Serotype and antimicrobial resistance patterns of Streptococcus pneumoniae isolated from Taiwanese children: comparison of nasopharyngeal and clinical isolates.

This report describes the serotypes and antimicrobial resistance patterns of 860 strains of Streptococcus pneumoniae isolated from nasopharyngeal (NP) carriers and clinical specimens collected from Taiwanese children during the years 1997 to 2003. The 6 most common serotypes/groups were 23F, 19F, 6B, 14, 6A, and 3. These accounted for 652/716 (91.1%) of the NP and 131/144 (91.0%) of the clinical isolates. Serotype 23F was the most common isolate in the NP carriers (25.7%, 184/716). Serogroup14 was most common in the clinical isolates (29.2%, 42/144) and the most frequent invasive isolate (43.4%, 33/76). It was more frequently associated with invasive infection than all other serotypes/groups (odds ratio = 7.2; 95% confidence interval, 4.16-12.46; P < .0001). Resistance to macrolides was high in all serotypes/groups, which ranged from 70% to 97%. Resistance to penicillin varied among the 6 leading serotypes/groups, ranging from 3% in serogroup 3 to 99% in serotype 19F. Serotype 23F was most likely to be multidrug resistant to penicillin, macrolides, and chloramphenicol compared with all others (107/150 [71%] versus 105/461 [23%], P < .0001). The potential coverage by the pentavalent and heptavalent vaccines was 83% for all isolates, but was significantly lower for NP than clinical isolates (81% versus 92%, P< .01). These findings provide baseline data to compare trends in the distribution of pneumococcal serotypes and antibiotic resistance patterns with the introduction of childhood pneumococcal vaccination in Taiwan and other countries.

High carriage rate of high-level penicillin-resistant Streptococcus pneumoniae in a Taiwan kindergarten associated with a case of pneumococcal meningitis.

BACKGROUND: The Taiwan19F-14 Streptococcus pneumoniae clone and its variants are being found with increasing frequency in the Asia-Pacific region. A 5-year old child with S. pneumoniae meningitis caused by a high-level penicillin resistant strain (MIC = 4 microg/ml) was admitted to a hospital in southern Taiwan. We carried out a study to determine the potential source of this strain. METHODS: Nasopharyngeal cultures were obtained from all children attending the same kindergarten as the index case. To determine their relatedness all isolates were compared by serotype, antimicrobial susceptibility profile and pulsed field gel electrophoresis (PFGE). RESULTS: A high proportion of the children including the index case (32/78, 41.0%) carried S. pneumoniae in their nasopharynx (NP). The most common serotype was 19F (13/32, 40.6%). The PFGE types of the 19F serotype isolates obtained from the patient's blood, CSF and NP were identical and were related to 11 other serotype 19F NP isolates including 10 that were indistinguishable from the Taiwan19F-14 clone. All 14 isolates had similar high-level penicillin and multi-drug resistance. The serotypes of the other 19 NP isolates included 6A (2), 6B (10), 23F (5), 9V (1) and 3 (1). The overall rate of penicillin resistance in these S. pneumoniae from these children was 87.5% (28/32), with an MIC50 of 2 and MIC90 of 4 ug/ml. In addition, multi-drug resistant-isolates (isolates resistant to 3 different classes of antimicrobials) accounted for 87.5% (28/32) of all isolates. CONCLUSION: The high carriage rate of high-level penicillin- and multi-drug- resistant S. pneumoniae in a kindergarten associated with a case of pneumococcal meningitis emphasizes the need for restraint in antibiotic use and consideration of childhood immunization with conjugate pneumococcal vaccine to prevent the further spread of resistant S. pneumoniae in Taiwan.

Pneumococcal infection in children: rational antibiotic choice for drug-resistant Streptococcus pneumoniae.

Streptococcus pneumoniae is one of the most common bacterial causes of otitis media, sinusitis, bacteremia, pneumonia and bacterial meningitis in the pediatric population. The resistance of S. pneumoniae to penicillin and other antimicrobial agents is increasing in many parts of the world. In Taiwan, extremely high prevalence (70%) of penicillin-resistant S. pneumoniae among children with nasopharyngeal carriage has been reported. The mechanism of resistance to penicillin is the alteration of penicillin binding protein (PBP) instead of the production of beta-lactamase. Thus beta-lactamase inhibitors are not the solution to the treatment of infections caused by penicillin-resistant S. pneumoniae. The adequate treatment of infections caused by penicillin-resistant S. pneumoniae should be based on (1) site of infection (2) degree of resistance. Currently, the MIC breakpoints for S. pneumoniae are divided to 2 categories; one for CNS infection and the other for non-CNS infections. For non-CNS infections caused by susceptible or intermediate S. pneumoniae, penicillin still remains the drug of choice with excellent bactericidal activity. Vancomycin should not be the first choice in treating all pneumococcal infections.