Detection of colistin resistance mcr-1 gene in Salmonella enterica serovar Rissen isolated from mussels, Spain, 2012- to 2016.

Nineteen Salmonella strains were isolated from 5,907 randomly selected mussel samples during a monitoring programme for the presence of Salmonella in shellfish in Galicia, north-west Spain (2012-16). Serovars, sequence type and antimicrobial resistance genes were determined through genome sequencing. Presence of the mcr-1 gene in one strain belonging to serovar Rissen and ST-469 was identified. The mcr-1 gene had not been isolated previously in environmental Salmonella isolated from mussels in Spain.

Epidemic Dynamics of Vibrio parahaemolyticus Illness in a Hotspot of Disease Emergence, Galicia, Spain.

Galicia in northwestern Spain has been considered a hotspot for Vibrio parahaemolyticus infections. Infections abruptly emerged in 1998 and, over the next 15 years, were associated with large outbreaks caused by strains belonging to a single clone. We report a recent transition in the epidemiologic pattern in which cases throughout the region have been linked to different and unrelated strains. Global genome-wide phylogenetic analysis revealed that most of the pathogenic strains isolated from infections were associated with globally diverse isolates, indicating frequent episodic introductions from disparate and remote sources. Moreover, we identified that the 2 major switches in the epidemic dynamics of V. parahaemolyticus in the regions, the emergence of cases and an epidemiologic shift in 2015-2016, were associated with the rise of sea surface temperature in coastal areas of Galicia. This association may represent a fundamental contributing factor in the emergence of illness linked to these introduced pathogenic strains.

Preliminary Results on the Evaluation of the Occurrence of Tetrodotoxin Associated to Marine Vibrio spp. in Bivalves from the Galician Rias (Northwest of Spain).

Tetrodotoxins (TTX) are a potent group of natural neurotoxins putatively produced by symbiotic microorganisms and affecting the aquatic environment. These neurotoxins have been recently found in some species of bivalves and gastropods along the European Coasts (Greece, UK, and The Netherlands) linked to the presence of high concentrations of Vibrio, in particular Vibrio parahaemolyticus. This study is focused on the evaluation of the presence of Vibrio species and TTX in bivalves (mussels, oysters, cockles, clams, scallops, and razor clams) from Galician Rias (northwest of Spain). The detection and isolation of the major Vibrio spp. and other enterobacterial populations have been carried out with the aim of screening for the presence of the pathways genes, poliketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) possibly involved in the biosynthesis of these toxins. Samples containing Vibrio spp. were analyzed by biochemical (API20E-galery) and genetic tests (PCR-RT). These samples were then screened for TTX toxicity by a neuroblastoma cell-based assay (N2a) and the presence of TTX was further confirmed by LC-MS/MS. TTX was detected in two infaunal samples. This is the first confirmation of the presence of TTX in bivalve molluscs from the Galician Rias.

An Evaluation of the Pathogenic Potential, and the Antimicrobial Resistance, of Salmonella Strains Isolated from Mussels.

Salmonella spp. and antimicrobial resistant microorganisms are two of the most important health issues worldwide. In the present study, strains naturally isolated from mussels harvested in Galicia (one of the main production areas in the world), were genetically characterized attending to the presence of virulence and antimicrobial resistance genes. Additionally, the antimicrobial profile was also determined phenotypically. Strains presenting several virulence genes were isolated but lacked all the antimicrobial resistance genes analyzed. The fact that some of these strains presented multidrug resistance, highlighted the possibility of bearing different genes than those analyzed, or resistance based on completely different mechanisms. The current study highlights the importance of constant surveillance in order to improve the safety of foods.

Influence of on-site cytopathology evaluation on the diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of solid pancreatic masses.

