VILLAVICENCIO ZAMBRANO, FERNANDO XAVIER

Preferred name
VILLAVICENCIO ZAMBRANO, FERNANDO XAVIER
Main Affiliation
SF
ORCID
0000-0001-9092-2858
Scopus Author ID
57215576497

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    Genomic characterization of a WHO critical priority isolate Enterobacter kobei ST2070 harboring OXA-10, KPC-2, and CTX-M-12 recovered from a water irrigation channel in Ecuador
    (Elsevier BV, 2024-03)
    Joselyn Corrales-Martínez
    ;
    Katherine Jaramillo
    ;
    Daniel A. Tadesse
    ;
    Carolina Satán
    ;
    VILLAVICENCIO ZAMBRANO, FERNANDO XAVIER  
    The discharge of untreated or partially treated wastewater can have detrimental impacts on the quality of water bodies, posing a significant threat to public health and the environment. In Ecuador, previous research indicates a high prevalence of antimicrobial resistant (AMR) bacteria in surface waters affected by human activities, including irrigation channels. In this study, we analyzed sediment samples collected from an irrigation channel utilized for agricultural purposes in northern Ecuador, using microbiological techniques and whole-genome sequencing (WGS). Our investigation revealed the first documented occurrence of E. kobei in Ecuador and the initial report of environmental E. kobei ST2070. Furthermore, we identified the coexistence of OXA-10-type class D β-lactamase and KPC-2-type class A β-lactamase in the E. kobei isolate (UTA41), representing the first report of such a phenomenon in this species. Additionally, we detected various antibiotic resistance genes in the E. kobei UTA41 isolate, including blaCTX-M-12, fosA, aac(6′)-lb, sul2, msr(E), and mph(A), as well as virulence genes such as bacterial efflux pump and siderophore biosynthesis genes. We also identified two intact prophage regions (Entero_186 and Klebsi_phiKO2) in the isolate. Our study presents the first evidence of E. kobei isolate containing two carbapenemase-encoding genes in environmental samples from Latin America. This finding indicates the potential spread of critical-priority bacteria in water samples originating from anthropogenic sources, such as urban wastewater discharges and livestock facilities.
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    Research note: High-resolution detection of Salmonella serovar diversity in broilers from Ecuador using CRISPR-SeroSeq
    (Elsevier BV, 2026-04)
    Christian Vinueza-Burgos
    ;
    José L. Medina-Santana
    ;
    Sofía de Janon
    ;
    VILLAVICENCIO ZAMBRANO, FERNANDO XAVIER  
    ;
    David Ayala-Velastegui
    Salmonella enterica is a major foodborne pathogen associated with poultry, representing a critical challenge for food safety worldwide. Accurate identification of serovar diversity is essential for designing control strategies; however, conventional culture-based methods often underestimate this complexity. In this study, we report the first application of CRISPR-SeroSeq in Ecuador to characterize Salmonella serovar diversity in commercial broilers. A total of 76 flocks (one hose of one farm in different cycles) originated across 19 broiler farms were sampled. All flocks belonged to an integrated poultry company. From all samples, 77.6% tested positive for Salmonella. CRISPR-SeroSeq analysis revealed a clear dominance of serovar Infantis, even within mixed populations. Importantly, serovars of significant public health concern, including Enteritidis and Typhimurium, were detected at low frequencies that would likely be missed by conventional methods. These findings highlight the utility of high-resolution serotyping approaches, providing valuable insights for targeted interventions to improve poultry production biosecurity and food safety.
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    Salmonella enterica Serovar Infantis KPC-2 Producer: First Isolate Reported in Ecuador
    (Mary Ann Liebert Inc, 2024-12-01)
    VILLAVICENCIO ZAMBRANO, FERNANDO XAVIER  
    ;
    Viviana Albán
    ;
    Carolina Satán
    ;
    Hidaleisy Quintana
    ;
    Wladimir Enríquez
    Antimicrobial resistance is currently considered a public health threat. Carbapenems are antimicrobials for hospital use, and Enterobacterales resistant to these β-lactams have spread alarmingly in recent years, especially those that cause health care-associated infections. The blaKPC gene is considered one of the most important genetic determinants disseminated by plasmids, promoting horizontal gene transfer. This study describes, for the first time in Ecuador, and worldwide, the presence of a blaKPC-2 gene in an isolate of Salmonella enterica serovar Infantis from a clinical sample. Through whole-genome sequencing, we characterized the genetic determinants of antimicrobial resistance in this Salmonella ST-32 strain. Our results showed the presence of several resistance genes, including blaCTX-M-65, and a conjugative plasmid Kpn-WC17-007-03 that may be responsible for the horizontal transference of these resistance mechanisms.