Commercially available CD4 + and CD8 + IFN-γ release assays combined with an HBHA-induced IGRA improve the characterization of the tuberculosis spectrum and monitoring of treatment in children.

Commercially available Interferon-γ release assays (IGRAs), including the last-generation QuantiFERON TB-Plus (QFT-Plus), are effective in aiding the diagnosis of tuberculosis (TB) infection but cannot distinguish latent TB subjects from active TB patients. The aim of this study was to prospectively evaluate the performance of an HBHA-based IGRA, combined with commercially available IGRAs, to assess their usefulness as a prognostic biomarkers and aid in the monitoring of TB treatment in children. Following clinical, microbiological, and radiological assessment, children younger than 18 years of age classified as either LTBI or active TB were tested at baseline and during treatment by the QuantiFERON TB-Plus (QFT) assay and an aliquot of whole-blood was stimulated with HBHA. Among the 655 children evaluated, 559 (85.3%) were classified as "Non TB", 44 patients (6.7%) with active TB, and 52 (7.9%) with LTBI. The median HBHA-IGRA IFN-gamma responses were able to discriminate active TB from LTBI (0.13 IU/ml vs 1.995, (p < 0,0001), those with asymptomatic TB from those with symptomatic TB (1.01 IU/ml vs 0.115 IU/ml, p 0.017), or more severe TB (p 0.022), and significantly raised during successful TB treatment (p < 0.0001). Conversely, CD4 + and CD8 + responses were similar in all groups of patients, although active TB patients had higher CD4 + responses and LTBI higher CD8 + responses.  Conclusion: HBHA-based IGRA, combined with CD4 + and CD8 + responses assessed by commercially available IGRAs, is a useful support in the characterization of the TB spectrum in children and monitoring of TB-therapy. What is Known: • Current immune diagnostics are not able to discriminate active and latent Ttuberculosis, including the recently approved QFT-PLUS.. • New immunological assays with prognostic value are highly needed. What is New: • HBHA-based IGRA, combined with CD4+ and CD8+ responses assessed by commercially available IGRAs, is a useful support for the differentiation of active and latent TB in children.. • HBHA-based IGRA, combined with CD4+ and CD8+ responses assessed by commercially available IGRAs, is a useful support in the monitoring of TBtherapy in children..

Profiling the Urobiota in a Pediatric Population with Neurogenic Bladder Secondary to Spinal Dysraphism.

The human bladder has been long thought to be sterile until that, only in the last decade, advances in molecular biology have shown that the human urinary tract is populated with microorganisms. The relationship between the urobiota and the development of urinary tract disorders is now of great interest. Patients with spina bifida (SB) can be born with (or develop over time) neurological deficits due to damaged nerves that originate in the lower part of the spinal cord, including the neurogenic bladder. This condition represents a predisposing factor for urinary tract infections so that the most frequently used approach to treat patients with neurogenic bladder is based on clean intermittent catheterization (CIC). In this study, we analyzed the urobiota composition in a pediatric cohort of patients with SB compared to healthy controls, as well as the urobiota characteristics based on whether patients received CIC or not.

Cysteamine/Cystamine Exert Anti-Mycobacterium abscessus Activity Alone or in Combination with Amikacin.

Host-directed therapies are emerging as a promising tool in the curing of difficult-to-treat infections, such as those caused by drug-resistant bacteria. In this study, we aim to test the potential activity of the FDA- and EMA-approved drugs cysteamine and cystamine against Mycobacterium abscessus. In human macrophages (differentiated THP-1 cells), these drugs restricted M. abscessus growth similar to that achieved by amikacin. Here, we use the human ex vivo granuloma-like structures (GLS) model of infection with the M. abscessus rough (MAB-R) and smooth (MAB-S) variants to study the activity of new therapies against M. abscessus. We demonstrate that cysteamine and cystamine show a decrease in the number of total GLSs per well in the MAB-S and MAB-R infected human peripheral blood mononuclear cells (PBMCs). Furthermore, combined administration of cysteamine or cystamine with amikacin resulted in enhanced activity against the two M. abscessus morpho variants compared to treatment with amikacin only. Treatment with cysteamine and cystamine was more effective in reducing GLS size and bacterial load during MAB-S infection compared with MAB-R infection. Moreover, treatment with these two drugs drastically quenched the exuberant proinflammatory response triggered by the MAB-R variant. These findings showing the activity of cysteamine and cystamine against the R and S M. abscessus morphotypes support the use of these drugs as novel host-directed therapies against M. abscessus infections.