OBJECTIVES: The aim of this study was to evaluate the influence of on-site cytopathological evaluation on the diagnostic yield of endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) for the differential diagnosis of solid pancreatic masses in an unselected series of consecutive patients. METHODS: Patients undergoing EUS-guided FNA of solid pancreatic lesions over a 2-year study period were included. Samples were either evaluated on site by a cytopathologist or processed by the endoscopist and sent to the pathology department for evaluation. Diagnostic accuracy for malignancy, number of needle passes, adequate-specimen collection rate, cytological diagnosis, and final diagnosis, and complication rate according to the presence or absence of on-site cytopathologist were evaluated. RESULTS: A total of 182 patients were included. An on-site cytopathologist was available in 95 cases (52.2%). There was no difference between groups in terms of age, sex, location, and size of the lesions. A significantly higher number of needle passes was performed when an on-site cytopathologist was not available (3.5±1.0 vs. 2.0±0.7; P<0.001). The presence of an on-site cytopathologist was associated with a significantly lower number of inadequate samples (1.0 vs. 12.6%, P=0.002), and a significantly higher diagnostic sensitivity (96.2 vs. 78.2%; P=0.002) and overall accuracy (96.8 vs. 86.2%; P=0.013) for malignancy. Three patients developed complications (two acute pancreatitis, one local bleeding), all of them belonging to the group without on-site cytopathology. CONCLUSIONS: On-site cytopathological evaluation improves the diagnostic yield of EUS-guided FNA for the cytological diagnosis of solid pancreatic masses. This is associated with a significantly lower number of inadequate samples and a lower number of needle passes.

Environmental determinants of the occurrence and distribution of Vibrio parahaemolyticus in the rias of Galicia, Spain.

Infections associated with Vibrio parahaemolyticus on the coast of Galicia (in northwestern Spain) were reported to be linked to large outbreaks of illness during 1999 and 2000. Little information is available about the ecological factors that influence the emergence of V. parahaemolyticus infections in this temperate region. We carried out a 3-year study to investigate the occurrence and distribution of V. parahaemolyticus at 26 sites located in the four main rias of Galicia in association with environmental and oceanographic variables. V. parahaemolyticus was detected in all the areas investigated and throughout the complete period of study with an overall incidence of 12.5%. Salinity was the primary factor governing the temporal and spatial distribution of V. parahaemolyticus, whereas seawater temperature had a secondary effect and only modulated the abundance in periods and areas of reduced salinities. Higher occurrence of V. parahaemolyticus was observed during periods of lower salinity in autumn, with a total of 61 positive samples (18%) and a mean density of 1,234 most probable number/100 g. V. parahaemolyticus was primarily detected in areas of reduced salinity close to freshwater discharge points, where it was found in up to 45% of the samples. Characterization of the isolates obtained from the study resulted in the first identification of two pathogenic tdh-positive strains of V. parahaemolyticus recovered from the marine environment in Galicia. These isolates showed serotypes identical to and DNA profiles indistinguishable from those of the clinical clone of V. parahaemolyticus dominant in infections in Spain in the last 10 years.

[Intraductal papillary mucinous tumor: diagnostic and therapeutic approach]. / Tumor papilar, mucinoso e intraductal: abordaje diagnóstico y terapéutico.

Primary cystic pancreatic neoplasms are rare tumors, with an approximate prevalence of 10% of cystic pancreatic lesions. Most of these lesions correspond to mucinous cystic neoplasm, serous cystoadenoma and intraductal papillary mucinous tumor (IPMT). IPMT is characterized by diffuse dilatation of the main pancreatic duct and/or side branches with inner defects related to mucin or tumor, or mucin extrusion from a patent ampulla. IPMT has a low potential for malignancy, with a low growth rate, a low rate of metastatic spread and postsurgical recurrence. Over the last few years, major advances have been made in the diagnostic and therapeutic management of this tumor.

Relationship between clinical features of Crohn's disease and the risk of developing extraintestinal manifestations.

