Recently, a news of "a man washing fish was stabbed with a high fever and coma, and his right hand was swollen and blackened and amputated" caused a lot of discussion and panic, and the news content pointed out that the culprit of the incident was Marine V. vulnificus. Since I have been engaged in the research of Vibrio for a long time, there are not a few people who consult me on WeChat or QQ. Everyone's concern has been from Vibrio can lead to fish, shrimp and shellfish and other diseases, escalated to how much Vibrio is harmful to humans. So, how terrible is Vibrio? Let's get to know each other today.
Vibrio belongs to the genus Vibrio of the Family Vibrio, is a quiescent phase arc-shaped Gram-negative bacillus, which is 0.5 to 0.8 μm wide and 1.5 to 3.0 μm long, with single flagella or periphery flagella at one end, does not form spores and pods, and has a g+c content of 38% to 51% in dna; the optimal temperature for the growth of Vibrio is 18 °C to 37 °C, the most suitable ph is 6 to 9, and it is a facultative anaerobic bacteria, and some species have salt-loving and oxidase positive, which can ferment glucose. TCBs can be used as selective medium, and some species such as Vibrio algae and Vibrio cholerae form yellow colonies in tcbs, and some species such as Vibrio parahaelyticus and Vibrio traumatis form green colonies.
Vibrio is one of the most common flora in the marine environment, and in estuarine areas with a rich flora, Vibrio can account for more than 1% of all bacteria and more than 10% of the cultureable flora. The generation time of Vibrio is shorter than that of E. coli, generally no more than ten minutes, so its reproduction is fast and the mutation is also fast.
In fact, disease is also a life phenomenon - especially biological infection diseases, which reflect not only the imbalance of the body, but also the interaction between organisms. So we should not just treat Vibrio as a pathogen, but as an important member of the marine environment. Because compared with its pathogenicity, the role of Vibrio in the chitin cycle and even in the ocean carbon cycle is irreplaceable. In the marine environment, copepods alone can produce 1011 tons of chitin per year, and almost all Vibrio have chitinase, and some even contain more than a dozen chitinase genes, it can be said that it is precisely because of the presence of Vibrio that our ocean is not a garbage mountain.
However, there are two sides to everything. Vibrio is widely distributed, from protozoa, corals, sponges, and hydra to shellfish, crustaceans, fish, etc. Distribution, not infection, is because most Vibrio do not harm their hosts – which is why Vibrio is considered conditionally pathogenic. In fact, I do not agree with the statement that conditional pathogenic bacteria, because in fact, any pathogenic infection requires certain conditions. The key is that Vibrio itself has a strong strain and a weak strain - under the same conditions of the same bacterium, the strong strain can cause disease even if the concentration is very small, and the weak strain can not be infected even if it is a high concentration. Of course, there is a shift between strong and weak strains, which is the most terrifying thing about bacteria. For example, the strong strains maintained in our laboratory will slowly weaken after a few years, while the weak or non-toxic strains in the environment will resize or mutate into strong strains during contact with strong strains or other bacteria. The protein and coding genes of vibrio strong and weak strains are not one-to-one correspondence, we have used comparative proteomics to obtain the proteins unique to strong strains, and then obtain their coding genes; gene expression studies have found that the coding genes of these so-called strong strain-specific proteins also exist in non-toxic strains or weak strains, and some are highly expressed - this is a very complex academic problem, which shows that the performance of strong strains and weak strains may not only be a problem at the gene level, but also involves the secretion of virulence proteins in the later stage. Even the issue of the host's regulation is involved.
Humans should not be counted as the normal host of Vibrio, humans infected with Vibrio, mostly because they eat food or water that carries Vibrio. In the case of the most harmful Vibrio cholerae, there are about 3 to 5 million cholera cases each year, and another 100,000 to 120,000 people die. In the AMERICAN FDA bacteriological analysis manual, 13 kinds of Vibrio cholerae type 01, Vibrio cholerae non-type 01, Vibrio parahaemolyticus, Vibrio traumaticus, Vibrio algae, Vibrio mimeticus, Vibrio Hollis, Vibrio Fornis, Vibrio river, Vibrio cincinnatie, Vibrio marine, Vibrio myrtles, And Vibrio sharks were included in the test of foodborne pathogenic microorganisms.
Vibrio infection can cause symptoms such as enteritis, otitis media, wound infection, and sepsis in humans. The Vibrio vulnificus referred to in the news, if it is infected by mouth, will have symptoms such as fever, chills, vomiting and diarrhea at most, but through wound infection (percutaneous infection), coupled with its own low immune function, it is easy to cause sepsis, and in severe cases, diffuse intravascular coagulation, shock and death occur. Therefore, when dealing with this situation every day, first of all, we must pay attention to protection, it is best to wear gloves; secondly, when being stabbed by a fish, we should immediately treat the wound; finally, we call on everyone to protect our marine environment, global warming will promote the multiplication of Vibrio and has led to the expansion of Vibrio to Nordic countries and other countries, and environmental pollution will promote the mutation and resistance of Vibrio.
1. Author | Lu Yishan Guangdong Ocean University
2. Source | Teng's Aquatic Products Business Network - Contemporary Aquatic Products Magazine
3. This article is the exclusive original manuscript of Contemporary Aquatic Products - Teng's Aquatic Products Business Network, and unauthorized reproduction is prohibited!