Misuse of antibiotics in veterinary medicine has the potential to generate residues in animal derived products, which could contributing to the development of an important health risk either through the exposure to antibiotic residues or the transfer of antibiotic resistance among foodborne pathogens as well. Tetracycline (TE) and eptomycin (ST) are commonly used as antibiotics in the Egyptian animal husbandry. The objective of this study, quick detection of TE and ST in fresh local beef tissue samples using radioimmunoassay Charm II technique, isolation and identification of relevant highly resistant bacterial strains. In addition to investigating the effect of gamma radiation on the susceptibility of such resistant strains to TE and ST. Tetracycline (TE) was detected in all collected samples, while ST was detected in 38.46% (5/13) and 87.5% (7/8) of meat and liver samples, respectively. Fifty-one bacterial isolates were isolated from the tested samples, among them, the highest resistant isolates to TE or ST were identified as Streptococcus thoraltensis, Proteus mirabilis (2 isolates) and E. coli (3 isolates). Among them, the highest D10-values in phosphate buffer; 0.807 and 0.480; kGy were recorded with S. thoraltensis and E. coli no.3, respectively. Such values increased to record 0.840 and 0.549 kGy, respectively after artificial inoculation into meat, indicating increased resistance to gamma radiation. Gamma radiation at dose 3 kGy increased the susceptibility of S. thoraltensis up to 50% to TE and ST, while the sensitivity of E. coli no.3 reached up 56% to both antibiotics at the same dose. High prevalence of TE in all fresh collected tissue samples suggests an extensively use of TE as antimicrobial in conventional beef production as compared to ST in the Egyptian cows’ husbandry. Moreover, irradiation of food from animal origin by gamma radiation could potentially provide protection against resistant strains. In spite of limited samples used in this study, our data could raise the concerns of public health professionals about a withdrawal period before animals slaughtering, and address the importance of gamma radiation to minimize the hazards of foodborne resistant bacteria.

中文翻译：

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使用Charm II检测牛肉组织中的四环素和链霉素，分离相关抗性细菌，并通过伽马射线控制其抗性。

兽药中抗生素的滥用有可能在动物衍生产品中产生残留物，这可能通过暴露于抗生素残留物或在食源性病原体之间转移抗生素耐药性而导致重要的健康风险。四环素（TE）和表霉素（ST）在埃及畜牧业中通常用作抗生素。这项研究的目的是使用放射免疫分析法Charm II技术快速检测新鲜本地牛肉组织样品中的TE和ST，分离和鉴定相关的高抗性细菌菌株。除了研究γ射线对这种抗性菌株对TE和ST的敏感性的影响外。在所有收集的样品中检测到四环素（TE），而在38.46％（5/13）和87中检测到ST。分别有5％（7/8）的肉和肝样品。从测试样品中分离出51个细菌分离株，其中对TE或ST抗性最高的分离株被鉴定为Thhortensis链球菌，Proteus mirabilis（2个分离株）和E.coli（3个分离株）。其中，磷酸盐缓冲液中的D10值最高；0.807和0.480；kGy分别记录与沙门氏菌和3号大肠杆菌。人工接种到肉后，该值分别增加到记录的0.840和0.549 kGy，表明对伽玛射线的抵抗力增强。剂量为3 kGy的伽马射线辐射可使沙门氏菌对TE和ST的敏感性高达50％，而在相同剂量下，3号大肠杆菌对两种抗生素的敏感性高达56％。与埃及奶牛饲养中的ST相比，TE在所有新鲜采集的组织样本中的高流行表明在常规牛肉生产中广泛使用TE作为抗菌剂。此外，通过伽马射线辐照动物来源的食物可能会提供抵抗耐药菌株的保护作用。尽管本研究使用的样本有限，但我们的数据仍可能引起公共卫生专业人员对动物宰杀前的戒断期的关注，并解决了伽马辐射对最大程度地减少食源性耐药菌危害的重要性。