1 Department of Bacteriology, First Affiliated Hospital of Nanchang University, Nanchang University, Nanchang, P.R. China.
2 Department of Infectious Disease, First Affiliated Hospital of Nanchang University, Nanchang University, Nanchang, P.R. China.
Microb Drug Resist. 2019 Jun;25(5):681-689. doi: 10.1089/mdr.2018.0173. Epub 2019 Jan 7.
Thirty-five serotype K1 hypervirulent (K1-hvKP) isolates collected from a Chinese hospital during the whole year of 2017 were evaluated to characterize the prevalence of the plasmid-mediated quinolone resistance (PMQR) genes. In total, 18 (51.4%) isolates were detected to carry PMQR genes, and the most frequently detected gene was (37.5%), followed by (15%) and (2.5%). Remarkably, some -carrying strains had only a single or more quinolone resistance-determining region mutations in GyrA or ParC, and most exhibited high-level ciprofloxacin resistance. However, only 11.4% (4/35) isolates were resistant to quinolones. Furthermore, 34.3% (12/35) carried extended-spectrum β-lactamase (ESBL) genes, but only 14.3% (5/35) exhibited ESBL phenotype. The most prevalent virulence genes were (100%, 21/21), followed by (97.1%, 34/35), (97.1%, 34/35), (97.1%, 34/35), (94.3%, 33/35), (94.3%, 33/35), (91.4%, 32/35), (91.4%, 32/35), (62.9%, 22/35), (62.9%, 22/35), (51.4%, 18/35), (45.7%, 16/35), and (22.9%, 8/35). Multilocus sequence typing (MLST) analysis assigned the 35 K1-hvKP isolates into 5 sequence types (STs), with ST23 encompassing 77.1% of the strains. Pulsed field gel electrophoresis (PFGE) typing showed that strains closely related by MLST clustered in major PFGE clusters, of which cluster A accounts for 16 ST23 isolates and cluster B includes 11 ST23 isolates. The analysis of the transconjugants showed decreased susceptibility to quinolones and revealed a cotransfer of with the S1 alleles. Cumulatively, our findings showed that the PMQR-producing K1-hvKP strain is covertly spreading even when K1-hvKP is rarely resistant to fluoroquinolones (FQs) according to the Clinical and Laboratory Standards Institute criteria. It is therefore critical to continuously monitor the PMQR-producing K1-hvKP epidemiology and minimize potential risks from FQ-resistant K1-hvKP.
2017 年全年，从中国一家医院采集了 35 株血清型 K1 高毒力（K1-hvKP）分离株，用于评估质粒介导的喹诺酮耐药（PMQR）基因的流行情况。总共有 18 株（51.4%）分离株被检测到携带 PMQR 基因，最常检测到的基因是 （37.5%），其次是 （15%）和 （2.5%）。值得注意的是，一些携带 基因的菌株在 GyrA 或 ParC 中只有单个或更多的喹诺酮耐药决定区突变，且大多数表现出高水平的环丙沙星耐药性。然而，仅有 11.4%（4/35）的分离株对喹诺酮类药物耐药。此外，34.3%（12/35）携带超广谱β-内酰胺酶（ESBL）基因，但仅有 14.3%（5/35）表现出 ESBL 表型。最常见的毒力基因是 （100%，21/21），其次是 （97.1%，34/35）、 （97.1%，34/35）、 （97.1%，34/35）、 （94.3%，33/35）、 （94.3%，33/35）、 （91.4%，32/35）、 （91.4%，32/35）、 （62.9%，22/35）、 （62.9%，22/35）、 （51.4%，18/35）、 （45.7%，16/35）和 （22.9%，8/35）。多位点序列分型（MLST）分析将 35 株 K1-hvKP 分离株分为 5 种序列型（STs），其中 ST23 占菌株的 77.1%。脉冲场凝胶电泳（PFGE）分型显示，通过 MLST 聚类的密切相关的菌株聚集在主要的 PFGE 簇中，其中簇 A 占 16 株 ST23 分离株，簇 B 包括 11 株 ST23 分离株。转导子的分析显示对喹诺酮类药物的敏感性降低，并显示出 与 S1 等位基因的共转移。总的来说，我们的研究结果表明，尽管根据临床和实验室标准协会的标准，K1-hvKP 很少对氟喹诺酮类药物（FQs）耐药，但产生 PMQR 的 K1-hvKP 菌株正在秘密传播。因此，持续监测产生 PMQR 的 K1-hvKP 的流行病学并将 FQ 耐药的 K1-hvKP 的潜在风险降到最低至关重要。
