Respiratory syncytial virus-associated hospitalizations among children: an Italian retrospective observational study.

BACKGROUND: Respiratory syncytial virus (RSV), a single-stranded RNA virus, is a leading cause of hospitalization in infants, especially ≤ 2 months of life. In the light new immunization strategies adoption, we described epidemiological and clinical characteristics of RSV-associated hospitalizations in pediatric and neonatal intensive care units of the Policlinico Foggia Hospital, Apulia Region, Italy. METHODS: Hospitalized children with a laboratory-confirmed RSV infection from 2011 to 2023 were retrospectively evaluated. Clinical information was collected from Hospital Discharge Registry in the period 2011-2020. The proportion of the hospitalization for acute respiratory infections (ARIs) associated to RSV was calculated and the hospitalization cost was analyzed by using the diagnosis-related group reimbursement rate. The anticipated impact of immunization either with monoclonal antibodies or maternal immunization on the number of hospitalizations was estimated. All analyses and quality assessment were performed using STATA/SE15.0. RESULTS: A total of 1,005 RSV-cases were included in the study, of which 86.3% occurred between December-March. In the period 2011-2020, 832 RSV-cases were matched with the corresponding hospital admissions; 75.2% were aged < 1 year (49.6% 0-2 months). Bronchiolitis was the most frequent admission diagnosis occurring in 63.3% of patients; 25% of children were affected by a very severe RSV-disease. Younger age ≤ 2 months (OR:14.8, 95%CI:8.30-26.31, p = 0.000), higher length-of-hospital-stay (OR:1.01, 95%CI:1.0-1.02, p = 0.030) and history of prematurity (OR:4.4, 95%CI:1.57-12.11, p = 0.005) were associated with a higher disease severity. RSV caused 48.9% of ARIs among children < 1 year. The mean cost of an RSV-associated hospitalization was 3,036 euros/year, with the higher cost in the 0-2 months age group (4,225 euros/year). Immunization programs with nirsevimab could prevent 51.4 RSV hospitalizations/year and 18.1 very severe RSV disease/year in infants < 1 year of age. RSV vaccine could prevent 46.1 of hospitalizations/year caused by RSV within 180 days after birth. CONCLUSIONS: Our study contributes to outlining the baseline profile of RSV-associated hospitalizations among Italian children by providing epidemiological/clinical/economic estimates. While awaiting new recommendations on immunization, healthcare-workers should persist in implementing public health measures and appropriate case management to control RSV seasonal epidemics. Strengthened laboratory RSV surveillance is needed to inform the implementation of the new immunization strategies.

Prevalence of Blastocystis sp. and other gastrointestinal pathogens among diarrheic COVID-19 patients in Italy.

Background: Gastrointestinal pathogens (GPs) contribute significantly to the burden of illness worldwide with diarrhoea being the most common among gastrointestinal symptoms (GSs). In the COVID-19 disease, diarrhoea, could be one of the initial presenting symptoms. However, no data on the potential correlation between diarrhoea-causing pathogens and SARS-CoV-2 infection are available. Therefore, we carried out a 2-years retrospective study aimed to evaluate the prevalence of "classic" GPs among SARS-CoV-2 infected and non-infected patients with diarrhoea in Italy. Methods: Results of SARS-CoV-2 research from nasopharyngeal and detection of GPs from stool swab samples by Allplex™ SARS-CoV-2 and GI Virus, Bacteria and Parasite Assay were analysed for all patients with diarrhoea referring to Policlinico Ospedaliero Universitario, Foggia, (Italy) from February 2022 to October 2023. Results: Out of the 833 involved patients, 81 (3.9%) were COVID-19 positive, while 752 (90.3%) were COVID-19 negative. Among COVID-19-positive patients, 37% (n = 30/81) were found positive for one or more GPs with a higher prevalence of protozoan parasites (18.5%) (Blastocystis ST1-ST4 subtypes, Dientamoeba fragilis genotype I), followed by bacteria (7.4%) (Campylobacter sp., Salmonella sp.). Viral pathogens were more frequent among COVID-19 negative patients (Adenovirus, Norovirus). Among GPs, Blastocystis ST3 subtype was the most prevalent registered in the 16% of patients (p = 0.0001). Conclusions: Based on obtained results, a likely interaction between the classic GPs and SARS-CoV-2 infection can be speculated, driven by protozoan parasites. Moreover, these results also provide baseline data to understand more deeply Blastocystis sp. role in this scenario of dysbiosis, particularly in those cases of SARS-CoV-2 co-infection.

