Shayegan Mehr Farahnaz Sadat, Azimirad Masoumeh, Mansouri Gilani Seyedeh Nazanin, Ghafurian Ayub, Yadegar Abbas
Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Gastroenterol Hepatol Bed Bench. 2019;12(Suppl1):S163-S168.
This study intends to investigate the effect of sub-minimum inhibitory concentration (sub-MIC) of metronidazole, ciprofloxacin, and imipenem on the growth and toxin production in .
is the most common causative agent of hospital-acquired diarrhea. Toxin production in appears to be a critical process for induction of the disease. Several factors such as antibiotics can facilitate growth and toxin production in .
Five strains were grown with and without sub-MIC concentrations of metronidazole, ciprofloxacin, and imipenem (0.5x MIC). The bacterial growth was measured by density at OD620 nm in 0, 4, 8, 12 and 24 h post inoculation. Toxin production was detected using ELISA in culture supernatants as well as in cell pellet.
The five strains showed minor growth variations in the presence and absence of antibiotic sub-MIC values, except for metronidazole, in which the sub-MIC concentration reduced the growth rate of the resistant isolate in comparison with the control without antibiotic. There were no significant variations in the levels of toxin production with the sub-MIC values of antibiotics examined in comparison with antibiotic-free controls. However, the amount of toxin production in the culture supernatant was greater than in the cell pellet.
The findings of this study suggested that sub-MIC concentrations of antibiotics may have minor effects on bacterial growth and toxin production of . Taken together, these findings suggest that presence of antimicrobial agents increased expression levels of certain genes, particularly virulence genes, which may help to survive.
本研究旨在调查甲硝唑、环丙沙星和亚胺培南的亚最小抑菌浓度（亚 MIC）对[研究对象]生长和毒素产生的影响。
[研究对象]是医院获得性腹泻最常见的病原体。[研究对象]产生毒素似乎是诱发该疾病的关键过程。抗生素等多种因素可促进[研究对象]的生长和毒素产生。
五株[研究对象]菌株分别在有和没有亚 MIC 浓度的甲硝唑、环丙沙星和亚胺培南（0.5x MIC）的情况下培养。在接种后 0、4、8、12 和 24 小时通过 OD620 nm 处的密度测量细菌生长。使用 ELISA 在培养上清液以及细胞沉淀中检测毒素产生。
除甲硝唑外，五株菌株在有无抗生素亚 MIC 值的情况下生长变化较小，与无抗生素对照相比，甲硝唑的亚 MIC 浓度降低了耐药菌株的生长速率。与无抗生素对照相比，所检测抗生素的亚 MIC 值对毒素产生水平没有显著差异。然而，培养上清液中的毒素产生量大于细胞沉淀中的毒素产生量。
本研究结果表明，抗生素的亚 MIC 浓度可能对[研究对象]的细菌生长和毒素产生有轻微影响。综上所述，这些发现表明抗菌剂的存在增加了某些基因，特别是毒力基因的表达水平，这可能有助于[研究对象]存活。
