Clostridioides difficile infection (CDI) is the primary cause of hospital-acquired diarrhea, and responsible for over 500,000 enteric infections a year in the United States alone. Although most patients with CDI are successfully treated with metronidazole or vancomycin, the high rate of recurrence is still a serious problem, in which case these antibiotics are usually not very effective. The primary objective of this research is to develop a potentially effective therapeutic agent against C. difficile that are resistant to metronidazole or vancomycin. The susceptibility to metronidazole and vancomycin was examined with 194 C. difficile clinical isolates. Sixty of these isolates chosen based on a variety of criteria were examined for their susceptibility against the 4-chloro-1-piperidin-1ylmethyl-1H-indole-2,3-dione compound (Raja 42), a novel isatin–benzothiazole analogue containing a gamma-lactam structure, as we previously found that this novel compound is effective against a variety of different bacteria. Most of the 60 isolates were resistant to ceftriaxone and ciprofloxacin, raising the possibility that they might have been exposed previously to these or structurally similar antibiotics (e.g., β-lactam and quinolone compounds). Among the isolates, 48 (80%) and 54 (90%) were susceptible to metronidazole and vancomycin, respectively. Raja 42 was found to be effective against most of the isolates, especially so against metronidazole-resistant C. difficile. Most importantly, five isolates that show resistance to metronidazole and vancomycin were sensitive to Raja 42. Thus, Raja 42, a gamma lactam antibiotic, has the potential to effectively control C. difficile strains that are resistant to metronidazole and vancomycin.
Clostridioides difficile感染(CDI)是医院获得性腹泻的主要原因,仅在美国每年就导致超过50万肠道感染。尽管大多数CDI患者成功地接受了甲硝唑或万古霉素治疗,但高复发率仍然是一个严重的问题,在这种情况下,这些抗生素通常不是非常有效。本研究的主要目标是开发一种可能有效的治疗剂,用于治疗对甲硝唑或万古霉素耐药的Clostridioides difficile。使用194个C. difficile临床分离株检查其对甲硝唑和万古霉素的敏感性。基于各种标准选择了60个分离株,检查它们对4-氯-1-哌啶-1-甲基-1H-吲哚-2,3-二酮化合物(Raja 42)的敏感性,这是一种含有γ-内酰胺结构的新型吲哚-苯并噻唑类似物,我们之前发现这种新型化合物对各种不同的细菌都有效。60个分离株中大多数对头孢曲松和环丙沙星具有耐药性,这提高了它们可能之前接触过这些或结构类似的抗生素(例如β-内酰胺和喹诺酮化合物)的可能性。在这些分离株中,48个(80%)和54个(90%)对甲硝唑和万古霉素具有敏感性。发现Raja 42对大多数分离株都很有效,特别是对甲硝唑耐药的C. difficile。最重要的是,5个对甲硝唑和万古霉素耐药的分离株对Raja 42敏感。因此,gamma内酰胺类抗生素Raja 42具有有效控制对甲硝唑和万古霉素耐药的C. difficile菌株的潜力。