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In response to the in vivo environment, the Salmonella enterica serovar Typhimurium lipopolysaccharide (LPS) is modified. These modifications are controlled in part by the two-component regulatory system PmrA-PmrB, with the addition of 4-aminoarabinose (Ara4N) to the lipid A and phosphoethanolamine (pEtN) to the lipid A and core. Here we demonstrate that the PmrA-regulated STM4118 (cptA) gene is necessary for the addition of pEtN to the LPS core. pmrC, a PmrA-regulated gene necessary for the addition of pEtN to lipid A, did not affect core pEtN addition. Although imparting a similar surface charge modification as Ara4N, which greatly affects polymyxin B resistance and murine virulence, neither pmrC nor cptA plays a dramatic role in antimicrobial peptide resistance in vitro or virulence in the mouse model. Therefore, factors other than surface charge/electrostatic interaction contribute to resistance to antimicrobial peptides such as polymyxin B.

Fusarium solani is a species complex (FSSC) containing isolates that cause diseases in important crops such as root and fruit rot of Cucurbita spp., root and stem rot of pea, sudden death syndrome of soybean, foot rot of bean and dry rot of potato tubers during storage. Based on host range tests, F. solani were subdivided into different formae specialis (f. sp.) and varieties, while DNA sequences of 28S rDNA, internally transcribed spacers (ITS) rDNA and elongation factor (EF-1α) distinguished the ‘ F. solani complex’ in 50 subspecific lineages. In this study we characterized, by cultural, morphological and molecular criteria, 34 isolates of F. solani obtained from potato, other crops and soil. The 34 isolates in the FSSC showed wide variability for their cultural, morphological and molecular traits. The wide variability observed with amplified fragment-length polymorphism (AFLP) and mini-microsatellite analyses is in agreement with the polymorphism observed, in a previous study, within FSSC. Nine of 34 isolates in the FSSC, classified as F. solani var. coeruleum, were morphologically distinguishable from the other F. solani isolates but they were distributed in different clusters; moreover, the nine isolates showed instability of the coeruleum pigmentation of the colonies, supporting the ambiguity of the taxa of this variety of F. solani. Using sequence data from ITS plus 5.8S rDNA region, the isolates were classified into different clades. In particular eight isolates were classified into a well-supported clade including F. solani f. sp . pisi, nine into a clade including only isolates of F. solani f. sp . radicicola and four into a clade including F. solani f. sp . cucurbitae, but this classification could not be used if is not in agreement with host specificity. Two of the nine F. solani var. coeruleum isolates were phylogenetically distinct from all the other FSSC strains. [ABSTRACT FROM AUTHOR]

Abstract Background The Salmonella PreA/PreB two-component system (TCS) is an ortholog of the QseBC TCS of Escherichia coli. In both Salmonella and E. coli, this system has been shown to affect motility and virulence in response to quorum-sensing and hormonal signals, and to affect the transcription of the Salmonella enterica serovar Typhimurium (S. Typhimurium) pmrAB operon, which encodes an important virulence-associated TCS. Results To determine the PreA/PreB regulon in S. Typhimurium, we performed DNA microarrays comparing the wild type strain and various preA and/or preB mutants in the presence of ectopically expressed preA (qseB). These data confirmed our previous findings of the negative effect of PreB on PreA gene regulation and identified candidate PreA-regulated genes. A proportion of the activated loci were previously identified as PmrA-activated genes (yibD, pmrAB, cptA, etc.) or were genes located in the local region around preA, including the preAB operon. The transcriptional units were defined in this local region by RT-PCR, suggesting three PreA activated operons composed of preA-preB, mdaB-ygiN, and ygiW-STM3175. Several putative virulence-related phenotypes were examined for preAB mutants, resulting in the observation of a host cell invasion and slight virulence defect of a preAB mutant. Contrary to previous reports on this TCS, we were unable to show a PreA/PreB-dependent effect of the quorum-sensing signal AI-2 or of epinephrine on S. Typhimurium with regard to bacterial motility. Conclusion This work further characterizes this unorthadox OmpR/EnvZ class TCS and provides novel candidate regulated genes for further study. This first in-depth study of the PreA/PreB regulatory system phenotypes and regulation suggests significant comparative differences to the reported function of the orthologous QseB/QseC in E. coli.

