Pathogenic and Opportunistic Vibrio spp. Associated with Vibriosis Incidences in the Greek Aquaculture: The Role of Vibrio harveyi as the Principal Cause of Vibriosis.

A monitoring program to follow vibriosis incidents in the Greek marine aquaculture was implemented over the past 13 years. 273 isolates, from various cases originating from eight regions and nine hosts, were collected and characterized. The main aquaculture species of the survey were the European seabass (Dicentrarchus labrax) and the gilthead seabream (Sparus aurata). Various species of Vibrionaceae were associated with vibriosis. Vibrio harveyi had the highest prevalence and was isolated throughout the year from all hosts. During the warm months, Vibrio harveyi prevailed with frequent co-isolations of Photobacterium damselae subsp. damselae and Vibrio alginolyticus, while during spring, other Vibrio species were more abundant, such as Vibrio lentus, Vibrio cyclitrophicus, and Vibrio gigantis. Phylogenetic analysis using the mreB gene and the metabolic fingerprint of the isolates showed great variability within the species of the collection. The severity of the disease and the frequency of outbreaks make vibriosis (that is, mainly attributed to V. harveyi) an important concern for the regional aquaculture sector.

Development of autogenous vaccines for farmed European seabass against Aeromonas veronii using zebrafish as a model for efficacy assessment.

Aeromonas veronii bv. sobria is an emerging pathogen for the European seabass cultured in the Aegean Sea (Mediterranean) causing significant problems in the Greek and Turkish aquaculture industry since no licensed vaccine is currently available for the disease. A bivalent vaccine was developed based on two phenotypically distinct strains of the pathogen, PDB (motile, pigment-producing strain) and NS (non-motile, non-pigment-producing). The two strains comprising the bivalent vaccine were evaluated as monovalent products in zebrafish before the seabass trials. Challenges using the homologous or the heterologous strain showed that both vaccines were protective with RPS values ranging between 66 and 100% in zebrafish. The bivalent vaccine was then tested in European seabass following dip or intraperitoneal administration. Efficacy was evaluated separately against both strains comprising the bivalent vaccine. Dip vaccination applied to juvenile seabass of 2.5 g average weight provided protection following challenge tests 30 days post vaccination only in one of the two strains tested (strain PDB, RPS: 88%). This was also the case in the injection vaccination of adult seabass of 60 g average weight where the vaccine was effective only against the PDB strain (RPS: 63%). High antibody titers against both strains were found at 30 and 60 days after intraperitoneal vaccination in the adult seabass. The use of zebrafish as a model for vaccine development for aquaculture species is discussed.

Prevalence and factors associated with hyperkalaemia in stable kidney transplant recipients.

BACKGROUND: Hyperkalaemia is a frequent and potentially life-threatening condition in patients with chronic kidney disease (CKD). Even after successful kidney transplantation (KTx), KTx recipients have mild to severe CKD. Moreover, they share comorbid conditions and frequently use medications that predispose to hyperkalaemia. This study aimed to examine the prevalence and factors associated with hyperkalaemia in this population. METHODS: Over a pre-specified period of 6 months (1 September 2019 to 31 March 2020), we recorded in cross-sectional fashion information on serum potassium (K+) and relevant demographics, comorbidities, medications, laboratory and transplant-associated variables in clinically stable KTx recipients attending the Transplant Outpatient Clinic of our Department. Ηyperkalaemia was classified as follows: serum K+ level >5.0 mEq/L; and further as >5.0 mEq/L with concomitant use of sodium (Na+) polystyrene sulphonate; serum K+ ≥5.2 mEq/L; serum K+ ≥5.5 mEq/L. Univariate and multiple logistic regression analyses were used to identify factors associated with serum K+ >5.0 mEq/L. RESULTS: The study population consisted of 582 stable KTx recipients, 369 (63.4%) males, aged 52.4 ± 13.5 years, with estimated glomerular filtration rate (eGFR) of 55.8 ± 20.1 mL/min/1.73 m2 transplanted for >1 year. The prevalence of hyperkalaemia defined as K+ >5.0 mEq/L; >5.0 mEq/L and use of Na+ polystyrene sulphonate; K+ ≥5.2; or K+ ≥5.5 mEq/L, was: 22.7, 22.7, 14.4 and 4.1% (132, 132, 84 and 24 patients), respectively. In multivariate analysis, male gender [odds ratio (OR) = 2.020, 95% confidence interval (CI) 1.264-3.227] and use of renin-angiotensin-aldosterone system (RAAS) blockers (OR = 1.628, 95% CI 1.045-2.536) were independently associated with hyperkalaemia, while higher eGFR (OR = 0.967, 95% CI 0.955-0.979) and use of non-K+-sparing diuretics (OR = 0.140, 95% CI 0.046-0.430) were associated with lower odds of the disorder. CONCLUSIONS: The prevalence of mild hyperkalaemia in stable KTx recipients is relatively high but that of moderate or severe hyperkalaemia is low. Among a wide range of factors studied, only male gender and RAAS blockade were associated with increased odds of hyperkalaemia, while higher eGFR and diuretics were associated with decreased odds of hyperkalaemia.