Ecology and Machine Learning-Based Classification Models of Gut Microbiota and Inflammatory Markers May Evaluate the Effects of Probiotic Supplementation in Patients Recently Recovered from COVID-19.

Gut microbiota (GM) modulation can be investigated as possible solution to enhance recovery after COVID-19. An open-label, single-center, single-arm, pilot, interventional study was performed by enrolling twenty patients recently recovered from COVID-19 to investigate the role of a mixed probiotic, containing Lactobacilli, Bifidobacteria and Streptococcus thermophilus, on gastrointestinal symptoms, local and systemic inflammation, intestinal barrier integrity and GM profile. Gastrointestinal Symptom Rating Scale, cytokines, inflammatory, gut permeability, and integrity markers were evaluated before (T0) and after 8 weeks (T1) of probiotic supplementation. GM profiling was based on 16S-rRNA targeted-metagenomics and QIIME 2.0, LEfSe and PICRUSt computational algorithms. Multiple machine learning (ML) models were trained to classify GM at T0 and T1. A statistically significant reduction of IL-6 (p < 0.001), TNF-α (p < 0.001) and IL-12RA (p < 0.02), citrulline (p value < 0.001) was reported at T1. GM global distribution and microbial biomarkers strictly reflected probiotic composition, with a general increase in Bifidobacteria at T1. Twelve unique KEGG orthologs were associated only to T0, including tetracycline resistance cassettes. ML classified the GM at T1 with 100% score at phylum level. Bifidobacteriaceae and Bifidobacterium spp. inversely correlated to reduction of citrulline and inflammatory cytokines. Probiotic supplementation during post-COVID-19 may trigger anti-inflammatory effects though Bifidobacteria and related-metabolism enhancement.

3D-printed graphene polylactic acid devices resistant to SARS-CoV-2: Sunlight-mediated sterilization of additive manufactured objects.

Additive manufacturing has played a crucial role in the COVID-19 global emergency allowing for rapid production of medical devices, indispensable tools for hospitals, or personal protection equipment. However, medical devices, especially in nosocomial environments, represent high touch surfaces prone to viral infection and currently used filaments for 3D printing can't inhibit transmission of virus [1]. Graphene-family materials are capable of reinforcing mechanical, optical and thermal properties of 3D printed constructs. In particular, graphene can adsorb near-infrared light with high efficiency. Here we demonstrate that the addition of graphene nanoplatelets to PLA filaments (PLA-G) allows the creation of 3D-printed devices that can be sterilized by near-infrared light exposure at power density analog to sunlight. This method has been used to kill SARS-CoV-2 viral particles on the surface of 3D printed PLA-G by 3 min of exposure. 3D-printed PLA-G is highly biocompatible and can represent the ideal material for the production of sterilizable personal protective equipment and daily life objects intended for multiple users.

First description of the katG gene deletion in a Mycobacterium tuberculosis clinical isolate and its impact on the mycobacterial fitness.

Isoniazid (INH) is the cornerstone of the anti-tuberculosis regimens and emergence of Mycobacterium tuberculosis (Mtb) resistant strains is a major threat to our ability to control tuberculosis (TB) at global level. Mutations in the gene coding the catalase KatG confer resistance to high level of INH. In this paper, we describe for the first time a complete deletion of the genomic region containing the katG gene in an Mtb clinical strain isolated in Italy in a patient with HIV infection that previously completed INH preventive therapy. We genotypically characterized the Mtb strain and showed that katG deletion confers high-level resistance to INH (MIC > 25.6 µg/mL). The katG deletion did not impact significantly on Mtb fitness as we did not detect enhanced susceptibility to H2O2 compared to the wild type Mtb strains nor impaired growth in in vitro infection models. These findings highlight the ability of Mtb to acquire resistance to INH while maintaining fitness and pathogenic potential.

