Microbiology and Immunology Department, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt.
Microbiology and Biotechnology Department, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, 11152, Egypt.
J Antibiot (Tokyo). 2024 Nov;77(11):768-777. doi: 10.1038/s41429-024-00761-z. Epub 2024 Aug 1.
Escherichia coli and Klebsiella pneumoniae are important members of the Enterobacteriaceae family, involved in many infections. The increased resistance rate towards β-lactams and fluoroquinolones -which are the main therapeutic options- limits their treatment options. This study aimed to assess the local resistance patterns against different antimicrobials and to determine the extended-spectrum β-lactamase (ESBLs) producers. The study revealed that 36% of clinical isolates were ESBL producers, showing high resistance rates towards β-lactams and non-β-lactams, especially sulphamethoxazole-trimethoprim and fluoroquinolones. However, they were susceptible to chloramphenicol and doxycycline (33% and 20%; respectively). Also, the investigation aimed to screen the plasmid profile of quinolone-resistant ESBLs-producers and to detect the plasmid-mediated quinolone resistance genes including qnrA, qnrS, qnrB, qnrC, qnrD, and qnrVC. Moreover, the conjugative plasmid among the quinolone-resistant isolates was elucidated. The results showed that extracted plasmids of sizes ranging from ≈0.9 to 21.23 Kb, divided into 7 plasmid patterns were detected. A plasmid of approximately 21.23 Kb was found in all isolates and the QnrS gene was the most predominant gene. Moreover, the frequency of transconjugation within the same genus was higher than that recorded between different genera; where 68% of E. coli isolates transferred the resistance genes compared to Klebsiella isolates (36.6%). Plasmid profiles of transconjugants demonstrated great similarity, where 21.23 Kb plasmid was detected in all transconjugants. Since these transconjugants were quinolone-resistant ESBL producers, it has been suggested that quinolone resistance determinants might be carried on that plasmid.
大肠埃希菌和肺炎克雷伯菌是肠杆菌科的重要成员，参与多种感染。β-内酰胺类和氟喹诺酮类（主要治疗选择）的耐药率增加限制了它们的治疗选择。本研究旨在评估不同抗菌药物的局部耐药模式，并确定产超广谱β-内酰胺酶（ESBLs）的细菌。研究表明，36%的临床分离株为 ESBL 产酶菌，对β-内酰胺类和非β-内酰胺类药物，尤其是磺胺甲恶唑-甲氧苄啶和氟喹诺酮类药物表现出高度耐药性。然而，它们对氯霉素和多西环素（分别为 33%和 20%）敏感。此外，该研究旨在筛选耐氟喹诺酮类 ESBLs 产酶菌的质粒谱，并检测包括 qnrA、qnrS、qnrB、qnrC、qnrD 和 qnrVC 在内的质粒介导的喹诺酮耐药基因。此外，还阐明了耐氟喹诺酮类分离株中的可接合质粒。结果表明，检测到大小约为 0.9 至 21.23 Kb 的质粒，分为 7 种质粒图谱。所有分离株中均发现约 21.23 Kb 的质粒，其中 qnrS 基因最为常见。此外，同一属内的转导频率高于不同属之间的转导频率；68%的大肠埃希菌分离株转移了耐药基因，而肺炎克雷伯菌分离株（36.6%）则低于该频率。转导子的质粒图谱显示出很大的相似性，所有转导子中均检测到 21.23 Kb 的质粒。由于这些转导子是耐氟喹诺酮类 ESBL 产酶菌，因此推测氟喹诺酮类耐药决定因素可能存在于该质粒上。