Activity of a foam in preventing rebound of vancomycin-resistant Enterococcus faecium-containing droplets generated from the toilet bowl.

In hospital environments, droplets generated by urination within shared toilets may represent a route of dissemination for bacteria such as vancomycin-resistant Enterococcus faecium (VREfm), which contributes significantly to the burden of hospital-acquired infections. We investigated the potential activity of a foam in preventing the generation of droplets containing Enterococcus spp. during urination. A uniform layer of foam was deposited in the inner walls and at the bottom of an experimental toilet contaminated with suspensions of Enterococcus strains (including a VREfm strain). Human urination was simulated, and colonies of Enterococcus were recovered through a toilet lid where agar plates had been placed. Results showed that the foam was able to suppress production of droplets containing Enterococcus spp. generated by a liquid hitting inner toilet walls. Conversely, Enterococcus colonies were recovered in absence of foam. Moreover, the foam did not show antibacterial activity. We propose a new non-antimicrobial approach aimed at limiting transmission of multidrug-resistant bacteria, particularly in healthcare settings.

Multidrug-Resistant Bacteria Contaminating Plumbing Components and Sanitary Installations of Hospital Restrooms.

Antimicrobial resistance (AMR) poses several issues concerning the management of hospital-acquired infections, leading to increasing morbidity and mortality rates and higher costs of care. Multidrug-resistant (MDR) bacteria can spread in the healthcare setting by different ways. The most important are direct contact transmission occurring when an individual comes into physical contact with an infected or colonized patient (which can involve healthcare workers, patients, or visitors) and indirect contact transmission occurring when a person touches contaminated objects or surfaces in the hospital environment. Furthermore, in recent years, toilets in hospital settings have been increasingly recognised as a hidden source of MDR bacteria. Different sites in restrooms, from toilets and hoppers to drains and siphons, can become contaminated with MDR bacteria that can persist there for long time periods. Therefore, shared toilets may play an important role in the transmission of nosocomial infections since they could represent a reservoir for MDR bacteria. Such pathogens can be further disseminated by bioaerosol and/or droplets potentially produced during toilet use or flushing and be transmitted by inhalation and contact with contaminated fomites. In this review, we summarize available evidence regarding the molecular features of MDR bacteria contaminating toilets of healthcare environments, with a particular focus on plumbing components and sanitary installation. The presence of bacteria with specific molecular traits in different toilet sites should be considered when adopting effective managing and containing interventions against nosocomial infections potentially due to environmental contamination. Finally, here we provide an overview of traditional and new approaches to reduce the spreading of such infections.

Prevalence and genetic diversity of Blastocystis sp. among autochthonous and immigrant patients in Italy.

The prevalence of Blastocystis sp., its genetic diversity and the distribution of circulating subtypes (STs) were molecularly investigated in a cohort of autochthonous and immigrant patients with gastrointestinal symptoms hospitalized over the period February 2022-June 2023 at the Policlinico Ospedaliero-Universitario "Riuniti", Foggia, in Southern Italy. The population variables, including patient geographical origin, gender and age classes were reported. Out of the 927 investigated patients, 36 (3.9%) were positive for Blastocystis sp. A statistically significant association with African origin and age classes >18 years old was found. ST1 (allele 4), ST2 (alleles 9, 13), ST3 (alleles 34, 36) and ST4 (allele 92) were the subtypes detected with a different distribution between autochthonous and immigrant patients. Co-infections with enteric protozoa such as Giardia duodenalis and Dientamoeba fragilis, pathogenic bacteria as Clostridioides difficile, Campylobacter jejuni and Aeromonas sp. and viral infections such as Norovirus were found in 33% of cases. This is the first study of Blastocystis sp., its circulating subtypes and allele variability among patients with different geographical origin in an area of Southern Italy, in the Central Mediterranean, characterized by high immigrant pressure. These results provide baseline data to better investigate a potential interaction between Blastocystis sp. and other risk factors in patients with gastrointestinal symptoms.

