An overview of SARS-CoV-2 variants circulating in the 2020-2022 period in Lombardy.

Since the beginning of the pandemic, SARS-CoV-2 has shown genetic variability. All the variants that have sustained pandemic waves have shown several mutations, especially in the Spike protein that could affect viral pathogenesis. A total of 15,729 respiratory samples, collected between December 2020 and August 2022, have been included in this study. We report the circulation of SARS-CoV-2 variants in the Lombardy region, Italy, in a 2-year study period. Alpha, Delta, and Omicron variants became predominant causing the majority of cases whereas Beta or Gamma variants mostly caused local outbreaks. Next-generation sequencing revealed several mutations and few deletions in all of the main variants. For example, 147 mutations were observed in the Spike protein of Omicron sublineages; 20% of these mutations occurred in the receptor-binding domain region.

Preliminary results on an autochthonous dengue outbreak in Lombardy Region, Italy, August 2023.

In August 2023, six locally acquired dengue virus 1 infections were detected in Lodi province, Lombardy Region, in northern Italy, where the vector Aedes albopictus is present. Four cases were hospitalised, none died. The viruses clustered with Peruvian and Brazilian strains collected between 2021 and 2023. This preliminary report highlights the importance of continued integrated surveillance of imported vector-borne virus infections and the potential for tropical disease outbreaks in highly populated regions of northern Italy where competent vectors are present.

Comparing BamHI-W and CE-marked assays to detect circulating Epstein-Barr Virus (EBV) DNA of nasopharyngeal cancer patients in a non-endemic area.

OBJECTIVES: Plasma Epstein-Barr Virus (EBV)-DNA is a well-established prognostic biomarker in nasopharyngeal carcinoma (NPC). Different methods for assessment include single-copy gene targeted, European Conformity (CE)-marked assays, which are mostly employed in non-endemic settings, vs multiple-copy gene targeted, in-house BamHI-W based assays, which currently represent the most widely used method for EBV-DNA quantification. To date, evidence concerning the commutability of these different assays is still limited. MATERIALS AND METHODS: From August 2016 to March 2018, 124 plasma and 124 whole blood (WB) samples from 93 NPC patients were collected at different time-points for each patient. EBV-DNA viral load was quantified in pre- (n = 12) and post-treatment (n = 9), follow-up (n = 53), and recurrent/metastatic (R/M) (n = 50) phase. For each sample, one in-house BamHI-W vs three different CE-marked plasma assays were compared; the performance of plasma vs WB matrix was also assessed. Quantitative agreement of EBV-DNA values was evaluated by linear correlation and Bland-Altman analysis. RESULTS: A statistically significant (p = 0.0001) agreement between all CE-marked and the BamHI-W assays was found using plasma matrix, regardless of clinical phase. The results obtained in copies/ml were comparable to those expressed in IU/ml. When using WB matrix, the number of positive detections increased in the post-treatment phase. CONCLUSIONS: Our retrospective comparison supported an agreement between Plasma BamHI-W and CE-marked assays in measuring EBV-DNA for non-endemic NPC patients. There were no significant interferences from different measurement units (IU/ml vs copies/ml). Further evaluations are needed to better clarify the role of WB.

Characteristics and outcomes of vaccinated and nonvaccinated patients hospitalized in a single Italian hub for COVID-19 during the Delta and Omicron waves in Northern Italy.

OBJECTIVE: We compared the characteristics and outcomes of vaccinated and nonvaccinated patients hospitalized with COVID-19. DESIGN: We analyzed patients hospitalized in a COVID hub during three one-month periods: (i) October 15, 2020-November 15, 2020 (prevaccination peak); (ii) October 15, 2021-November 15, 2021 (Delta wave); (iii) December 15, 2021-January 15, 2022 (Omicron wave). To define the epidemiologic context, SARS-CoV-2 infection in healthcare workers was analyzed. RESULTS: SARS-CoV-2 infection incidence in healthcare workers was 146 cases per 1000 persons in 2020 (prevaccination) and 67 in 2021 (postvaccination, when the Omicron variant caused most infections). There were 420 hospitalized patients in the prevaccination period, 51 during the Delta wave (52.1% vaccinated) and 165 during the Omicron wave (52.9% vaccinated). During the Delta wave, a significantly higher number of nonvaccinated (29.2%) than vaccinated patients (3.7%) were admitted to the intensive care unit (ICU) (p = 0.019). Nonvaccinated patients were younger and had a lower rate of concomitant medical conditions (53.2% vs 83.7%; p < 0.001) during the Omicron wave when 80% of patients admitted to ICU and all those who died were still infected by the Delta variant. CONCLUSIONS: Vaccine effectiveness in fragile individuals appears to be lower because of a faster immunity decline. However, the Omicron variant seems to cause less severe COVID-19.

