Objective:To characterize the minimal inhibitory concentration (MIC) of macrolides against clinical Mycoplasma pneumoniae (MP) isolates and to investigate the significance of 23S rRNA mutations. Methods:Cross-sectional study.A total of 288 clinical MP strains preserved in the laboratory from 2016 to 2021 were taken for macrolide resistance gene testing and the evaluation of in vitro susceptibility to Azithromycin and Erythromycin.MIC 50 and MIC 90 values were calculated separately for macrolide-susceptible and -resistant strains. Results:All 288 MP strains underwent the test of in vitro susceptibility to Azithromycin, while 86 of them were additionally tested for Erythromycin.Among these strains, 22 strains were Azithromycin-sensitive, and 266 strains were Azithromycin-resistant.A2063G mutations were detected in 260 (97.7%) strains, while A2064G mutations were detected in 6 (2.3%) strains.Azithromycin-resistant strains had an MIC 50 of 128.000 μg/mL and an MIC 90 of 512.000 μg/mL, with the MIC ranging between 16.000 and 512.000 μg/mL.Seven strains were sensitive and 79 strains were resistant to Erythromycin.Among Erythromycin-resistant strains, A2063G mutations were detected in 73 (92.4%) strains, while A2064G mutations were detected in 6 (7.6%) strains.Erythromycin-resistant strains had an MIC 50 of 256.000 μg/mL and an MIC 90 of 512.000 μg/mL, with the MIC ranging between 64.000 and 1 024.000 μg/mL. Conclusions:A2063G and A2064G mutations in the 23S rRNA gene of MP are associated with high-level in vitro resistance to Azithromycin and Erythromycin, significantly limiting the clinical effectiveness of these antibiotics.Early resistance gene testing is recommended for suspected MP patients, which can help optimize the treatment, improve prognosis, and prevent resistance spread.

Objective:To characterize the minimal inhibitory concentration (MIC) of macrolides against clinical Mycoplasma pneumoniae (MP) isolates and to investigate the significance of 23S rRNA mutations. Methods:Cross-sectional study.A total of 288 clinical MP strains preserved in the laboratory from 2016 to 2021 were taken for macrolide resistance gene testing and the evaluation of in vitro susceptibility to Azithromycin and Erythromycin.MIC 50 and MIC 90 values were calculated separately for macrolide-susceptible and -resistant strains. Results:All 288 MP strains underwent the test of in vitro susceptibility to Azithromycin, while 86 of them were additionally tested for Erythromycin.Among these strains, 22 strains were Azithromycin-sensitive, and 266 strains were Azithromycin-resistant.A2063G mutations were detected in 260 (97.7%) strains, while A2064G mutations were detected in 6 (2.3%) strains.Azithromycin-resistant strains had an MIC 50 of 128.000 μg/mL and an MIC 90 of 512.000 μg/mL, with the MIC ranging between 16.000 and 512.000 μg/mL.Seven strains were sensitive and 79 strains were resistant to Erythromycin.Among Erythromycin-resistant strains, A2063G mutations were detected in 73 (92.4%) strains, while A2064G mutations were detected in 6 (7.6%) strains.Erythromycin-resistant strains had an MIC 50 of 256.000 μg/mL and an MIC 90 of 512.000 μg/mL, with the MIC ranging between 64.000 and 1 024.000 μg/mL. Conclusions:A2063G and A2064G mutations in the 23S rRNA gene of MP are associated with high-level in vitro resistance to Azithromycin and Erythromycin, significantly limiting the clinical effectiveness of these antibiotics.Early resistance gene testing is recommended for suspected MP patients, which can help optimize the treatment, improve prognosis, and prevent resistance spread.

Adult ; Aged ; Aged, 80 and over ; China ; epidemiology ; Female ; Hemorrhagic Fevers, Viral ; epidemiology ; Hospitalization ; Humans ; Male ; Middle Aged

The digital music editor software "Cool Edit Pro 2.0" is used to design a virtual hearing testing system. This system has following advantages. First, its signal frequency can be set at will. Second, its dynamic range of signal intensity can reach up to 80dB. Third, the measuring accuracy of decibel value may reach 0.1dB. Forth, the system can be used in single and dual channel measurements. Last but not least, it can carry on data processing and drawing along with the same computer.
Audiometry ; instrumentation ; Computers ; Hearing Tests ; instrumentation ; Music ; Signal Processing, Computer-Assisted ; Software ; User-Computer Interface