Rapid Decrease in Fluoroquinolones Consumption following Implementation of a Simple Antimicrobial Stewardship Bundled Intervention in a University Hospital during the COVID-19 Pandemic.

Fluoroquinolones (FQs) represent an class of antibiotics of medical importance, but their use has been restricted due to their ecologic impact and associated side effects. The reduction of FQs use is an important goal of antimicrobial stewardship programs (ASP). This work describes an ASP focused on overall antibiotics and FQs consumption reduction. From January 2021, an ASP was implemented in a 700-bed teaching hospital. The ASP was based on: (i) antibiotics consumption monitoring system (DDD/100 bed days); (ii) mandatory antibiotic prescription-motivation (using a dedicated informatic format) with the goal of >75% of motivated prescriptions; and (iii) data feedback and training on FQs use indications. We evaluated the impact of the intervention on overall systemic antibiotics and FQs consumption according to the objectives posed by Italian PNCAR (National Action Plan on Antimicrobial Resistance). A decrease of 6.6% in antibiotic use was observed (2019 vs. 2021). Notably, the FQs consumption fell by 48.3% from 7.1 DDD/100 bd in 2019 to 3.7 DDD/100 bd in 2021 (p < 0.001). After six months of mandatory antibiotic prescription-indication, all units achieved the target set. The study suggests that a simple, bundled ASP intervention can be rapidly effective obtaining the objectives of PNCAR on the reduction of overall antibiotics and FQs consumption.

Successful Treatment of Aortic Endocarditis by Achromobacter xylosoxidans with Cefiderocol Combination Therapy in a Non-Hodgkin Lymphoma Patient: Case Report and Literature Review.

Achromobacter xylosoxidans is a Gram-negative aerobic opportunistic bacterium, belonging to the order of Burkholderiales, that can cause infections of virtually all body districts in patients with underlying diseases. However, A. xylosoxidans has rarely been associated with infective endocarditis. The treatment of A. xylosoxidans infections is complicated by both intrinsic and acquired resistance. Here we report on a case of aortic endocarditis by A. xylosoxidans in a Non-Hodgkin lymphoma patient treated with a combination of cefiderocol and other antibiotics, and summarize the available literature.

Resistance and virulence features of hypermucoviscous Klebsiella pneumoniae from bloodstream infections: Results of a nationwide Italian surveillance study.

Among Enterobacterales, Klebsiella pneumoniae (Kp) is one of the major opportunistic pathogens causing hospital-acquired infections. The most problematic phenomenon linked to Kp is related to the dissemination of multi-drug resistant (MDR) clones producing carbapenem-hydrolyzing enzymes, representing a clinical and public health threat at a global scale. Over the past decades, high-risk MDR clones (e.g., ST512, ST307, ST101 producing bla KPC-type carbepenemases) have become endemic in several countries, including Italy. Concurrently, the spread of highly virulent Kp lineages (e.g., ST23, ST86) able to cause severe, community-acquired, pyogenic infections with metastatic dissemination in immunocompetent subjects has started to be documented. These clones, designated as hypervirulent Kp (hvKp), produce an extensive array of virulence factors and are highly virulent in previously validated animal models. While the prevalence and distribution of MDR Kp has been previously assessed at local and national level knowledge about dissemination of hvKp remains scarce. In this work, we studied the phenotypic and genotypic features of hypermucoviscous (HMV, as possible marker of increased virulence) Kp isolates from bloodstream infections (BSI), obtained in 2016-17 from 43 Italian Laboratories. Antimicrobial susceptibility testing, whole genome sequencing and the use of two animal models (G. mellonella and murine) were employed to characterize collected isolates. Over 1502 BSI recorded in the study period, a total of 19 Kp were selected for further investigation based on their HMV phenotype. Results showed that hvKp isolates (ST5, ST8, ST11, ST25) are circulating in Italy, although with a low prevalence and in absence of a clonal expansion; convergence of virulence (yersiniabactin and/or salmochelin, aerobactin, regulators of mucoid phenotype) and antimicrobial-resistance (extended-spectrum beta-lactamases) features was observed in some cases. Conventional MDR Kp clones (ST307, ST512) may exhibit an HMV phenotype, but with a low virulence potential in the animal models. To the best of our knowledge, this work represents the first systematic survey on HMV and hvKp in Italy, employing a functional characterization of collected isolates. Future surveillance programs are warranted to monitor the threatening convergence of virulence and resistance among MDR Kp and the spread of hvKp.

