Summary
The accelerated growth of finfish aquaculture has resulted in a series of developments detrimental to the environment and human health. The latter is illustrated by the widespread and unrestricted use of prophylactic antibiotics in this industry, especially in developing countries, to forestall bacterial infections resulting from sanitary shortcomings in fish rearing. The use of a wide variety of antibiotics in large amounts, including non-biodegradable antibiotics useful in human medicine, ensures that they remain in the aquatic environment, exerting their selective pressure for long periods of time. This process has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase of antibiotic resistance in fish pathogens, in the transfer of these resistance determinants to bacteria of land animals and to human pathogens, and in alterations of the bacterial flora both in sediments and in the water column. The use of large amounts of antibiotics that have to be mixed with fish food also creates problems for industrial health and increases the opportunities for the presence of residual antibiotics in fish meat and fish products. Thus, it appears that global efforts are needed to promote more judicious use of prophylactic antibiotics in aquaculture as accumulating evidence indicates that unrestricted use is detrimental to fish, terrestrial animals, and human health and the environment.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1462-2920.2006.01054.x

Heavy use of prophylactic antibiotics in aquaculture: a growing problem for human and animal health and for the environment

Vibrio parahaemolyticus: A concern of seafood safety

Vibrio parahaemolyticus is recognized as a cause of food-borne gastroenteritis, particularly in the Far East, where raw seafood consumption is high. An unusual increase in admissions of V. parahaemolyticus cases was observed at the Infectious Diseases Hospital in Calcutta, a city in the northeastern part of India, beginning February 1996. Analysis of the strains revealed that a unique serotype, O3:K6, not previously isolated during the surveillance in Calcutta accounted for 50 to 80% of the infections in the following months. After this report, O3:K6 isolates identical to those isolated in Calcutta were reported from food-borne outbreaks and from sporadic cases in Bangladesh, Chile, France, Japan, Korea, Laos, Mozambique, Peru, Russia, Spain, Taiwan, Thailand, and the United States. Other serotypes, such as O4:K68, O1:K25, and O1:KUT (untypeable), that had molecular characteristics identical to that of the O3:K6 serotype were subsequently documented. These serotypes appeared to have diverged from the O3:K6 serotype by alteration of the O:K antigens and were defined as "serovariants" of the O3:K6 isolate. O3:K6 and its serovariants have now spread into Asia, America, Africa, and Europe. This review traces the genesis, virulence features, molecular characteristics, serotype variants, environmental occurrence, and global spread of this unique clone of V. parahaemolyticus.

https://cmr.asm.org/content/cmr/20/1/39.full.pdf

Global Dissemination of Vibrio parahaemolyticus Serotype O3:K6 and Its Serovariants

background Vibrio parahaemolyticus, the leading cause of seafood-associated gastroenteritis in the United States, typically is associated with the consumption of raw oysters gathered from warm-water estuaries We describe a recognized outbreak of V parahaemolyticus infection associated with the consumption of seafood from Alaska methods After we received reports of the occurrence of gastroenteritis on a cruise ship, we conducted a retrospective cohort study among passengers, as well as active surveillance throughout Alaska to identify additional cases, and an environmental study to identify sources of V parahaemolyticus and contributors to the outbreak results Of 189 passengers, 132 (70 percent) were interviewed; 22 of the interviewees (17 percent) met our case definition of gastroenteritis In our multiple logistic-regression analysis, consumption of raw oysters was the only significant predictor of illness; the attack rate among people who consumed oysters was 29 percent Active surveillance identified a total of 62 patients with gastroenteritis V parahaemolyticus serotype O6:K18 was isolated from the majority of patients tested and from environmental samples of oysters Patterns on pulsed-field gel electrophoresis were highly related across clinical and oyster isolates All oysters associated with the outbreak were harvested when mean daily water temperatures exceeded 150°C (the theorized threshold for the risk of V parahaemolyticus illness from the consumption of raw oysters) Since 1997, mean water temperatures in July and August at the implicated oyster farm increased 021°C per year (P<0001 by linear regression); 2004 was the only year during which mean daily temperatures in July and August at the shellfish farm did not drop below 150°C conclusions This investigation extends by 1000 km the northernmost documented source of oysters that caused illness due to V parahaemolyticus Rising temperatures of ocean water seem to have contributed to one of the largest known outbreaks of V parahaemolyticus in the United States

https://www.nejm.org/doi/pdf/10.1056/NEJMoa051594

Outbreak of Vibrio parahaemolyticus gastroenteritis associated with Alaskan oysters.

Vibrio is a genus of ubiquitous bacteria found in a wide variety of aquatic and marine habitats; of the >100 described Vibrio spp., ~12 cause infections in humans. Vibrio cholerae can cause cholera, a severe diarrhoeal disease that can be quickly fatal if untreated and is typically transmitted via contaminated water and person-to-person contact. Non-cholera Vibrio spp. (for example, Vibrio parahaemolyticus, Vibrio alginolyticus and Vibrio vulnificus) cause vibriosis - infections normally acquired through exposure to sea water or through consumption of raw or undercooked contaminated seafood. Non-cholera bacteria can lead to several clinical manifestations, most commonly mild, self-limiting gastroenteritis, with the exception of V. vulnificus, an opportunistic pathogen with a high mortality that causes wound infections that can rapidly lead to septicaemia. Treatment for Vibrio spp. infection largely depends on the causative pathogen: for example, rehydration therapy for V. cholerae infection and debridement of infected tissues for V. vulnificus-associated wound infections, with antibiotic therapy for severe cholera and systemic infections. Although cholera is preventable and effective oral cholera vaccines are available, outbreaks can be triggered by natural or man-made events that contaminate drinking water or compromise access to safe water and sanitation. The incidence of vibriosis is rising, perhaps owing in part to the spread of Vibrio spp. favoured by climate change and rising sea water temperature.

Vibrio spp. infections.

Analysis of clinical isolates of Vibrio parahaemolyticus from outbreaks in Chile in the cities of Puerto Montt in 2004 and Antofagasta in 1998 indicated that 23 of 24 isolates from Puerto Montt and 19 of 20 from Antofagasta belonged to the pandemic clonal complex that emerged in Southeast Asia in 1996.

https://wwwnc.cdc.gov/eid/article/11/1/pdfs/04-0762.pdf

Juan A. Vergara

Papers

Vibrio parahaemolyticus diarrhea, Chile, 1998 and 2004.