Comparative analysis of SARS-CoV-2 quasispecies in the upper and lower respiratory tract shows an ongoing evolution in the spike cleavage site.

Studies are needed to better understand the genomic evolution of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to describe viral quasispecies population of upper and lower respiratory tract by next-generation sequencing in patients admitted to intensive care unit. A deep sequencing of the S gene of SARS-CoV-2 from 109 clinical specimens, sampled from the upper respiratory tract (URT) and lower respiratory tract (LRT) of 77 patients was performed. A higher incidence of non-synonymous mutations and indels was observed in the LRT among minority variants. This might be explained by the ability of the virus to invade cells without interacting with ACE2 (e.g. exploiting macrophage phagocytosis). Minority variants are highly concentrated around the gene portion encoding for the Spike cleavage site, with a higher incidence in the URT; four mutations are highly recurring among samples and were found associated with the URT. Interestingly, 55.8% of minority variants detected in this locus were T>G and G>T transversions. Results from this study evidenced the presence of selective pressure and suggest that an evolutionary process is still ongoing in one of the crucial sites of spike protein associated with the spillover to humans.

Emergence of Letermovir-resistant HCMV UL56 mutant during rescue treatment in a liver transplant recipient with ganciclovir-resistant infection HCMV: a case report.

BACKGROUND: Human Cytomegalovirus (HCMV) still represents a crucial concern in solid organ transplant recipients (SOTRs) and the use of antiviral therapy are limited by side effects and the selection of viral mutations conferring antiviral drug resistance. CASE PRESENTATION: Here we reported the case of an HCMV seronegative patient with common variable immunodeficiency (CVID), multiple hepatic adenomatosis, hepatopulmonary syndrome and portal hypertension who received a liver transplant from an HCMV seropositive donor. The patient was treated with Valganciclovir (vGCV) and then IV Ganciclovir (GCV) at 5 week post-transplant for uncontrolled HCMV DNAemia. However, since mutation A594V in UL97 gene conferring resistance to ganciclovir was reported, GCV therapy was interrupted. Due to the high toxicity of Foscarnet (FOS) and Cidofovir (CDV), Letermovir (LMV) monotherapy at the dosage of 480 mg per day was administered, with a gradual viral load reduction. However, a relapse of HCMV DNAemia revealed the presence of mutation C325Y in HCMV UL56 gene conferring resistance to LMV. CONCLUSIONS: In conclusion, even if LMV is an effective and favorable safety molecule it might have a lower genetic barrier to resistance. A warning on the use of LMV monotherapy as rescue treatments for HCMV GCV-resistant infections in transplant recipients is warranted.

Human Herpesvirus 6 Encephalitis in Immunocompetent and Immunocompromised Hosts.

OBJECTIVE: The aim of this study was to analyze the clinical, radiologic, and biological features associated with human herpesvirus 6 (HHV-6) encephalitis in immunocompetent and immunocompromised hosts to establish which clinical settings should prompt HHV-6 testing. METHODS: We performed a retrospective research in the virology database of Fondazione IRCCS Policlinico San Matteo (Pavia, Italy) for all patients who tested positive for HHV-6 DNA in the CSF and/or in blood from January 2008 to September 2018 and separately assessed the number of patients meeting the criteria for HHV-6 encephalitis in the group of immunocompetent and immunocompromised hosts. RESULTS: Of the 926 patients tested for HHV-6 during the period of interest, 45 met the study criteria. Among immunocompetent hosts (n = 17), HHV-6 encephalitis was diagnosed to 4 infants or children presenting with seizures or mild encephalopathy during primary HHV-6 infection (CSF/blood replication ratio <<1 in all cases). Among immunocompromised hosts (n = 28), HHV-6 encephalitis was diagnosed to 7 adolescents/adults with hematologic conditions presenting with altered mental status (7/7), seizures (3/7), vigilance impairment (3/7), behavioral changes (2/7), hyponatremia (2/7), and anterograde amnesia (1/7). Initial brain MRI was altered only in 2 patients, but 6 of the 7 had a CSF/blood replication ratio >1. CONCLUSIONS: The detection of a CSF/blood replication ratio >1 represented a specific feature of immunocompromised patients with HHV-6 encephalitis and could be of special help to establish a diagnosis of HHV-6 encephalitis in hematopoietic stem cell transplant recipients lacking radiologic evidence of limbic involvement.

