The dominant sequence types of vancomycin-resistant Enterococcus faecium among transplantation ward patients.

OBJECTIVES: Vancomycin-resistant enterococci (VRE) frequently cause therapeutic problems and provide information about the epidemiological condition of the ward. MATERIALS AND METHODS: VRE isolated from patients on transplantation wards in 2007-2008 were compared using 2 molecular methods: RFLP-PFGE (restriction fragment length polymorphism-pulse field gel electrophoresis) and MLST (multilocus sequence typing). RESULTS: The analysis covered 29 Enterococcus faecium strains resistant to glycopeptides, each from a different patient. All organisms were typed using 2 molecular methods. MLST results were compared with an international base. The 30 examined strains belonged to 8 different worldwide known sequence types. All could be recognized as representatives of a single clonal complex CC17. CONCLUSION: Both methods of typing appeared to be useful to asses the epidemiological condition of the investigated wards.

Molecular epidemiology of vancomycin-resistant Enterococcus faecalis among patients of transplantology wards.

OBJECTIVE: Vancomycin-resistant enterococci (VRE) require epidemiological monitoring especially in transplantation wards. The aim of our work was to perform a molecular analysis of vancomycin-resistant Enterococcus faecalis (VREfl) strains among solid organ recipients during various years. MATERIALS AND METHODS: Strains were examined for the presence of different genes determining vancomycin resistance: vanA, vanB, vanD, or vanG by polymerase chain reaction (PCR). Restriction fragment length polymorphism (RFLP)-pulsed field gel electrophoresis (PFGE) was performed on bacterial DNA digested with SmaI enzyme. RESULTS: From 2003 to 2006, we isolated 12 strains of VREfl from 8 patients (2 liver and 6 kidney transplantations). All strains harbored the vanA gene. Among the strains, 5 displayed patterns similar to each other, despite being isolated from different patients, and were susceptible to ampicillin with high resistance to aminoglycosides. CONCLUSIONS: These results suggested that a single strain of VREfl was present for 3 years in closely related hospital wards, but it disappeared in the following years.

Molecular epidemiology of vancomycin-resistant Enterococcus faecium infecting recipients of solid organs in the transplant surgery ward in 2005 and 2006.

BACKGROUND: The aim of the investigations was to compare the vancomycin-resistant Enterococcus faecium (VREfm) strains obtained from our patients. MATERIALS AND METHODS: Strains were compared using restriction fragment length polymorphism-pulsed field gel electrophoresis (RFLP-PFGE) of bacterial DNA. RESULTS: VREfm infected 26 liver recipients, 22 kidney recipients, and 9 other surgery or nephrology patients. Only five strains possessed the vanB determinant. The PFGE analysis revealed two large and several small groups of related strains. CONCLUSIONS: The PFGE analysis enabled the investigation of VRE epidemiology among patients after transplantation. Strains with similar patterns most probably originated from one source and clearly suggested an outbreak.

Cardiocyte nuclear chromatin density correlates with transplanted heart left ventricular mass.

INTRODUCTION: Cardiocyte hypertrophy is accompanied by polyploidy, seen as a decrease in chromatin density in the enlarged nucleus. Repeated biopsies of a transplanted heart offer the possibility of a dynamic evaluation of these phenomena. The aim of this work was an evaluation of cardiocyte nuclear chromatin density in transplanted hearts during long-term follow-up. MATERIALS AND METHODS: The material encompassed myocardial biopsy specimens taken during the first week, first month, and then on an annual basis up to 10 years after surgery. Only biopsy specimens with no rejection were considered (grade "0" International Society for Heart and Lung Transplantation [ISHLT] 122 biopsy specimens). The control group consisted of 7 donor heart specimens. We evaluated the optical density-mean gray level-of cardiomyocyte nuclear chromatin. We determined correlations of this index with the nuclear area, and with left ventricle ultrasound measurements, using correlation analysis. RESULTS: The chromatin mean gray level decreased with time, correlating positively with interventricular septum thickness, left ventricle posterior wall diameter, and left ventricular mass. Analysis of individual periods showed a significant positive correlation of the mean grey level with the cardiocyte nuclear surface in year 3, 4, and 9 after transplantation, thereby suggesting the occurrence of polyploidy at those times. The significant negative correlation of these values (1 week and 1 year) indicated normalization of early cardiocyte hypertrophy. CONCLUSIONS: With the passage of time chromatin condenses, leading to pyknosis. The activity of cardiocyte chromatin correlated with left ventricular hypertrophy. Compensatory cardiomyocyte polyploidy is a periodical phenomenon.