OBJECTIVES: Crohn's disease is frequently associated with extraintestinal manifestations. The aim of this study was to evaluate the degree of association between the development of extraintestinal manifestations, the clinical forms of Crohn's disease according to the Vienna Classification and to the presence of several potential risk factors of the disease. METHODS: One hundred and seventy-three consecutive Crohn's disease patients were studied. Sex, smoking habits, previous Crohn's disease-related surgery, family history of Crohn's disease, steroid dependency, steroid resistance and the presence of at least one mutant allele in any of the three considered variants of CARD15 gene were considered as potential risk factors. The Vienna Classification was applied, and the presence of extraintestinal manifestations was evaluated. RESULTS: A total of 61 (35.3%) patients developed extraintestinal manifestations. They were more frequently seen in women than in men (41.1 vs. 26.7%), (odds ratio 1.92, 95% confidence interval: 0.99-3.70; P=0.05) and in steroid-dependent patients than in steroid responders (61.1 vs. 28.5%), (odds ratio 3.94, 95% confidence interval: 1.83-8.49; P<0.01). No relationship was found in general between the extraintestinal manifestations of Crohn's disease and smoking habits, previous Crohn's disease-related surgery, a family history of Crohn's disease, steroid resistance and CARD15 mutations. Such relationships were, however, detected for some individual extraintestinal manifestations as between both smoking habits (odds ratio 9.09, 95% confidence interval: 1.15-71.66; P<0.05) and the G908R CARD15 mutation (odds ratio 4.76, 95% confidence interval: 1.11-20.43; P<0.05), respectively, and erythema nodosum. Patients with any colonic involvement of Crohn's disease (L2+L3) suffered from extraintestinal manifestations of the disease more frequently than patients without colonic involvement (42.7 vs. 25.9%, respectively; odds ratio 2.12, 95% confidence interval: 1.10-4.07; P<0.05). CONCLUSIONS: Female gender, steroid-dependency and colonic involvement are associated with the risk of developing extraintestinal manifestations of Crohn's disease.

Impact of endoscopic ultrasound-guided fine needle biopsy for diagnosis of pancreatic masses.

AIM: To evaluate the diagnostic accuracy of histological evaluation of pancreatic tissue samples obtained by a modified method for recovering and processing the endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) material in the differential diagnosis of pancreatic solid masses. METHODS: Sixty-two consecutive patients with pancreatic masses were prospectively studied. EUS was performed by the linear scanning Pentax FG-38UX echoendoscope. Three FNAs (22G needle) were carried out during each procedure. The materials obtained with first and second punctures were processed for cytological study. Materials of the third puncture were recovered into 10% formol solution by careful injection of saline solution through the needle, and processed for histological study. RESULTS: Length of the core specimen obtained for histological analysis was 6.5 +/- 5.3 mm (range 1-22 mm). Cytological and histological samples were considered as adequate in 51 (82.3%) and 52 cases (83.9%), respectively. Overall sensitivity of both pancreatic cytology and histology for diagnosis of malignancy was 68.4%. Contrary to cytology, histology was able to diagnose tumours other than adenocarcinomas, and all cases of inflammatory masses. Combination of cytology and histology allowed obtaining an adequate sample in 56 cases (90.3%), with a global sensitivity of 84.21%, specificity of 100% and an overall accuracy of 90.32%. The complication rate was 1.6%. CONCLUSION: Adequate pancreatic core specimens for histological examination can be obtained by EUS-guided FNA. This technique is mainly useful for the diagnosis of different types of pancreatic tumours and evaluation of benign diseases.

Differences in the API 20E biochemical patterns of clinical and environmental Vibrio parahaemolyticus isolates.

