Logical Identification of an Allantoinase Analog (puuE) Recruited from Polysaccharide Deacetylases

The hydrolytic cleavage of the hydantoin ring of allantoin, catalyzed by allantoinase, is required for the utilization of the nitrogen present in purine-derived compounds. The allantoinase gene (DAL1), however, is missing in many completely sequenced organisms able to use allantoin as a nitrogen source. Here we show that an alternative allantoinase gene (puuE) can be precisely identified by analyzing its logic relationship with three other genes of the pathway. The novel allantoinase is annotated in structure and sequence data bases as polysaccharide deacetylase for its homology with enzymes that catalyze hydrolytic reactions on chitin or peptidoglycan substrates. The recombinant PuuE protein from Pseudomonas fluorescens exhibits metal-independent allantoinase activity and stereospecificity for the S enantiomer of allantoin. The crystal structures of the protein and of protein-inhibitor complexes reveal an overall similarity with the polysaccharide deacetylase beta/alpha barrel and remarkable differences in oligomeric assembly and active site geometry. The conserved Asp-His-His metal-binding triad is replaced by Glu-His-Trp, a configuration that is distinctive of PuuE proteins within the protein family. An extra domain at the top of the barrel offers a scaffold for protein tetramerization and forms a small substrate-binding cleft by hiding the large binding groove of polysaccharide deacetylases. Substrate positioning at the active site suggests an acid/base mechanism of catalysis in which only one member of the catalytic pair of polysaccharide deacetylases has been conserved. These data provide a structural rationale for the shifting of substrate specificity that occurred during evolution

Il futuro degli italiani. Demografia, economia e società verso il nuovo secolo

Il futuro della scuola, della sanità, del lavoro e di altri rilevanti aspetti del "sistema Italia", alla luce dei mutamenti demografici previsti dalle proiezioni demografiche ufficiali: le prospettive al 2007.- Indice #7- Introduzione, Marcello Pacini #11- Cap.I Le grandi tendenze del mutamento demografico, Stefano Molina e Alessandro Monteverdi #25- Cap.II Il lavoro, Stefano Molina, Alessandro Monteverdi, Daniela Del Boca #61- Cap.III L'istruzione, Carla Marchese #105- Cap.IV La sanità, Carla Marchese #129- Cap.V La rappresentanza politica, Stefano Molina #155- Cap.VI Considerazioni conclusive, Piero Gastaldo #177- Appendice Le prospettive delle singole regioni italiane #191- Segnalazioni bibliografiche #27

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come

An outbreak of sepsis due to extensively drug- resistant originating from an environmental source in an Italian haematologic unit

Background: Multidrug-resistant (MDR) or extensively-drug-resistant (XDR) Pseudomonas aeruginosa (PSA) strains infections are a major concern in nosocomial environments being associated both with worse outcomes and with high mortality rates especially in oncologic and haematogic settings. In the Trieste University hospital, we experienced an outbreak of XDR-PSA bacteremia in the haematology unit probably caused by a reservoir in the toilets faucets. Materials/methods: The haematology unit in Trieste hospital has twelve double-bed rooms and a protected area with three single-bed rooms reserved to patients undergoing marrow transplants and severe neutropenia (neutrophils <0.5 x103/\u3bcL). From August until September 2017 we found 5 patients with sepsis or septic-shock due to an XDR-PSA. The bacterial identification was performed by Vitek-2 (bioM\ue9rieux). Minimal inhibitory concentrations (MICs) were determined by a micro-dilution method (Sensititre Diagnostic System, Trek), and interpreted according to the EUCAST criteria. MIC for ceftolozane/tazobactam was determined by e-test. Genotyping to determine genetic relatedness between isolates was performed by analysis of pulsed-field gel electrophoresis (PFGE) profiles of chromosomal DNA digested with SpeI. Results: All 5 consecutive strains of PSA from blood culture were resistant to piperacillin/tazobactam, ceftazidime, cefepime, ciprofloxacin, gentamicin, imipenem, meropenem and ceftolozane/tazobactam and susceptible to colistin and amikacin. None of these patients had any apparent source of bacteremia. Four out of five patients occupied the three isolation rooms. Two out of five patients had CVC-related sepsis and two died because of the XDR-PSA bacteremia (40% in-hospital mortality). No culture from rectal swabs and samples from ventilation filters was found positive for XDR-PSA which was instead found in the faucets of the toilets in the protected area. Pulse field analysis demonstrated that the strains both from blood cultures and from the toilets tabs were highly related suggesting that the outbreak was due to a single clone, probably originating from the tap water. The environmental disinfection of the ward succeeded in clearing the XDR-PSA strain and allowed to resume the regular transplant activity. Conclusions: The investigation of this dramatic outbreak of XDR PSA highlights the potential role of environmental sources acting as a reservoir of MDR/XDR nosocomial pathogens