Staphylococcus aureus ventilator-associated pneumonia in patients with COVID-19: clinical features and potential inference with lung dysbiosis.

BACKGROUND: Hospitalized patients with COVID-19 admitted to the intensive care unit (ICU) and requiring mechanical ventilation are at risk of ventilator-associated bacterial infections secondary to SARS-CoV-2 infection. Our study aimed to investigate clinical features of Staphylococcus aureus ventilator-associated pneumonia (SA-VAP) and, if bronchoalveolar lavage samples were available, lung bacterial community features in ICU patients with or without COVID-19. METHODS: We prospectively included hospitalized patients with COVID-19 across two medical ICUs of the Fondazione Policlinico Universitario A. Gemelli IRCCS (Rome, Italy), who developed SA-VAP between 20 March 2020 and 30 October 2020 (thereafter referred to as cases). After 1:2 matching based on the simplified acute physiology score II (SAPS II) and the sequential organ failure assessment (SOFA) score, cases were compared with SA-VAP patients without COVID-19 (controls). Clinical, microbiological, and lung microbiota data were analyzed. RESULTS: We studied two groups of patients (40 COVID-19 and 80 non-COVID-19). COVID-19 patients had a higher rate of late-onset (87.5% versus 63.8%; p = 0.01), methicillin-resistant (65.0% vs 27.5%; p < 0.01) or bacteremic (47.5% vs 6.3%; p < 0.01) infections compared with non-COVID-19 patients. No statistically significant differences between the patient groups were observed in ICU mortality (p = 0.12), clinical cure (p = 0.20) and microbiological eradication (p = 0.31). On multivariable logistic regression analysis, SAPS II and initial inappropriate antimicrobial therapy were independently associated with ICU mortality. Then, lung microbiota characterization in 10 COVID-19 and 16 non-COVID-19 patients revealed that the overall microbial community composition was significantly different between the patient groups (unweighted UniFrac distance, R2 0.15349; p < 0.01). Species diversity was lower in COVID-19 than in non COVID-19 patients (94.4 ± 44.9 vs 152.5 ± 41.8; p < 0.01). Interestingly, we found that S. aureus (log2 fold change, 29.5), Streptococcus anginosus subspecies anginosus (log2 fold change, 24.9), and Olsenella (log2 fold change, 25.7) were significantly enriched in the COVID-19 group compared to the non-COVID-19 group of SA-VAP patients. CONCLUSIONS: In our study population, COVID-19 seemed to significantly affect microbiological and clinical features of SA-VAP as well as to be associated with a peculiar lung microbiota composition.

Nasopharyngeal Microbiota Profiling of SARS-CoV-2 Infected Patients.

We analyzed the bacterial communities of the nasopharynx in 40 SARS-CoV-2 infected and uninfected patients. All infected patients had a mild COVID-19 disease. We did not find statistically significant differences in either bacterial richness and diversity or composition. These findings suggest a nasopharyngeal microbiota at least early resilient to SARS-CoV-2 infection.

Accuracy of QuantiFERON-TB Gold Plus Test for Diagnosis of Mycobacterium tuberculosis Infection in Children.

Compared to its predecessor QuantiFERON-TB Gold In Tube (QFT-IT), QuantiFERON-TB Gold Plus (QFT-Plus) contains an additional antigen tube (TB2), stimulating both CD4+ and CD8+ T cells. The ability to discriminate CD4+ and CD8+ responses is suggested to be useful in differentiating stages of Mycobacterium tuberculosis infection. While QFT-Plus has already been evaluated in adults, there are not enough data in children evaluated for suspected active tuberculosis (TB) or latent TB infection (LTBI). A prospective cross-sectional study was conducted among children aged 0 to 17 years who were evaluated for suspected active TB or screened for LTBI. All children underwent QFT-Plus and further clinical, radiological, and/or microbiological analyses according to clinical scenario. Of the 198 children enrolled, 43 (21.7%) were tested because of suspicion of active TB. A total of 12/43 (27.9%) were diagnosed with active TB, and among these, 10/12 (83.3%) had a positive QFT-Plus assay. Of the 155 children screened for LTBI, 18 (11.6%) had a positive QFT-Plus, and 5 (2.5%) had an indeterminate result. TB1 and TB2 quantitative responses were not able to discriminate active disease from latent infection. The percent agreement between TB1 and TB2 was 100%. QFT-Plus assay showed good sensitivity for active TB and was particularly useful for the evaluation of children with suspected LTBI, giving a low rate of indeterminate results in this group. More studies are needed to properly evaluate QFT-Plus ability in discriminating active disease from latent infection.

