School of Public Health, Curtin University, Kent Street, Bentley, Western Australia, Australia; CSIRO Agriculture and Food, Coopers Plains, Queensland, Australia.
School of Public Health, Curtin University, Kent Street, Bentley, Western Australia, Australia.
Food Microbiol. 2021 Jun;96:103711. doi: 10.1016/j.fm.2020.103711. Epub 2020 Dec 17.
Detection and isolation of Shiga toxin-producing Escherichia coli (STEC) from manufacturing beef is challenging and it may be affected by microbial changes during enrichment. This study was designed to understand population changes during enrichment of beef from an integrated (Samples A and B) and a fragmented (Samples C and D) abattoir. The samples were enriched in buffered peptone water (BPW), Assurance GDS MPX top 7 STEC mEHEC®, BAX® E. coli O157:H7 MP and PDX-STEC media then were processed for 16 S rRNA sequencing. Escherichia dominated Sample B enrichment broths regardless of the media used (71.6-97.9%) but only in mEHEC broth (79.6%) of Sample A. Escherichia was dominant in Sample C in mEHEC (95.2%) and PDX-STEC (99.2%) broths but less in BPW (58.5%) and MP (64.9%) broths. In Sample D, Clostridium dominated in mEHEC (65.5%), MP (80.2%) and PDX-STEC (90.6%) broths. O157 STEC was isolated from Sample C only. The study suggested that MP may not be as effective as mEHEC and PDX-STEC and that Clostridium could interfere with enrichment of Escherichia. Understanding the ecological changes during enrichment provides meaningful insight to optimising the enrichment protocol for STEC and subsequently enhance the efficiency of STEC detection.
从牛肉中检测和分离产志贺毒素大肠杆菌（STEC）具有挑战性，并且可能会受到富集过程中微生物变化的影响。本研究旨在了解来自综合（样品 A 和 B）和碎片化（样品 C 和 D）屠宰场的牛肉富集过程中的种群变化。这些样品在缓冲蛋白胨水中进行富集（BPW），然后在 Assurance GDS MPX top 7 STEC mEHEC®、BAX® E. coli O157：H7 MP 和 PDX-STEC 培养基中进行处理，然后进行 16S rRNA 测序。无论使用哪种培养基，样品 B 的富集肉汤中都以大肠杆菌为主（71.6-97.9%），但在样品 A 的 mEHEC 肉汤中仅为 79.6%。在样品 C 中，大肠杆菌在 mEHEC（95.2%）和 PDX-STEC（99.2%）肉汤中占优势，但在 BPW（58.5%）和 MP（64.9%）肉汤中占优势较少。在样品 D 中，在 mEHEC（65.5%）、MP（80.2%）和 PDX-STEC（90.6%）肉汤中以梭菌为主。仅从样品 C 中分离出 O157 STEC。该研究表明，MP 可能不如 mEHEC 和 PDX-STEC 有效，并且梭菌可能会干扰大肠杆菌的富集。了解富集过程中的生态变化为优化 STEC 的富集方案提供了有意义的见解，从而提高 STEC 的检测效率。
