Elbehiry Ayman, Marzouk Eman, Hamada Mohamed, Al-Dubaib Musaad, Alyamani Essam, Moussa Ihab M, AlRowaidhan Anhar, Hemeg Hassan A
Department of Bacteriology, Mycology and Immunology, Faculty of Veterinary Medicine, Sadat City University, Egypt.
Department of Public Health, College of Public Health and Health Informatics, Qassim University, Kingdom of Saudi Arabia.
New Microbiol. 2017 Oct;40(4):269-278. Epub 2017 Aug 21.
Foodborne pathogens can be associated with a wide variety of food products and it is very important to identify them to supply safe food and prevent foodborne infections. Since traditional techniques are timeconsuming and laborious, this study was designed for rapid identification and clustering of foodborne pathogens isolated from various restaurants in Al-Qassim region, Kingdom of Saudi Arabia (KSA) using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Sixty-nine bacterial and thirty-two fungal isolates isolated from 80 food samples were used in this study. Preliminary identification was carried out through culture and BD Phoenix™ methods. A confirmatory identification technique was then performed using MALDI-TOF MS. The BD Phoenix results revealed that 97% (67/69 isolates) of bacteria were correctly identified as 75% Enterobacter cloacae, 95.45% Campylobacter jejuni and 100% for Escherichia coli, Salmonella enterica, Staphylococcus aureus, Acinetobacter baumannii, and Klebsiella pneumoniae. While 94.44% (29/32 isolates) of fungi were correctly identified as 77.77% Alternaria alternate, 88.88% Aspergillus niger and 100% for Aspergillus flavus, Penicillium digitatum, Candida albicans and Debaryomyces hansenii. However, all bacterial and fungal isolates were 100% properly identified by MALDI-TOF MS fingerprinting with a score value ≥2.00. A gel view illustrated that the spectral peaks for the identified isolates fluctuate between 3,000 and 10,000 Da. The results of main spectra library (MSP) dendrogram showed that the bacterial and fungal isolates matched with 19 and 9 reference strains stored in the Bruker taxonomy, respectively. Our results indicated that MALDI-TOF MS is a promising technique for fast and accurate identification of foodborne pathogens.
食源性病原体可与多种食品相关联，识别它们对于提供安全食品和预防食源性感染非常重要。由于传统技术既耗时又费力，本研究旨在利用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）对从沙特阿拉伯王国卡西姆地区各餐馆分离出的食源性病原体进行快速鉴定和聚类。本研究使用了从80份食品样本中分离出的69株细菌和32株真菌分离物。通过培养和BD Phoenix™方法进行初步鉴定。然后使用MALDI-TOF MS进行确证鉴定技术。BD Phoenix结果显示，97%（67/69株分离物）的细菌被正确鉴定为75%的阴沟肠杆菌、95.45%的空肠弯曲菌以及100%的大肠杆菌、肠炎沙门氏菌、金黄色葡萄球菌、鲍曼不动杆菌和肺炎克雷伯菌。而94.44%（29/32株分离物）的真菌被正确鉴定为77.77%的链格孢、88.88%的黑曲霉以及100%的黄曲霉、指状青霉、白色念珠菌和汉逊德巴利酵母。然而，所有细菌和真菌分离物通过MALDI-TOF MS指纹图谱均以得分值≥2.00被100%正确鉴定。凝胶视图显示，已鉴定分离物的光谱峰在3000至10000 Da之间波动。主谱库（MSP）树状图结果表明，细菌和真菌分离物分别与布鲁克分类学中存储的19株和9株参考菌株匹配。我们的结果表明，MALDI-TOF MS是一种用于快速准确鉴定食源性病原体的有前景的技术。
