Search

Background: Candidaemia is an important infectious complication for haematological malignancy patients. Antifungal prophylaxis reduces the incidence of candidaemia but may be associated with breakthrough candidaemia. Objective: To analyse the Candida species' distribution and relative antifungal susceptibility profiles of candidaemia episodes in relation to the use of antifungal prophylaxis among Italian SEIFEM haematology centres. Methodology: This multicentre retrospective observational SEIFEM study included 133 single‐species candidaemia episodes of haematological malignancy patients for whom antifungal susceptibility testing results of blood Candida isolates were available between 2011 and 2015. Each participating centre provided both clinical and microbiological data. Results: Non‐Candida albicans Candida (NCAC) species were the mostly isolated species (89, 66.9%), which accounted for C parapsilosis (35, 26.3%), C glabrata (16, 12.0%), C krusei (14, 10.5%), C tropicalis (13, 9.8%) and uncommon species (11, 8.3%). C albicans caused the remaining 44 (33.1%) episodes. Excluding 2 C albicans isolates, 23 of 25 fluconazole‐resistant isolates were NCAC species (14 C krusei, 6 C glabrata, 2 C parapsilosis and 1 C tropicalis). Fifty‐six (42.1%) of 133 patients developed breakthrough candidaemia. Systemic antifungal prophylaxis consisted of azoles, especially fluconazole and posaconazole, in 50 (89.3%) of 56 patients in whom a breakthrough candidaemia occurred. Interestingly, all these patients tended to develop a C krusei infection (10/56, P =.02) or a fluconazole‐resistant isolate's infection (14/50, P =.04) compared to patients (4/77 and 10/77, respectively) who did not have a breakthrough candidaemia. Conclusions: Optimisation of prophylactic strategies is necessary to limit the occurrence of breakthrough candidaemia and, importantly, the emergence of fluconazole‐resistant NCAC isolates' infections in haematological malignancy patients. [ABSTRACT FROM AUTHOR]

Background & aims: Alcohol use disorder (AUD) represents the most common cause of liver disease. The gut microbiota plays a critical role in the progression of alcohol‐related liver damage. Aim of this study was to characterize the gut microbial composition and function in AUD patients with alcohol‐associated liver disease (AALD). Methods: This study included 36 AUD patients (14 with cirrhosis) who were active drinkers and an equal number of matched controls. Stool microbial composition, serum levels of lipopolysaccharide, cytokines/chemokines and gut microbiota functional profile were assessed. Results: AUD patients had a decreased microbial alpha diversity as compared to controls (0.092 vs 0.130, P =.047) and a specific gut microbial signature. The reduction of Akkermansia and the increase in Bacteroides were able to identify AUD patients with an accuracy of 93.4%. Serum levels of lipopolysaccharide (4.91 vs 2.43, P =.009) and pro‐inflammatory mediators (tumour necrosis factor alpha 60.85 vs 15.08, P =.001; interleukin [IL] 1beta 4.43 vs 1.72, P =.0001; monocyte chemoattractant protein 1 225.22 vs 16.43, P =.006; IL6 1.87 vs 1.23, P =.008) were significantly increased in AUD patients compared to controls and in cirrhotic patients compared to non‐cirrhotic ones (IL6 3.74 vs 1.39, P =.019; IL8 57.60 vs 6.53, P =.004). The AUD‐associated gut microbiota showed an increased expression of gamma‐aminobutyric acid (GABA) metabolic pathways and energy metabolism. Conclusions: AUD patients present a specific gut microbial fingerprint, associated with increased endotoxaemia, systemic inflammatory status and functional alterations that may be involved in the progression of the AALD and in the pathogenesis of AUD. [ABSTRACT FROM AUTHOR]

