Sabry Maha, Abd El-Moein Khaled, Hamza Eman, Abdel Kader Fatma
Department of Zoonoses, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt.
J Food Prot. 2016 Jun;79(6):994-1000. doi: 10.4315/0362-028X.JFP-15-569.
Fish remains among the most traded of food commodities, and Egypt is one of the emerging countries being recognized as an important world fish exporter. Clostridium perfringens is an important foodborne pathogen to consider in fish trade, as it has been implicated as the causative organism of two fish outbreaks. The aim of the present study was to investigate the occurrence and toxin diversity of C. perfringens associated with fresh and canned fish and to examine the public health significance of C. perfringens infection in fish. Isolation and identification of C. perfringens showed a significantly higher prevalence of the bacterium in fresh fish collected from aquaculture (54.5%) and from markets (71%) as well as in humans in contact with fish (63%) compared with water used for keeping fresh fish (27.3%) and water used in canned fish (17.8%). The isolation level was significantly higher in samples from the external surface of fresh fish (31.8% in aquaculture, 45.6% in markets) than from the intestinal contents of the same fish (9.1% in aquaculture, 6.7% in markets). Thus, markets represent a risk factor for contamination of the external surface of fish from the surrounding environment. Genotyping of the C. perfringens-positive isolates by using multiplex PCR revealed that type A enterotoxin-negative (CPE(-)) is the predominant strain among fish (fresh and canned), humans, and water in contact with fresh fish. Interestingly, C. perfringens types A enterotoxin-positive (CPE(+)) and C were found only in fresh fish, and these two strains have great health importance in humans. Strikingly, C. perfringens type E strain was detected for the first time in fish, humans, and water in contact with fresh fish. Our results demonstrate for the first time that fish act as a reservoir for C. perfringens, particularly for types A CPE(+), C, and E. The external surface of fish represents a vehicle for contamination of fish from the surrounding environment as well as a source of infection of humans, thereby representing a public health hazard.
鱼类仍然是交易最为频繁的食品商品之一，埃及是被公认为重要世界鱼类出口国的新兴国家之一。产气荚膜梭菌是鱼类贸易中需要考虑的一种重要食源性病原体，因为它被认为是两起鱼类疫情爆发的致病微生物。本研究的目的是调查与新鲜鱼和罐装鱼相关的产气荚膜梭菌的发生情况和毒素多样性，并研究产气荚膜梭菌感染鱼类对公共卫生的意义。产气荚膜梭菌的分离和鉴定显示，与用于保存鲜鱼的水（27.3%）和罐装鱼中使用的水（17.8%）相比，从水产养殖收集的鲜鱼（54.5%）、市场上的鲜鱼（71%）以及接触鱼类的人群（63%）中产气荚膜梭菌的流行率显著更高。鲜鱼外表面样本（水产养殖中为31.8%，市场上为45.6%）的分离水平显著高于同一条鱼的肠道内容物（水产养殖中为9.1%，市场上为6.7%）。因此，市场是鱼类外表面被周围环境污染的一个风险因素。通过多重PCR对产气荚膜梭菌阳性分离株进行基因分型显示，A型肠毒素阴性（CPE(-)）是鱼类（新鲜和罐装）、人类以及与鲜鱼接触的水中的主要菌株。有趣的是，A型肠毒素阳性（CPE(+)）和C型产气荚膜梭菌仅在鲜鱼中被发现，这两种菌株对人类健康具有重要意义。引人注目的是，E型产气荚膜梭菌首次在鱼类、人类以及与鲜鱼接触的水中被检测到。我们的结果首次证明鱼类是产气荚膜梭菌的储存宿主，特别是对于A型CPE(+)、C型和E型。鱼的外表面是鱼类被周围环境污染的媒介以及人类感染源，从而构成公共卫生危害。
