Ahad Inteshar Ibn, Hossain M Mahtab, Uddin M Aftab, Bari M Latiful, Hossain Muktadir S
Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Bashundhara, Dhaka, 1229, Bangladesh.
Bangladesh Sericulture Research and Training Institute, Rajshahi, Bangladesh.
Curr Microbiol. 2020 Sep;77(9):2172-2180. doi: 10.1007/s00284-020-02023-1. Epub 2020 May 16.
The increasing clinical incidence of antibiotic resistance in bacteria is a major global health care issue. Rampant use of antimicrobials is one of the major reasons of the dramatic rise in antibiotic-resistant bacterial strains. Suitable animal models are required to improve our understanding of bacterial pathogenicity, evolution and search for novel antibiotics. The larvae of the silk moth (commonly called silkworm), Bombyx mori, have been used as an animal model for testing the pathogenicity of a clinically isolated strain of enterohemorrhagic Escherichia coli O157:H7 upon injection through hemolymph. Here, we show that a foodborne E. coli O157:H7 strain can kill silkworm larvae upon injection through either hemolymph (blood) or midgut. Bacterial number in the hemolymph started to increase after 3 h of injection into hemolymph, while the number of viable circulating hemocytes decreased. Administration of four well-known antibiotics into the larval hemolymph up to 100 µg per larva showed therapeutic effect with varying efficacies against E. coli O157:H7 with ceftriaxone and imipenem showing better effect. Our findings indicate that silkworm larvae can be used as an animal model to screen for novel antibiotics that are effective against E. coli O157:H7.
细菌对抗生素耐药性的临床发病率不断上升是一个重大的全球医疗保健问题。抗菌药物的滥用是抗生素耐药菌株急剧增加的主要原因之一。需要合适的动物模型来增进我们对细菌致病性、进化的理解，并寻找新型抗生素。家蚕（通常称为蚕）的幼虫已被用作动物模型，用于测试通过血淋巴注射临床分离的肠出血性大肠杆菌O157:H7菌株的致病性。在此，我们表明，食源性大肠杆菌O157:H7菌株通过血淋巴（血液）或中肠注射均可杀死家蚕幼虫。注射到血淋巴3小时后，血淋巴中的细菌数量开始增加，而存活的循环血细胞数量减少。向幼虫血淋巴中注射高达每只幼虫100μg的四种知名抗生素，对大肠杆菌O157:H7显示出不同疗效的治疗效果，其中头孢曲松和亚胺培南效果更佳。我们的研究结果表明，家蚕幼虫可作为动物模型，用于筛选对大肠杆菌O157:H7有效的新型抗生素。