Positive HCMV DNAemia in stem cell recipients undergoing letermovir prophylaxis is expression of abortive infection.

Letermovir (LMV) inhibits HCMV replication by binding to components of the HCMV-terminase complex showing a potential role in prevention of HCMV-related complications in allogenic hematopoietic stem cell transplant recipients (allo-HSCTRs). However, little is known about breakthrough HCMV infection and the relevance of HCMV DNAemia during prophylaxis. We reported the results of a multicenter prospective study involving five Italian centers in the management of HCMV DNAemia in 75 adult HCMV-seropositive allo-HSCTRs undergoing LMV prophylaxis. The aim of the present study was to characterize the presence of real HCMV reactivation during LMV prophylaxis. Then, the presence of circulating infectious HCMV particles was determined by virus isolation and degradation of free-floating viral DNA. This report provides the first evidence that during LMV prophylaxis the clinical relevance of HCMV DNAemia should be critically considered.

Inherited Chromosomally Integrated Human Herpesvirus 6: An Unexpected Finding in a Septic Neonate.

Human herpesvirus 6 (HHV-6) can integrate its genome in human chromosomes and be germline transmitted (inherited chromosomally integrated HHV-6). We report a case of chromosomally integrated HHV-6 inherited from the mother unexpectedly diagnosed in a septic neonate. Since HHV-6 has recently been included in multiplex polymerase chain reaction assays for meningitis/encephalitis, diagnosing inherited chromosomally integrated HHV-6 status is essential to avoid misdiagnosis of active HHV-6 infection and unnecessary antiviral treatment.

Kinetics of cytomegalovirus and Epstein-Barr virus DNA in whole blood and plasma of kidney transplant recipients: Implications on management strategies.

This retrospective multicenter cohort study investigated the kinetics (ascending and descending phases) of cytomegalovirus (CMV) and Epstein-Barr virus (EBV)-DNA in whole blood (WB) and plasma samples collected from adult kidney transplant (KT) recipients. CMV-DNA kinetics according to antiviral therapy were investigated. Three hundred twenty-eight paired samples from 42 episodes of CMV infection and 157 paired samples from 26 episodes of EBV infection were analyzed by a single commercial molecular method approved by regulatory agencies for both matrices. CMV-DNAemia followed different kinetics in WB and plasma. In the descending phase of infection, a slower decay of viral load and a higher percentage of CMV-DNA positive samples were observed in plasma versus WB. In the 72.4% of patients receiving antiviral therapy, monitoring with plasma CMV-DNAemia versus WB CMV-DNAemia could delay treatment interruption by 7-14 days. Discontinuation of therapy based on WB monitoring did not result in relapsed infection in any patients. Highly different EBV-DNA kinetics in WB and plasma were observed due to lower positivity in plasma; EBV positive samples with a quantitative result in both blood compartments were observed in only 11.5% of cases. Our results emphasize the potential role of WB as specimen type for post-KT surveillance of both infections for disease prevention and management.

Onset of valganciclovir resistance in two infants with congenital cytomegalovirus infection.

Ganciclovir and its prodrug valganciclovir are elective treatments for cCMV. Neonates with important symptoms undergo 6 months of therapy to ameliorate/prevent symptoms and late sequelae, but evidence of resistance is emerging. Over the last 5 years, we took care of 59 cCMV infants and experienced two cases of resistance among nine cCMV infants receiving long-term valganciclovir therapy. In the first case, valganciclovir therapy was prolonged beyond 6 months due to severity of symptoms, control of viral load, and absence of adverse events. Resistance was detected in the 8th month of therapy. In the second case, after a significant reduction following valganciclovir administration and no adverse events, CMV viral load suddenly increased in the 6th month of therapy due to resistance. Both events were associated with UL97 gene mutation. The cCMV infants, affected by severe symptoms, remained in a steady state during treatment, and their later neurological development was coherent with initial seriousness of diagnosis. Prolonged therapeutic exposure may therefore be a risk for resistance, suggesting that constant dosage/weight adjustments, monthly surveillance of viral load, and therapeutic drug monitoring could be proposed to monitor resistance onset and optimize the therapy regime. The risk-benefit ratio for long-term therapy, including the possibility of resistance onset, alongside SNHL and neurodevelopmental improvement, should also be evaluated.

