Comparative proteomics reveals stress responses of Vibrio parahaemolyticus biofilm on different surfaces: Internal adaptation and external adjustment. Guo Linxia,Wang Jingjing,Gou Yi,Tan Ling,Liu Haiquan,Pan Yingjie,Zhao Yong The Science of the total environment Vibrio parahaemolyticus is a kind of gram-negative marine pathogen, which usually adheres to stainless steel (SS), glass (GS) and other abiotic surfaces in aquaculture and food processing in the form of biofilm and causes the spread of gastrointestinal illness. However, the deeply survival adaptation mechanism of V. parahaemolyticus biofilm cells on these contact surface remained unclear. Here, proteomics was used to investigated the physiological response of the V. parahaemolyticus biofilms cells to different abiotic surfaces (SS, GS and polystyrene (PS)). In addition, the effect of contact materials on the physical-chemical properties of biofilms are also characterized. Results showed that the expression of proteins of biofilm cells established on the SS surface were mainly related to the alleviation of metal ion stress and toxicity. The up-regulated proteins in the biofilm cells formed on the GS surface were mainly involved in the biological processes of sugar uptake, protein synthesis and bacterial chemotaxis. Meanwhile, the significantly expressed proteins in the biofilm cells formed on the PS surface were mainly involved in the cellular physiological activity of aromatic compound metabolism, osmotic stress and nutrient transport. All functional proteins mentioned above were closely related to the interaction characteristics of the contact surface and biofilm. This study provided an in-depth comparison of V. parahaemolyticus biofilm formation on these three abiotic surfaces, and presented a model in first time for the adaptation behavior of biofilm cells on different surfaces as affected by metal ion stress, nutrition, osmotic stress, and sugar utilization, which could facilitate an efficient control strategy for biofilm formation in industrial field. 10.1016/j.scitotenv.2020.138386

The Seasonal Microbial Ecology of Plankton and Plankton-Associated Vibrio parahaemolyticus in the Northeast United States. Hartwick Meghan A,Berenson Audrey,Whistler Cheryl A,Naumova Elena N,Jones Stephen H Applied and environmental microbiology Microbial ecology studies have proven to be important resources for improving infectious disease response and outbreak prevention. Vibrio parahaemolyticus is an ongoing source of shellfish-borne food illness in the Northeast United States, and there is keen interest in understanding the environmental conditions that coincide with V. parahaemolyticus disease risk, in order to aid harvest management and prevent further illness. Zooplankton and chitinous phytoplankton are associated with V. parahaemolyticus dynamics elsewhere; however, this relationship is undetermined for the Great Bay estuary (GBE), an important emerging shellfish growing region in the Northeast United States. A comprehensive evaluation of the microbial ecology of V. parahaemolyticus associated with plankton was conducted in the GBE using 3 years of data regarding plankton community, nutrient concentration, water quality, and V. parahaemolyticus concentration in plankton. The concentrations of V. parahaemolyticus associated with plankton were highly seasonal, and the highest concentrations of V. parahaemolyticus cultured from zooplankton occurred approximately 1 month before the highest concentrations of V. parahaemolyticus from phytoplankton. The two V. parahaemolyticus peaks corresponded with different water quality variables and a few highly seasonal plankton taxa. Importantly, V. parahaemolyticus concentrations and plankton community dynamics were poorly associated with nutrient concentrations and chlorophyll , commonly applied proxy variables for assessing ecological health risks and human health risks from harmful plankton and V. parahaemolyticus elsewhere. Together, these statistical associations (or lack thereof) provide valuable insights to characterize the plankton-V. parahaemolyticus dynamic and inform approaches for understanding the potential contribution of plankton to human health risks from V. parahaemolyticus for the Northeast United States. The -plankton interaction is a focal relationship in disease research; however, little is known about this dynamic in the Northeast United States, where V. parahaemolyticus is an established public health issue. We integrated phototactic plankton separation with seasonality analysis to determine the dynamics of the plankton community, water quality, and V. parahaemolyticus concentrations. Distinct bimodal peaks in the seasonal timing of V. parahaemolyticus abundance from phyto- versus zooplankton and differing associations with water quality variables and plankton taxa indicate that monitoring and forecasting approaches should consider the source of exposure when designing predictive methods for V. parahaemolyticus. Helicotheca tamensis has not been previously reported in the GBE. Its detection during this study provides evidence of the changes occurring in the ecology of regional estuaries and potential mechanisms for changes in V. parahaemolyticus populations. The monitoring approaches can be translated to aid other areas facing similar public health challenges. 10.1128/AEM.02973-20

