Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan
Abstract Background Nemonoxacin is a new quinolone with an antibacterial efficacy against methicillin-resistant Staphylococcus aureus (MRSA). Certain sequence types (STs) have been emerging in Taiwan, including fluoroquinolone-resistant ST8/USA300. It’s an urgent need to determine nemonoxacin suscep...
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BMC
2025-01-01
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| Series: | Annals of Clinical Microbiology and Antimicrobials |
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| Online Access: | https://doi.org/10.1186/s12941-024-00772-6 |
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| author | Pao -Yu Chen Mao-Wang Ho Po-Liang Lu Hung-Jen Tang Cheng Len Sy Jann-Tay Wang Taiwan Staphylococcus aureus Consortium (TSAC) |
| author_facet | Pao -Yu Chen Mao-Wang Ho Po-Liang Lu Hung-Jen Tang Cheng Len Sy Jann-Tay Wang Taiwan Staphylococcus aureus Consortium (TSAC) |
| author_sort | Pao -Yu Chen |
| collection | DOAJ |
| description | Abstract Background Nemonoxacin is a new quinolone with an antibacterial efficacy against methicillin-resistant Staphylococcus aureus (MRSA). Certain sequence types (STs) have been emerging in Taiwan, including fluoroquinolone-resistant ST8/USA300. It’s an urgent need to determine nemonoxacin susceptibility against ST8/USA300 and other emerging lineages, if any. Additionally, molecular characterization of nemonoxacin resistance among different lineages has yet to be defined. Methods Non-duplicated MRSA blood isolates from five hospitals during 2019–2020 were collected and genotyped by pulsed-field gel electrophoresis, and further correlated to their STs. Antimicrobial susceptibility testing for all antibiotics was performing by using Sensititre standard panel, except nemonoxacin by using agar dilution method. Selected isolates with nemonoxacin MICs ≥ 0.5 mg/mL were sequenced for quinolone resistance-determining regions (QRDRs). Results Overall, 915 MRSA isolates belonged to four major lineages, ST8 (34.2%), ST59 (23.5%), ST239 (13.9%), and clonal complex 45 (13.7%). Two-thirds of tested isolates were non-susceptible to moxifloxacin, especially ST8/USA300 and ST239. Of them, proportions of nemonoxacin non-susceptibility by a tentative clinical breakpoint (tCBP) of 1 µg/mL among four major lineages appeared to be different (P = 0.06) and highest in ST239 (22.2%), followed by ST8/USA300 (13.5%). Among 89 isolates sequenced, 44.1% of ST8 and all ST239 isolates had ≥ 3 amino acid substitutions (AAS) in gyrA/parC (group A) or 2 AAS in gyrA/parC with additional AAS in gyrB/parE (group B). Compared to other AAS patterns, isolates in group A had the greatest non-susceptible proportions to nemonoxacin (86.9%; overall/pair-wised comparisons, P < 0.05). Conclusions Our study confirmed ST8/USA300 MRSA has disseminated in Taiwan. Using a tCBP defined by a higher parenteral daily dosage, nemonoxacin retained potency against moxifloxacin non-susceptible isolates. Patterns of AAS in QRDRs among different lineages may contribute to difference of nemonoxacin susceptibility. |
| format | Article |
| id | doaj-art-73b6ca0949b3420da2d0d84e7af863ce |
| institution | Kabale University |
| issn | 1476-0711 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | BMC |
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| series | Annals of Clinical Microbiology and Antimicrobials |