In vitro activity of ceftazidime/avibactam against carbapenem-nonsusceptible Klebsiella penumoniae isolates collected during the first wave of the SARS-CoV-2 pandemic: a Southern Italy, multicenter, surveillance study.

OBJECTIVES: Carbapenemase-producing Enterobacterales (CPE) represent a serious threat for human health being frequently resistant to most of available antibiotics classes. Recently, ceftazidime/avibactam (CAZ/AVI) has been approved for treatment of infections by Gram-negative bacteria, including class A CPE (including KPC-producing K. pneumoniae). Following CAZ/AVI commercialization, resistance to this combination has been reported. The aim of this study was to evaluate the prevalence of CAZ/AVI resistance among carbapenem-resistant K. pneumoniae(CR-Kp) isolates recovered from bloodstream infections (BSI) and hospital-acquired pneumonia (HAP), representative of the contemporary southern Italy epidemiology, during the first pandemic wave of SARS-CoV-2. METHODS: From Jan...20-Jun...20, 4 Laboratories, collected all consecutive, non-replicated CR-Kp from BSIs and HAPs. All isolates were subjected to i) MALDI-ToF identification; ii) antimicrobial susceptibility testing by microdilution method. CAZ/AVI resistant (CAZ/AVI-R) isolates were screened for presence of most common carbapenemase genes and subjected to whole genome sequencing for characterization. RESULTS: A total of 89 isolates were collected. The majority of strains retained susceptibility to colistin, gentamicin and amikacin. Three strains (3/89, 3,4%) were CAZ/AVI-R (MIC range 16/4-64/4 mg/L). Among CAZ/AVI-R, one was KPC-type producer (an ST101) while the remaining where NDM-type and VIM-type producers and belonged to ST147, and ST45, respectively. CONCLUSION: During the pandemic period, in southern Italy, CAZ/AVI resistance remained infrequent but high-risk Klebsiella pneumoniae epidemic clones, producing the KPC-31 variant and class B carbapenamases were reported from some of the included centers.

Hypervirulent Klebsiella pneumoniae Strains Modulate Human Dendritic Cell Functions and Affect TH1/TH17 Response.

Hypervirulent Klebsiella pneumoniae (Hv-Kp) strains have emerged as pathogens causing life-threatening, invasive disease even in immunocompetent hosts. Systemic dissemination usually occurs following perturbations of the gut microbiota and is facilitated by Hv-Kp resistance to phagocytosis and complement activity. Hv-Kp are usually associated with K1 or K2 capsular types, produce several iron uptake systems (e.g., aerobactin and salmochelin) and are often but not invariably, capsular material hyper-producers (hypermucoviscous phenotype: HMV). Whether Hv-Kp escape the immune response at mucosal site is unknown. In this work, we studied the effects of Hv-Kp on human dendritic cells (DCs), central players of the IL-23/IL-17 and IL-12/IFN-γ axis at mucosal sites, essential for pathogen clearance. Four Hv-Kp and HMV strains were selected and their activity on DC maturation and cytokine production was compared to that of non-virulent Kp strains with classic or HMV phenotypes. While the maturation process was equally induced by all Kp strains, significant differences between virulent and non-virulent strains were found in the expression of genes for cytokines involved in T-cell activation and differentiation. The non-virulent KP04C62 and the classic Kp, KPC157 induced high expression of TH1 (IL-12p70 and TNFα) and TH17 cytokines (IL-23, IL-1ß and IL-6), while Hv-Kp poorly activated these cytokine genes. Moreover, conditioned media from DCs cultured with non-virulent Kp, either classical or hypercapsulated, induced the activation of IL-17 and IFN-γ genes in preactivated CD4+-cells suggesting their TH17/TH1 differentiation. Conditioned media from Hv-Kp poorly activated IL-17 and IFN-γ genes. In summary, our data indicate that Hv-Kp interfere with DC functions and T-cell differentiation and suggest that the escape from the IL-23/IL-17 and IL-12/IFN-γ axes may contribute to pathogen dissemination in immunocompetent hosts.

