Use of molecular techniques for the analysis of the microbiological quality of fish marketed in the municipality of Cuiabá, Mato Grosso, Brazil

ABSTRACT The present study was stimulated by the growing demand for healthy food and the technology available for the detection and identification of microbial organisms in fishery products. Molecular tools were used to identify the bacterial community and detect the presence of pathogenic species in samples of farmed and wild-caught fish. Samples of muscle tissue were obtained from the local market in Cuiabá, Mato Grosso, Brazil. The 16S rDNA gene was used to detect 11 bacterial genera: Enterobacter (29.29%), Aeromonas (24.24%), Pseudomonnas (17.17%), Enterococcus (10.10%), Acinetobacter (6.06%), Citrobacter (4.04%), Bacillus (3.03%), Klebsiella and Lactococcus (2.02%), and Clostridium and Lysinibacillus (1.01%). High percentages of deleterious bacteria were recorded. Species-specific primers were used to detect the presence of Escherichia coli (35.71%), Staphylococcus aureus (12.5%), and Salmonella (7.14%), although Shigella was absent. These concentrations exceeded the limits established by the currently public health legislation. The molecular techniques used in the present study provide an alternative approach for the reliable diagnosis of contamination, which can be used on a large scale.

摘要 本研究受健康食品需求日益增长的推动，以及可用于渔业产品中微生物检测与鉴定的相关技术启发。研究采用分子工具鉴定养殖及野生捕捞鱼类样本中的细菌群落，并检测致病菌的存在。样本取自巴西马托格罗索州库亚巴当地市场的肌肉组织。通过16S核糖体DNA（16S rDNA）基因检测，共鉴定出11个细菌属：肠杆菌属（Enterobacter，29.29%）、气单胞菌属（Aeromonas，24.24%）、假单胞菌属（Pseudomonas，17.17%）、肠球菌属（Enterococcus，10.10%）、不动杆菌属（Acinetobacter，6.06%）、柠檬酸杆菌属（Citrobacter，4.04%）、芽孢杆菌属（Bacillus，3.03%）、克雷伯菌属（Klebsiella）与乳球菌属（Lactococcus，2.02%），以及梭菌属（Clostridium）与赖氨酸芽孢杆菌属（Lysinibacillus，1.01%）。研究中检出较高比例的有害细菌。采用物种特异性引物检测发现，大肠埃希氏菌（Escherichia coli，35.71%）、金黄色葡萄球菌（Staphylococcus aureus，12.5%）与沙门氏菌（Salmonella，7.14%）均有检出，但未检出志贺氏菌（Shigella）。上述污染物浓度超出了现行公共卫生法律法规规定的限值。本研究采用的分子技术为污染的可靠诊断提供了一种可规模化应用的替代方案。