A Novel Mouse Model of Enteric Vibrio parahaemolyticus Infection Reveals that the Type III Secretion System 2 Effector VopC Plays a Key Role in Tissue Invasion and Gastroenteritis. Yang Hyungjun,de Souza Santos Marcela,Lee Julia,Law Hong T,Chimalapati Suneeta,Verdu Elena F,Orth Kim,Vallance Bruce A mBio The Gram-negative marine bacterium is a common cause of infectious gastroenteritis due to the ingestion of contaminated seafood. Most virulent strains encode two type III secretion systems (T3SS1 and T3SS2); however, the roles they and their translocated effectors play in causing intestinal disease remain unclear. While studies have identified T3SS1 effectors as responsible for killing epithelial cells in culture, the T3SS2 effectors caused massive epithelial cell disruption in a rabbit ileal loop model. Additional models are thus needed to clarify the pathogen-host interactions that drive -associated gastroenteritis. Germfree mice were infected with a pathogenic clinical isolate of , RIMD2210633 (RIMD). The pathogen was found to adhere to as well as invade the cecal mucosa, accompanied by severe inflammation and dramatic mucosal damage, including widespread sloughing of infected epithelial cells. Mice infected with a strain lacking the T3SS1 (POR2) also developed severe pathology, similar to that seen with RIMD. In contrast, the strain (POR3) appeared unable to invade the intestinal mucosa or cause any mucosal pathology. Confirming a role for TS332 effectors, a strain expressing the T3SS2 but lacking VopC (POR2), a T3SS2 effector implicated in epithelial cell invasion in culture, was strongly attenuated in invading the intestinal mucosa and in causing gastroenteritis, although infection with this mutant resulted in more pathology than the strain. We thus present an experimental system that enables further characterization of T3SS effectors as well as the corresponding host inflammatory response involved in the gastroenteritis caused by invasive causes severe gastroenteritis following consumption of contaminated seafood. Global warming has allowed this pathogen to spread worldwide, contributing to recent outbreaks. Clinical isolates are known to harbor an array of virulence factors, including T3SS1 and T3SS2; however, the precise role these systems play in intestinal disease remains unclear. There is an urgent need to improve our understanding of how infects hosts and causes disease. We present a novel mouse model for this facultative intracellular pathogen and observe that the T3SS2 is essential to pathogenicity. Moreover, we show that the T3SS2 effector VopC, previously shown to be a Rac and Cdc42 deamidase that facilitates bacterial uptake by nonphagocytic cells, also plays a key role in the ability of to invade the intestinal mucosa and cause gastroenteritis. This experimental model thus provides a valuable tool for future elucidation of virulence mechanisms used by this facultative intracellular pathogen during infection. 10.1128/mBio.02608-19

Occurrence of pathogenic Vibrio parahaemolyticus in seafood distribution channels and their antibiotic resistance profiles in S. Korea. Lee Y,Choi Y,Lee S,Lee H,Kim S,Ha J,Lee J,Oh H,Kim Y,Yoon Y Letters in applied microbiology This study investigated the occurrence of Vibrio parahaemolyticus in seafood distribution channels, and the incidence of pathogenic and antibiotic-resistant strains. One hundred sixty-seven samples (126 fishery samples and 41 environmental samples) were collected from fishery auction markets, fish markets and online markets in S. Korea from March to September, 2017. The samples were enriched in polymyxin broth and plated on CHROM agar Vibrio to isolate typical colonies. These were analysed by PCR to identify V. parahaemolyticus strains containing the hns gene and to examine the presence of pathogenic genes (tdh and trh). The isolates were screened for antibiotic susceptibility (amoxycillin/clavulanic acid, ampicillin (AMP), ampicillin/sulbactam, chloramphenicol, ciprofloxacin, erythromycin, gentamicin and tetracycline). Twenty-eight samples (16·8%) were V. parahaemolyticus-positive, and from the positive samples, three isolates (SMFM201708-OY1, SMFM201709-CO2-2 and SMFM201709-CO1-2) were pathogenic which contained thermostable direct haemolysin or thermostable direct-related haemolysin. These are the virulence factors associated with gastrointestinal symptoms. These three isolates were also resistant to AMP. These results indicate that there is high incidence of V. parahaemolyticus in seafood distribution channels, and three of the isolates were pathogenic, and the pathogenic strains showed AMP resistance. Therefore, food safety measures are necessary in a seafood distribution channel. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides evidence for the incidence of pathogenic Vibrio parahaemolyticus in seafood distribution channels, especially for a fishery auction market, which showed the highest contamination and is a first place for a seafood distribution channel. Thus, V. parahaemolyticus in a fishery auction market may be cross-contaminated during distribution, underlying the need of food safety regulation to control this pathogen in fishery auction market. Therefore, food safety regulation for fishery auction market should be established to control V. parahaemolyticus. 10.1111/lam.13099

Experimental evaluation of survival of Vibrio parahaemolyticus in fertilized cold-water sediment. Collin B,Hernroth B Journal of applied microbiology AIMS:This experimental study focuses on survival and consistence of Vibrio parahaemolyticus in cold-water sediments and how increasing temperature and nutritional availability can affect growth. METHODS AND RESULTS:A pathogenic strain of V. parahaemolyticus was inoculated in seawater microcosms containing bottom sediment. Gradually, during 14 days, the temperature was upregulated from 8 to 21°C. Culturable V. parahaemolyticus was only found in the sediment but declined over time and did not recover even after another 2 days at 37°C. Numbers of culturable bacteria matched the amount found by q-PCR indicating that they did not enter a dormant state, contrary to those in the water layer. After adding decaying phytoplankton as fertilizer to the microcosms of 8 and 21°C for 7 and 14 days, the culturability of the bacteria increased significantly in the sediments at both temperatures and durations of exposure. CONCLUSION:The study showed that V. parahaemolyticus can stay viable in cold-water sediment and growth was stimulated by fertilizers rather than by temperature. SIGNIFICANCE AND IMPACT OF THE STUDY:Vibrio parahaemolyticus is a common cause of seafood-borne gastroenteritis and is today recognized in connection to increasing ocean temperature. The results indicate that this pathogen should be considered a risk in well-fertilized environments, such as aquacultures, even during cold periods. 10.1111/jam.14618