Zarandi Ebrahim Rezazadeh, Mansouri Shahla, Nakhaee Nouzar, Sarafzadeh Farhad, Moradi Mohammad
Department of Microbiology and Virology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
Department of Community Medicine, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
Microb Pathog. 2017 Jun;107:249-253. doi: 10.1016/j.micpath.2017.03.002. Epub 2017 Mar 7.
Toxin production in Clostridium difficile (C. difficile) is a key process for induction of diarrhea. Several factors such as sub-MIC of antibiotics impact on toxin production. The aim of this research is investigation of sub-minimum inhibitory concentration (sub-MIC) of vancomycin (VAN), clindamycin (CLI) separately and in combination with ceftazidime (CAZ) on toxin production in C. difficile. About ∼10 colony forming units (CFU) from 18-h culture of C. difficile ATCC 9689 and clinical isolates A/B/CTD, were cultured anaerobically in the pre-reduced medium with appropriate concentration of separated and in combination antibiotics. After 24 and 48 h, 1 mL of culture was removed, centrifuged and the supernatant stored at-70 °C for later use. The evaluation of toxin production was carried out by the ELISA technique. All antibiotics alone and in combination formats inhibited toxin production over a period of 24 h. This effect is also observed in presence of VAN and CLI during a period of 48 h. Over a 4 h period, CAZ increased toxin production alone and in combination, especially with CLI. The data showed VAN and CLI decrease the level of toxins. In contrast, the CAZ not only increases the level of produced toxin, but also can interfere with VAN and CLI. Based on the results, combination therapy which is performed for treatment or prevention of other infections may cause toxin production and probably the severity of C. difficile AAD to increase.
艰难梭菌产生毒素是引发腹泻的关键过程。抗生素亚最小抑菌浓度等多种因素会影响毒素产生。本研究旨在分别探究万古霉素（VAN）、克林霉素（CLI）以及它们与头孢他啶（CAZ）联合使用时的亚最小抑菌浓度（sub - MIC）对艰难梭菌毒素产生的影响。将来自艰难梭菌ATCC 9689和临床分离株A/B/CTD的18小时培养物中的约10个菌落形成单位（CFU），在含有适当浓度的单独及联合抗生素的预还原培养基中进行厌氧培养。24小时和48小时后，取出1 mL培养物，离心，将上清液储存在 - 70°C以备后用。通过ELISA技术评估毒素产生情况。所有单独使用及联合使用的抗生素在24小时内均抑制毒素产生。在48小时内，万古霉素和克林霉素存在时也观察到这种效果。在4小时内，头孢他啶单独及联合使用时均增加毒素产生，尤其是与克林霉素联合时。数据显示万古霉素和克林霉素降低毒素水平。相反，头孢他啶不仅增加产生的毒素水平，还会干扰万古霉素和克林霉素。基于这些结果，用于治疗或预防其他感染的联合疗法可能会导致毒素产生，并可能增加艰难梭菌相关性腹泻（AAD）的严重程度。