Remodeling of human transplanted myocardium in ten-year follow-up: a clinical pathology study.

UNLABELLED: Remodeling taking place in transplanted myocardium leads to a change in the number of cardiocytes. Ultrasound measurements and biopsy evaluation should reflect their loss and compensation. We sought to evaluate the morphology of the transplanted heart upon long-term follow-up. MATERIAL AND METHODS: Myocardial biopsies were obtained in the first week, first month, and then annually for 10 years from transplantation that did not show rejection (grade "0" ISHLT, 122 biopsies). The control group encompassed 7 donor heart fragments. Proliferation in biopsies was evaluated with Ki67 (M7240, DAKO), cardiocyte hypertrophy by measuring their diameter, the surface area of the nuclei, nuclear-sarcoplasmic index, and stromal fibrosis evaluated as the surface area fraction. Ultrasound measurements included diastolic thickness of the interventricular septum, posterior wall of the left ventricle, and left ventricular mass. The correlation of measurements with time from transplantation was evaluated using Spearman's test. RESULTS: A positive Ki67 reaction was observed in fibroblasts and endothelial cells. The increased cardiocyte nuclear area correlated with the time elapsed since transplantation (r = 0.2; P < .05) with a simultaneous decrease in cardiocyte thickness (r = -0.3; P < .05), without changes in the nuclear-cytoplasmic index (r = 0.02; P > .05). Stromal fibrosis also increased (r = 0.1; P < .05). Ultrasound measurements of the left ventricle showed a decreased tendency with the passage of time (r = -0.2 to -0.3; P < .05). CONCLUSION: A transplanted heart does not undergo hypertrophy but rather fibrous atrophy with apparent compensatory hypertrophy of the cardiomyocytes.

Cardiocyte nucleus shape as an indicator of heart graft aging.

UNLABELLED: Morphometric publications based on the measurement of cardiocyte nuclei indicated their progressive hypertrophy ignoring, however, their shape, which is a deciding factor for the microscopic-based diagnosis of hypertrophy. We sought was to demonstrate how the shapes of cardiocyte nuclei change over time and correlate them with the thickness of the interventricular septum, (IVS) the biopsy site. MATERIAL: We evaluated myocardial biopsies taken in the first week, first month, and then annually until posttransplant year 10. Only biopsies with no rejection were considered: grade "0" ISHLT (122 biopsies). The control group encompassed fragments from seven donor hearts. METHODS: Cardiomyocyte nuclei were evaluated morphometrically. We calculated the length, breadth, perimeter, roundness, elongation, and fullness factors for correlation with the IVS thickness, and selected indices. The relationships between karyometry and IVS thickness (measured by ultrasound) as well as time were calculated by Spearman's correlation test. RESULTS: Among the examined indices, only nuclear length did not correlate significantly with follow-up time. Among the remaining indices, the strongest correlations with time were observed with regard to breadth (r = 0.214), perimeter (r = 0.150), roundness (r = -0.06) and fullness (r = 0.06), and finally elongation (r = 0.02). The decreasing thickness of the interventricular septum (r = -0.31) showed a weak correlation only with the cardiocyte nuclear length (r = -0.05). CONCLUSION: Graft aging imitates hypertrophy inasmuch as cardiocyte nuclei become wider despite the decreased thickness of the interventricular septum. Therefore, karyometric measurements do not reflect myocardial morphology.