Sebastián Zavala

Mr. Sebastián Zavala

Universidad de Chile
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 June 2020 in Animals
Verified
Journal Article
Open access
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LLLisette Lapierre
Lisette Lapierre
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javiera cornejo kelly
SZSebastián Zavala
Sebastián Zavala
Nicolás GalarceNicolás Galarce
Nicolás Galarce
FSFernando Sánchez
Fernando Sánchez
LSLeonardo Sáenz
Leonardo Sáenz
Salmonella Infantis is a zoonotic pathogen that causes gastroenteritis in humans and animals, with poultry being its main reservoir. In Chile, there are no data to characterize S. Infantis strains in poultry production. In this study, 87 S. Infantis strains were isolated from chicken meat for sale in supermarkets in Santiago, Chile, and characterized according to their virulence genes, biofilm formation abilities, antibiotic susceptibility, and resistance genes. Through polymerase chain reaction or PCR, the strains were analyzed to detect the presence of 11 virulence genes, 12 antibiotic resistance genes, and integrase genes. Moreover, disc diffusion susceptibility to 18 antimicrobials and the ability to form biofilm in vitro were evaluated. Results demonstrated six different virulence gene profiles. Ninety-four percent of the strains were multi-resistant to antibiotics with weak biofilm formation abilities, 63.2% of the strains were broad spectrum β- lactam resistant, and the bla CTX-M-65 gene was amplified in 13 strains. Only 3.4% of the strains were fluoroquinolone resistant, and the qnrB gene was amplified in two strains. Colistin resistance was exhibited in 28.7% of the strains, but mrc genes were not amplified in any strain under study. The isolated S. Infantis strains are pathogenic and antibiotic multi-resistant, and thus, this Salmonella serotype should be under surveillance in the poultry food production chain with the aim of protecting public health.

21 October 2024 in Preventive Veterinary Medicine
Verified
Journal Article
Closed access
MVMaria Belen Vargas
Maria Belen Vargas
EPEkaterina Pokrant
Ekaterina Pokrant
IGIsidora García
Isidora García
RCRocío Cadena
Rocío Cadena
FMFrancisco Mena
Francisco Mena
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javiera cornejo kelly

29 July 2022 in Antibiotics
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Journal Article
Open access
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javiera cornejo kelly
GAGabriela Asenjo
Gabriela Asenjo
SZSebastián Zavala
Sebastián Zavala
LVLucas Venegas
Lucas Venegas
Nicolás GalarceNicolás Galarce
Nicolás Galarce
LLLisette Lapierre
Lisette Lapierre
Antimicrobial resistance (AMR) is a growing global health concern for both animal and public health, and collaborative strategies are needed to combat the threat. The level of awareness and funding for policies focused on reducing AMR varies between countries. The aim of this study was to compare the integrated surveillance systems for AMR in high and low–middle economies of the Asia-Pacific Economic Cooperation and determine whether there was any improvement from 2015 to 2018. We conducted a survey with a group of 21 countries at different development levels. Associations between the economic development level and the questions of AMR awareness and funding were established using Fisher’s exact test. Improvements were identified where countries established public policies for integrated surveillance of AMR. High economies showed greater advancement in several topics related to AMR than low–middle economies. The survey revealed that there is a better understanding surrounding the implications of the emergence of AMR in human medicine than in veterinary medicine, agriculture, and food production. Our results show that countries enhanced overall AMR surveillance over the 4-year-period; however, more research is needed concerning these advances, especially in low–middle economies and the food production sector.

14 August 2023 in Journal of Insects as Food and Feed
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Journal Article
Closed access
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Valeria Sofía VillanuevaValeria Sofía Villanueva
Valeria Sofía Villanueva
FVFabrizzio Valdés
Fabrizzio Valdés
SZSebastián Zavala
Sebastián Zavala
JYJ.M. YáñeZ
J.M. YáñeZ
CVCarolina Valenzuela
Carolina Valenzuela
Currently, insects represent a sustainable alternative to animal-based ingredients for pet food, but there is little information on the willingness of cat owners to incorporate insects into their pet diets. The objective of this study was to assess the perception of cat owners to feed insect-based feed. Between June and August 2021, an on-line survey was provided to cat owners in Chile; of the total number of participants (1684), the majority were female (89.2%), with university education (73%) and omnivorous eating habits (63.7%). Participants had an average of 2 cats per household with indoor lifestyle (70.2%). Most participants (63.6%) were willing to feed insects to their cats. Participants were more willing to feed their cats treats containing 20% insect meal (Overall willingness (OW) = 7.1 ± 3.1, on a scale of 1 to 10), than pure insect meal (OW = 4.9 ± 3.3) or whole insects (OW = 4.4 ± 3.3). Cricket meal treats were the most acceptable. Acceptance toward insects increased when mentioning the environmental benefits of insect production (OW = 7.6 ± 2.9). Participants more willing to offer insect-based treats to their cats were also more willing to use pure insect meal and even whole insects. The reasons for not wanting to include insects in cat feed were disgust, unfamiliarity and preference for traditional pet foods.

12 June 2026 in Animals
Verified
Journal Article
Open access
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PCPaula Cortés
Paula Cortés
MSMaximiliano Antonio Castillo Soto
Maximiliano Antonio Castillo Soto
KVKatherine Codoceo Valenzuela
Katherine Codoceo Valenzuela
KGKevin Gerardo Manriquez González
Kevin Gerardo Manriquez González
BPBelén Pinto
Belén Pinto
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javiera cornejo kelly
Ampicillin residues in animal-derived foods may cause allergic reactions and promote antimicrobial resistance in consumers; however, data on residue behavior in poultry remain limited. This study aimed to evaluate the depletion of ampicillin in muscle and skin plus fat of broiler chickens. Thirty birds were treated with ampicillin intramuscularly (20 mg kg−1 every 24 h for three days) and sacrificed at 0.5, 1, 2, 5, and 9 days post-administration. Samples were analyzed by liquid chromatography coupled with tandem mass spectrometry, a method successfully validated according to Commission Implementing Regulation (EU) 2021/808, VICH GL49 and GL2. Quantification was performed by linear regression from matrix-matched calibration curves. Residue depletion was evaluated following the European Medicines Agency guidelines. Ampicillin residues in muscle were detected only during the first 24 h post-administration (6.50–8.48 µg kg−1). Residues in skin plus fat remained detectable until day 5 post-administration (6.87–59.88 µg kg−1). Based on this, the withdrawal period calculated for skin plus fat was 9 days considering EU maximum residue limit (MRL) and 19 days considering method limit of quantification, with 95% confidence. These results provide critical data on ampicillin residue kinetics under controlled experimental conditions, supporting risk assessments and the establishment of MRLs in broiler chickens by the Codex Alimentarius.