Simplified Testing Method for Direct Detection of Carbapenemase-Producing Organisms from Positive Blood Cultures Using the NG-Test Carba 5 Assay.

We directly tested 484 organisms from clinical (n = 310) and simulated (n = 174) positive blood cultures using the NG-Test Carba 5 assay for carbapenemase-producing Enterobacterales detection. The assay identified all but 4 of the KPC (170/171), OXA-48-like (22/22), VIM (19/21), and NDM (14/15) producers with no false positives. Among the clinical Klebsiella pneumoniae organisms tested, 122 of 123 KPC, 1 of 1 OXA-48-like, and 1 of 2 VIM producers were detected by the assay. Some VIM and NDM producers yielded scant but still-readable bands with the assay. No organisms produced the IMPs that the assay was designed to detect.

IP-10 contributes to the inhibition of mycobacterial growth in an ex vivo whole blood assay.

Interferon-γ inducible protein 10 (IP-10), is a potent chemoattractant that promotes migration of monocytes and activated T-cells to inflammation foci. IP-10 is elevated in serum of patients with chronic hepatitis C virus (HCV) and tuberculosis (TB) infections, although it remains to be determined the contribution of IP-10 in restricting Mycobacterium tuberculosis (Mtb) replication. Here, we investigated the impact of IP-10 on mycobacteria replication using the ex vivo model of human whole-blood (WB) assay. In particular, we compared the levels of IP-10 upon infection with different Mtb clinical strains and species of non-tuberculous mycobacteria (NTM) and evaluated how IP-10 may contain bacterial replication. Interestingly, we observed that the inhibition of the host enzyme dipeptidyl peptidase IV (DPP-IV), which inactivates IP-10 through cleavage of two amino acids at the chemokine N-terminus, restricted mycobacterial persistence in WB, supporting the critical role of full length IP-10 in mediating an anti-Mtb response. Addition of recombinant IP-10 expressed in eukaryotic cells enhanced the anti-mycobacterial activity in WB, although no differences were observed when IP-10 containing different proportions of cleaved and non-cleaved forms of the chemokine were added. Moreover, recombinant IP-10 did not exert a direct anti-mycobacterial effect. Our results underscore the clinical relevance of IP-10 in mycobacteria pathogenesis and support the potential outcomes that may derive by targeting the IP-10/CXCR3 pathway as host directed therapies for the treatment of Mtb or NTM infections.

PE_PGRS3 of Mycobacterium tuberculosis is specifically expressed at low phosphate concentration, and its arginine-rich C-terminal domain mediates adhesion and persistence in host tissues when expressed in Mycobacterium smegmatis.

PE_PGRSs of Mycobacterium tuberculosis (Mtb) represent a family of complex and peculiar proteins whose role and function remain elusive. In this study, we investigated PE_PGRS3 and PE_PGRS4, two highly homologous PE_PGRSs encoded by two contiguous genes in the Mtb genome. Using a gene-reporter system in Mycobacterium smegmatis (Ms) and transcriptional analysis in Mtb, we show that PE_PGRS3, but not PE_PGRS4, is specifically expressed under low phosphate concentrations. Interestingly, PE_PGRS3, but not PE_PGRS4, has a unique, arginine-rich C-terminal domain of unknown function. Heterologous expression of PE_PGRS3 in Ms was used to demonstrate cellular localisation of the protein on the mycobacterial surface, where it significantly affects net surface charge. Moreover, expression of full-length PE_PGRS3 enhanced adhesion of Ms to murine macrophages and human epithelial cells and improved bacterial persistence in spleen tissue following infection in mice. Expression of the PE_PGRS3 functional deletion mutant lacking the C-terminal domain in Ms did not enhance adhesion to host cells, showing a phenotype similar to the Ms parental strain. Interestingly, enhanced persistence of Ms expressing PE_PGRS3 did not correlate with increased concentrations of inflammatory cytokines. These results point to a critical role for the ≈ 80 amino acids long, arginine-rich C-terminal domain of PE_PGRS3 in tuberculosis pathogenesis.

