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Unlabelled: Colistin is used as a last-line therapy against carbapenem-resistant (CRKP). However, colistin resistance in is increasingly reported worldwide. This study aims to investigate the instrumental role of insertion sequence (IS) elements in colistin resistance through disruption in during treatment. Five clinical isolates of CRKP, designated KPN1~KPN5 were collected from the lower respiratory tract of a patient with chest infection before and after treatment with colistin. Antimicrobial susceptibility testing was performed using the broth microdilution method. Whole genome sequencing and bioinformatics were used to analyze the sequence types (STs), resistance genes, and genetic characteristics of the five isolates of . Antimicrobial susceptibility testing indicated that all five isolates were resistant to cephalosporins (ceftriaxone, ceftazidime, and cefepime), several carbapenems (imipenem, meropenem), cefoperazone-sulbactam, piperacillin-tazobactam, ciprofloxacin, and fosfomycin, whereas they were sensitive to amikacin and tigecycline. In addition, three of these isolates were resistant to colistin, with minimum inhibitory concentration values of >8 mg/L. Whole genome sequencing revealed that all five isolates belonged to sequence type 1 (ST1), which shared an identical . Notably, disruption of by the IS insertion sequence was shown to be the primary colistin resistance mechanism during the treatment. To our knowledge, this is the first report of IS element mediating disruption in the ST1 colistin and CRKP obtained from a patient with chest infection in mainland China. This study provides new research ideas to explore the clinical drug resistance mechanism of CRKP and the critical need to monitor and understand resistance mechanisms to preserve the efficacy of last-line antibiotics such as colistin.
Importance: Of note, this chapter gives an update on colistin resistance in sequence type 1 , by focusing on the disrupted by IS element.
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http://dx.doi.org/10.1128/spectrum.00952-24 | DOI Listing |
J Microbiol Immunol Infect
August 2025
Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Electronic address:
Background: Acinetobacter seifertii, a recently identified member of the Acinetobacter calcoaceticus-Acinetobacter baumannii (Acb) complex, has emerged as a cause of severe human infections. It is closely related to Acinetobacter nosocomialis, a major pathogen of the Acb complex. Here, we aimed to explore the clinical and molecular differences between these two species.
View Article and Find Full Text PDFJ Glob Antimicrob Resist
September 2025
Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Changchun Veterinary Research Institute, Chinese Academy of Agriculture Sciences, Changchun, Jilin 130122, China. Electronic address:
Objectives: The usage of cephalosporins (CEFs) and co-existence of extended-spectrum β-lactamase (ESBL) gene bla in the same host may promote the prevalence of colistin (CST) resistance gene mcr-1. This study aims to investigate the underlying mechanisms how the mcr-1 and bla demonstrate significant co-occurrence in Escherichia coli (E. coli).
View Article and Find Full Text PDFInt J Hyg Environ Health
September 2025
ISGlobal, Barcelona, Spain; Faculty of Medicine and Health Sciences, University of Barcelona (UB), Barcelona, Spain; CIBER Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain. Electronic address:
The misuse and overuse of antimicrobials drive the emergence of antimicrobial resistance (AMR), a critical global health concern. While wastewater treatment plants (WWTPs) are essential for removing microorganisms and contaminants, they also serve as hotspots for antibiotic-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs), facilitating their persistence and dissemination. This study investigated AMR in two WWTPs and one drinking water treatment plant (DWTP) in the Baix Llobregat area of Barcelona, Spain.
View Article and Find Full Text PDFPLoS One
September 2025
Faculty of Health, Institute of Pharmacology and Toxicology, Centre for Biomedical Education and Research (ZBAF), School of Medicine, Witten/Herdecke University, Witten, Germany.
The emergence of antibiotic resistance continues to pose a significant global challenge. Drug repurposing, wherein existing therapeutics are evaluated for new applications, offers a promising strategy to address this issue. Farnesyltransferase inhibitors (FTIs), initially developed for cancer therapy, have demonstrated antimicrobial activity against several gram-positive bacteria.
View Article and Find Full Text PDFCurr Opin Crit Care
October 2025
ADVANCE-ID, Saw Swee Hock School of Public Health, National University of Singapore, Singapore.
Purpose Of Review: This review aims to summarize current recommendations for the management of serious infections, such as bloodstream infections (BSIs) and ventilator-associated pneumonia, caused by multidrug-resistant (MDR) and extensively drug-resistant (XDR) pathogens, focusing on evidence from randomized controlled trials (RCTs) and emerging treatment options.
Recent Findings: Vancomycin, linezolid, and daptomycin represent the main therapeutic options for the management of methicillin-resistant Staphylococcus aureus infections; among newer agents, ceftobiprole has recently gained approval for BSI treatment. For vancomycin-resistant Enterococcus faecium BSIs, linezolid and daptomycin remain commonly employed despite the lack of comparative RCTs guiding treatment decisions.