Detection of Delafloxacin Resistance Mechanisms in Multidrug-Resistant <i>Klebsiella pneumoniae</i>

<b>Background:</b> In this study, the mechanisms implicated in delafloxacin resistance in <i>Klebsiella pneumoniae</i> strains were investigated. Delafloxacin is a novel, broad-spectrum fluoroquinolone that has been approved for clinical application. <b>Methods:</b&g...

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Main Authors: András Kubicskó, János Juhász, Katalin Kamotsay, Dora Szabo, Béla Kocsis
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Antibiotics
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Online Access:https://www.mdpi.com/2079-6382/14/1/62
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author András Kubicskó
János Juhász
Katalin Kamotsay
Dora Szabo
Béla Kocsis
author_facet András Kubicskó
János Juhász
Katalin Kamotsay
Dora Szabo
Béla Kocsis
author_sort András Kubicskó
collection DOAJ
description <b>Background:</b> In this study, the mechanisms implicated in delafloxacin resistance in <i>Klebsiella pneumoniae</i> strains were investigated. Delafloxacin is a novel, broad-spectrum fluoroquinolone that has been approved for clinical application. <b>Methods:</b> In our study, 43 <i>K. pneumoniae</i> strains were assessed, antimicrobial susceptibility testing was performed via the broth microdilution method, and the minimum inhibitory concentration (MIC) values for ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin, ceftazidime, cefotaxime, and imipenem were determined. Four delafloxacin-resistant <i>K. pneumoniae</i> strains were selected for whole-genome sequencing (WGS). <b>Results:</b> The MIC50 values for the 43 <i>K. pneumoniae</i> strains were as follows: ciprofloxacin 0.5 mg/L, levofloxacin 0.25 mg/L, moxifloxacin 0.5 mg/L, and delafloxacin 0.25 mg/L. All four selected delafloxacin-resistant <i>K. pneumoniae</i> strains showed extended-spectrum beta-lactamase production, and one strain exhibited carbapenem resistance. WGS enabled us to determine the sequence types (STs) of these strains, namely, ST307 (two strains), ST377, and ST147. Multiple mutations in quinolone-resistance-determining regions (QRDRs) were detected in all the delafloxacin-resistant <i>K. pneumoniae</i> strains; specifically, <i>gyrA</i> Ser83Ile and <i>parC</i> Ser80Ile were uniformly present in the strains of ST307 and ST147. However, in the ST377 strain, <i>gyrA</i> Ser83Tyr, Asp87Ala, and <i>parC</i> Ser80Ile, amino acid substitutions were detected. We also identified OqxAB and AcrAB efflux pumps in all delafloxacin-resistant <i>K. pneumoniae</i> strains. The association between beta-lactamase production and delafloxacin resistance was determined; specifically, CTX-M-15 production was detected in the ST147, ST307, and ST377 strains. Moreover, NDM-1 was detected in ST147. <b>Conclusions:</b> We conclude that multiple mutations in QRDRs, in combination with OqxAB and AcrAB efflux pumps, achieved delafloxacin resistance in <i>K. pneumoniae</i>. In our study, we report on NDM-1-producing <i>K. pneumoniae</i> ST147 in Hungary.