Background: There is strong evidence that alcoholism leads to dysbiosis in both humans and animals. However, it is unclear how changes in the intestinal microbiota (IM) relate to ethanol (EtOH)‐induced disruption of gut–liver homeostasis. We investigated this issue using selectively bred Sardinian alcohol‐preferring (sP) rats, a validated animal model of excessive EtOH consumption. Methods: Independent groups of male adult sP rats were exposed to the standard, home‐cage 2‐bottle "EtOH (10% v/v) versus water" choice regimen with unlimited access for 24 h/d (Group Et) for 3 (T1), 6 (T2), and 12 (T3) consecutive months. Control groups (Group Ct) were composed of matched‐age EtOH‐naïve sP rats. We obtained samples from each rat at the end of each experimental time, and we used blood and colon tissues for intestinal barrier integrity and/or liver pathology assessments and used stool samples for IM analysis with 16S ribosomal RNA gene sequencing. Results: Rats in Group Et developed hepatic steatosis and elevated serum transaminases and endotoxin/lipopolysaccharide (LPS) levels but no other liver pathological changes (i.e., necrosis/inflammation) or systemic inflammation. While we did not find any apparent alteration of the intestinal colonic mucosa, we found that rats in Group Et exhibited significant changes in IM composition compared to the rats in Group Ct. These changes were sustained throughout T1, T2, and T3. In particular, Ruminococcus, Coprococcus, and Streptococcus were the differentially abundant microbial genera at T3. The KEGG Ortholog profile revealed that IM functional modules, such as biosynthesis, transport, and export of LPS, were also enriched in Group Et rats at T3. Conclusions: We showed that chronic, voluntary EtOH consumption induced liver injury and endotoxemia together with dysbiotic changes in sP rats. This work sets the stage for improving our knowledge of the prevention and treatment of EtOH‐related diseases. [ABSTRACT FROM AUTHOR]

The epidemiology of Candida infections has changed in recent years. Although Candida albicans is still the main cause of invasive candidiasis in most clinical settings, a substantial proportion of patients is now infected with non- albicans Candida species. The various Candida species vary in their susceptibility to the most commonly used antifungal agents, and the intrinsic resistance to antifungal therapy seen in some species, along with the development of acquired resistance during treatment in others, is becoming a major problem in the management of Candida infection. A better understanding of the mechanisms and clinical impact of antifungal drug resistance is essential for the efficient treatment of patients with Candida infection and for improving treatment outcomes. Herein, we report resistance to the azoles and echinocandins among Candida species. [ABSTRACT FROM AUTHOR]

The oligopeptide transport systems Opp belong to the nickel/peptide/opine PepT subfamily of ABC-transporters. The opportunist pathogen Staphylococcus aureus encodes four putative Opps and one orphean substrate binding protein Opp5A. Here, we report that the Opp2 permease complex (Opp2BCDF) and Opp5A are involved in nickel uptake and then renamed them NikBCDE and NikA respectively. S. aureus carries also a high-affinity nickel transporter NixA belonging to the NiCoT family of secondary transporters. The activity of these two nickel transporters determine that of urease, a multimeric nickel-dependent enzyme mainly involved in the neutralization of acidic environments. However, only the Nik system was responsible for the neutralization and deposit of pH-dependent crystals in human urine. Inactivation of the nik genes affected bacterial colonization of mouse urinary tract, as well as the 50% infective dose levels compared with the parental and nixA strains. Finally, complementation of the nik mutations restored bacterial colonization. Together, our results suggest a role for the Nik system in the urinary tract infection by S. aureus, probably due to the urease-mediated pH increase of the urine. [ABSTRACT FROM AUTHOR]