Risk Factors of the Development of Diabetes Mellitus After Kidney Transplantation.

BACKGROUND: The occurrence of diabetes mellitus is common after kidney transplantation (posttransplant diabetes mellitus [PTDM]) and enhances the cardiovascular risk and risk for kidney graft loss. The incidence of PTDM is about 5% to 40%. This study aimed to examine the potential risk factors that determine the occurrence of PTDM. METHODS: This study retrospectively included 298 patients from transplantation unit of Evangelismos who underwent kidney transplantation during a 10-year period (January 1, 2009, to January 1, 2019). Kidney transplant recipients with diabetes mellitus prior to transplantation or those with follow-up of <6 months were rejected from the study. In total, the study included 274 recipients with a mean age of 50 ± 18 years. The mean time of monitoring was 63 ± 18 months. The PTDM diagnosis was based on the 2018 criteria of the American Diabetes Association. RESULTS: Of 274 kidney transplant recipients, PTDM developed in 38 (13.8%) patients over a period of 11 ± 9 months after transplantation. Given that immunosuppressive therapy was identical in most patients, statistical analysis did not correlate the incidence of diabetes with treatment. However, there was a correlation for the occurrence of PTDM between the presence of hypomagnesemia and increased uric acid levels. Finally, there was a negative correlation between the age of the recipient and the time of PTDM onset. CONCLUSION: Hypomagnesemia and hyperuricemia increased the risk of PTDM in these patients. Given the association between hypomagnesemia and the development of diabetes mellitus after kidney transplantation, prospective studies are needed to identify the causes of PTDM and to develop prevention strategies.

Resistive Renal Index of the Recipient and its Correlation With the Outcome of Kidney Transplantation at the End of the First Year: Preliminary Results.

BACKGROUND: Renal resistive index (RRI) of ultrasonography is a useful and potent tool for the assessment of patients who have undergone transplantations. The aim of this study was to evaluate the association of RRI with renal function 1 year after transplant. METHODS: We retrospectively evaluated 93 kidney allograft recipients. Data were collected from transplantations performed in our medical center between January 2014 and September 2018. Patients with acute loss of the renal function and renal survival <1 year were excluded from the study. We longitudinally compared the RRI at the first week after transplant and the third month, with estimated glomerular filtration rate (eGFR, by Chronic Kidney Disease Epidemiology Collaboration equation) at the end of the first year of transplantation. RRI was divided into 2 groups (RRI ≤0.80 or >0.80). RESULTS: From the total of 86 recipients, 59 (68.6%) were male recipients and 27 female recipients with a mean age of 48.3 ± 12.1 years. No correlations were found between the first week's RRI with sex and age of both donors and recipients (P > .05). Similarly, the first week's RRI was not correlated with delayed graft function (DGF) and 1-year eGFR after transplant (P > .05). On the contrary, RRI performed at the third month was strongly correlated to DGF and eGFR at the end of the first year. Last but not least, neither higher recipient age nor sex affects the value of resistive index in the third month after transplantation (P < .05). CONCLUSIONS: RRI values <0.80 in the third month after kidney transplantation were related to better annual renal function and a lower incidence of DGF.

Body Mass Index and Kidney Donor Profile Index as Prognostic Markers of the Outcome of Renal Transplantation.

BACKGROUND: The aim of this study was to determine the effects of Kidney Donor Profile Index (KDPI) and body mass index (BMI) of the deceased donor on the kidney allograft outcome 1 year after transplantation. METHODS: We retrospectively studied 98 deceased kidney allograft donors with a mean age of 56 ± 12 years. The donors were divided into 5 groups according to their BMI: Normal ΒΜΙ = 25 (n = 25); ΒΜΙ 25 to 29 = Overweight (n = 33); ΒΜΙ 30 to 34.9 = Obese class I (n = 19); ΒΜΙ 35 to 39 = Obese class ΙΙ (n = 11); and ΒΜΙ >40 = Obese class III (n = 10). We examined the impact of the deceased donor's BMI and KDPI on delayed graft function (DGF) and estimated renal glomerular filtration rate (eGFR) (measured by the Chronic Kidney Disease Epidemiology Collaboration equation) 1 year after transplantation. RESULTS: Donor BMI significantly increased the prevalence of DGF (P = .031), and it was associated with higher cold ischemia time (P = .021). However, there was no significant association between the aforementioned BMI groups and 1-year eGFR (P = 0.57), as deceased grafts from donors with increased BMI (BMI > 40) gained sufficient renal function during the first year of transplantation. Moreover, high KDPI was associated not only with DGF (P = .015), but also with decreased values of eGFR (P = .033). CONCLUSION: In this population, we identified no significant association between donor BMI and long-term clinical outcomes in deceased donor kidney transplants. KDPI, and not ΒΜΙ, of the deceased donor seems to be a good prognostic factor of renal function at the end of the first year after kidney transplant, whereas high BMI and high KDPI markedly induce DGF.

