Disinfection of gloved hands during routine care

Healthcare-associated infections are a major issue in public health. After several decades of hand hygiene programmes, it is time to admit that we have failed to achieve our goal. One of the reasons is the overuse of gloves, which is in part justified by the nature of the nursing care. Several experimental studies supported the effectiveness of disinfecting gloves, but evidence for routine feasibility and effectiveness is lacking. The aim of this study was to evaluate the effectiveness of alcohol-based disinfection of gloves during nursing care. Swabs were taken from the most contaminated part of both hands at different times: T0 (before wearing gloves), T10 (after 10 minutes of nursing care) from both gloves, T10A (just after the gloves were disinfected for 30 seconds with bedside disposable hydroalcoholic solution) and when possible at T20 and T20A. After 10 minutes of nursing care, gloves were contaminated in 72.5% of cases. After alcohol-based disinfection, gloves became free of microorganism in 79.3% of cases. Alcohol-based disinfection of gloves during routine care is effective and appears to be a reasonable alternative to current recommendations.

An engineered toluene dioxygenase for a single step biocatalytical production of (-)-(1S,2R)-cis-1,2-dihydro-1,2-naphthalenediol

cis-1,2-Dihydro-1,2-naphthalenediol (DHND) is a valuable molecule employed for the pharmaceutical synthesis of bioactive compounds, such as bicyclic conduritol analogues. Enantiopure (+)-(1R,2S)-DHND (>98 % ee) is easily biosynthesized through the dearomatizing dihydroxylation of naphthalene, catalyzed by toluene dioxygenase (TDO) from Pseudomonas putida F1. However, the opposite enantiomer (-)-(1S,2R)-DHND could not be directly accessed, neither by chemical synthesis nor via biocatalytic approaches. Herein, we report a one-step biosynthesis of the opposite enantiomer (-)-(1S,2R)-DHND in a recombinant TDO E. coli BW25113 platform. We based on a semi-rational approach to generate a set of TDO variants, targeting exclusively the hotspot position F366, in order to enable an enantiomeric switch in the generated product. Eight out of nine single point variants were active and showed not only an alteration in enantioselectivity, but also generated an enantiomeric excess of the pursued product. Variant TDO_F366V outperformed above the rest of the set, enabling the synthesis of (-)-(1S,2R)-DHND not only with an excellent enantiomeric excess of 90 %, but also with an advantageous product formation. A comparative semi-preparative biosynthesis yielded, 287 mg of (+)-(1R,2S)-DHND (>98 % ee) and 101 mg of (-)-(1S,2R)-DHND (90 % ee), when performed in a total volume of 100 mL with TDO wild-type and TDO_F366V resting cells, respectively.

Percutaneous isolated hepatic perfusion (chemosaturation) with melphalan following right hemihepatectomy in patients with cholangiocarcinoma and metastatic uveal melanoma: peri- and post-interventional adverse events and therapy response compared to a matched group without prior liver surgery

To evaluate feasibility, frequency and severity of peri-procedural complications and post-procedural adverse events (AEs) in patients with advanced cholangiocarcinoma or liver metastasis of uveal melanoma and prior hemihepatectomy undergoing chemosaturation percutaneous hepatic perfusion (CS-PHP) and to analyze therapy response and overall survival compared to a matched group without prior surgery. CS-PHP performed between 10/2014 and 02/2018 were retrospectively assessed. To determine peri-procedural safety and post-procedural adverse events, hospital records and hematological, hepatic and biliary function were categorized using Common Terminology Criteria for Adverse Events (CTCAE) v5.0 (1–5; mild-death). Significance was tested using Wilcoxon signed-rank and Mann–Whitney U test. Kaplan–Meier estimation and log-rank test assessed survival. Overall 21 CS-PHP in seven patients (4/7 males; 52 ± 10 years) with hemihepatectomy (group^hemihep) and 22 CS-PHP in seven patients (3/7 males; 63 ± 12 years) without prior surgery (group^noresection) were included. No complications occurred during the CS-PHP procedures. Transient changes (CTCAE grade 1–2) of liver enzymes and blood cells followed all procedures. In comparison, group^hemihep presented slightly more AEs grade 3–4 (e.g. thrombocytopenia in 57% (12/21) vs. 41% (9/22; p = 0.37)) 5–7 days after CS-PHP. These AEs were self-limiting or responsive to treatment (insignificant difference of pre-interventional to 21–45 days post-interventional values (p > 0.05)). One patient in group^hemihep with high tumor burden died eight days following CS-PHP. No deaths occurred in group^noresection. In comparison, overall survival after first diagnosis was insignificantly shorter in group^noresection (44.7(32–56.1) months) than in group^hemihep (48.3(34.6–72.8) months; p = 0.48). The severity of adverse events following CS-PHP in patients after hemihepatectomy was comparable to a matched group without prior liver surgery. Thus, the performance of CS-PHP is not substantially compromised by a prior hemihepatectomy.

Regioselective biocatalytic self-sufficient Tishchenko-type reaction via formal intramolecular hydride transfer

A self-sufficient nicotinamide-dependent intramolecular bio-Tishchenko-type reaction was developed. The reaction is catalyzed by alcohol dehydrogenases and proceeds through formal intramolecular hydride transfer on dialdehydes to deliver lactones. Regioselectivity on [1,1'-biphenyl]-2,2'-dicarbaldehyde substrates could be controlled via the electronic properties of the substituents. Preparative scale synthesis provided access to substituted dibenzo[c,e]oxepin-5(7H)-ones.

Approaching boiling point stability of an alcohol dehydrogenase through computationally-guided enzyme engineering

Enzyme instability is an important limitation for the investigation and application of enzymes. Therefore, methods to rapidly and effectively improve enzyme stability are highly appealing. In this study we applied a computational method (FRESCO) to guide the engineering of an alcohol dehydrogenase. Of the 177 selected mutations, 25 mutations brought about a significant increase in apparent melting temperature (ΔTm ≥ +3 °C). By combining mutations, a 10-fold mutant was generated with a Tm of 94 °C (+51 °C relative to wild type), almost reaching water's boiling point, and the highest increase with FRESCO to date. The 10-fold mutant's structure was elucidated, which enabled the identification of an activity-impairing mutation. After reverting this mutation, the enzyme showed no loss in activity compared to wild type, while displaying a Tm of 88 °C (+45 °C relative to wild type). This work demonstrates the value of enzyme stabilization through computational library design.