Search

We analyzed the whole genome sequences (WGS) and antibiograms of 35 Enterobacter isolates, including E. hormaechei and E. asburiae , and the recently described E. bugandensis , E. kobei , E. ludwigii , and E. roggenkampii species. Isolates were obtained from human blood and urinary tract infections in patients in the United States. Our goal was to understand the genetic diversity of antimicrobial resistance genes and virulence factors among the various species. Thirty-four of 35 isolates contained an AmpC class bla ACT allele; however, the E. roggenkampii isolate contained bla MIR-5 . Of the six Enterobacter isolates resistant to ertapenem, imipenem, and meropenem, four harbored a carbapenemase gene, including bla KPC or bla NDM . All four isolates were mCIM-positive. The remaining two isolates had alterations in ompC genes that may have contributed to the resistance phenotype. Interpretations of cefepime test results were variable when disk diffusion and automated broth microdilution results were compared due to the Clinical Laboratory and Standards Institute use of the "susceptible dose-dependent" classification. The diversity of the bla ACT alleles paralleled species identifications, as did the presence of various virulence genes. The classification of recently described Enterobacter species is consistent with their resistance gene and virulence gene profiles.

Purpose: Donor-derived infection (DDI) has become an important factor affecting the prognosis of lung transplantation patients. The risks versus benefits of using donor organs infected with multidrug-resistant organisms (MDRO), especially carbapenem-resistant organisms (CRO), are frequently debated. Traditional microbial culture and antimicrobial susceptibility testing at present fail to meet the needs of quick CRO determination for donor lungs before acquisition. In this study, we explored a novel screening method by using Xpert ® Carba-R assay for CRO in donor lungs in a real-time manner to reduce CRO-associated DDI mortality., Methods: This study was registered on chictr.org.cn (ChiCTR2100053687) on November 2021. In the Xpert Carba-R screening group, donor lungs were screened for CRO infection by the Xpert Carba-R test on bronchoalveolar fluid (BALF) before acquisition. If the result was negative, donor lung acquisition and subsequent lung transplantation were performed. In the thirty-five potential donors, nine (25.71%) with positive Xpert Carba-R results in BALF were declined for lung transplantation. Twenty-six recipients and the matching CRO-negative donor lungs (74.29%) were included in the Xpert Carba-R screening group. In the control group, nineteen recipients underwent lung transplants without Xpert Carba-R screening. The incidence and mortality of CRO-associated DDI were collected and contrasted between the two groups., Results: Multivariate analysis showed that CRO-related death due to DDI within 60 days was significantly lower in the Xpert Carba-R screening group than that in the control group (OR = 0.05, 95% CI 0.003-0.74, p = 0.03)., Conclusion: Real-time CRO screening of donor lungs before transplantation at the point of care by the Xpert Carba-R helps clinicians formulate lung transplantation strategies quickly and reduces the risk of subsequent CRO infection improving the prognosis of lung transplantation., (© 2023. The Author(s).)

Objectives: We investigated the amino acid substitutions in the GES family of ESBLs that were most likely to be involved in the evolution of carbapenemase activity., Methods: To identify the substitutions that are functionally important, we analysed the evolutionary history of the GES β-lactamases using an alignment and phylogeny to identify sites in GES that show evidence of positive selection and the selected phenotypes., Results and Conclusions: Data indicate that the substitutions G170S and G243A are associated with carbapenemase activity. The substitutions Q43E, E104K and T237A are most likely associated with ESBL activity., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.)