Multicenter Evaluation of Anyplex Plus MTB/NTM MDR-TB Assay for Rapid Detection of Mycobacterium tuberculosis Complex and Multidrug-Resistant Isolates in Pulmonary and Extrapulmonary Specimens.

The rapid diagnosis of tuberculosis (TB) and the detection of drug-resistant Mycobacterium tuberculosis strains are critical for successful public health interventions. Therefore, TB diagnosis requires the availability of diagnostic tools that allow the rapid detection of M. tuberculosis and drug resistance in clinical samples. Here, we performed a multicenter study to evaluate the performance of the Seegene Anyplex MTB/NTM MDR-TB assay, a new molecular method based on a multiplex real-time PCR system, for detection of Mycobacterium tuberculosis complex (MTBC), nontuberculous mycobacteria (NTM), and genetic determinants of drug resistance. In total, the results for 755 samples (534 pulmonary and 221 extrapulmonary samples) were compared with the results of smears and cultures. For pulmonary specimens, the sensitivities of the Anyplex assay and acid-fast bacillus smear testing were 86.4% and 75.0%, respectively, and the specificities were 99% and 99.4%. For extrapulmonary specimens, the sensitivities of the Anyplex assay and acid-fast bacillus smear testing were 83.3% and 50.0%, respectively, and the specificities of both were 100%. The negative and positive predictive values of the Anyplex assay for pulmonary specimens were 97% and 100%, respectively, and those for extrapulmonary specimens were 84.6% and 100%. The sensitivities of the Anyplex assay for detecting isoniazid resistance in MTBC strains from pulmonary and extrapulmonary specimens were 83.3% and 50%, respectively, while the specificities were 100% for both specimen types. These results demonstrate that the Anyplex MTB/NTM MDR-TB assay is an efficient and rapid method for the diagnosis of pulmonary and extrapulmonary TB and the detection of isoniazid resistance.

Antifungal susceptibility profiles of bloodstream yeast isolates by Sensititre YeastOne over nine years at a large Italian teaching hospital.

Sensititre YeastOne (SYO) is an affordable alternative to the Clinical and Laboratory Standards Institute (CLSI) reference method for antifungal susceptibility testing. In this study, the MICs of yeast isolates from 1,214 bloodstream infection episodes, generated by SYO during hospital laboratory activity (January 2005 to December 2013), were reanalyzed using current CLSI clinical breakpoints/epidemiological cutoff values to assign susceptibility (or the wild-type [WT] phenotype) to systemic antifungal agents. Excluding Candida albicans (57.4% of all isolates [n = 1,250]), the most predominant species were Candida parapsilosis complex (20.9%), Candida tropicalis (8.2%), Candida glabrata (6.4%), Candida guilliermondii (1.6%), and Candida krusei (1.3%). Among the non-Candida species (1.9%), 7 were Cryptococcus neoformans and 17 were other species, mainly Rhodotorula species. Over 97% of Candida isolates were susceptible (WT phenotype) to amphotericin B and flucytosine. Rates of susceptibility (WT phenotype) to fluconazole, itraconazole, and voriconazole were 98.7% in C. albicans, 92.3% in the C. parapsilosis complex, 96.1% in C. tropicalis, 92.5% in C. glabrata, 100% in C. guilliermondii, and 100% (excluding fluconazole) in C. krusei. The fluconazole-resistant isolates consisted of 6 C. parapsilosis complex isolates, 3 C. glabrata isolates, 2 C. albicans isolates, 2 C. tropicalis isolates, and 1 Candida lusitaniae isolate. Of the non-Candida isolates, 2 C. neoformans isolates had the non-WT phenotype for susceptibility to fluconazole, whereas Rhodotorula isolates had elevated azole MICs. Overall, 99.7% to 99.8% of Candida isolates were susceptible (WT phenotype) to echinocandins, but 3 isolates were nonsusceptible (either intermediate or resistant) to caspofungin (C. albicans, C. guilliermondii, and C. krusei), anidulafungin (C. albicans and C. guilliermondii), and micafungin (C. albicans). However, when the intrinsically resistant non-Candida isolates were included, the rate of echinocandin nonsusceptibility reached 1.8%. In summary, the SYO method proved to be able to detect yeast species showing antifungal resistance or reduced susceptibility.

