Tenofovir alafenamide prophylaxis post-liver transplantation: a real-world study in patients with chronic kidney disease.

Background & aims: Tenofovir alafenamide fumarate (TAF) was shown equally efficacious in suppressing hepatitis B virus (HBV) but with less renal toxicity than tenofovir disoproxil fumarate (TDF). The aim of this real-world study was to evaluate renal function in post-liver transplantation (LT) patients that changed TDF with TAF. Methods: The TAF group (n=17) included patients who switched to TAF due to low (<60 ml/min/1.73m2) Glomerular Filtration Rate (GFR). The control group included patients that remained on TDF (n=30), although some (n= 14) had chronic kidney disease (CKD) (TDF-CKD group). GFR was assessed using: i) MDRD-6 variable; ii) CKD-EPI formula; iii) radionuclide technique (rGFR). Results: There were no significant differences between the two groups except for the presence of diabetes and follow-up period, which were more common and shorter, respectively, in the TAF group (35% vs. 10%, p=0.03; 13.7 vs. 35.5 months, p<0.001). At the end of follow-up there were no significant changes in renal function between the TAF and the TDF group or TDF-CKD group, although the numerical change in rGFR in the latter comparison was greater in the TAF group (ΔrGFR 3 vs. -2.14 ml/min, p=0.26). The use of everolimus was associated with improvement in renal function (ΔrGFR 2 vs. -7.75 ml/min, p=0.06 [TAF vs. TDF group]; 2 vs. -12 ml/min, p=0.01 [TAF vs. TDF-CKD group]). There were no TAF- related side effects or cases of HBV recurrence. Conclusion: Conversion to TAF in post-LT patients who develop CKD does not lead to improvement of kidney function after a period of one year.

RT-TGGE as a guide for the successful isolation of phosphonoacetate degrading bacteria.

AIMS: Use of molecular techniques for the isolation of bacteria capable of phosphonoacetate mineralization as carbon, phosphorus and energy source. METHODS AND RESULTS: RNA extracts obtained at three different stages of an enrichment selecting for phosphonoacetate degrading bacteria were reverse transcribed using 16S rRNA-specific primers, amplified and analysed by temperature gradient gel electrophoresis (TGGE). This information was used to devise a strategy for the isolation of members of the enrichment that were otherwise difficult to obtain in pure culture. We were able to pull out, in total, four out of the six main microbial cultures that were detected by TGGE. Two of the isolates belonging to Mycobacterium and Agromyces genera were for the first time shown to grow in the presence of phosphonoacetate as sole carbon, phosphorus and energy source releasing almost equimolar levels of inorganic phosphate into the culture medium, and they were shown to exhibit phosphonoacetate hydrolase activity in vitro. CONCLUSIONS: The ubiquity of pseudomonad in degradation processes is more likely a consequence of our ignorance of bacterial requirements and physiology, rather than their possession of unique metabolic properties. SIGNIFICANCE AND IMPACT OF THE STUDY: RT-TGGE analysis can be used to guide the successful isolation of micro-organisms difficult to obtain by culture-dependent methods alone.

Evaluation of freeze-dried kefir coculture as starter in feta-type cheese production.

The use of freeze-dried kefir coculture as a starter in the production of feta-type cheese was investigated. Maturation of the produced cheese at 4 degrees C was monitored for up to 70 days, and the effects of the starter culture, the salting method, and the ripening process on quality characteristics were studied. The use of kefir coculture as a starter led to increased lactic acid concentrations and decreased pH values in the final product associated with significantly higher conversion rates compared to salted rennet cheese. Determination of bacterial diversity at the end of the ripening process in salted kefir and rennet cheeses by denaturing gradient gel electrophoresis technology, based on both DNA and RNA analyses, suggested a potential species-specific inhibition of members of the genera Staphylococcus and Psychrobacter by kefir coculture. The main active microbial associations in salted kefir cheese appeared to be members of the genera Pseudomonas and Lactococcus, while in salted rennet cheese, Oxalobacteraceae, Janthinobacterium, Psychrobacter, and Pseudomonas species were noted. The effect of the starter culture on the production of aroma-related compounds responsible for cheese flavor was also studied by the solid-phase microextraction-gas chromatography-mass spectrometry technique. Kefir coculture also appeared to extend the shelf life of unsalted cheese. Spoilage of kefir cheese was observed on the 9th and 20th days of preservation at 10 and 5 degrees C, respectively, while spoilage in the corresponding rennet cheese was detected on the 7th and 16th days. Microbial counts during preservation of both types of unsalted cheese increased steadily and reached similar levels, with the exception of staphylococci, which were significantly lower in unsalted kefir cheese. All types of cheese produced with kefir as a starter were approved and accepted by the panel during the preliminary sensory evaluation compared to commercial feta-type cheese.