Genetic differences in clinical and environmental strains of Vibrio parahaemolyticus have been widely used as criteria in identifying pathogenic isolates. However, few studies have been carried out to assess the differences in biochemical characteristics of V. parahaemolyticus isolates from human and environmental sources. We compared the biochemical profiles obtained by the characterization of V. parahaemolyticus isolates from human infections and the marine environment using the API 20E system. Environmental and clinical isolates showed significant differences in the gelatin and arabinose tests. Additionally, clinical isolates were correctly identified according to the API 20E profile using 0.85% NaCl diluent, but they presented nonspecific profiles with 2% NaCl diluent. In contrast, use of 2% NaCl diluent facilitated correct identification of the environmental isolates. Clinical isolates showed significant differences in up to five biochemical tests with respect to the API 20E database. The API 20E system is widely used in routine identification of bacteria in clinical laboratories, and this discrepancy in an important number of biochemical tests may lead to misidentification of V. parahaemolyticus infection.

The Common Chymotrypsinogen C (CTRC) Variant G60G (C.180T) Increases Risk of Chronic Pancreatitis But Not Recurrent Acute Pancreatitis in a North American Population.

OBJECTIVES: Recurrent acute pancreatitis (RAP) is a complex inflammatory disorder that may progress to fibrosis and other irreversible features recognized as chronic pancreatitis (CP). Chymotrypsinogen C (CTRC) protects the pancreas by degrading prematurely activated trypsinogen. Rare mutations are associated with CP in Europe and Asia. We evaluated the occurrence of CTRC variants in subjects with RAP, CP, and controls from the North American Pancreatitis Study II cohort. METHODS: CP (n=694), RAP (n=448), and controls (n=1017) of European ancestry were evaluated. Subgroup analysis included CFTR and SPINK1 variants, alcohol, and smoking. RESULTS: We identified previously reported rare pathogenic CTRC A73T, R254W, and K247_R254del variants, intronic variants, and G60G (c.180 C>T; rs497078). Compared with controls (minor allele frequency (MAF)=10.8%), c.180T was associated with CP (MAF=16.8%, P<0.00001) but not RAP (MAF=11.9% P=NS). Trend test indicated co-dominant risk for CP (CT odds ratio (OR)=1.36, 95% confidence interval (CI)=1.13-1.64, P=0.0014; TT OR=3.98, 95% CI=2.10-7.56, P<0.0001). The T allele was significantly more frequent with concurrent pathogenic CFTR variants and/or SPINK1 N34S (combined 22.9% vs. 16.1%, OR 1.92, 95% C.I. 1.26-2.94, P=0.0023) and with alcoholic vs. non-alcoholic CP etiologies (20.8% vs. 12.4%, OR=1.9, 95% CI=1.30-2.79, P=0.0009). Alcohol and smoking generally occurred together, but the frequency of CTRC c.180 T in CP, but not RAP, was higher among never drinkers-ever smokers (22.2%) than ever drinker-never smokers (10.8%), suggesting that smoking rather than alcohol may be the driving factor in this association. CONCLUSIONS: The common CTRC variant c.180T acts as disease modifier that promotes progression from RAP to CP, especially in patients with CFTR or SPINK1 variants, alcohol, or smoking.

Identification of tdh-positive Vibrio parahaemolyticus from an outbreak associated with raw oyster consumption in Spain.

Between August and September 1999, a total of 64 cases of illness were identified in three episodes of acute gastroenteritis associated with the consumption of live oysters from a typical outdoor street market in Galicia (northwest Spain). Nine case patients were hospitalized and analysis of their stool samples revealed the presence of Vibrio parahaemolyticus. The strains isolated from two stool samples were studied for antibiotic susceptibility, biochemical characteristics and presence of virulence factors. Both isolates were Kanagawa phenomenon positive and produced thermostable direct hemolysin, which is related to pathogenicity in humans. These results show the presence of pathogenic V. parahaemolyticus in mollusks harvested in Europe and reveal the risk of illness associated with their consumption, suggesting the revision of V. parahaemolyticus risk assessment associated with consumption of raw live shellfish.

Detection of Salmonella Senftenberg associated with high saline environments in mussel processing facilities.