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spelling doaj-art-910a0f76daa34846a49ff0c58d16689a2025-01-24T13:18:48ZengMDPI AGAntibiotics2079-63822025-01-011416210.3390/antibiotics14010062Detection of Delafloxacin Resistance Mechanisms in Multidrug-Resistant <i>Klebsiella pneumoniae</i>András Kubicskó0János Juhász1Katalin Kamotsay2Dora Szabo3Béla Kocsis4Institute of Medical Microbiology, Semmelweis University, 1089 Budapest, HungaryInstitute of Medical Microbiology, Semmelweis University, 1089 Budapest, HungaryInstitute of Medical Microbiology, Semmelweis University, 1089 Budapest, HungaryInstitute of Medical Microbiology, Semmelweis University, 1089 Budapest, HungaryInstitute of Medical Microbiology, Semmelweis University, 1089 Budapest, Hungary<b>Background:</b> In this study, the mechanisms implicated in delafloxacin resistance in <i>Klebsiella pneumoniae</i> strains were investigated. Delafloxacin is a novel, broad-spectrum fluoroquinolone that has been approved for clinical application. <b>Methods:</b> In our study, 43 <i>K. pneumoniae</i> strains were assessed, antimicrobial susceptibility testing was performed via the broth microdilution method, and the minimum inhibitory concentration (MIC) values for ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin, ceftazidime, cefotaxime, and imipenem were determined. Four delafloxacin-resistant <i>K. pneumoniae</i> strains were selected for whole-genome sequencing (WGS). <b>Results:</b> The MIC50 values for the 43 <i>K. pneumoniae</i> strains were as follows: ciprofloxacin 0.5 mg/L, levofloxacin 0.25 mg/L, moxifloxacin 0.5 mg/L, and delafloxacin 0.25 mg/L. All four selected delafloxacin-resistant <i>K. pneumoniae</i> strains showed extended-spectrum beta-lactamase production, and one strain exhibited carbapenem resistance. WGS enabled us to determine the sequence types (STs) of these strains, namely, ST307 (two strains), ST377, and ST147. Multiple mutations in quinolone-resistance-determining regions (QRDRs) were detected in all the delafloxacin-resistant <i>K. pneumoniae</i> strains; specifically, <i>gyrA</i> Ser83Ile and <i>parC</i> Ser80Ile were uniformly present in the strains of ST307 and ST147. However, in the ST377 strain, <i>gyrA</i> Ser83Tyr, Asp87Ala, and <i>parC</i> Ser80Ile, amino acid substitutions were detected. We also identified OqxAB and AcrAB efflux pumps in all delafloxacin-resistant <i>K. pneumoniae</i> strains. The association between beta-lactamase production and delafloxacin resistance was determined; specifically, CTX-M-15 production was detected in the ST147, ST307, and ST377 strains. Moreover, NDM-1 was detected in ST147. <b>Conclusions:</b> We conclude that multiple mutations in QRDRs, in combination with OqxAB and AcrAB efflux pumps, achieved delafloxacin resistance in <i>K. pneumoniae</i>. In our study, we report on NDM-1-producing <i>K. pneumoniae</i> ST147 in Hungary.https://www.mdpi.com/2079-6382/14/1/62delafloxacinfluoroquinolone resistancehigh-risk cloneESBLNDMWGS
spellingShingle András Kubicskó
János Juhász
Katalin Kamotsay
Dora Szabo
Béla Kocsis
Detection of Delafloxacin Resistance Mechanisms in Multidrug-Resistant <i>Klebsiella pneumoniae</i>
Antibiotics
delafloxacin
fluoroquinolone resistance
high-risk clone
ESBL
NDM
WGS
title Detection of Delafloxacin Resistance Mechanisms in Multidrug-Resistant <i>Klebsiella pneumoniae</i>
title_full Detection of Delafloxacin Resistance Mechanisms in Multidrug-Resistant <i>Klebsiella pneumoniae</i>
title_fullStr Detection of Delafloxacin Resistance Mechanisms in Multidrug-Resistant <i>Klebsiella pneumoniae</i>
title_full_unstemmed Detection of Delafloxacin Resistance Mechanisms in Multidrug-Resistant <i>Klebsiella pneumoniae</i>
title_short Detection of Delafloxacin Resistance Mechanisms in Multidrug-Resistant <i>Klebsiella pneumoniae</i>
title_sort detection of delafloxacin resistance mechanisms in multidrug resistant i klebsiella pneumoniae i
topic delafloxacin
fluoroquinolone resistance
high-risk clone
ESBL
NDM
WGS
url https://www.mdpi.com/2079-6382/14/1/62
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