PNEUMOCOCCI CAUSING INVASIVE DISEASE IN NEW-ZEALAND, 1987-94 - SEROGROUP AND SEROTYPE COVERAGE AND ANTIBIOTIC RESISTANCES

Aims. Development of polysaccharide-conjugated pneumococcal vaccines, prompted by the ineffectiveness of the current 23-valent vaccine for y oung children, requires an understanding of the pneumococci causing in vasive disease worldwide. We have reviewed the capsular serogroups and serotypes, and the antibiotic resistances of pneumococci identified f rom invasive disease in New Zealand, for the period 1987-94. Methods. Pneumococci referred from invasive disease were serogrouped and seroty ped using the Neufeld test and allocated a capsular type according to the Danish system of nomenclature. Antibiotic susceptibility testing w as performed by an agar dilution method following National Committee f or Clinical Laboratory Standards (NCCLS) guidelines. Results. A total of 1506 pneumococci were examined of which, 584 (39.8%) were sourced f rom children less than 15 years and 573 (39%) were from adults 60 year s or greater. The majority (88.3%) were from blood cultures. In descen ding order of frequency serogroups or serotypes 14, 19, 6, 9, 23, 7, 4 and 1 were common to all age-groups but serogroups 6 and 18 were sign ificantly (p<0.001) associated with children under 15 years and seroty pe 3 with adult patients. Penicillin resistance was demonstrated by 22 (1.4%) isolates, five of which showed high level resistance (MIG grea ter than or equal to 2 mg/L) and multidrug resistance. Fourteen percen t of all isolates were resistant to at, least one antibiotic and serog roups 23, 6, 18, 19 and serotype 14 accounted for 82.6% of these resis tant isolates. Conclusions. The serogroups and serotypes found mast fr equently associated with pneumococcal disease, and antibiotic resistan ce, were consistent with those described overseas. Continuing surveill ance of antibiotic resistances and serotypes of pneumococci causing in vasive disease is recommended.