A contamination by Salmonella Senftenberg in frozen mussels was detected in 1998 during a routine analytical surveillance. From June 1998 to December 2001, a total of 3,410 samples of steamed frozen mussels and items related to their manufacture were analyzed for the presence of Salmonella. Salmonella Senftenberg was isolated in 573 (16.8%) samples, and no other serovar was detected. The contamination episodes extended for several months. Salmonella Senftenberg colonies from the first contamination events showed a rugose morphology on agar with a shiny crystalline layer and limited colony formation on microbiological media. These contaminations were mainly associated with brine (300 g of NaCl per liter), while the live molluscs that were being processed were free of Salmonella. When the brine contaminations were nearly controlled, new episodes were detected that were associated with live mussels. In the new episodes, colonies showed the typical characteristics of Salmonella and normal growth on agar. Salmonella Senftenberg presented a high resistance to unfavorable environments and showed a preference for clean environments. While Salmonella Senftenberg could be isolated from mussels after steam treatment, it could not survive after immersion in water at 80 degrees C for 1 min. This fact was used to develop a process to remove contamination from products, minimizing the health risk associated with frozen mussel consumption. The general incidence of Salmonella Senftenberg in facilities and mussels was reduced from 31.2% in 1998 to 2.5% in 2001. During this study, no cases of illness from consumption of frozen mussels were reported, indicating a possible lack of virulence of Salmonella Senftenberg in these contamination events.

Citrobacter freundii infection after acute necrotizing pancreatitis in a patient with a pancreatic pseudocyst: a case report.

INTRODUCTION: Infections are the most frequent and severe complications of acute necrotizing pancreatitis with a mortality rate of up to 80 percent. Although experimental and clinical studies suggest that the microbiologic source of pancreatic infection could be enteric, information in this regard is controversial. CASE PRESENTATION: We describe a Citrobacter freundii isolation by endoscopy ultrasound fine needle aspiration in a 80-year-old Caucasian man with pancreatic pseudocyst after acute necrotizing pancreatitis. CONCLUSION: Our case report confirms that this organism can be recovered in patients with a pancreatic pseudocyst. On-site cytology feedback was crucial to the successful outcome of this case as immediate interpretation of the fine needle aspiration sample directed the appropriate cultures and, ultimately, the curative therapy. To the best of our knowledge, this is the first reported case of isolated pancreatic C. freundii diagnosed by endoscopy ultrasound fine needle aspiration.

Ductal adenocarcinoma of the pancreas: Expression of growth factor receptors, oncogenes and suppressor genes, and their relationship to pathological features, staging and survival.

Pancreatic ductal adenocarcinoma results in high short-term mortality despite recent advances in diagnostics, surgery and chemotherapy. Modern chemotherapeutic agents directed to specific tumor receptors have higher therapeutic efficacy and lower adverse effects. However, few studies exist that evaluate the clinical impact in pancreatic cancer. The expression of tumor growth factor receptors, oncogenes and tumor suppressor oncogenes in surgical pancreatic cancer specimens as related to pathological characteristics, staging and prognosis was evaluated. Data were recorded for 50 patients who underwent a pancreatic cancer resection and were suitable for immunohistochemical evaluation (32 male, mean age 61 years, range 44-78) with regard to pTN, tumor size and location, histological differentiation grade, vascular and perineural invasion, adjuvant chemotherapy and survival time. Tumor specimens and normal pancreatic tissue were deparaffinized and the expression of vascular epidermal growth factor (VEGF) receptors (R)-1 and -2, epidermal growth factor receptor (EGFR), Her-2/neu, COX-2, p16, p21 and p53 was immunohistochemically evaluated using tissue microarrays. Associations between molecular marker expression and clinicopathological tumor characteristics were evaluated using the Chi-square test (SPSS) and the survival time was defined. The Kaplan-Meier method was utilized to analyze survival curves, verified by the log-rank test. No molecular markers evaluated were expressed in normal tissue. Tumor expression data included VEGF-R1 (74%), EGFR (52%), Her-2/neu (7.84%), COX-2 (21.5%), p16 (29.4%), p21 (21.7%) and p53 (50%). Tumors expressing VEGF-R1, EGFR and/or p53 were larger (p<0.02), frequently poorly differentiated (p<0.05) and more frequently associated with perineural and lymph node invasion (p<0.05). Marker expression did not correlate with pathological tumor characteristics. The median post-surgery survival was 15 months; 60 and 27% patients survived to 12 and 24 months, respectively, with a longer survival time in patients receiving adjuvant chemotherapy (n=20) (median 36 vs. 15 months, p<0.02). Growth factor receptors, oncogenes and tumor suppressor genes were frequently expressed in pancreatic cancer tissue. VEGF-R1, EGFR and p53 expression were associated with poor tissue differentiation and perineural and lymph node infiltration. Only VEGF-R1 expression was associated with a longer survival time and a more favorable response to adjuvant chemotherapy.

