Antibiotic resistance bacteria and antibiotic resistance genes survived from the extremely acidity posing a risk on intestinal bacteria in an in vitro digestion model by horizontal gene transfer

• Published in: Ecotoxicology and environmental safety 2022-12, Vol.247, p.114247-114247, Article 114247
• Main Authors: Zhou, Min, Cai, Qiujie, Zhang, Chaonan, Ouyang, Pengqian, Yu, Ling, Xu, Yanbin
• Format: Article
• Language: English
• Subjects: Antibiotic resistance bacteria; Antibiotic resistance genes; Digestion model; Health risk; Horizontal gene transfer
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2022.114247

Antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) are emerging contaminants posing risk to human health. To investigate the pathogenic ARBs and the horizontal gene transfer (HGT) via both extracellular ARGs (eARGs) and intracellular ARGs (iARGs), an in vitro digestion simulation system was established to monitoring the ARB and ARGs passing through the artificial digestive tract. The results showed that ARB was mostly affected by the acidity of the gastric fluid with about 99% ARB (total population of 2.45 × 109–2.54 × 109) killed at pH 2.0 and severe damage of bacterial cell membrane. However, more than 80% ARB (total population of 2.71 × 109–3.90 × 109) survived the challenge when the pH of the gastric fluid was 3.0 and above. Most ARB died from the high acidity, but its ARGs, intI1 and 16 S rRNA could be detected. 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 that transformation occurred more easily than conjugation. The transferring potential followed: tet (100%) > sul (75%) > bla (58%), related to the high correlation of intI1 with tetA and sul2 (p