Optimization of an efficient solid-phase enrichment medium for Salmonella detection using response surface methodology
Feng Tang,
Zhi Chen,
Feng Wang,
Hongyan Hou,
Weiyong Liu,
Han Xiao,
Jiao Hu,
Yan Xiong,
Hui Zhang,
Zhongju Chen,
Hanming Peng,
Jun Lu,
Wanjun Luo,
Ying Zhao,
Miao Lin
Affiliations
Feng Tang
Department of Laboratory Medicine, Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science & Technology
Zhi Chen
Microbiological Laboratory, Wuhan Center for Disease Control and Prevention
Feng Wang
Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology
Hongyan Hou
Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology
Weiyong Liu
Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology
Han Xiao
Biobank, Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science & Technology
Jiao Hu
Institute of Environmental Safety, Wuhan Academy of Agricultural Sciences
Yan Xiong
Microbiological Laboratory, Wuhan Center for Disease Control and Prevention
Hui Zhang
Microbiological Laboratory, Qiaokou District Center for Disease Control and Prevention
Zhongju Chen
Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology
Hanming Peng
Gastroenterology Department, Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science & Technology
Jun Lu
Microbiological Laboratory, Jianghan District Center for Disease Control and Prevention
Wanjun Luo
Hospital Acquired Infection Control Department, Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science & Technology
Ying Zhao
Microbiological Laboratory, Wuhan Center for Disease Control and Prevention
Miao Lin
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, Wuhan University
Abstract Salmonella is a pathogenic bacterium contributing to food poisoning and acute infectious intestinal disease. The traditional standard detection method is based on the principle of liquid phase enrichment and has a low sensitivity on targeted bacteria. We previously developed a visual immunosensor technique for efficient detection and isolation of Salmonella by applying fluorescent nanobioprobes on a specially-designed cellulose-based swab. In this study, a whole-sample solid-phase enrichment assay (WSEA) was established by optimization of the enrichment medium using response surface methodology (RSM), a powerful statistical tool for regression analysis. The optimal formula was determined as: 0.60% polyvalent poly peptone, 0.40% buffered peptone water, 0.09% ferric citrate amine, 0.24% sodium hyposulfite, 0.035% cystine, 0.01 µg mL−1 super absorbing polymer, 0.011% sodium deoxycholate, 15.00 µg mL−1 ethyl green and 30.00 µg mL−1 sodium selenite. Using this formula, Salmonella was visualized with naked eyes by relying on the indication of black spots formed on the swab. The analytic sensitivity of the assay was determined as 101 cells mL−1 with a concentration of interfering bacteria (Escherichia coli) at 105 cells mL−1. This optimized formula was confirmed with 4006 patients’ fecal samples, in which the positive rate was 0.42% by the conventional culture-based method and 2.12% by WSEA. The optimized formulation on solid phase enrichment by RSM allows relatively quick, low-cost, and large-scale detection of Salmonella, and could be used in grassroots medical institutions.
