Cellular and Humoral Responses in Dialysis Patients after Vaccination with the BNT162b2 or mRNA-1273 Vaccines.

The outbreak of SARS-CoV-2 has raised considerable concern about the detrimental effects it can induce in public health, with the interest of the scientific community being focused on the development of preventive and therapeutic approaches. Patients with end-stage renal disease (ESRD) are amongst vulnerable populations for critical illness owing to the presence of other comorbidities, their defective immune system, and their inability of self-isolation. To date, vaccination constitutes the most promising method to manage viral dispersion. Therefore, it is particularly important to investigate the effectiveness of available vaccines against SARS-CoV-2 in this risk group. Here, we summarize initial experience regarding the humoral and cellular immune responses elicited in dialysis patients after completion of the recommended vaccination regimen, as well as after booster dose administration, with one of the two mRNA vaccines, namely, BNT162b2 and mRNA-1273. In conclusion, a significantly diminished and delayed immune pattern was observed in ESRD patients compared to healthy population, with a peak in antibody titers occurring 3-5 weeks after the second dose. A booster dose significantly augmented the immune response in dialysis patients with either mRNA-based vaccine. Variables adversely correlating with the weak immunogenicity observed in dialysis patients include immunosuppressive therapy, older age, comorbidities, longer time in hemodialysis treatment, and higher body mass index. On the contrary, previous COVID-19 infection and administration of the mRNA-1273 vaccine are deemed to induce a more favorable immune response. Further investigation is needed to thoroughly understand the efficacy of mRNA-based vaccines in hemodialysis patients and define predictive factors that can influence it.

Prospective evaluation of specimen pooling strategy for detection of SARS-CoV-2 using pools of five and six specimens.

The increased demand for SARS-CoV-2 molecular testing during the COVID-19 pandemic resulted in shortage of reagents and consumables. Pooling of specimens could be an alternative strategy to overcome these problems. Initial evaluation of the pooling strategy was performed using known positive specimens, previously tested individually, and their respective pools of plus four (5X), five (6X) and nine (10X) known negative specimens. Subsequently, 35 positive 5X and 35 positive 6X pools containing only one positive specimen per pool were analyzed prospectively regarding the difference in Ct values in pooled versus individual specimens. When the number of samples in the pool were five or six, the average deviation of Ct differences was < 1; therefore, this strategy was followed in the prospective study. Significant difference in Ct values was observed in positive specimens when tested individually and in 5X pools (p = 0.006), while the difference was not significant when positive specimens were tested individually and in 6X pools (p = 0.07). The difference in Ct values was not significant between the 5X and 6X pools. Testing in pools of five or six specimens is a reliable option for SARS-CoV-2 RNA detection when mass testing is needed.

Epidemiology and antimicrobial susceptibility of Staphylococcus lugdunensis in a Greek tertiary-care hospital.

Staphylococcus lugdunensis is considered more pathogenic than other coagulase-negative Staphylococci (CoNS), with its virulence resembling that of Staphylococcus aureus. We report a retrospective study of all S. lugdunensis infection cases during a 3.5-year period in a large tertiary university hospital in Greece. S.lugdunensis was susceptible to most tested antibiotics, although a high resistance percentage was found to clindamycin (27%) and erythromycin (25%). The susceptibility rate to penicillin was 49%, much lower than previously reported elsewhere, indicating that penicillin may not be an optimal treatment choice for S. lugdunensis infections in our region.

Effect of crocin on antioxidant gene expression, fibrinolytic parameters, redox status and blood biochemistry in nicotinamide-streptozotocin-induced diabetic rats.