Symptomatic SARS-CoV-2 Infection with Ageusia after Two mRNA Vaccine Doses.

To raise awareness about preventive measures in COVID-19 pandemic, even though fully vaccinated. Although recent trials showed high efficacy of vaccines in preventing symptomatic infections, there are some individuals experiencing symptomatic SARS-CoV-2 infection. In this case report, a fully vaccinated young dental practitioner experienced symptomatic SARS-CoV-2 infection 55 days postvaccination with BNT162b2 Pfizer vaccine with evident ageusia. Diagnostic swabs were performed and used for viral genome sequencing. The patient fully recovered 15 days after diagnosis. Loss of smell and taste, together with nasal congestion were the main reported symptoms. The use of personal protective equipment prevented spread of infection in patients and co-workers. With the increase of people being fully vaccinated, it is still necessary to follow infection preventive protocols by correctly applying personal protective equipment. Although high efficacy has been proved, some individuals may still be vulnerable to symptomatic infection and new guidelines and markers should be adopted and investigated to find out patients for whom vaccination may not determine full immunization.

Interaction of Klebsiella pneumoniae with tissue macrophages in a mouse infection model and ex-vivo pig organ perfusions: an exploratory investigation.

BACKGROUND: Hypervirulent Klebsiella pneumoniae (hvKp) strains of capsule type K1 and K2 cause invasive infections associated with hepatic abscesses, which can be difficult to treat and are frequently associated with relapsing infections. Other K pneumoniae strains (non-hvKp), including lineages that have acquired carbapenem resistance, do not manifest this pathology. In this work we aimed to test the hypothesis that within-macrophage replication is a key mechanism underpinning abscess formation in hvKp infections. METHODS: In this exploratory investigation, to study the pathophysiology of abscess formation, mice were intravenously infected with 106 colony forming units (CFU) of either hvKp isolates (six strains) or non-hvKp isolates (seven strains). Intracellular bacterial replication and neutrophil influx in liver and spleen was quantified by fluorescence microscopy of sliced cryopreserved organs of mice collected 30 min, 6 h, and 24 h after infection with the aim to provide data of bacterial association to Kupffer cells in the liver and to the different tissue macrophages in the spleen. Microbiological and microscopy analysis of an ex-vivo model of pig liver and spleen infection were used to confirm within-macrophage replication. Pig organs were perfused with heparinised, autologous pig's blood and injected with 6·5 × 107 CFU of hvKp K2 sequence type 25 strain GMR151. Blood and tissue biopsies collected before infection and 30 min, 1 h, 2 h, 3 h, 4 h, and 5 h after infection were used to measure bacterial counts and to identify the subcellular localisation of bacteria by immunohistochemistry analysis. FINDINGS: We show that hvKp resisted phagocyte-mediated clearance and replicated in mouse liver macrophages to form clusters 6 h after infection, with a mean of 7·0 bacteria per Kupffer cell (SD 6·2); however, non-hvKp were efficiently cleared (mean 1·5 bacteria per cell [SD 1·1]). HvKp infection promoted neutrophil recruitment to sites of infection, which in the liver resulted in histopathological signs of abscess formation as early as 24 h post-infection. Experiments in pig organs which share a high functional and anatomical resemblance to human organs, provided strong evidence for the propensity of hvKp to replicate within the hepatic macrophages. INTERPRETATION: These findings show subversion of innate immune processes in the liver by K pneumoniae and resistance to Kupffer cell mediated clearance as an explanation for the propensity of hvKp strains to cause hepatic abscesses. FUNDING: University of Oxford and a Royal Society Wolfson grant funded biosafety facility.