Performance of two resin-containing blood culture media in detection of bloodstream infections and in direct matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) broth assays for isolate identification: clinical comparison of the BacT/Alert Plus and Bactec Plus systems.

We compared the clinical performances of the BacT/Alert Plus (bioMérieux) and Bactec Plus (Becton Dickinson) aerobic and anaerobic blood culture (BC) media with adsorbent polymeric beads. Patients ≥ 16 years old with suspected bloodstream infections (BSIs) were enrolled in intensive care units and infectious disease wards. A single 40-ml blood sample was collected from each and used to inoculate (10 ml/bottle) one set of BacT/Alert Plus cultures and one set of Bactec Plus cultures, each set consisting of one aerobic and one anaerobic bottle. Cultures were incubated ≤ 5 days in the BacT/Alert 3D and Bactec FX instruments, respectively. A total of 128 unique BSI episodes were identified based on the recovery of clinically significant growth in 212 aerobic cultures (106 BacT/Alert and 106 Bactec) and 151 anaerobic cultures (82 BacT/Alert and 69 Bactec). The BacT/Alert aerobic medium had higher recovery rates for Gram-positive cocci (P = 0.024), whereas the Bactec aerobic medium was superior for recovery of Gram-negative bacilli (P = 0.006). BacT/Alert anaerobic medium recovery rates exceeded those of the Bactec anaerobic medium for total organisms (P = 0.003), Gram-positive cocci (P = 0.013), and Escherichia coli (P = 0.030). In terms of capacity for diagnosing the 128 septic episodes, the BacT/Alert and Bactec sets were comparable, although the former sets diagnosed more BSIs caused by Gram-positive cocci (P = 0.008). They also allowed earlier identification of coagulase-negative staphylococcal growth (mean, 2.8 h; P = 0.003) and growth in samples from patients not on antimicrobial therapy that yielded positive results (mean, 1.3 h; P < 0.001). Similarly high percentages of microorganisms in BacT/Alert and Bactec cultures (93.8% and 93.3%, respectively) were identified by direct matrix-assisted laser desorption ionization-time of flight mass spectrometry assay of BC broths. The BacT/Alert Plus media line appears to be a reliable, timesaving tool for routine detection of BSIs in the population we studied, although further studies are needed to evaluate their performance in other settings.

Fecal Microbiota Transplantation in Amyotrophic Lateral Sclerosis: Clinical Protocol and Evaluation of Microbiota Immunity Axis.

The fecal microbial transplantation (FMT) is a therapeutic transplant of fecal microbiota from healthy donors to patients. This practice is aimed at restoring eubiosis and rebalancing the enteric and systemic immune responses, and then eliminating pathogenic triggers of multiple disease, including neurodegenerative diseases. Alterations of gut microbiota (GM) affect the central nervous system (CNS) health, impacting neuro-immune interactions, synaptic plasticity, myelination, and skeletal muscle function. T-regulatory lymphocytes (Treg) are among the most important players in the pathogenesis of amyotrophic lateral sclerosis (ALS), altering the disease course. Along with circulating neuropeptides, other immune cells, and the gut-brain axis, the GM influences immunological tolerance and controls Treg's number and suppressive functions. A double-blind, controlled, multicenter study on FMT in ALS patients has been designed to evaluate if FMT can modulate neuroinflammation, by restoring Treg number, thus modifying disease activity and progression.

PDZ2-conjugated-PLGA nanoparticles are tiny heroes in the battle against SARS-CoV-2.

