Bacteriology unit, Tanta lab. (AHRI), Animal Health Research Institute, Agricultural Research Center (ARC), Giza, Egypt.
Pharmacology unit, Tanta lab. (AHRI), Animal Health Research Institute, Agricultural Research Center (ARC), Giza, Egypt.
BMC Vet Res. 2023 Aug 4;19(1):108. doi: 10.1186/s12917-023-03643-y.
Colibacillosis is one of the broilers' most dominant bacterial diseases, either as a primary or a secondary infection. As E. coli antimicrobial drug resistance is rising; there is a need to develop new approaches to its control. In light of this, a comparative study of the in-vitro antibacterial activity of Arabic gum stabilized zinc and copper nanoparticles (AG-ZnNPs and AG-CuNPs) against PCR-identified field avian pathogenic E. coli (APEC) strains and virulence genes (ibeA, hlyA, iss, pap C and ompA) was applied to study the therapeutic effect of zinc and copper nanoparticles to be used as an antibiotic alternative (Nanobiotic). Furthermore, the in-vivo effects of CuNPs were evaluated. Additionally, the CuNPs liver and muscle residues with or without infection were examined. The eighty broilers were divided into four groups; G1: negative control, G2: infected control with E. coli O17, G3: non-infected treated (AG-CuNPs 50 mg/kg body weight), and G4: infected treated (AG-CuNPs 50 mg/kg body weight). AG-CuNPs treatment was given to broilers for five days in drinking water.
E. coli was isolated from diseased broilers at an average incidence rate of 20% from intestinal and liver samples. All identified serotypes (O17, O78, O91, O121, and O159) were resistant to AG-ZnNPs and sensitive to AG-CuNPs. AG-CuNPs minimal inhibitory and bactericidal concentrations (MIC and MBC) for O17 were 7.5 and 60 mg/ml, respectively. Conventional uniplex PCR results showed that strain O17 contained virulence genes (ibeA, hlyA, iss, and papC), where AG-CuNPs significantly reduced the expression of all target genes when examined by Real-time quantitative PCR. Additionally, the bactericidal activity of AG-CuNPs on O17 was 100% at 20 minutes and 40 mg/ml and confirmed by transmission electron microscopy. Furthermore, no mortality was recorded in treated groups compared to G2. Subsequently, no E. coli was re-isolated from the liver in the G4 after treatment. The total protein, albumin, globulin, and lysozyme activity were significantly increased in G4 compared to G2, while the activities of liver enzymes (alanine aminotransferase (ALT), Gamma-glutamyl transferase (GGT), and alkaline phosphatase (ALP)) were markedly decreased in G4 compared to G2. Additionally, uric acid, creatinine, and C-reactive protein levels were decreased in G4 compared to G2. However, the liver enzymes, kidney functions, C-reactive protein levels, and Cu residues were non-significantly changed in G4 compared to G1.
Green synthesized AG-CuNPs are recommended as an effective antimicrobial alternative against APEC strains.
大肠杆菌病是肉鸡最主要的细菌性疾病之一，无论是原发性感染还是继发性感染。由于大肠杆菌对抗菌药物的耐药性不断上升，因此需要开发新的控制方法。有鉴于此，本研究应用阿拉伯胶稳定的锌和铜纳米粒子（AG-ZnNPs 和 AG-CuNPs）的体外抗菌活性的比较研究，针对 PCR 鉴定的禽源致病性大肠杆菌（APEC）菌株和毒力基因（ibeA、hlyA、iss、papC 和 ompA）进行了研究，以探讨锌和铜纳米粒子作为抗生素替代品（纳米生素）的治疗效果。此外，还评估了 CuNPs 的体内效果。另外，还检查了有无感染的 CuNPs 肝和肌肉残留。将 80 只肉鸡分为 4 组；G1：阴性对照，G2：大肠杆菌 O17 感染对照，G3：未感染治疗（AG-CuNPs 50mg/kg 体重），G4：感染治疗（AG-CuNPs 50mg/kg 体重）。AG-CuNPs 治疗在饮用水中给予肉鸡 5 天。
从肠道和肝脏样本中分离出平均发病率为 20%的患病肉鸡大肠杆菌。所有鉴定的血清型（O17、O78、O91、O121 和 O159）均对 AG-ZnNPs 有耐药性，对 AG-CuNPs 敏感。O17 的 AG-CuNPs 最小抑菌和杀菌浓度（MIC 和 MBC）分别为 7.5 和 60mg/ml。常规的单重 PCR 结果显示，O17 菌株含有毒力基因（ibeA、hlyA、iss 和 papC），而实时定量 PCR 显示 AG-CuNPs 显著降低了所有靶基因的表达。此外，AG-CuNPs 对 O17 的杀菌活性在 20 分钟和 40mg/ml 时为 100%，并通过透射电子显微镜得到证实。此外，与 G2 相比，治疗组无死亡记录。随后，G4 中未从肝脏中重新分离出大肠杆菌。与 G2 相比，G4 中的总蛋白、白蛋白、球蛋白和溶菌酶活性显著升高，而 G4 中的丙氨酸氨基转移酶（ALT）、γ-谷氨酰转移酶（GGT）和碱性磷酸酶（ALP）的活性显著降低。此外，与 G2 相比，G4 中的尿酸、肌酐和 C 反应蛋白水平降低。然而，与 G1 相比，G4 中的肝酶、肾功能、C 反应蛋白水平和 Cu 残留量没有显著变化。
建议使用绿色合成的 AG-CuNPs 作为对抗 APEC 菌株的有效抗菌替代品。
