Background:Accurate detection of β-lactam resistance genes in bloodstream infections is critical for guiding antimicrobial therapy. This study evaluates the Alifax Gram-negative resistance (GNR) microchip assay for detecting β-lactam resistance genes directly from positive blood cultures (PBCs) for Gram-negative (GN) bacteria, including Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii. Methods:Simulated (n=146) and clinical (n=106) GN-PBC samples were tested for bla KPC, bla VIM, bla NDM, bla IMP, bla OXA-23-like, bla OXA-48-like, bla SHV-ESBL, bla CTX-M-1/9 group, and bla CMY-2-like genes using the GNR microchip assay. Whole-genome sequencing (WGS) served as the reference assay for simulated samples and, selectively, for clinical samples. The bioMérieux BioFire Blood Culture Identification 2 (BCID2) panel assay was used as a comparator for clinical samples. Results:The GNR microchip assay correctly identified 203 (99.5%) of 204 β-lactam resistance genes in simulated samples. One sample tested false negative for a bla SHV-ESBL gene but true positive for a bla KPC gene. In clinical samples, GNR results were concordant with BCID2 for 113 (100%) of 113 genes included in both assays. Additionally, the GNR assay detected bla CMY-2 -like (n=6), bla OXA-23-like (n=5), and bla SHV-ESBL (n=2), which are not targeted by BCID2, all confirmed by WGS. In two β-lactam-resistant P. aeruginosa samples but negative by the GNR assay, WGS confirmed the absence of acquired β-lactam resistance genes, suggesting alternative resistance mechanisms. Conclusion:The GNR microchip assay demonstrated high concordance and broader β-lactam resistance gene coverage compared to BCID2, supporting its potential role in routine diagnostics. Further validation in larger, prospective studies is warranted.

Carbapenem-Resistant Gram-Negative Bacteria, including Carbapenem-Resistant Enterobacterales (CRE) and Carbapenem-Resistant Pseudomonas aeruginosa (CRPA), are common causes of infections in intensive care units (ICUs) in Italy. This prospective observational study evaluated the epidemiology, management, microbiological characterization, and outcomes of hospital-acquired CRE or CRPA infections treated in selected ICUs in Italy. The study included patients with hospital-acquired infections due to CRE and CRPA treated in 20 ICUs from June 2021 to February 2023. The primary endpoint was the 1-year incidence of CRE/CRPA infections. Secondary endpoints included the rate of CRE/CRPA infections, mortality in ICU, infection outcome, and microbiological characterization. Among 13,088 patients admitted over the 12-month study period across each of the 20 ICUs, 283 had CRE infections, and 138 had CRPA infections. The incidence of CRE and CRPA infections was 3.57 per 1000 patient days and 1.74 per 1000 patient days, respectively. The proportion of CRE and CRPA infections over the total number of infections due to Enterobacterales and Pseudomonas aeruginosa was 19.2

Objective: To assess whether 48-h negative blood culture (BC) bottles are still negative at the classic 120-h incubation endpoint and whether 48 h might be the time to make antimicrobial therapy decisions. Methods: Data from the first collected bottles from bloodstream infection (BSI) episodes of single patients were retrospectively analyzed. Probabilities of bottles being negative at the classic endpoint were calculated from 0 to 120 h of incubation. Results: Among BC-negative episodes (4018/4901 [82.0%]), most (2097/4018 (52.2%) occurred in medicine patients. At 48 h, probability was 100.0% (95% CI, 99.9-100.0) for all 4018 patients. Of these, 1244 (31.0%) patients remained on antibiotics until 120 h. Excluding 401 (32.2%) patients who received antibiotics for another (non-bloodstream) infection, 843 (67.8%) of 1244 patients could have merited early (48-h) discontinuation of antibiotics. Stopping treatment in these patients would have led to saving 5201 days of access (943 [18.1%] days), watch (3624 [69.7%] days), or reserve (634 [12.2%]) AWaRe groups' antibiotics, which correspond to 65.6% (5201/7928) of days of administered antibiotics in all 1244 patients. Conclusion: As an early indicator of BC negativity, the 48-h endpoint could reliably support antimicrobial stewardship, but the clinical judgment remains imperative especially when BSI is highly suspected.

