Banca de DEFESA: PAULA FERNANDA ALVES FERREIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : PAULA FERNANDA ALVES FERREIRA
DATE: 17/02/2025
TIME: 09:00
LOCAL: videoconferência
TITLE:

Influence of Agricultural Management Systems and Heavy Metals on Antimicrobial Resistance in Soils and Animal Waste from a One Health Perspective.

KEY WORDS:

Antibiotic. Environmental impacts. One Health. Bacterial resistance.

PAGES: 151
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Ciência do Solo
SUMMARY:

Agricultural environments play a significant role as sources and pathways for the dissemination of antimicrobial resistance. Furthermore, factors such as the presence of metals can promote the persistence of resistance. This study aimed to evaluate how different management systems and the presence of heavy metals influence antimicrobial resistance in soils and animal residues. A literature review was conducted to identify articles addressing antimicrobial resistance in agricultural environments, with a focus on animal residues used as fertilizers, soils, and irrigation water in Brazil up to the year 2023. Although the number of studies exploring this topic is still quite limited, all the reviewed articles reported the detection of resistant bacteria, antimicrobial resistance genes (ARGs) from various classes, and mobile genetic elements. The chemical characterization, bacterial diversity, and abundance of ARGs in soils from areas of intensive vegetable cultivation and forested regions were evaluated. Different land uses affected chemical attributes, leading to variations in the diversity and structure of the microbial community. Among the 18 target genes evaluated, seven were detected in the soils studied, with the oprD gene standing out due to its higher abundance, being identified exclusively in cultivated areas. Bacteria belonging to the genera Enterobacter, Escherichia, Klebsiella and Proteus, isolated during the composting of horse manure and organic and conventional poultry litter, were assessed for growth under varying concentrations of copper sulfate, zinc sulfate, and lead nitrate. Most isolates exhibited reduced growth with increasing concentrations of salts, followed by growth recovery at the highest concentration. Additionally, 102 bacterial isolates from the composting process were evaluated for antimicrobial resistance in the presence and absence of heavy metals using the disk diffusion method. Most bacterial isolates were sensitive to antimicrobials under both conditions; however, some showed alterations in their sensitivity or resistance profiles when exposed to heavy metals, particularly in zinc-containing media. Bacteria that developed resistance to imipenem in the presence of zinc sulfate were subsequently tested for resistance to meropenem. Among these, 16 isolates became resistant to meropenem in the presence of zinc. These resistant strains were further tested for the production of metallobetalactamases (MBLs), resulting in four MBLs positive isolates belonging to the species Enterobacter cloacae, Enterobacter kobei and Proteus mirabilis. Based on these findings, it is evident that management systems influence the structure of the bacterial community and play a critical role in modulating antimicrobial resistance in soils and animal waste. This underscores the need for further studies on this topic. Agricultural environments can act as reservoirs and sources of resistance, posing significant risks to public health. These findings highlight the importance of addressing this issue through a One Health approach that integrates human, animal, and environmental health.

COMMITTEE MEMBERS:
Externo à Instituição - EDNALDO DA SILVA ARAÚJO - EMBRAPA
Interno - 2213075 - EVERALDO ZONTA
Externo à Instituição - GUSTAVO RIBEIRO XAVIER - EMBRAPA
Presidente - 1815763 - IRENE DA SILVA COELHO
Externa ao Programa - 1722406 - SHANA DE MATTOS DE OLIVEIRA COELHO - null