Attachment of Escherichia coli O157:H7 to the surfaces and internal structures of apples as detected by confocal scanning laser microscopy
Attachment of Escherichia coli O157:H7 to the surfaces and internal structures of apples as detected by confocal scanning laser microscopy
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DOI：
10.1128/aem.66.11.4679-4687.2000
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发表时间：
2000-11-01
影响因子：
4.4
通讯作者：
Beuchat, LR
中科院分区：
文献类型：
--
作者：
Burnett, SL;Chen, JR;Beuchat, LR
使用共焦扫描激光显微镜 (CSLM) 来证明用编码绿色荧光蛋白 (GFP) 的质粒转化的大肠杆菌 O157:H7 附着在未打蜡的 Red Delicious 品种的表面和内部结构内。苹果。将 2 或 25 ℃ 的苹果在 2 或 25 ℃ 下接种大肠杆菌 O157:H7 细胞悬液，负温差（冷接种物、暖苹果）、正温差（温接种物、冷苹果）和无温差（温接种物、暖苹果）与压差（大气压与 10,130 Pa）相结合对细胞附着和浸润的影响 已确定。接受所有测试参数组合的苹果外表面的 CSLM 立体图像显示，细胞优先附着于表面蜡质角质层的不连续性和刺伤周围的受损组织，其中在皮肤表面以下 70 微米的深度观察到病原体。皮孔的附着是零星的，但偶尔在深度达 40 微米处观察到。无论接种期间的温差如何，在所有检查的苹果中都观察到通过花管的渗透以及对种子、软骨果皮和内部毛的附着。压差对大肠杆菌 O157:H7 的渗透或附着没有影响，使用图像分析对组织内不同深度的细胞进行计数，以定量比较渗透到不同苹果结构的程度以及温差的影响。与其他检查部位相比，穿刺伤口的深度更深，含有更多数量的病原体。与在无温差下接种的苹果相比，在负温差下接种的苹果的完整皮肤以及皮孔、赤褐色区域和花管上的细胞附着或浸润更多。结果表明，附着在苹果内部核心结构或组织内的 E. call O157:H7 可能会逃避去污处理。旨在将消毒剂输送到这些位置或去除活细胞的干预措施。需要开发和验证通过其他方式从苹果中提取的大肠杆菌 O157:H7 和其他病原体。
Confocal scanning laser microscopy (CSLM) was used to demonstrate the attachment of Escherichia coli O157:H7 transformed with a plasmid encoding for green fluorescent protein (GFP) to the surface and within the internal structures of nonwaxed Red Delicious cv. apples. Apples at 2 or 25 degreesC were inoculated with an E. coli O157:H7 cell suspension at 2 or 25 degreesC, The effect of a negative temperature differential (cold inoculum, warm apple), a positive differential (warm inoculum, cold apple), and no differential (warm inoculum, warm apple), in combination with a pressure differential (atmospheric versus 10,130 Pa), on the attachment and infiltration of cells was determined. CSLM stereo images of external surfaces of apples subjected to all combinations of test parameters showed preferential cellular attachment to discontinuities in the waxy cuticle on the surface and to damaged tissue surrounding puncture wounds, where the pathogen was observed at depths up to 70 mum below the skin surface. Attachment to lenticels was sporadic but was occasionally observed at depths of up to 40 mum, Infiltration through the floral tube and attachment to seeds, cartilaginous pericarp, and internal trichomes were observed in all apples examined, regardless of temperature differential during inoculation. The pressure differential had no effect on infiltration or attachment of E. coli O157:H7, Image analysis to count cells at various depths within tissues was used to quantitatively compare the extent of infiltration into various apple structures as well as the effects of the temperature differential. Puncture wounds harbored greater numbers of the pathogen at greater depths than did other sites examined. Attachment or infiltration of cells was greater on the intact skin and in lenticels, russet areas, and the floral tube of apples inoculated under a negative temperature differential compared to those inoculated under no temperature differential, The results suggest that E. call O157:H7 attached to internal core structures or within tissues of apples may evade decontamination treatments. Interventions designed to deliver disinfectants to these locations or to remove viable cells off. coli O157:H7 and other pathogens from apples by other means need to be developed and validated.