摘要

    背景：抗生素抗性细菌（ARB）和抗生素抗性基因（ARGs）已被
被视为新兴污染物，甚至可能与人类健康息息相关。
方法：探讨ARB的致病风险和ARB的水平基因转移（HGT）风险。
无论是细胞外ARG（eARG）和细胞内ARG（iARG），体外消化模型都是
建立以模拟ARB和ARGs通过消化道的过程。 CTC / DAPI-FCM
检测用于研究ARB在消化过程中的存活情况以及基因（包括tetA，
tetG，tetM，sul1，sul2，bla EBC
，bla FOX
，intl1和16S rRNA）通过QPCR确定。
结果：结果表明，ARB主要受胃液pH值的影响。约99％ARB（总计
pH值为2.0的胃液杀死了2.45×109–2.54×109的人群，造成了严重的肝损伤。
细菌细胞膜，但仍超过80％的ARB（总人口为2.71×109–3.90×109）
当胃液的pH值增加到3.0或更高时，它会与完整的细胞膜一起存活。 ARGs，int1和
当大多数细菌死亡时，即使在极端pH下也可以检测到16S rRNA。 eARG（占
总基因的0.03％–24.56％）明显小于iARG。 eARGs显示出更大的HGT潜力
与iARG相比，这表明转化比共轭更容易发生。转移
电位的顺序为：tet（100％）> sul（75％）> bla（58％），与intI1的高度相关
使用tetA和sul2（p <0.01）。此外，pH 1.0的胃液可能会降低胃液的转移频率。
与对照组相比，ARGs降低了2-3个数量级，但仍威胁着人类健康。
结论：在消化液的作用下，ARGs仍具有较高的基因水平转移能力
潜在的可能性，表明食源性ARB会引起ARGs水平转移到肠道细菌的风险。

    Background: Antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) have been
considered as emerging contaminants, which even might be closely related to human health.
Methods: To investigate the disease-producing risk of ARB and the horizontal gene transfer (HGT) risks of
both extracellular ARGs (eARGs) and intracellular ARGs (iARGs), an in vitro digestion model was
established to simulate the process of ARB and ARGs going through digestive tract. CTC/DAPI-FCM
assay was used to study the survival of ARB during digestion, and the changes of genes (including tetA,
tetG, tetM, sul1, sul2, bla EBC
, bla FOX
, intI1 and 16S rRNA) were determined by QPCR.
Results: The results showed that ARB were mostly affected by pH of gastric juice. About 99% ARB (total
population of 2.45 × 109–2.54 × 109) were killed by the gastric juice of pH 2.0 for the severely damage of
bacterial cell membrane, but more than 80% ARB (total population of 2.71 × 109–3.90 × 109) were still
alive with intact cell membrane when the pH of gastric juice increased to 3.0 and above. ARGs, intI1 and
16S rRNA could be detectable even at extreme pH when most bacteria died. The eARGs (accounting for
0.03%–24.56% of total genes) were less than iARGs obviously. The eARGs showed greater HGT potential
than that of iARGs, suggesting transformation occurs more easily than conjugation. The transfer
potential followed the order as: tet (100%) > sul (75%) > bla (58%), related to the high correlation of intI1
with tetA and sul2 (p < 0.01). Moreover, gastric juice of pH 1.0 could decrease the transfer frequency of
ARGs by 2–3 order of magnitude compared to the control, but still threatening human health.
Conclusions: Under the treatment of digestive juice, ARGs still have high gene horizontal transfer
potential, suggesting that food-borne ARB pose a risk of ARGs horizontal transfer to intestinal bacteria.

    https://assets.researchsquare.com/files/rs-392269/v1/d05bb295-1157-4719-bba6-4513dc84eefb.pdf