general indiscriminate use of antibiotics in treatment of respiratory infections in Hong Kong.