Bardsley Cameron A, Weller Daniel L, Ingram David T, Chen Yuhuan, Oryang David, Rideout Steven L, Strawn Laura K
Department of Food Science and Technology, Eastern Shore Agricultural Research and Extension Center, Virginia Tech, Painter, VA, United States.
Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY, United States.
Front Microbiol. 2021 Mar 16;12:590303. doi: 10.3389/fmicb.2021.590303. eCollection 2021.
The use of untreated biological soil amendments of animal origin (BSAAO) have been identified as one potential mechanism for the dissemination and persistence of in the produce growing environment. Data on factors influencing concentration in amended soils are therefore needed. The objectives here were to (i) compare die-off between 12 strains following inoculation in amended soil and (ii) characterize any significant effects associated with soil-type, irrigation regimen, and amendment on survival and die-off. Three greenhouse trials were performed using a randomized complete block design. Each strain (~4 log CFU/g) was homogenized with amended or non-amended sandy-loam or clay-loam soil. levels were enumerated in 25 g samples 0, 0.167 (4 h), 1, 2, 4, 7, 10, 14, 21, 28, 56, 84, 112, 168, 210, 252, and 336 days post-inoculation (dpi), or until two consecutive samples were enrichment negative. Regression analysis was performed between strain, soil-type, irrigation, and (i) time to last detect (survival) and (ii) concentration at each time-point (die-off rate). Similar effects of strain, irrigation, soil-type, and amendment were identified using the survival and die-off models. Strain explained up to 18% of the variance in survival, and up to 19% of variance in die-off rate. On average survived for 129 days in amended soils, however, survived, on average, 30 days longer in clay-loam soils than sandy-loam soils [95% Confidence interval (CI) = 45, 15], with survival time ranging from 84 to 210 days for the individual strains during daily irrigation. When strain-specific associations were investigated using regression trees, Javiana and Saintpaul were found to survive longer in sandy-loam soil, whereas most of the other strains survived longer in clay-loam soil. also survived, on average, 128 days longer when irrigated weekly, compared to daily (CI = 101, 154), and 89 days longer in amended soils, than non-amended soils (CI = 61, 116). Overall, this study provides insight into survival following contamination of field soils by BSAAO. Specifically, survival may be strain-specific as affected by both soil characteristics and management practices. These data can assist in risk assessment and strain selection for use in challenge and validation studies.
未经处理的动物源生物土壤改良剂（BSAAO）的使用已被确定为农产品生长环境中病原菌传播和持续存在的一种潜在机制。因此，需要有关影响改良土壤中病原菌浓度的因素的数据。本研究的目的是：（i）比较接种到改良土壤中的12种病原菌菌株的死亡情况；（ii）描述与土壤类型、灌溉方式和改良剂对病原菌存活和死亡的任何显著影响。采用随机完全区组设计进行了三次温室试验。将每种菌株（约4 log CFU/g）与改良或未改良的砂壤土或粘壤土混合均匀。在接种后0、0.167（4小时）、1、2、4、7、10、14、21、28、56、84、112、168、210、252和336天（dpi），或直到连续两个样本富集阴性时，对25 g土壤样本中的病原菌数量进行计数。对菌株、土壤类型、灌溉方式与（i）最后检测到病原菌的时间（存活）和（ii）每个时间点的病原菌浓度（死亡速率）进行回归分析。使用存活和死亡模型确定了菌株、灌溉、土壤类型和改良剂的相似影响。菌株可解释存活差异的18%，以及死亡速率差异的19%。在改良土壤中，病原菌平均存活129天，然而，在粘壤土中，病原菌平均比在砂壤土中多存活30天[95%置信区间（CI）=45，15]，在每日灌溉期间，单个菌株的存活时间为84至210天。当使用回归树研究菌株特异性关联时，发现Javiana菌和Saintpaul菌在砂壤土中存活时间更长，而其他大多数菌株在粘壤土中存活时间更长。与每日灌溉相比，每周灌溉时病原菌平均也多存活128天（CI = 101，154），在改良土壤中比在未改良土壤中多存活89天（CI = 61，116）。总体而言，本研究深入了解了BSAAO污染田间土壤后病原菌的存活情况。具体而言，病原菌的存活可能因菌株而异，受土壤特性和管理措施的影响。这些数据有助于风险评估和菌株选择，用于挑战和验证研究。
