Serotypes and Penicillin Susceptibility of Streptococcus pneumoniae Isolated from Clinical Specimens and Healthy Carriers of Korean Children

PURPOSE: Pneumoccocus is one of the most important causes of invasive infection through the childhood period and the prevelance of antibiotics resistance of pneumococcus is increasing worldwide. A 7-valent conjugate vaccine has been developed. It is important to know the prevalence of each serotype of pneumococci in the countries where the vaccine is used to estimate the coverage rate by the vaccine. METHODS: One hundred and twenty seven strains of clinical isolates and 72 strains from healthy carriers recovered from Korean children during the period from 1997 to 2002 were subjected to determination of serotype by Quellung reaction and penicillin susceptibility with oxacillin disc diffusion test. RESULTS: Forty-three per cent of clinical isolates were obtained from children under two years of age. Thirty strains(24%) were isolated from normally sterile body fluids. The frequent serotypes were 19F, 19A, 23F, 6A, 6B and 9V. Fifty-six per cent of the clinical isolates were represented in the current 7-valent protein conjugate pneumococccal vaccine, and 84% when the cross-reactive serotypes were included. Frequent serotypes of strains isolated from one to five year-old healthy children were 19F, 14, 11A, 23F, 18C, and 19A. Seventy-one per cent of the carrier strains were included in the 7-valent vaccine. Ninety-three per cent of the clinical isolates and 86% of carrier strains were not susceptible to penicilline. CONCLUSION: Fifty-six to 84% of pneumococci recovered from Korean children are covered by the current 7-valent protein conjugate pneumococcal vaccine and the prevalence of penicillin resistance was very high.

Surveillance for antimicrobial resistance of Streptococcus pneumoniae among children attending day care center in Seoul, Korea / 대한임상병리학회지

BACKGROUND: Multidrug-resistant Streptococcus pneumoniae occasionally cause treatment failure in various pneumococcal infection in children. The pneumococcal strains carried at the nosopharynx are frequently found at the time of invasive infection in one individual. We investigated the prevalence of nasopharyngeal carriage of S. pneumoniae and antibiotic susceptibility patterns among children attending day care center and compared the rates of antibiotic resistance of those strains with strains recovered from clinical specimens of patients at a tertiary care hospital. METHODS: Two-hundred nine children from 3 centers distributed at Jong-Ro area of Seoul, Korea were enrolled from May to June, 1998. Swabs were obtained from posterior nasopharynx and cultured onto tryptic soy agar containing 5% sheep blood without and with 10 microgram/mL gentamicin for 24 hours. Clinical isolates included the non-invasive isolates from sputum, ear discharge and sinus aspirate and the invasive isolates from cerebrospinal fluid and blood. Antimicrobial susceptibilities were determined with E-test and agar dilution method. RESULTS: The overall prevalence of nasopharyngeal carriage was 32.5%(68/209). The children >4, 5< OR = years of age have the highest carriage rate(36.7%). But there were no significant differences of prevalence in gender and centers. The prevalences of decreased antibiotic susceptibilities in the nasopharyngeal isolates and clinical isolates were, respectively: penicillin(75% vs 86%, NS); cefotaxime(20% vs 48%, p<0.05); multiresistance(57% vs 86%, p<0.05). Younger the age and female in gender, higher the resistance rate to penicillin. CONCLUSIONS: There was no significant difference in antimicrobial resistance of pneumococci between healthy nosopharyngeal carriages and clinical isolates causing invasive or non-invasive infections. The results acquired from this surveillence would provide a useful guide in an appropriate choice of antimicrobial agents for management of pneumococcal diseases.