Diagnosing acute encephalitis in patients with hematological disorders: caveats and pitfalls.

The aim of this study was to review the quality of the diagnostic work-up for acute encephalitis carried out at our center in a cohort of patients with hematological disorders. Our data showed substantial heterogeneity in investigating patients. Not all patients had their CSF tested for viruses commonly responsible for encephalitis in immunocompetent individuals (e.g., VZV, enterovirus). A blood sample for the calculation of the CSF/blood replication ratio was collected in 74% of cases. CSF cultures and immunophenotyping of CSF cells were performed in 77% and 21% of patients, respectively. A multidisciplinary consensus is needed to improve current guidelines and standardize diagnostic protocols.

Rotavirus molecular epidemiology in hospitalized patients, Northern Italy, 2015-2018.

About 15,000 hospitalizations due to group A Rotavirus gastroenteritis (RVA) are recorded each year in Italy. In the present study, we report the seasonal distribution and molecular characterization of RVA in pediatric and adult hospitalized patients in the period September 2015-April 2018 in Pavia province, Lombardy Region. During the study period, stool samples of 1450 patients with acute gastroenteritis were analyzed and 122 were RVA positive, the majority belonging to pediatric patients (94.0%) while only a minority of patients (6.0%) were adults. G3P[8], G1P[8], G9P[8] and G2P[4] were the most detected RVA strains, with a prevalence of 82.4%. However, a variety of RVA strains circulated in Northern Italy in hospitalized patients over a period of three years, emphasizing distinct patterns of distribution in different age groups and between years.

Identification of a novel antiviral micro-RNA targeting the NS1 protein of the H1N1 pandemic human influenza virus and a corresponding viral escape mutation.

The influenza A virus (IAV) NS1 protein is one of the major regulators of pathogenicity, being able to suppress innate immune response and host protein synthesis. In this study we identified the human micro RNA hsa-miR-1307-3p as a novel potent suppressor of NS1 expression and influenza virus replication. Transcriptomic analysis indicates that hsa-miR-1307-3p also negatively regulates apoptosis and promotes cell proliferation. In addition, we identified a novel mutation in the NS1 gene of A(H1N1)pdm09 strains circulating in Italy in the 2010-11 season, which enabled the virus to escape the hsa-miR-1307-3p inhibition, conferring replicative advantage to the virus in human cells. To the best of our knowledge, this is the first validation of suppression of IAV H1N1 NS1 by a human micro RNA and the first example of an escape mutation from micro RNA-mediated antiviral response for the A(H1N1)pdm09 virus.

Cellular DNA quantification in respiratory samples for the normalization of viral load: a real need?

BACKGROUND: Respiratory tract infections have an enormous social economic impact, with high incidence of hospitalization and high costs. Adequate specimen collection is the first crucial step for the correct diagnosis of viral respiratory infections. OBJECTIVES: The present retrospective study aimed: i) to verify the cell yield obtained from sampling the nasal respiratory tract using mid-turbinate flocked swabs; ii) to evaluate the normalization of viral load, based on cell number; and iii) to compare the kinetics of viral infection obtained with normalized vs non-normalized viral load. STUDY DESIGN: The number of cells were quantified by real-time PCR in residual extract of nasal swabs tested for respiratory viruses detection and stored at -80 °C in a universal transport medium (UTM™). RESULTS: A total of 513 virus-positive and 226 virus-negative samples were analyzed. Overall, a median of 4.42 log10 ß2-microgolubin DNA copy number/ml of UTM™ (range 1.17-7.26) was detected. A significantly higher number of cells was observed in virus-positive as compared to virus-negative samples (4.75 vs 3.76; p < 0.001). Viral loads expressed as log10 RNA copies/ml of UTM™ and log10 RNA copies/median number of cells were compared in virus-positive samples and a strict correlation (r = 0.89, p < 0.001) and agreement (R2 = 0.82) were observed. In addition, infection kinetics were compared using the two methods with a follow-up series of eight episodes of viral infection and the mean difference was -0.57 log10 (range -1.99 to 0.40). CONCLUSIONS: The normalization of viral load using cellular load compliments the validation of real-time PCR results in the diagnosis of respiratory viruses but is not strictly needed.

