ABSTRACT
Background An ethylnitrosourea(ENU)-induced mutant strain C57BL/6 mouse model has been established by our research group.This model is proved to have the spontaneous phenotype of corneal opacity and the typical pathological process similar to human keratitis.Therefore,this model is expected to be a good animal model in the research of the mechanism,hereditary property,and development of drugs for corneal infectious diseases.Objective The present study is to investigate the biological features of opportunistic pathogens using a mouse Staphylococcus-infected corneal model(C57BL/6 mouse) induced by N-ethyl-N-nitrosourea(ENU),and offers an evidence of stability in this animal model.Methods Ten-week-old male C57BL/6 mice were treated with ENU at 150mg/kg by intraperitoneal injection,and then mated with female mice after 60 days.Corneal opacity mutant mice in the F1 generation were selected to backcross with C57BL/6 mice.The bacteria were isolated from the eyeballs of the mutants and cultivated,purified and identified.Drug sensitivity assay was carried out to screen for effective antibiotics for clinic medical care.Results The staphylococcus-infected corneal mouse model(B6-Co) was established successfully,and the Staphylococcus sciuri strain was separated and purified,and then the sensitive antibiotics were distinguished from resistant ones.The sensitive drugs for Staphylococcus sciuri included azithromycin,clindamycin,chloramphenicol,gentamicin,rifampicin,tetracycline,amikacin,sulfamethoxazole compound sinomin,minocycline,levofloxacin,cephalothin,cefotaxime,and furazolidone;whereas this Staphylococcal strain was resistant to cefoxitin,penicillin,ampicillin,novobiocin.Nitrofurantoin showed an intermediate sensitivity.Conclusion The C57BL/6 mouse model is a spontaneous-derived animal model that is infected by coagulase-negative staphylococci,among which the most abundant strain is Staphylococcus sciuri.