Clinical relevance of epidermal growth factor receptor (EGFR) alterations in human pancreatic tumors.

Pancreatic cancer is a malignant neoplasm with an extremely poor prognosis. The mechanisms of aggressive growth and metastasis are currently not well understood. Expression of epidermal growth factor receptor (EGFR) has been suggested to be associated with the malignant transformation of pancreatic cancer. In this study, we examined the EGFR status of 52 pancreatic tumors by PCR-sequencing (exons 19 and 21), immunohistochemistry and FISH probes. We subsequently investigated the relationship between EGFR status and clinicopathological factors. Somatic alterations in EGFR (R841R, T571T and R831C) were observed only in ductal adenocarcinoma (3/34). In 4 (8%) of the 52 tumors analyzed EGFR was overexpressed, 6 (12%) of the tumors showed moderate expression while 19 (32%) were weakly stained. EGFR overexpression (3+ score) was frequently found in endocrine tumors (29%) followed of ampullary tumors (13%; p < 0.01). No significant correlation was observed between the presence of a somatic EGFR mutation and clinicopathological variables. Fluorescence in situ hybridization (FISH) analysis did not demonstrate amplification in any tumors. Only three somatic mutations in the EGFR gene were detected in pancreatic ductal adenocarcinoma and no association was observed with the clinical variables. Our results suggest that EGFR mutations are rare in pancreatic tumors and not associated with clinical prognosis, and treatment response.

Targeting ALDH(bright) human carcinoma-initiating cells with ALDH1A1-specific CD8⁺ T cells.

PURPOSE: Cancer-initiating cells (CIC) are considered to represent the subpopulation of tumor cells that is resistant to conventional cancer treatments, highly tumorigenic in immunodeficient mice, and responsible for tumor recurrence and metastasis. Based on an elevated aldehyde dehydrogenase (ALDH) activity attributable to ALDH1/3 isoforms, ALDH(bright) cells have been identified and isolated from tumors and shown to have characteristics of CIC. The ALDH1A1 isoform was previously identified as a tumor antigen recognized by CD8(+) T cells. This study examines the ability of ALDH1A1-specific CD8(+) T cells to eliminate ALDH(bright) cells and control tumor growth and metastases. EXPERIMENTAL DESIGN: ALDH(bright) cells were isolated by flow cytometry using ALDEFLUOR from HLA-A2(+) human head and neck, breast, and pancreas carcinoma cell lines and tested for their tumorigenicity in immunodeficient mice. ALDH1A1-specific CD8(+) T cells were generated in vitro and tested for their ability to eliminate CICs in vitro and in vivo by adoptive transfer to immunodeficient mice bearing human tumor xenografts. RESULTS: ALDH(bright) cells isolated by flow cytometry from HLA-A2(+) breast, head and neck, and pancreas carcinoma cell lines at low numbers (500 cells) were tumorigenic in immunodeficient mice. ALDH(bright) cells present in these cell lines, xenografts, or surgically removed lesions were recognized by ALDH1A1-specific CD8(+) T cells in vitro. Adoptive therapy with ALDH1A1-specific CD8(+) T cells eliminated ALDH(bright) cells, inhibited tumor growth and metastases, or prolonged survival of xenograft-bearing immunodeficient mice. CONCLUSIONS: The results of this translational study strongly support the potential of ALDH1A1-based immunotherapy to selectively target CICs in human cancer.