Our previous investigation on Candida glabrata azole-resistant isolates identified two isolates with unaltered expression of CgCDR1/ CgCDR2, but with upregulation of another ATP-binding cassette transporter, CgSNQ2, which is a gene highly similar to ScSNQ2 from Saccharomyces cerevisiae. One of the two isolates (BPY55) was used here to elucidate this phenomenon. Disruption of CgSNQ2 in BPY55 decreased azole resistance, whereas reintroduction of the gene in a CgSNQ2 deletion mutant fully reversed this effect. Expression of CgSNQ2 in a S. cerevisiae strain lacking PDR5 mediated not only resistance to azoles but also to 4-nitroquinoline N-oxide, which is a ScSNQ2-specific substrate. A putative gain-of-function mutation, P822L, was identified in CgPDR1 from BPY55. Disruption of CgPDR1 in BPY55 conferred enhanced azole susceptibility and eliminated CgSNQ2 expression, whereas introduction of the mutated allele in a susceptible strain where CgPDR1 had been disrupted conferred azole resistance and CgSNQ2 upregulation, indicating that CgSNQ2 was controlled by CgPDR1. Finally, CgSNQ2 was shown to be involved in the in vivo response to fluconazole. Together, our data first demonstrate that CgSNQ2 contributes to the development of CgPDR1-dependent azole resistance in C. glabrata. The overlapping in function and regulation between CgSNQ2 and ScSNQ2 further highlight the relationship between S. cerevisiae and C. glabrata. [ABSTRACT FROM AUTHOR]

The opportunistic pathogen Enterococcus faecalis is well equipped with peroxidatic activities. It harbours three loci encoding a NADH peroxidase, an alkyl hydroperoxide reductase and a protein (EF2932) belonging to the AhpC/TSA family. We present results demonstrating that ef2932 does encode a thiol peroxidase (Tpx) and show that it is part of the regulon of the hydrogen peroxide regulator HypR. Characterization of unmarked deletion mutants showed that all three peroxidases are important for the defence against externally provided H2O2. Exposure to internal generated H2O2 by aerobic growth on glycerol, lactose, galactose or ribose showed that Npr was absolutely required for aerobic growth on glycerol and optimal growth on the other substrates. Growth on glycerol was also dependent on Ahp. Addition of catalase restored growth of the mutants, and therefore, extracellular H2O2 concentrations have been determined. This showed that the time point of growth arrest of the Δ npr mutant correlated with the highest H2O2 concentration measured. Analysis of the survival of the different strains inside peritoneal macrophages revealed that Tpx was the most important antioxidant activity for protecting the cells against the hostile phagocyte environment. Finally, the Δ tpx and the triple mutant showed attenuated virulence in a mouse peritonitis model. [ABSTRACT FROM AUTHOR]

Summary Resistance to fluconazole is a possible event during prolonged suppressive drug therapy for cryptococ-cal meningitis, the most frequently encountered life-threatening manifestation of cryptococcosis. The knowledge of this resistance at the molecular level is important for management of cryptococcosis. In order to identify genes involved in azole resistance in Cryptococcus neoformans , a cDNA subtraction library technique was chosen as a strategy. First, a fluconazole-resistant mutant BPY22.17 was obtained from a susceptible clinical isolate BPY22 by in vitro exposure to the drug. Then, a subtractive hybridization procedure was used to compare gene expression between the obtained strains. We identified a cDNA overexpressed in the fluconazole-resistant strain BPY22.17 that was used as a probe to isolate the entire gene in a C. neoformans genomic library. Sequence analysis of this gene identified an ATP Binding Cassette (ABC) transporter-encoding gene called C. neoformans AntiFungal Resistance 1 ( CnAFR1 ). Disruption of CnAFR1 gene in the resistant isolate (BPY22.17) resulted in an enhanced susceptibility of the knock-out mutant cnafr1 against fluconazole, whereas reintroduction of the gene in cnafr1 resulted in restoration of the resistance phenotype, thus confirming that CnAFR1 is involved in fluconazole resistance of C. neoformans . Our findings therefore reveal that an active drug efflux mechanism can be involved in the development of azole resistance in this important human pathogen. [ABSTRACT FROM AUTHOR]

An abstract of the article "Advances in the management of fungal infections," by Patricia MuMuñozoz and colleagues is presented.

A correction to the article "A nickel ABC-transporter of Staphylococcus aureus is involved in urinary tract infection," by Aurelia Hiron, et al., published in the previous issue is presented.