| spelling | doaj-art-73b6ca0949b3420da2d0d84e7af863ce2025-01-19T12:13:29ZengBMCAnnals of Clinical Microbiology and Antimicrobials1476-07112025-01-0124111010.1186/s12941-024-00772-6Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in TaiwanPao -Yu Chen0Mao-Wang Ho1Po-Liang Lu2Hung-Jen Tang3Cheng Len Sy4Jann-Tay Wang5Taiwan Staphylococcus aureus Consortium (TSAC)Division of Infectious Diseases, Department of Internal Medicine, National Taiwan University HospitalDivision of Infectious Diseases, Department of Internal Medicine, China Medical University HospitalDivision of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University HospitalDivision of Infectious Diseases, Department of Internal Medicine, Chi Mei Medical CenterDivision of Infectious Diseases, Department of Internal Medicine, Kaohsiung Veteran General HospitalDivision of Infectious Diseases, Department of Internal Medicine, National Taiwan University HospitalAbstract Background Nemonoxacin is a new quinolone with an antibacterial efficacy against methicillin-resistant Staphylococcus aureus (MRSA). Certain sequence types (STs) have been emerging in Taiwan, including fluoroquinolone-resistant ST8/USA300. It’s an urgent need to determine nemonoxacin susceptibility against ST8/USA300 and other emerging lineages, if any. Additionally, molecular characterization of nemonoxacin resistance among different lineages has yet to be defined. Methods Non-duplicated MRSA blood isolates from five hospitals during 2019–2020 were collected and genotyped by pulsed-field gel electrophoresis, and further correlated to their STs. Antimicrobial susceptibility testing for all antibiotics was performing by using Sensititre standard panel, except nemonoxacin by using agar dilution method. Selected isolates with nemonoxacin MICs ≥ 0.5 mg/mL were sequenced for quinolone resistance-determining regions (QRDRs). Results Overall, 915 MRSA isolates belonged to four major lineages, ST8 (34.2%), ST59 (23.5%), ST239 (13.9%), and clonal complex 45 (13.7%). Two-thirds of tested isolates were non-susceptible to moxifloxacin, especially ST8/USA300 and ST239. Of them, proportions of nemonoxacin non-susceptibility by a tentative clinical breakpoint (tCBP) of 1 µg/mL among four major lineages appeared to be different (P = 0.06) and highest in ST239 (22.2%), followed by ST8/USA300 (13.5%). Among 89 isolates sequenced, 44.1% of ST8 and all ST239 isolates had ≥ 3 amino acid substitutions (AAS) in gyrA/parC (group A) or 2 AAS in gyrA/parC with additional AAS in gyrB/parE (group B). Compared to other AAS patterns, isolates in group A had the greatest non-susceptible proportions to nemonoxacin (86.9%; overall/pair-wised comparisons, P < 0.05). Conclusions Our study confirmed ST8/USA300 MRSA has disseminated in Taiwan. Using a tCBP defined by a higher parenteral daily dosage, nemonoxacin retained potency against moxifloxacin non-susceptible isolates. Patterns of AAS in QRDRs among different lineages may contribute to difference of nemonoxacin susceptibility.https://doi.org/10.1186/s12941-024-00772-6MoxifloxacinLevofloxacinCiprofloxacinQuinolone resistance determination regionsSequence type 8 |
| spellingShingle | Pao -Yu Chen Mao-Wang Ho Po-Liang Lu Hung-Jen Tang Cheng Len Sy Jann-Tay Wang Taiwan Staphylococcus aureus Consortium (TSAC) Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan Annals of Clinical Microbiology and Antimicrobials Moxifloxacin Levofloxacin Ciprofloxacin Quinolone resistance determination regions Sequence type 8 |
| title | Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan |
| title_full | Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan |
| title_fullStr | Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan |
| title_full_unstemmed | Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan |
| title_short | Comparative In vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin-resistant Staphylococcus aureus blood isolates in Taiwan |
| title_sort | comparative in vitro antibacterial activity of nemonoxacin and other fluoroquinolones in correlation with resistant mechanisms in contemporary methicillin resistant staphylococcus aureus blood isolates in taiwan |
| topic | Moxifloxacin Levofloxacin Ciprofloxacin Quinolone resistance determination regions Sequence type 8 |
| url | https://doi.org/10.1186/s12941-024-00772-6 |
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