MUNITA SEPULVEDA, JOSE MANUEL
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MUNITA SEPULVEDA, JOSE MANUEL
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josemunita@udd.cl
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24825037700

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2024 2024 2023 2023 0.0 0.0 0.2 0.2 0.4 0.4 0.6 0.6 0.8 0.8 1.0 1.0

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Cefiderocol heteroresistance associated with mutations in TonB-dependent receptor genes in Pseudomonas aeruginosa of clinical origin

2024 , Stephanie L. Egge , Samie A. Rizvi , Shelby R. Simar , ALCALDE RICO, MANUEL , JOSE RODRIGO WALDEMAR MARTINEZ SOLIS , Blake M. Hanson , An Q. Dinh , Rodrigo P. Baptista , Truc T. Tran , Samuel A. Shelburne , MUNITA SEPULVEDA, JOSE MANUEL , Cesar A. Arias , Morgan Hakki , William R. Miller , Ryan K. Shields

ABSTRACT The siderophore-cephalosporin cefiderocol (FDC) presents a promising treatment option for carbapenem-resistant (CR) P. aeruginosa (PA). FDC circumvents traditional porin and efflux-mediated resistance by utilizing TonB-dependent receptors (TBDRs) to access the periplasmic space. Emerging FDC resistance has been associated with loss of function mutations within TBDR genes or the regulatory genes controlling TBDR expression. Further, difficulties with antimicrobial susceptibility testing (AST) and unexpected negative clinical treatment outcomes have prompted concerns for heteroresistance, where a single lineage isolate contains resistant subpopulations not detectable by standard AST. This study aimed to evaluate the prevalence of TBDR mutations among clinical isolates of P. aeruginosa and the phenotypic effect on FDC susceptibility and heteroresistance. We evaluated the sequence of pirR , pirS , pirA , piuA , or piuD from 498 unique isolates collected before the introduction of FDC from four clinical sites in Portland, OR (1), Houston, TX (2), and Santiago, Chile (1). At some clinical sites, TBDR mutations were seen in up to 25% of isolates, and insertion, deletion, or frameshift mutations were predicted to impair protein function were seen in 3% of all isolates ( n = 15). Using population analysis profile testing, we found that P. aeruginosa with major TBDR mutations were enriched for a heteroresistant phenotype and undergo a shift in the susceptibility distribution of the population as compared to susceptible strains with wild-type TBDR genes. Our results indicate that mutations in TBDR genes predate the clinical introduction of FDC, and these mutations may predispose to the emergence of FDC resistance.

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Multisite Detection of Tn 1549 -Mediated vanB Vancomycin Resistance in Multidrug-Resistant Enterococcus faecalis ST6 in Texas and Florida

2023 , Shelby R. Simar , Truc T. Tran , Kirsten B. Rydell , Diana Panesso , German A. Contreras , MUNITA SEPULVEDA, JOSE MANUEL , Renzo O. Cifuentes , Lilian M. Abbo , Pranoti Sahasrabhojane , An Q. Dinh , Dierdre B. Axell-House , Tor Savidge , Samuel A. Shelburne , Blake M. Hanson , Cesar A. Arias

In the United States, vanB -mediated resistance in enterococci is rare. We characterized three sequence type (ST) 6, vancomycin-resistant Enterococcus faecalis isolates causing bacteremia in unique patients in spatiotemporally distinct settings.

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