The COVID-19 pandemic caused by SARS-CoV-2 has highlighted the urgent need for innovative antiviral strategies to fight viral infections. Although a substantial part of the overall effort has been directed at the Spike protein to create an effective global vaccination strategy, other proteins have also been examined and identified as possible therapeutic targets. Among them, although initially underestimated, there is the SARS-CoV-2 E-protein, which turned out to be a key factor in viral pathogenesis due to its role in virus budding, assembly and spreading. The C-terminus of E-protein contains a PDZ-binding motif (PBM) that plays a key role in SARS-CoV-2 virulence as it is recognized and bound by the PDZ2 domain of the human tight junction protein ZO-1. The binding between the PDZ2 domain of ZO-1 and the C-terminal portion of SARS-CoV-2 E-protein has been extensively characterized. Our results prompted us to develop a possible adjuvant therapeutic strategy aimed at slowing down or inhibiting virus-mediated pathogenesis. Such innovation consists in the design and synthesis of externally PDZ2-ZO1 functionalized PLGA-based nanoparticles to be used as intracellular decoy. Contrary to conventional strategies, this innovative approach aims to capitalize on the E protein-PDZ2 interaction to prevent virus assembly and replication. In fact, the conjugation of the PDZ2 domain to polymeric nanoparticles increases the affinity toward the E protein effectively creating a "molecular sponge" able to sequester E proteins within the intracellular environment of infected cells. Our in vitro studies on selected cellular models, show that these nanodevices significantly reduce SARS-CoV-2-mediated virulence, emphasizing the importance of exploiting viral-host interactions for therapeutic benefit.

In-depth characterization of multidrug-resistant NDM-1 and KPC-3 co-producing Klebsiella pneumoniae bloodstream isolates from Italian hospital patients.

Bloodstream infection (BSI) caused by carbapenem-resistant Klebsiella pneumoniae (KP) poses significant challenges, particularly when the infecting isolate carries multiple antimicrobial resistance (AMR) genes/determinants. This study, employing short- and long-read whole-genome sequencing, characterizes six New Delhi metallo-ß-lactamase (NDM) 1 and KP carbapenemase (KPC) 3 co-producing KP isolates, the largest cohort investigated in Europe to date. Five [sequence type (ST) 512] and one (ST11) isolates were recovered from patients who developed BSI from February to August 2022 or February 2023 at two different hospitals in Rome, Italy. Phylogenetic analysis revealed two distinct clusters among ST512 isolates and a separate cluster for the ST11 isolate. Beyond blaNDM-1 and blaKPC-3, various AMR genes, indicative of a multidrug resistance phenotype, including colistin resistance, were found. Each cluster-representative ST512 isolate harbored a blaNDM-1 plasmid (IncC) and a blaKPC-3 plasmid [IncFIB(pQil)/IncFII(K)], while the ST11 isolate harbored a blaNDM-1 plasmid [IncFII(pKPX1)] and a blaKPC-3 plasmid [IncFIB(K)/IncFII(K)]. The blaNDM-1 plasmids carried genes conferring resistance to clinically relevant antimicrobial agents, and the aminoglycoside resistance gene aac(6')-Ib was found on different plasmids. Colistin resistance-associated mgrB/pmrB gene mutations were present in all isolates, and the yersiniabactin-encoding ybt gene was unique to the ST11 isolate. In conclusion, our findings provide insights into the genomic context of blaNDM-1/blaKPC-3 carbapenemase-producing KP isolates.IMPORTANCEThis study underscores the critical role of genomic surveillance as a proactive measure to restrict the spread of carbapenemase-producing KP isolates, especially when key antimicrobial resistance genes, such as blaNDM-1/blaKPC-3, are plasmid borne. In-depth characterization of these isolates may help identify plasmid similarities contributing to their intra-hospital/inter-hospital adaptation and transmission. Despite the lack of data on patient movements, it is possible that carbapenem-resistant isolates were selected to co-produce KP carbapenemase and New Delhi metallo-ß-lactamase via plasmid acquisition. Studies employing long-read whole-genome sequencing should be encouraged to address the emergence of KP clones with converging phenotypes of virulence and resistance to last-resort antimicrobial agents.