Wei Shi1, Kai Zhou2, Lin Yuan1, Qinghong Meng1, Fang Dong3, Wei Gao1, Changhui Chen4, Denian Wen5, Kaihu Yao6. 1. Key Laboratory of Major Diseases in Children, National Clinical Research Center for Respiratory Diseases, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Laboratory of Microbiology, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, 56 Nan Lishi Road, 100045 Beijing, China. 2. Infective Department, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Gulou District, Nanjing, Jiangsu Province, China. 3. Clinical Laboratory, Beijing Children's Hospital, Capital Medical University, 56 Nan Lishi Road, 100045 Beijing, China. 4. Youyang Hospital, The First Affiliated Hospital of Chongqing Medical University, People's Hospital of Chongqing Youyang County, 102 Tao-hua-yuan Road, 409899 Youyang, Chongqing, China. 5. People's Hospital of Zhongjiang County, 96 Da-bei Street, 618100 Zhongjiang, Sichuan, China. 6. Key Laboratory of Major Diseases in Children, National Clinical Research Center for Respiratory Diseases, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Laboratory of Microbiology, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, 56 Nan Lishi Road, 100045 Beijing, China. Electronic address: yaokaihu@bch.com.cn.
Abstract
OBJECTIVES: Streptococcus pneumoniae is an important pathogen in infectious diseases worldwide, and serogroup 6 S. pneumoniae strains are very common in China. This study investigated the serotype distribution, antibiotic resistance patterns and molecular characteristics of 215 serogroup 6 S. pneumoniae isolates collected from hospitalised children in China during 2013-2016. METHODS: Serotypes were determined using the Quellung reaction with antisera. Antibiotic resistance against 11 antimicrobials was tested by Etest or the disk diffusion method. Sequence types (STs) were assigned using multilocus sequence typing (MLST). Data analysis was performed with WHONET 5.6 software. RESULTS: The percentages of serotype 6A, 6B, 6C and 6D among the 215 serogroup 6 isolates were 50.7% (109/215), 36.3% (78/215), 12.6% (27/215) and 0.5% (1/215), respectively. All isolates were susceptible to levofloxacin and were resistant to erythromycin. No isolate was resistant to parenteral penicillin, but the intermediate and resistant rates reached 72.6% (156/215) and 5.1% (11/215), respectively, based on the oral breakpoint. Sixty-seven STs were detected, with 14 STs being newly assigned. The most common clonal complexes (CCs) were CC3173 (26.5%; 57/215), CC9789 (13.5%; 29/215), CC90 (13.0%; 28/215) and CC902 (8.8%; 19/215), and the non-susceptibility rates of these four CCs against penicillin and cefuroxime (penicillin, 98.2%, 100%, 100% and 100%, respectively; cefuroxime, 98.2%, 100%, 96.4% and 94.7%, respectively) were higher than the overall level of serogroup 6 isolates (penicillin, 77.7%; cefuroxime, 70.2%). CONCLUSIONS: Serotype 6A is the most common serotype of serogroup 6 S. pneumoniae strains in Chinese children, and different CCs/STs express diverse antibiotic resistance patterns.
OBJECTIVES:Streptococcus pneumoniae is an important pathogen in infectious diseases worldwide, and serogroup 6 S. pneumoniae strains are very common in China. This study investigated the serotype distribution, antibiotic resistance patterns and molecular characteristics of 215 serogroup 6 S. pneumoniae isolates collected from hospitalised children in China during 2013-2016. METHODS: Serotypes were determined using the Quellung reaction with antisera. Antibiotic resistance against 11 antimicrobials was tested by Etest or the disk diffusion method. Sequence types (STs) were assigned using multilocus sequence typing (MLST). Data analysis was performed with WHONET 5.6 software. RESULTS: The percentages of serotype 6A, 6B, 6C and 6D among the 215 serogroup 6 isolates were 50.7% (109/215), 36.3% (78/215), 12.6% (27/215) and 0.5% (1/215), respectively. All isolates were susceptible to levofloxacin and were resistant to erythromycin. No isolate was resistant to parenteral penicillin, but the intermediate and resistant rates reached 72.6% (156/215) and 5.1% (11/215), respectively, based on the oral breakpoint. Sixty-seven STs were detected, with 14 STs being newly assigned. The most common clonal complexes (CCs) were CC3173 (26.5%; 57/215), CC9789 (13.5%; 29/215), CC90 (13.0%; 28/215) and CC902 (8.8%; 19/215), and the non-susceptibility rates of these four CCs against penicillin and cefuroxime (penicillin, 98.2%, 100%, 100% and 100%, respectively; cefuroxime, 98.2%, 100%, 96.4% and 94.7%, respectively) were higher than the overall level of serogroup 6 isolates (penicillin, 77.7%; cefuroxime, 70.2%). CONCLUSIONS: Serotype 6A is the most common serotype of serogroup 6 S. pneumoniae strains in Chinese children, and different CCs/STs express diverse antibiotic resistance patterns.