In vivo microbial challenge models are an important tool to study the mechanistic details of bovine mastitis. A critical element of these studies is the enumeration of the bacterial load in milk to determine if interventions induce physiological changes that affect bacterial clearance. Herein, we use Escherichia coli P4 enumeration from milk in the context of mastitis microbial challenge models to show that use of a microdrip method reduces cost and time without negatively affecting rigor and reproducibility. We used E. coli P4–spiked milk samples as a model to test an alternative to Escherichia and costly standard plating methods. Importantly, linear regression analysis comparing the microdrip and standard plate count shows no difference between the methods or technicians, and Bland–Altman analysis shows enumeration via microdrip method has a slight positive bias, proportional across the tested concentrations compared with the standard method. Additionally, the microdrip method has a sensitivity of 103 cfu/mL compared with 104 cfu/mL for quantitative PCR. Economic analysis of consumable cost shows the microdrip method is nearly half as expensive compared with the standard plate method. Furthermore, these data also show milk samples can be stored at 4°C or −80°C without affecting colony-forming unit count, enabling batched sample processing. Taken together, the data presented here indicate that the microdilution and microdrip method can be used to decrease time and cost of E. coli P4 enumeration from milk without negatively affecting the rigor and reproducibility of the data. Future studies can develop this method for use in broader applications, such as validation of additional challenge pathogens for research purposes, clinical monitoring of mastitis cases, or bulk tank monitoring of pathogens.
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号