Comparison of antimicrobial activities and resistance mechanisms of eravacycline and tigecycline against clinical Acinetobacter baumannii isolates in China.
{"title":"Comparison of antimicrobial activities and resistance mechanisms of eravacycline and tigecycline against clinical <i>Acinetobacter baumannii</i> isolates in China.","authors":"Xiandi Chen, Yitan Li, Yingzhuo Lin, Yingyi Guo, Guohua He, Xiaohu Wang, Mingzhen Wang, Jianbo Xu, Mingdong Song, Xixi Tan, Chao Zhuo, Zhiwei Lin","doi":"10.3389/fmicb.2024.1417237","DOIUrl":null,"url":null,"abstract":"<p><p>Tigecycline (TGC) is currently used to treat carbapenem-resistant <i>Acinetobacter baumannii</i> (CRAB) infections, while eravacycline (ERV), a new-generation tetracycline, holds promise as a novel therapeutic option for these infections. However, differences in resistance mechanism between ERV and TGC against <i>A. baumannii</i> remain unclear. This study sought to compare the characteristics and mechanisms of ERV and TGC resistance among clinical <i>A. baumannii</i> isolates. A total of 492 isolates, including 253 CRAB and 239 carbapenem-sensitive <i>A. baumannii</i> (CSAB) isolates, were collected from hospitalized patients in China. The MICs of ERV and TGC against <i>A. baumannii</i> were determined by broth microdilution. Genetic mutations and expressions of <i>adeB, adeG, adeJ, adeS, adeL</i>, and <i>adeN</i> in resistant strains were examined by PCR and qPCR, respectively. The <i>in vitro</i> recombination experiments were used to verify the resistance mechanism of ERV and TGC in <i>A. baumannii</i>. The MIC<sub>90</sub> of ERV in CRAB and CSAB isolates were lower than those of TGC. A total of 24 strains resistant to ERV and/or TGC were categorized into three groups: only ERV-resistant (<i>n</i> = 2), both ERV- and TGC-resistant (<i>n</i> = 7), and only TGC-resistant (<i>n</i> = 15). ST208 (75%, <i>n</i> = 18) was a major clone that has disseminated in all three groups. The IS<i>Aba1</i> insertion in <i>adeS</i> was identified in 66.7% (6/9) of strains in the only ERV-resistant and both ERV- and TGC-resistant groups, while the IS<i>Aba1</i> insertion in <i>adeN</i> was found in 53.3% (8/15) of strains in the only TGC-resistant group. The <i>adeABC</i> and <i>adeRS</i> expressions were significantly increased in the only ERV-resistant and both ERV- and TGC-resistant groups, while the <i>adeABC</i> and <i>adeIJK</i> expressions were significantly increased and <i>adeN</i> was significantly decreased in the only TGC-resistant group. Expression of <i>adeS</i> with the IS<i>Aba1</i> insertion in ERV- and TGC-sensitive strains significantly increased the ERV and TGC MICs and upregulated <i>adeABC</i> and <i>adeRS</i> expressions. Complementation of the wildtype <i>adeN</i> in TGC-resistant strains with the IS<i>Aba1</i> insertion in <i>adeN</i> restored TGC sensitivity and significantly downregulated <i>adeIJK</i> expression. In conclusion, our data illustrates that ERV is more effective against <i>A. baumannii</i> clinical isolates than TGC. ERV resistance is correlated with the IS<i>Aba1</i> insertion in <i>adeS</i>, while TGC resistance is associated with the IS<i>Aba1</i> insertion in <i>adeN</i> or <i>adeS</i> in <i>A. baumannii.</i></p>","PeriodicalId":12466,"journal":{"name":"Frontiers in Microbiology","volume":null,"pages":null},"PeriodicalIF":4.0000,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11458409/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Microbiology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.3389/fmicb.2024.1417237","RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/1/1 0:00:00","PubModel":"eCollection","JCR":"Q2","JCRName":"MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Tigecycline (TGC) is currently used to treat carbapenem-resistant Acinetobacter baumannii (CRAB) infections, while eravacycline (ERV), a new-generation tetracycline, holds promise as a novel therapeutic option for these infections. However, differences in resistance mechanism between ERV and TGC against A. baumannii remain unclear. This study sought to compare the characteristics and mechanisms of ERV and TGC resistance among clinical A. baumannii isolates. A total of 492 isolates, including 253 CRAB and 239 carbapenem-sensitive A. baumannii (CSAB) isolates, were collected from hospitalized patients in China. The MICs of ERV and TGC against A. baumannii were determined by broth microdilution. Genetic mutations and expressions of adeB, adeG, adeJ, adeS, adeL, and adeN in resistant strains were examined by PCR and qPCR, respectively. The in vitro recombination experiments were used to verify the resistance mechanism of ERV and TGC in A. baumannii. The MIC90 of ERV in CRAB and CSAB isolates were lower than those of TGC. A total of 24 strains resistant to ERV and/or TGC were categorized into three groups: only ERV-resistant (n = 2), both ERV- and TGC-resistant (n = 7), and only TGC-resistant (n = 15). ST208 (75%, n = 18) was a major clone that has disseminated in all three groups. The ISAba1 insertion in adeS was identified in 66.7% (6/9) of strains in the only ERV-resistant and both ERV- and TGC-resistant groups, while the ISAba1 insertion in adeN was found in 53.3% (8/15) of strains in the only TGC-resistant group. The adeABC and adeRS expressions were significantly increased in the only ERV-resistant and both ERV- and TGC-resistant groups, while the adeABC and adeIJK expressions were significantly increased and adeN was significantly decreased in the only TGC-resistant group. Expression of adeS with the ISAba1 insertion in ERV- and TGC-sensitive strains significantly increased the ERV and TGC MICs and upregulated adeABC and adeRS expressions. Complementation of the wildtype adeN in TGC-resistant strains with the ISAba1 insertion in adeN restored TGC sensitivity and significantly downregulated adeIJK expression. In conclusion, our data illustrates that ERV is more effective against A. baumannii clinical isolates than TGC. ERV resistance is correlated with the ISAba1 insertion in adeS, while TGC resistance is associated with the ISAba1 insertion in adeN or adeS in A. baumannii.
期刊介绍:
Frontiers in Microbiology is a leading journal in its field, publishing rigorously peer-reviewed research across the entire spectrum of microbiology. Field Chief Editor Martin G. Klotz at Washington State University is supported by an outstanding Editorial Board of international researchers. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to researchers, academics, clinicians and the public worldwide.