Droplets generated from toilets during urination as a possible vehicle of carbapenem-resistant Klebsiella pneumoniae.

BACKGROUND: In the health care setting, infection control actions are fundamental for containing the dissemination of multidrug-resistant bacteria (MDR). Carbapenemase-producing Enterobacterales (CPE), especially Klebsiella pneumoniae (CR-KP), can spread among patients, although the dynamics of transmission are not fully known. Since CR-KP is present in wastewater and microorganisms are not completely removed from the toilet bowl by flushing, the risk of transmission in settings where toilets are shared should be addressed. We investigated whether urinating generates droplets that can be a vehicle for bacteria and explored the use of an innovative foam to control and eliminate this phenomenon. METHODS: To study droplet formation during urination, we set up an experiment in which different geometrical configurations of toilets could be reproduced and customized. To demonstrate that droplets can mobilize bacteria from the toilet bowl, a standard ceramic toilet was contaminated with a KPC-producing Klebsiella pneumoniae ST101 isolate. Then, we reproduced urination and attached culture dishes to the bottom of the toilet lid for bacterial colony recovery with and without foam. RESULTS: Rebound droplets invariably formed, irrespective of the geometrical configuration of the toilet. In microbiological experiments, we demonstrated that bacteria are always mobilized from the toilet bowl (mean value: 0.11 ± 0.05 CFU/cm2) and showed that a specific foam layer can completely suppress mobilization. CONCLUSIONS: Our study demonstrated that droplets generated from toilets during urination can be a hidden source of CR-KP transmission in settings where toilets are shared among colonized and noncolonized patients.

Bluetooth 5.1: An Analysis of Direction Finding Capability for High-Precision Location Services.

This paper presents an in-depth overview of the Bluetooth 5.1 Direction Finding standard's potentials, thanks to enhancing the Bluetooth Low Energy (BLE) firmware. This improvement allows producers to create location applications based on the Angle of Departure (AoD) and the Angle of Arrival (AoA). Accordingly, it is conceivable to design proper Indoor Positioning Systems (IPS), for instance, for the traceability of resources, assets, and people. First of all, Radio Frequency (RF) radiogoniometry techniques, helpful in calculating AoA and AoD angles, are introduced in this paper. Subsequently, the topic relating to signal direction estimation is deepened. The Bluetooth Core Specification updates concerning version 5.1, both at the packet architecture and prototyping levels, are also reported. Some suitable platforms and development kits for running the new features are then presented, and some basic applications are illustrated. This paper's final part allows ascertaining the improvement made by this new definition of BLE and possible future developments, especially concerning applications related to devices, assets, or people's indoor localization. Some preliminary results gathered in a real evaluation scenario are also presented.

Diagnostic stewardship based on patient profiles: differential approaches in acute versus chronic infectious syndromes.

Introduction: New diagnostics may be useful in clinical practice, especially in contexts of high prevalence of multidrug-resistant organisms (MDRO). However, misuse of diagnostic tools may lead to increased costs and worse patient outcome. Conventional and new techniques should be appropriately positioned in diagnostic algorithms to guide an appropriate use of antimicrobial therapy.Areas covered: A panel of experts identified 4 main areas in which the implementation of diagnostic stewardship is needed. Among chronic infections, bone and prosthetic joint infections and subacute-chronic intravascular infections and endocarditis represent common challenges for clinicians. Among acute infections, bloodstream infections and community-acquired pneumonia may be associated with high mortality and require appropriate diagnostic approach.Expert opinion: Diagnostic stewardship aims to improve the appropriate use of microbiological diagnostics to guide therapeutic decisions through appropriate and timely diagnostic testing. Here, diagnostic algorithms based on different patient profiles are proposed for chronic and acute clinical syndromes. In each clinical scenario, combining conventional and new diagnostic techniques is crucial to make a rapid and accurate diagnosis and to guide the selection of antimicrobial therapy. Barriers related to the implementation of new rapid diagnostic tools, such as high initial costs, may be overcome through their rational and structured use.

