Serotype distribution and resistance to beta-lactams of Streptococcus pneumoniae isolated from children in Beijing, Shanghai and Guangzhou, 2000 - 2002 / 中华儿科杂志

<p><b>OBJECTIVE</b>The present study was designed to investigate the situation of serotype distribution and beta-lactam antibiotics resistance of Streptococcus pneumoniae (S. pneumoniae) isolated from Chinese children, and to further understand the significance of vaccine for preventing infection caused by the bactria and controlling the resistance to antibiotics.</p><p><b>METHODS</b>Nasopharageal swab specimens were collected from randomly selected less than 5-year-old out-patients with upper respiratory infection in Beijing, Shanghai and Guangzhou, 2000 - 2002. Capsular typing was performed by the Quellung reaction tested using a simplified chessboard system for typing of S. pneumoniae. The coverage rate of the 7-valent pneumococcal conjugate vaccine (4, 6B, 9V, 14, 18C, 19F and 23F) was calculated. Antibiotic susceptibility was determined by E-test MIC method for beta-lactam antibiotics (penicillin, amoxicillin/clavulanic acid, cefaclor, cefuroxime and ceftriaxone).</p><p><b>RESULTS</b>Totally 625 pneumococcal strains were typed. Serogroup 19, including 121 strains, was the most frequent serogroup observed (19.4%). Other frequently observed serotypes/serogroups in decreasing order of frequency were serotype/serogroups 23 (15.4%), 6 (13.3%), 14 (6.6%) and 15 (4.3%). Of all these isolates, about 57.6% (360/625) were in the 7-valent conjugate vaccine. Only 1, 6 and 12 strains were serotypes/serogroups 4, 9 and 18, respectively. The coverage rate for the 7-valent vaccine of penicillin nonsusceptible S. pneumoniae (PNSP) was higher than penicillin susceptible S. pneumoniae (PSSP) (73.2% and 46.1%). Serogroups 19 and 23, without other serotypes/serogroups, were significantly associated with PNSP (serogroup 19 accounted for 29.1% of PNSP and 12.2% of PSSP; serogroup 23 accounted for 23.8% of PNSP to 9.2% of PSSP). Overall, 140 strains (22.4%) could not be typed by using the chessboard system, and 117 strains (18.7%) were identified as other 28 kinds of serotype/serogroup. The strains showed different resistance change for beta-lactam antibiotics according to different serotype/serogroup during the three years.</p><p><b>CONCLUSIONS</b>Serotype/Serogroup 19, 23, 6, 14 and 15 were the common types among the pneumococcal strains isolated from Chinese children. Serogroups 19 and 23 were significantly associated with PNSP. The 7-valent pneumococcal conjugate vaccine could cover most of the islotes.</p>

Molecular epidemiology of penicillin-nonsusceptible Streptococcus pneumoniae in Beijing, China, 2000-2002 / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the molecular epidemiology of the penicillin-nonsusceptible Streptococcus pneumoniae (PNSP) in Beijing, China.</p><p><b>METHODS</b>The resistant profile of 63 PNSP strains isolated from children with upper respiratory infection in the outpatient department from 2000 to 2002 was analyzed. The isolates were compared by detecting restriction fragment length polymorphism (RFLP) of the penicillin-binding protein (PBP) genes pbp1a, pbp2b and pbp2x and by applying chromosomal macrorestriction patterns detected by pulsed-field gel electrophoresis (PFGE).</p><p><b>RESULTS</b>Sixty-one (96.8%) out of the 63 PNSP strains were multidrug-resistant Streptococcus pneumoniae (Sp). Overall, 16 resistance profiles were found, 14 of which were multidrug resistant profiles. Seven (33.3%), 6 (24.0%) and 8 (47.1%) strains resistant to one of cephalosporins were respectively isolated in 2000, 2001 and 2002, indicating an increasing trend but without any statistical significance (chi(2) = 2.42, P > 0.05). The RFLP results showed 8, 9 and 18 genotypes of pbp1a, pbp2b and pbp2x, respectively. A total of 30 patterns were found according to the three pbps types. And clearly, the most common 5 patterns had main resistant profiles. In the mean time, 35 different PFGE types were elucidated and the 9 PFGE types, with each consisting of more than 2 strains, covered 59% (37/63) of all isolates. One of the 9 PFGE type included 2 strains, both possibly related to each other, but one of them was detected to be the same PFGE pattern with clones prevalent in Asia, Vietnam-19 serogroup, Singapore-19 serogroup, Taiwan-19 serogroup, and the other was the same as that in Korea-19 serogroup.</p><p><b>CONCLUSION</b>Multidrug resistance is very common among PNSP isolates in Beijing. The spread of a few multidrug resistant clones is an important factor for the prevalence of PNSP. It deserves the concern that the resistant clones spread in Asia have been found in Beijing.</p>