Background: Pretransplant infection screening (IS) of potential organ recipients is essential to optimal outcome of solid organ transplantation (SOT)., Methods: A pre-post study was performed during 2020-2023 to investigate the impact of the STREAM (Solid organ TRansplant stEwArdship and Multidisciplinary approach) intervention to improve IS in SOT. The intervention, performed in 2022, included the implementation of IS through educational meetings, local guidelines, and the availability of a digital screening tool. The objective of the study was the assessment of IS completion, including a list of 17 laboratory tests and the investigation of vaccination status. The reduction of unnecessary tests was also analyzed. The test of proportions and a multilevel multivariate Poisson regression model were used to compare IS completion before and after STREAM. infectious diseases (ID) consultation and urgent evaluation were investigated as predictors of IS completion., Results: A total of 171 patients were enrolled, including liver (44%), heart (32%), and kidney (24%) transplant candidates. Mean age was 56 ± 11 years, and most patients (77%) were males. Ninety-five (56%) patients were included before the intervention and 76 (44%) after STREAM. IS completion increased after STREAM (IRR 1.41, p < 0.001) with significant improvement recorded for seven (39%) IS items. Unnecessary tests decreased by 43% after the intervention. ID consultation (IRR 1.13, p = 0.02) and urgent evaluation (p = 0.68, p < 0.001) were predictors of IS improvement., Conclusions: STREAM was successful in improving IS completion. Further research is needed to investigate the impact of this intervention on posttransplant infections., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Vaccine-preventable diseases and their related complications are associated with increased morbidity and mortality in patients with altered immunocompetence. Optimised immunisation in this patient population is challenging because of limited data from vaccine trials, suboptimal vaccine efficacy and safety concerns. Reliable efficacy data are lacking among patients with altered immunocompetence, and existing recommendations are mainly based on expert consensus and may vary geographically. Inactivated vaccines can be generally used without risks in this group, but their efficacy may be reduced, and immunisation schedules vary according to local guidelines, age, and type and stage of the underlying disease. Live vaccines, if indicated, should be administered with care because of the risk of vaccine-associated disease. We have reviewed the current evidence on vaccination principles and recommendations in adult patients with secondary immunodeficiencies, including asplenia, HIV infection, stem cell and solid organ transplant, haematological malignancies, inflammatory bowel disease and other chronic disorders.

Background: Strategies for prevention of HIV-1 mother-to-child transmission (PMTCT) have been continuously optimized. However, cases of vertical transmission continue to occur in high-income countries., Objectives: To investigate changes in PMTCT strategies adopted by Italian clinicians over time and to evaluate risk factors for transmission., Methods: Data from mother-child pairs prospectively collected by the Italian Register, born in Italy in 1996-2016, were analyzed. Risk factors for MTCT were explored by logistic regression analyses., Results: Six thousand five hundred three children (348 infections) were included. In our cohort, the proportion of children born to foreign mothers increased from 18.3% (563/3078) in 1996%-2003% to 66.2% (559/857) in 2011-2016 (P < 0.0001). Combination neonatal prophylaxis use significantly (P < 0.0001) increased over time, reaching 6.3% (56/857) after 2010, and it was largely (4.2%) adopted in early preterm infants. The proportion of vaginal deliveries in women with undetectable viral load (VL) increased over time and was 9.9% (85/857) in 2011-2016; no infection occurred among them. In children followed up since birth MTCT, rate was 3.5% (96/2783) in 1996-2003; 1.4% (36/2480) in 2004-2010; and 1.1% (9/835) in 2011-2016. At a multivariate analysis, factors associated with MTCT were vaginal delivery with detectable or missing VL or nonelective caesarean delivery, prematurity, breastfeeding, lack of maternal or neonatal antiretroviral therapy, detectable maternal VL, and age at first observation. Previously described increased risk of offspring of immigrant women was not confirmed., Conclusions: Risk of MTCT in Italy is ongoing, even in recent years, underling the need for implementation of the current screening program in pregnancy. Large combination neonatal prophylaxis use in preterm infants was observed, even if data on safety and efficacy in prematures are poor.

We report a case of successfully treated multiple liver abscesses in a liver-transplanted patient, sustained by combined multidrug-resistant infections. Two months after a liver transplant, a computed tomography scan revealed the presence of multiple abscesses in the liver graft. Blood cultures and abscessual liver fluid were both positive for acquired colistin- and carbapenem- resistant Klebsiella pneumoniae and an extended-spectrum of beta-lactamases-producing Enterobacter aerogenes. The treatment strategy consisted of different prolonged antimicrobial combinations and draining of the abscesses with complete recovery of the liver lesions.

Congenital Cytomegalovirus infection is the leading non-genetic cause of neurosensory deafness. We compared the outcomes of a treated group of children to an untreated group. The effect of antiviral therapy on hearing improvement between baseline and 2-year follow-up was statistically significant. These results suggest that the benefit of 6-week therapy is not limited to preventing further hearing deterioration.

Pseudomonas aeruginosa produces increased levels of alginate in response to oxygen-deprived conditions. The regulatory pathway(s) that links oxygen limitation to increased synthesis of alginate has remained elusive. In the present study, using immunofluorescence microscopy, we show that anaerobiosis-induced alginate production by planktonic PAO1 requires the diguanylate cyclase (DGC) SadC, previously identified as a regulator of surface-associated lifestyles. Furthermore, we found that the gene products of PA4330 and PA4331, located in a predicted operon with sadC, have a major impact on alginate production: deletion of PA4330 (odaA, for oxygen-dependent alginate synthesis activator) caused an alginate production defect under anaerobic conditions, whereas a PA4331 (odaI, for oxygen-dependent alginate synthesis inhibitor) deletion mutant produced alginate also in the presence of oxygen, which would normally inhibit alginate synthesis. Based on their sequence, OdaA and OdaI have predicted hydratase and dioxygenase reductase activities, respectively. Enzymatic assays using purified protein showed that unlike OdaA, which did not significantly affect DGC activity of SadC, OdaI inhibited c-di-GMP production by SadC. Our data indicate that SadC, OdaA and OdaI are components of a novel response pathway of P. aeruginosa that regulates alginate synthesis in an oxygen-dependent manner., (© 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.)