Characterization of pathogenic Vibrio parahaemolyticus isolates from clinical sources in Spain and comparison with Asian and North American pandemic isolates.

In spite of the potential risk involved with contamination of seafood with Vibrio parahaemolyticus, there is a lack of information on the occurrence of pathogenic V. parahaemolyticus in Europe. This organism was isolated in 1999 from a large outbreak (64 cases admitted to a single hospital) associated with raw oyster consumption in Galicia, Spain, one of the most important regions in shellfish production worldwide. Two V. parahaemolyticus isolates from the 1999 Galicia outbreak, three additional clinical isolates obtained in the same period from hospitals in Spain, two reference strains from clinical sources, and five Spanish environmental isolates were examined. Seventeen isolates belonging to the pandemic clone isolated in Asia and North America were included in the study for comparison. All isolates were characterized by serotyping, PCR for virulence-related genes, pulsed-field gel electrophoresis (PFGE), and plasmid analysis. Four of the five clinical isolates from hospitals in Spain belonged to serotype O4:K11; the remaining isolate was O4:K untypeable (KUT). All five isolates were positive for V. parahaemolyticus toxR and tlh (species-specific genes) and tdh and negative for trh and group-specific PCR (a PCR method for detection of the pandemic clone). PFGE analysis with NotI and SfiI discriminated the European isolates in two closely related PFGE types included in a homogeneous cluster, clearly differentiated from the Asian and North American isolates. The five environmental isolates belonged to serotypes O2:K28, O2:KUT, O3:K53, O4:KUT, and O8:K22 and were negative for all virulence genes. The five isolates were discriminated into five different PFGE types unrelated to any other isolate included in the study. While the virulence characteristics (tdh positive, trh negative) of the Spanish clinical isolates matched those of the O3:K6 clone from Asia and North America, they were clearly excluded from this clone by group-specific PCR, PFGE, and serotyping. The results of this study suggest that a unique and specific clone could be related to the V. parahaemolyticus infections in Europe.

Influence of environmental factors and human activity on the presence of Salmonella serovars in a marine environment.

The temporal and spatial distribution of Salmonella contamination in the coastal waters of Galicia (northwestern Spain) relative to contamination events with different environmental factors (temperature, wind, hours of sunlight, rainfall, and river flow) were investigated over a 4-year period. Salmonellae were isolated from 127 of 5,384 samples of molluscs and seawater (2.4%), and no significant differences (P < 0.05) between isolates obtained in different years were observed. The incidence of salmonellae was significantly higher in water column samples (2.9%) than in those taken from the marine benthos (0.7%). Of the 127 strains of Salmonella isolated, 20 different serovars were identified. Salmonella enterica serovar Senftenberg was the predominant serovar, being represented by 54 isolates (42.5%), followed by serovar Typhimurium (19 isolates [15%]) and serovar Agona (12 isolates [9.4%]). Serovar Senftenberg was detected at specific points on the coast and could not be related to any of the environmental parameters analyzed. All serovars except Salmonella serovar Senftenberg were found principally in the southern coastal areas close to the mouths of rivers, and their incidence was associated with high southwestern wind and rainfall. Using multiple logistic regression analysis models, the prevalence of salmonellae was best explained by environmental parameters on the day prior to sampling. Understanding this relationship may be useful for the control of molluscan shellfish harvests, with wind and rainfall serving as triggers for closure.