Objective: Klebsiella pneumoniae carbapenemase (KPC)-producing K.pneumoniae has represented a serious health problem in worldwide. The resistance to ceftazidime-avibactam (CAZ-AVI) began to emerge since its approval in 2015. We aim to explore the resistance mechanism of CAZ-AVI.
Methods: Phenotypic test and whole-genome sequencing (WGS) analysis were performed in KP-HX0917 and KP-HX1016 Klebsiella pneumoniae isolates, collected from the same patient following treatment with CAZ-AVI.
Results: We report a case of emergence of CAZ-AVI resistance in ST 11 KPC-2-producing K. pneumoniae (KP-HX1016) during 14 days of exposure with CZA-AVI. Molecular analysis highlighted the A533C mutation in the blaKPC-2 gene, resulting a D179A substitution in protein sequence, which restored the hydrolysis ability of imipenem and meropenem, but not for ertapenem, and the result of phenotypic test was negative. However, KP-HX0917 produced serine-carbapenemase by phenotypic detection and lost its capacity of hydrolyzing carbapenems.
Conclusion: The emergence of CAZ-AVI resistance should arouse our attention, the susceptibility testing should be followed by a combination of phenotypic and molecular methods, to make sure that no potential carbapenemase-producing bacteria are missed.
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http://dx.doi.org/10.1016/j.jiph.2022.04.002 | DOI Listing |
J Mater Chem B
January 2025
Drug Delivery, Disposition, and Dynamics Theme, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Pde, Parkville, VIC, 3052, Australia.
Infections caused by fungal pathogens are a global health problem, and have created an urgent need for new antimicrobial strategies. This report details the synthesis of lipidated 2-vinyl-4,4-dimethyl-5-oxazolone (VDM) oligomers an optimized Cu(0)-mediated reversible-deactivation radical polymerization (RDRP) approach. Cholesterol-Br was used as an initiator to synthesize a library of oligo-VDM (degree of polymerisation = 5, 10, 15, 20, and 25), with an α-terminal cholesterol group.
View Article and Find Full Text PDFAntimicrob Agents Chemother
January 2025
Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Ceftriaxone-resistant Enterobacterales remain a public health threat; contemporary data investigating their molecular epidemiology are limited. Five hundred consecutive ceftriaxone-resistant (MIC ≥ 4 µg/mL) Enterobacterales bloodstream isolates were collected between 2018 and 2022 from three Maryland hospitals. Broth microdilution confirmed antibiotic susceptibilities.
View Article and Find Full Text PDFBacteremia is a serious clinical condition in which pathogenic bacteria enter the bloodstream, putting patients at risk of septic shock and necessitating antibiotic treatment. Choosing the most effective antibiotic is crucial not only for resolving the infection but also for minimizing side effects, such as dysbiosis in the healthy microbiome and reducing the selection pressure for antibiotic resistance. This requires prompt identification of the pathogen and antibiotic susceptibility testing, yet these processes are inherently slow in standard clinical microbiology labs due to reliance on growth-based assays.
View Article and Find Full Text PDFUnlabelled: is a high-priority organism for the development of new antibacterial treatments. We found that the antimalarial medication mefloquine (MFQ) permeabilized the bacterial cell membrane of , decreased membrane fluidity, and caused physical injury to the membrane. MFQ also maintained activity across different pH conditions (PH range 5-8).
View Article and Find Full Text PDFKeystone engineers profoundly influence microbial communities by altering their shared environment, often by modifying key resources. Here, we show that in an antibiotic-treated microbial community, bacterial spread is controlled by keystone engineering affecting dispersal- an effect hidden in well-mixed environments. Focusing on two pathogens, non-motile Klebsiella pneumoniae and motile Pseudomonas aeruginosa, we found that both tolerate a β-lactam antibiotic, with Pseudomonas being more resilient and dominating in well-mixed cultures.
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