D'Souza Roshan, Pinto Naina A, Phuong Nguyen Le, Higgins Paul G, Vu Thao Nguyen, Byun Jung-Hyun, Cho Young Lag, Choi Jong Rak, Yong Dongeun
Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, South Korea.
J. Craig Venter Institute, Rockville, MD, United States.
Front Microbiol. 2019 Mar 26;10:559. doi: 10.3389/fmicb.2019.00559. eCollection 2019.
spp. have emerged as significant pathogens causing nosocomial infections. Treatment of these pathogens has become a major challenge to clinicians worldwide, due to their increasing tendency to antibiotic resistance. To address this, much revenue and technology are currently being dedicated toward developing novel drugs and antibiotic combinations to combat antimicrobial resistance. To address this issue, we have constructed a panel of spp. strains expressing different antimicrobial resistance determinants such as narrow spectrum β-lactamases, extended-spectrum β-lactamases, OXA-type-carbapenemase, metallo-beta-lactamase, and over-expressed AmpC β-lactamase. Bacterial strains exhibiting different resistance phenotypes were collected between 2008 and 2013 from Severance Hospital, Seoul. Antimicrobial susceptibility was determined according to the CLSI guidelines using agar dilution method. Selected strains were sequenced using Ion Torrent PGM system, annotated using RAST server and analyzed using Geneious pro 8.0. Genotypic determinants, such as acquired resistance genes, changes in the expression of efflux pumps, mutations, and porin alternations, contributing to the relevant expressed phenotype were characterized. Isolates expressing ESBL phenotype consisted of gene, the overproduction of intrinsic AmpC beta-lactamase associated with IS insertion, and carbapenem resistance associated with production of carbapenem-hydrolyzing Ambler class D β-lactamases, such as OXA-23, OXA-66, OXA-120, OXA-500, and metallo-β-lactamase, SIM-1. We have analyzed the relative expression of Ade efflux systems, and determined the sequences of their regulators to correlate with phenotypic resistance. Quinolone resistance-determining regions were analyzed to understand fluoroquinolone-resistance. Virulence factors responsible for pathogenesis were also identified. Due to several mutations, acquisition of multiple resistance genes and transposon insertion, phenotypic resistance decision scheme for for evaluating the resistance proved inaccurate, which highlights the urgent need for modification to this scheme. This complete illustration of mechanism contributing to specific resistance phenotypes can be used as a target for novel drug development. It can also be used as a reference strain in the clinical laboratory and for the evaluation of antibiotic efficacy for specific resistance mechanisms.
某些菌种已成为引起医院感染的重要病原体。由于这些病原体对抗生素的耐药性不断增强，对其进行治疗已成为全球临床医生面临的一项重大挑战。为应对这一问题，目前投入了大量资金和技术来研发新型药物和抗生素组合，以对抗抗菌药物耐药性。为解决这个问题，我们构建了一组表达不同抗菌耐药决定因素的菌株，如窄谱β-内酰胺酶、超广谱β-内酰胺酶、OXA型碳青霉烯酶、金属β-内酰胺酶和过表达的AmpCβ-内酰胺酶。2008年至2013年期间从首尔Severance医院收集了表现出不同耐药表型的细菌菌株。根据CLSI指南，采用琼脂稀释法测定抗菌药物敏感性。使用Ion Torrent PGM系统对选定的菌株进行测序，使用RAST服务器进行注释，并使用Geneious pro 8.0进行分析。对导致相关表达表型的基因型决定因素进行了表征，如获得性耐药基因、外排泵表达的变化、突变和孔蛋白改变。表达ESBL表型的分离株包括基因、与IS插入相关的固有AmpCβ-内酰胺酶的过度产生，以及与碳青霉烯水解Ambler D类β-内酰胺酶（如OXA-23、OXA-66、OXA-120、OXA-500和金属β-内酰胺酶SIM-1）产生相关的碳青霉烯耐药性。我们分析了Ade外排系统的相对表达，并确定了其调节因子的序列，以与表型耐药性相关联。分析喹诺酮耐药决定区以了解氟喹诺酮耐药性。还鉴定了负责发病机制的毒力因子。由于存在多种突变、获得多个耐药基因和转座子插入，用于评估耐药性的表型耐药判定方案被证明不准确，这突出表明迫切需要对该方案进行修改。这种对导致特定耐药表型机制的完整阐述可作为新型药物开发的靶点。它还可作为临床实验室的参考菌株，并用于评估针对特定耐药机制的抗生素疗效。
