多重耐药与药物敏感型大肠杆菌在牛肉中生长预测模型的研究

Predictive Growth Models of Multidrug-resistant and Drug-sensitive Escherichia coli in Beef

摘要:

本文以多重耐药与药物敏感大肠杆菌为研究对象，将其分别接种到新鲜牛肉中，置于10 ℃、20 ℃、30 ℃、40 ℃温度下培养，利用25 ℃和35 ℃两个温度作为验证。运用Origin 8.0建立一级和二级模型，得出这两种大肠杆菌在不同温度条件下的最大比生长速率与迟滞期。结果表明：修正的Gompertz模型和修正的Logistic模型可以很好地模拟牛肉中多重耐药与药物敏感型大肠杆菌在不同温度下的生长情况(R2>0.95)，其中药物敏感型大肠杆菌的迟滞期比多重耐药型大肠杆菌短。采用Belehradek模型说明模型中的参数值(U和LPD)与温度之间的函数关系，温度与最大比生长速率呈现线性关系。利用建立的生长动力学模型求得25 ℃和35 ℃的最大比生长速率，与实际值比较，二者相对误差较小，证明建立的模型可靠。本研究为控制牛肉中大肠杆菌提供理论依据。

Abstract:

Multidrug-resistant and drug-sensitive strains of Escherichia coli were inoculated separately into fresh beef, and cultured at 10 ℃, 20 ℃, 30 ℃, and 40 ℃. The growth data at 25 ℃ and 35 ℃ were used for validation. The primary and secondary models were set up using Origin 8.0 in order to obtain the maximum specific growth rate and lag phase of the two strains at different temperatures. The results showed that the modified Gompertz and Logistic models fit well with the growth parameters of the two multidrug-resistant and drug-sensitive strains in beef (R2＞0.95). The lag phase of drug-sensitive E. coli was shorter than that of the drug-resistant strain. The functional relationship between the parameter values (U and LPD) and temperature was explained by a Belehvadek model. The experimental results showed that the temperature and maximum specific growth rate presented a linear relationship. The maximum specific growth rates at 25 ℃ and 35 ℃ were computed by the secondary growth kinetic model. The deviation value was relatively small when compared with the predicted values and actual values, indicating that the growth model was reliable. These experimental results provide a theoretical basis for the control of E. coli in beef.