Determinants of Parathyroid Hormone Levels During the First Year After Kidney Transplantation.

BACKGROUND: Spontaneous remission of secondary hyperparathyroidism after kidney transplantation requires time to occur. The aim of the present study was to investigate factors that may be related to the reduction of parathyroid hormone (PTH) after transplantation as well as the rate of its reduction. METHODS: We studied 81 kidney transplant recipients at our transplantation center between January 2014 and September 2017. The relationship of PTH values during the first year after transplant with renal function, type of kidney graft origin (deceased or living), and delayed renal graft function was examined. Moreover, we determined the correlation of the rate of PTH reduction within the first year with the value of PTH before transplant. RESULTS: Of the total of 81 recipients, 28 (35.1%) were women and 53 (64.8%) were men, with a mean age of 47 ± 11.87 years. At the same time, there was a decrease of PTH by 33% in the first half of the first year after transplantation and by 57% in the second. In addition, a statistically significant correlation of PTH with renal function was found (P = .001), with PTH values decreasing as the glomerular filtration rate increased. Finally, transplants from deceased donors were associated with higher values of PTH, whereas the value of PTH before transplant was positively correlated with the value after it (P = .001). CONCLUSIONS: Secondary hyperparathyroidism, which accompanies end-stage chronic renal failure, usually resolves adequately after transplantation. The determinants of this resolution are the recipient's renal function, the kidney graft origin (deceased), and the pretransplant PTH values.

Comparative Study on A Novel Pathogen of European Seabass. Diversity of Aeromonas veronii in the Aegean Sea.

Aeromonas veronii is an emerging pathogen causing severe pathology and mortalities in European seabass aquaculture in the Aegean Sea, Mediterranean. More than 50 strains of the pathogen were characterized biochemically and genetically in order to study the epidemiology of the disease, as well as the phylogeny and virulence of the bacterium. Based on the phenotypic characteristics, the isolates form three groups consisting of: (a) the West Aegean Sea, non-motile, non-pigment-producing strains, (b) the West Aegean Sea, motile, and pigment-producing strains and (c) the East Aegean Sea motile strains that produce minute amounts of pigment. All strains were highly similar at the genomic level; however, the pattern of West/East geographic origin was reflected in biochemical properties, in general genomic level comparison and in the putative virulent factors studied. Type VI secretion system was not detected in the western strains. The outer membrane protein (OMP) profile which contains proteins that are putative antigenic factors, was very similar between strains from the different areas. Although most of the OMPs were detected in all strains with great sequence similarity, diversification according to geographic origin was evident in known antigenic factors such as the maltoporin LamB. A systematic comparative analysis of the strains is presented and discussed in view of the emergence of A. veronii as a significant pathogen for the Mediterranean aquaculture.

First report of Edwardsiellosis in cage-cultured sharpsnout sea bream, Diplodus puntazzo from the Mediterranean.

BACKGROUND: Edwardsiella tarda, is a serious bacterial pathogen affecting a broad range of aquaculture fish species. The bacterium has also been reported as a human pathogen, however recent studies have dissociated the fish pathogenic Edwardsiella from those isolated from humans by placing them in a new species, E. piscicida. Here we report the first case of Edwardsiellosis in cultured sharpsnout sea breams, Diplodus puntazzo in Greece. CASE PRESENTATION: The disease has affected cultured sharpsnout sea breams of a commercial fish farm in a single location in East Greece. Two populations of sharpsnout sea breams stocked in two consecutive years in floating cages presented signs of disease which included nodules and abscesses in spleen and kidney, morbidity and cumulative mortality reaching 5.3 %. Using microbiological, biochemical and molecular tools we have identified Edwardsiella sp. as the main aetiological factor of the disease. Following phylogenetic analysis the bacterial isolates are grouped with the newly described Edwardsiella piscicida species. CONCLUSIONS: This is the first report of Edwardsiellosis in this species but most importantly in sea cage-cultured fish in the Mediterranean which may pose a serious threat for aquaculture fish species in this region.

Enteromyxum leei infection in parrotfish, Sparisoma cretense: histopathological, morphological and molecular study.

Enteromyxum leei (Myxozoa) has been identified as the aetiological agent of morbidity and mortality in captive feral parrotfish, Sparisoma cretense held at the facilities of Cretaquarium, the public aquarium of the Hellenic Centre for Marine Research in Crete. The parasite caused substantial mortality to the parrotfish exceeding 60% over a period of 3.5 months. Here we describe the course of disease, the effects of the parasite on the host based on histopathological observations and we provide morphological and molecular data on the parasite.