BACKGROUND: Diabetes is regarded as an epidemiological threat for the twenty-first century. Phytochemicals with known pharmaceutical properties have gained interest in the field of alleviating secondary complications of diseases. Such a substance is crocin, a basic constituent of saffron (Crocus sativus). The present study aimed at examining the beneficial effects of per os crocin administration on the antioxidant status, blood biochemical profile, hepatic gene expression and plasminogen activator inhibitor-1 activity (PAI-1) in the liver, kidney and plasma (an important marker of pre-diabetic status and major factor of thrombosis in diabetes) of healthy rats, as well as of rats with nicotinamide-streptozotocin-induced diabetes. RESULTS: Diabetes disrupted the oxidation-antioxidation balance, while crocin improved the antioxidant state in the liver by significantly affecting SOD1 gene expression and/or by restoring SOD and total antioxidant capacity (TAC) levels. In the kidney, crocin improved hydrogen peroxide decomposing activity and TAC. In blood, hepatic transaminases ALT and AST decreased significantly, while there was a trend of decrease regarding blood urea nitrogen (BUN) levels. The expression of PAI-1 gene was affected in the liver by the dose of 50 mg kg-1. CONCLUSIONS: Crocin treatment contributed in restoring some parameters after diabetes induction, primarily by affecting significantly hepatic transaminases ALT and AST, SOD1 and PAI-1 gene expression and nephric H2O2 decomposing activity. In conclusion, crocin did contribute to the alleviation of some complications of diabetes.

Whole-genome sequencing study of KPC-encoding Klebsiella pneumoniae isolated in Greek private laboratories from non-hospitalised patients.

OBJECTIVES: Greece is endemic for KPC-encoding Klebsiella pneumoniae; however, until now, reports have referred only to hospital isolates. In this study, seven KPC-encoding K. pneumoniae isolated in private laboratories from non-hospitalised patients were characterised. METHODS: Whole-genome sequencing was performed on an Illumina MiniSeq Sequencing System. Multilocus sequence typing (MLST) was performed using a BLAST-based approach, and antimicrobial resistance genes and plasmid replicons were identified using ResFinder and PlasmidFinder, respectively. The Rapid Annotation using Subsystem Technology (RAST) v.2.0 server was used for genome annotation of virulence, pathogenesis and defence genes. RESULTS: Six isolates belonged to the major MLST sequence type 258 (ST258) and one to ST39. The resistome included genes encoding resistance mechanisms to ß-lactams, aminoglycosides, quinolones, sulfonamides, trimethoprim, fosfomycin and phenicols, conferring multidrug-resistant phenotypes. Moreover, various genes involved in virulence, pathogenesis and defence have been identified. CONCLUSIONS: It is highly probable that these isolates were acquired during previous hospitalisation in Greek hospitals. The presence of KPC-encoding K. pneumoniae in non-hospitalised patients is alarming, although it is not yet possible to assess its actual impact.

Whole-genome sequencing of a CTX-M-11-encoding and quinolone-non-susceptible Klebsiella pneumoniae ST194 isolate from a hospitalised dog in Greece.

OBJECTIVES: The emergence and spread of transferable ß-lactamases among Enterobacteriaceae is a major problem both to human and veterinary medicine and is an important contributing factor to the development of multidrug-resistant bacterial isolates. In the present study, whole-genome sequencing of a Klebsiella pneumoniae isolate (LKP817909) resistant to first- and second-generation cephalosporins and non-susceptible to fluoroquinolones, isolated from a urine sample of a hospitalised dog, was performed. METHODS: Genome sequencing was performed on an Illumina MiniSeq Sequencing System. Multilocus sequence typing (MLST) was performed using a BLAST-based approach, whereas antimicrobial resistance genes and plasmid replicons were identified by ResFinder and PlasmidFinder, respectively. The Rapid Annotation using Subsystem Technology (RAST) server v.2.0 was used for genome annotation. RESULTS: Data analyses revealed the complete resistome of isolate LKP817909, which included the cefotaximase-München-11 (CTX-M-11) extended-spectrum ß-lactamase together with 11 other resistance genes. Ten resistance genes were located on plasmids and two on the chromosome. CONCLUSIONS: To the best of our knowledge, this is the first detection of a CTX-M-11-producing K. pneumoniae isolated from a canine. The whole genome sequence of the isolate has been deposited at GenBank to serve as a future reference.