Low Prevalence of Antibodies to SARS-CoV-2 and Undetectable Viral Load in Seropositive Blood Donors from South-Eastern Italy.

Recently, a significant cluster of pneumonia caused by a novel betacoronavirus (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) was described initially in China and then spread throughout the world. Like other coronaviridae, the viral transmission occurs mainly through droplets. In addition, the virus has been detected in different clinical specimens, suggesting a potential transmission by other routes, including blood transfusion. However, the potential risk of transmission of SARS-CoV-2 via blood products is still unclear. The aim of our study was to investigate the prevalence of antibodies against SARS-CoV-2 among blood donors from South-Eastern Italy. Moreover, in the seropositive donors, we searched for the presence of the virus in nasopharyngeal swabs and in plasma samples. Overall, 1,797 blood donors from the Apulia region were tested for anti-SARS-CoV-2 antibodies, using a commercially available assay. Only 18/1,797 donors (1.0%) tested positive for anti-SARS-CoV-2 antibodies; in none of them SARS-CoV-2 viral RNA was detected in nasopharyngeal swabs and in plasma samples. Our results indicate that most of the blood donors in Apulia remained uninfected during this wave of the pandemic; further, none had detectable virus both in nasopharyngeal swabs and in blood samples. The risk to carry and transmit the virus by healthy and asymptomatic blood donors is probably very low.

Temporal profile of SARS-CoV-2 viral load in posterior nasopharyngeal samples: Analysis of 944 patients in Apulia, Italy.

OBJECTIVES: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has heavily impacted Italy. The government's restriction measures have attenuated the burden on hospitals. The association of high viral replication with disease severity suggests the potential for lower viral load in milder clinical presentations. METHODS: The reverse-transcription-polymerase-chain-reaction (RT-PCR) profile of 944 consecutive, non-replicate, positive retropharyngeal swabs was collected from 3 March to 8 June 2020 to investigate the temporal profile of SARS-CoV-2 viral load in the region of Capitanata, Apulia. Cycle threshold (Ct) values of 3 targets (N [nucleocapsid protein], E [envelope protein] and RdRP [RNA-dependent RNA-polymerase]) were analysed. RESULTS: The median Ct values of the 3 targets increased considerably over the study period, showing a progressive and constant weekly change. The negative detection rate of E and RdRP increased over time. These data suggest that SARS-CoV-2 viral load progressively decreased along the outbreak course. During the first epidemic peak (March and April) the viral load among patients >80-years was significantly higher than for younger subjects. However, in May this age-dependent difference disappeared, underlying viral load reduction in the elderly. CONCLUSIONS: An attenuation of viral transmission or pathogenicity during the epidemic course is suggested, likely due to restriction measures, although viral factors might also be considered.

Summary of the Available Molecular Methods for Detection of SARS-CoV-2 during the Ongoing Pandemic.

Since early 2020, the COVID-19 pandemic has caused an excess in morbidity and mortality rates worldwide. Containment strategies rely firstly on rapid and sensitive laboratory diagnosis, with molecular detection of the viral genome in respiratory samples being the gold standard. The reliability of diagnostic protocols could be affected by SARS-CoV-2 genetic variability. In fact, mutations occurring during SARS-CoV-2 genomic evolution can involve the regions targeted by the diagnostic probes. Following a review of the literature and an in silico analysis of the most recently described virus variants (including the UK B 1.1.7 and the South Africa 501Y.V2 variants), we conclude that the described genetic variability should have minimal or no effect on the sensitivity of existing diagnostic protocols for SARS-CoV-2 genome detection. However, given the continuous emergence of new variants, the situation should be monitored in the future, and protocols including multiple targets should be preferred.