Angamarca Evelyn, Castillejo Pablo, Tenea Gabriela N
Biofood and Nutraceutics Research and Development Group, Faculty of Engineering in Agricultural and Environmental Sciences, Universidad Técnica del Norte, Ibarra, Ecuador.
Grupo de Investigación en Biodiversidad, Medio Ambiente y Salud, Universidad de Las Américas, Quito, Ecuador.
Front Microbiol. 2023 Sep 7;14:1228079. doi: 10.3389/fmicb.2023.1228079. eCollection 2023.
Avocados are typically sold in unsanitary conditions at the retail markets in Ecuador, which can raise the risk of microbial contamination. These microorganisms could exhibit multi-antibiotic resistance (MAR), being a serious threat concern to human health. In this study, we aimed to evaluate the microbiota and its antibiotic resistance profile in avocado Guatemalan fruits ( var. ), at ripe stage: immature, firm light green (ready to eat in 4 days), peel (AFPE) and pulp (AFPU), and mature intense green (ready to eat) peel (AMPE) and pulp (AMPU), to gain baseline information on the prevalence of MAR bacteria.
Culture-independent (16S rRNA metagenomics) and culture-dependent approach (to detect specific indicator microorganisms) were used. Moreover, antibiotic susceptibility of selected target indicator bacteria was assessed providing information about the antibiotic resistance (AR) among the groups.
Based on 16S rRNA gene metagenomic analysis, over 99.78% of reads were classified as bacteria in all samples. Shannon diversity index varies from 1.22 to 2.22, with the highest bacterial population assigned to AFPE samples (1327 species). The highest microbial counts of indicator spp. (STAPHY), spp. (ENT), and Listeria spp. (LIST), were detected in AMPE samples. Thirty percent of the selected STAPHYs, and 20.91% of (ENT) clones were resistant to various classes of antibiotics. The MAR index varies between 0.25 to 0.88 and was clone-, and fruit ripe stage-dependent.
The results indicated that ready to eat avocados contained detectable levels of MAR bacteria, including methicillin resistant (MR)-STAPHY, which may act as a potential vector for the spread of antibiotic resistance. To achieve the increase of the production and marketing of Fuerte cultivar in Ecuador, it is vitally important to consider valuable strategies to protect the fruits at the early ripe stage in future. Thus, it is crucial to set up efficient control measures and develop coordinated strategies to guarantee the microbiological quality of the food.
在厄瓜多尔的零售市场上，牛油果通常在不卫生的条件下销售，这可能会增加微生物污染的风险。这些微生物可能表现出多重抗生素耐药性（MAR），对人类健康构成严重威胁。在本研究中，我们旨在评估危地马拉牛油果果实（品种 ）在成熟阶段（未成熟、硬的浅绿（4天后可食用）、果皮（AFPE）和果肉（AFPU））以及成熟深绿（可食用）果皮（AMPE）和果肉（AMPU）中的微生物群及其抗生素耐药性谱，以获取关于MAR细菌流行率的基线信息。
采用非培养法（16S rRNA宏基因组学）和培养法（检测特定指示微生物）。此外，评估了选定目标指示细菌的抗生素敏感性，提供了各群体中抗生素耐药性（AR）的信息。
基于16S rRNA基因宏基因组分析，所有样本中超过99.78%的读数被归类为细菌。香农多样性指数在1.22至2.22之间变化，AFPE样本中的细菌种类最多（1327种）。在AMPE样本中检测到指示菌 属（葡萄球菌属，STAPHY）、 属（肠球菌属，ENT）和李斯特菌属（李斯特菌属，LIST）的最高微生物计数。所选葡萄球菌属的30%和肠球菌属（ENT）克隆的20.91%对各类抗生素耐药。MAR指数在0.25至0.88之间变化，且因克隆和果实成熟阶段而异。
结果表明，即食牛油果含有可检测水平的MAR细菌，包括耐甲氧西林（MR）-葡萄球菌，这可能成为抗生素耐药性传播的潜在载体。为了增加厄瓜多尔富埃尔特品种的产量和市场销量，未来在果实成熟早期考虑采取有价值的保护策略至关重要。因此，建立有效的控制措施并制定协调策略以保证食品的微生物质量至关重要。