Cytomegalovirus and Epstein-Barr Virus DNA Kinetics in Whole Blood and Plasma of Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Currently, no consensus has been reached on the optimal blood compartment to be used for surveillance of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) DNAemia. Although several comparative studies have been performed correlating CMV and EBV DNA loads in whole blood (WB) versus plasma, to our knowledge, no studies to date have analyzed the kinetics of both viruses in the 2 blood compartments. In this retrospective noninterventional multicenter cohort study, the kinetics of CMV and EBV DNA in 121 hematopoietic stem cell transplantation (HSCT) recipients were investigated by analyzing in parallel 569 and 351 paired samples from 80 and 58 sequential episodes of CMV and EBV DNAemia, respectively. Unlike previous studies, this study used a single automated molecular method that was CE-marked and Food and Drug Administration-approved for use in quantifying CMV and EBV DNA in both plasma and WB. Furthermore, the complete viral replication kinetics of all episodes (including both the ascending and the descending phases of the active infection) was examined in each patient. The previously observed overall correlation between CMV DNA levels in WB and plasma was confirmed (Spearman's ρ = .85; P < .001). However, although WB and plasma CMV DNAemia reached peak levels simultaneously, in the ascending phase, the median CMV DNA levels in plasma were approximately 1 log10 lower than WB. Furthermore, in patients who received preemptive therapy, CMV DNA showed a delayed decrease in plasma compared with WB. A lower correlation between EBV DNA levels in plasma versus WB was found (Spearman's ρ = .61; P < .001). EBV DNA kinetics was not consistent in the 2 blood compartments, mostly due to the lower positivity in plasma. Indeed, in 19% of episodes, EBV DNA was negative at the time of the EBV DNA peak in WB. Our results suggest a preferential use of WB for surveillance of CMV and EBV infection in HSCT recipients.

An autochthonous sexually transmitted Zika virus infection in Italy 2016.

We describe two cases of Zika virus infection involving an Italian patient returning from the Dominican Republic and his wife, who remained in Italy and had not travelled to Zika virus endemic areas in the previous months. The infection was transmitted through unprotected sexual intercourse after the man's return to Italy.

FilmArray™ GI panel performance for the diagnosis of acute gastroenteritis or hemorragic diarrhea.

BACKGROUND: Acute gastroenteritis is a common cause of morbidity and mortality in humans worldwide. The rapid and specific identification of infectious agents is crucial for correct patient management. However, diagnosis of acute gastroenteritis is usually performed with diagnostic panels that include only a few pathogens. In the present bicentric study, the diagnostic value of FilmArray™ GI panels was assessed in unformed stool samples of patients with acute gastroenteritis and in a series of samples collected from pediatric patients with heamorragic diarrhea. The clinical performance of the FilmArray™ gastrointestinal (GI) panel was assessed in 168 stool samples collected from patients with either acute gastroenteritis or hemorragic diarrhea. Samples showing discordant results between FilmArray and routine methods were further analyzed with an additional assay. RESULTS: Overall, the FilmArray™ GI panel detected at least one potential pathogen in 92/168 (54.8%) specimens. In 66/92 (71.8%) samples, only one pathogen was detected, while in 26/92 (28.2%) multiple pathogens were detected. The most frequent pathogens were rotavirus 13.9% (22/168), Campylobacter 10.7% (18/168), Clostridium difficile 9.5% (16/168), and norovirus 8.9% (15/168). Clostridium difficile was identified only in patients with acute gastroenteritis (p < 0.01), while STEC was detected exclusively in patients with hemorragic diarrhea (p < 0.01). In addition, Campylobacter spp., Salmonella spp., EPEC and E. coli producing Shiga-like toxin were more frequently detected in patients with hemorragic diarrhea (p < 0.05). The overall percent agreement calculated in samples was 73.8% and 65.5%, while 34.5% were discordant. After additional confirmatory analyses, the proportion of discordant samples decreased to 7.7%. Rotavirus and astrovirus were the most frequently unconfirmed pathogens. CONCLUSION: In conclusion, the FilmArray™ GI panel has proved to be a valuable new diagnostic tool for improving the diagnostic efficiency of GI pathogens.

Swine influenza A (H1N1) virus (SIV) infection requiring extracorporeal life support in an immunocompetent adult patient with indirect exposure to pigs, Italy, October 2016.

We describe a case of severe swine influenza A(H1N1) virus infection in an immunocompetent middle-aged man in October 2016 in Italy who had only indirect exposure to pigs. The patient developed a severe acute distress respiratory syndrome which was successfully supported by extracorporeal membrane oxygenation and treated with antiviral therapy. The sole risk factor for influenza was a body mass index > 30 kg/m2. After a month of hospitalisation, the patient was discharged in good health.