ABSTRACTBloodstream 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-β-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-β-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.

Background/Objectives: Metallo-β-lactamases (MBLs) in Enterobacterales and other Gram-negative organisms pose significant public health threats due to their association with multidrug resistance (MDR). Although aztreonam (AZT) can target MBL-producing organisms, its efficacy is compromised in organisms expressing additional β-lactamases that inactivate it. Combining AZT with the β-lactamase inhibitor avibactam (AVI) may restore its activity against MBL-producing isolates. Methods: AZT-AVI, along with other clinically relevant antimicrobials, was tested against thirteen MBL-producing clinical isolates of Enterobacterales (nine Klebsiella pneumoniae, three Enterobacter cloacae, and one Providencia stuartii) using whole-genome sequencing (WGS) for genetic characterization. Results: AZT-AVI demonstrated full susceptibility across all isolates, whereas aztreonam alone was ineffective. The newer β-lactam/β-lactamase inhibitor combinations imipenem/relebactam and meropenem/vaborbactam were inactive in 100% and 92.3% of isolates, respectively. WGS-based analysis revealed multiple resistance mechanisms consistent with MDR phenotypes, including high-risk K. pneumoniae clones (ST147 and ST11). Conclusions: AZT-AVI is effective against MDR MBL-producing Enterobacterales, highlighting its therapeutic potential for challenging infections. While WGS does not replace phenotypic testing, it provides valuable insights for antimicrobial stewardship and the monitoring of resistance gene dissemination.

The identification of microorganisms at the species level has always constituted a diagnostic challenge for clinical microbiology laboratories. The aim of the present study has been the evaluation in a real-time assay of the performance of Autobio in comparison with the Bruker mass spectrometry system for the identification of bacteria and yeasts. A total of 535 bacteria and yeast were tested in parallel with the two systems by direct smear or fast formic acid extraction for bacteria and yeasts, respectively. Discordant results were verified by 16S, ITS rRNA or specific gene sequencing. Beyond giving comparable results for bacteria with respect to the MBT smart system, Autof MS2600 mass spectrometer provided excellent accuracy for the identification of yeast species of clinical interest.

ObjectiveTo evaluate whether acute histologic chorioamnionitis (HCA) diagnosed in the placenta may be associated with an increased occurrence of bronchopulmonary dysplasia (BPD) or death among extremely low gestational age neonates (ELGAN).MethodsThis Italian single-center case-control retrospective study involved ELGAN admitted to the neonatal intensive care unit between January 2019 and June 2022. Infants born from pregnant women with acute and severe HCA, identified as stage >= 2 and grade 2 HCA, (HCA-infants) were compared with infants of pregnant women without chorioamnionitis or with stage 1, grade 1 chorioamnionitis (no-HCA-infants).ResultsAmong 101 eligible ELGAN, 63 infants had complete clinical and histologic data relevant to the study: thirty infants were included in the HCA-infants group and 33 in the no-HCA-infants group. Neonatal and maternal demographic and clinical characteristics were similar between the two groups. Infants born from mothers with acute and severe HCA had significantly higher occurrence of composite BPD or death (18 [60%] vs. 9 [27%]; P = 0.012), as well as higher incidence of severe forms of BPD (6 [30%] vs. 2 [6%]; P = 0.045). In multiple logistic regression analysis, after adjustment for confounding covariates, HCA was an independent risk factor for BPD or death (OR, 4.49; 95% CI: 1.47-13.71).ConclusionsThis is the first study showing that in utero exposure to acute and severe HCA is an independent risk factor for the occurrence of composite BPD or death among ELGAN. Acute and severe histologic chorioamnionitis is an independent risk factor for the occurrence of bronchopulmonary dysplasia or death among extremely low gestational age neonates.

