Jing Li1, Liyong Liu2, Lihua He2, Fanliang Meng2, Jianzhong Zhang2, Fei Zhao3. 1. Office of Laboratory Management, Chinese Center for Disease Control and Prevention, Beijing 102206, China. 2. National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing 102206, China. 3. National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing 102206, China. Electronic address: zhaofei@icdc.cn.
Abstract
OBJECTIVES: The aim of this study was to investigate the biological characteristics and effect of antibiotic treatment for different Mycoplasma pneumoniae isolates co-infecting the same patient. METHODS: Two throat swab specimens from a single patient, on the day of admission (Sp01) and discharge (Sp13), were liquid cultured and subcultured on agar medium to obtain M. pneumoniae monoclones. The 23S rRNA gene of 50 monoclones from specimens Sp01 and Sp13 were analysed. Real-time PCR assay was used for detection of mutations and genotyping. Two typical monoclones were isolated for antimicrobial susceptibility testing. RESULTS: Genotype 1 monoclones accounted for 70.8% (34/48) in Sp01 and 95.7% (44/46) in Sp13. All genotype 1 monoclones were of the 4-5-7-2 multilocus variable-number tandem-repeat analysis (MLVA) type, while all genotype 2 monoclones were 3-5-6-2 MLVA type. The genotype 1 monoclone, which harboured the A2063G mutation in 23S rRNA gene, was resistant to erythromycin and azithromycin in vitro, whilst genotype 2, which did not carry the mutation, was susceptible to macrolides. The proportion of macrolide-resistant M. pneumoniae monoclones in the specimen cultures collected rose from 70.8% to 95.7% at the time of discharge. CONCLUSION: This is the first report on the isolation of macrolide-resistant and -susceptible strains of M. pneumoniae from the same patient. After treatment, the proportion of macrolide-resistant M. pneumoniae increased, but the patient still carried viable macrolide-susceptible strains, meaning that the macrolide-susceptible strains did not disappear completely.
OBJECTIVES: The aim of this study was to investigate the biological characteristics and effect of antibiotic treatment for different Mycoplasma pneumoniae isolates co-infecting the same patient. METHODS: Two throat swab specimens from a single patient, on the day of admission (Sp01) and discharge (Sp13), were liquid cultured and subcultured on agar medium to obtain M. pneumoniae monoclones. The 23S rRNA gene of 50 monoclones from specimens Sp01 and Sp13 were analysed. Real-time PCR assay was used for detection of mutations and genotyping. Two typical monoclones were isolated for antimicrobial susceptibility testing. RESULTS: Genotype 1 monoclones accounted for 70.8% (34/48) in Sp01 and 95.7% (44/46) in Sp13. All genotype 1 monoclones were of the 4-5-7-2 multilocus variable-number tandem-repeat analysis (MLVA) type, while all genotype 2 monoclones were 3-5-6-2 MLVA type. The genotype 1 monoclone, which harboured the A2063G mutation in 23S rRNA gene, was resistant to erythromycin and azithromycin in vitro, whilst genotype 2, which did not carry the mutation, was susceptible to macrolides. The proportion of macrolide-resistant M. pneumoniae monoclones in the specimen cultures collected rose from 70.8% to 95.7% at the time of discharge. CONCLUSION: This is the first report on the isolation of macrolide-resistant and -susceptible strains of M. pneumoniae from the same patient. After treatment, the proportion of macrolide-resistant M. pneumoniae increased, but the patient still carried viable macrolide-susceptible strains, meaning that the macrolide-susceptible strains did not disappear completely.