A 24-year-old male Bangladeshi asylum seeker presented to the emergency department of Policlinico A. Gemelli of Rome, Italy with multiple nodular, pruritic lesions on both lower limbs and both elbows. We present a skin disease typical for persons living in crowded conditions.

ObjectiveThe purpose of this study was to assess the rate and type of infections in gynecological cancer patients. We also performed an economic analysis to provide an overview of costs related to healthcare associated infections.MethodsWe retrospectively collected data from culture samples at the site of infection from patients undergoing surgery or chemotherapy, admitted to the Gynecologic Oncology Unit, Fondazione Policlinico Agostino Gemelli IRCCS, from January 2017 to December 2018. We performed univariate and multivariate analyses to calculate potential risk factors for prolonged length of hospitalization. The average cost per patient was calculated, including the cost of hospital stay, operating room, medications, and diagnostic and invasive procedures.ResultsAmong 5682 patients, 322 (5.6%) gynecological cancer patients with healthcare associated infections were identified. A total of 249 patients (77.3%) had undergone surgery in the previous 30 days and 73 (22.7%) patients were receiving chemotherapy. In the whole population, the most common healthcare associated infections were urinary infections (58%) and surgical wound infections (42.1%). In addition, 14.5% of patients had central venous catheter infections and 21.7% had blood stream infections. Median length of stay was 20 days (range 1–100). Among surgical patients, advanced age (odds ratio (OR) 1.233, 95% confidence interval (CI) 1.001 to 1.519, p=0.049), bowel resection (OR 2.659, 95% CI 1.493 to 4.735, p=0.001), surgical site infection (OR 10.447, 95% CI 1.143 to 95.5, p=0.038), and central venous catheter infection (OR 9.856, 95% CI 1.139 to 85.319, p=0.038) were independently associated with an increased risk of prolonged hospital stay (>20 days). The overall direct cost of healthcare associated infections was $6 273 852 per year.ConclusionsThe infection rate in our population was 5.6%. The most common healthcare associated infections were urinary and surgical wound infections. Among surgical patients, advanced age, bowel resection, surgical site, and central venous catheter infection were associated with an increased length of hospitalization. Healthcare associated infections cause an increase in the length of stay after surgery and hospital costs.

While echinocandins remain the preferred antifungal therapy for candidemia, bloodstream infections caused by C. auris , C. glabrata , or, at a lesser extent, C. parapsilosis may be difficult to treat with these antifungal agents. This is in view of the high propensity of the above-mentioned species to develop antifungal resistance or tolerance during treatment.

The growing phenomenon of antibiotic resistance and the presence of limited data concerning the pediatric area prompted us to focus on Staphylococcus aureus infection in this study, its antibiotic resistance profile, and the therapeutic management of affected children. We conducted a retrospective study by collecting clinical data on infants and children with antibiogram-associated S. aureus infection. We enrolled 1210 patients with a mean age of 0.9 years. We analyzed the resistance patterns and found 61.5% resistance to oxacillin, 58.4% resistance to cephalosporins, 41.6% resistance to aminoglycosides, and 38.3% resistance to fluoroquinolones. Importantly, we found no resistance to glycopeptides, a key antibiotic for MRSA infections whose resistance is increasing worldwide. We also found that the main risk factors associated with antibiotic resistance are being aged between 0 and 28 days, the presence of devices, and comorbidities. Antibiotic resistance is a growing concern; knowing the resistance profiles makes it possible to better target the therapy; however, it is important to use antibiotics according to the principles of antibiotic stewardship to limit their spread.

Objectives To explore the real-life performance of meropenem/vaborbactam for treating serious KPC-producing Klebsiella pneumoniae infections, including those resistant to ceftazidime/avibactam. Methods A retrospective observational cohort study was conducted in 12 Italian hospitals. Enrolled patients had K. pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-Kp) infections (59.5% of which were ceftazidime/avibactam resistant). Patients who received >= 72 h of meropenem/vaborbactam therapy (with or without other antimicrobials) in a compassionate-use setting were included. Results The 37 infections (all hospital-acquired) were mainly bacteraemic (BSIs, n = 23) or lower respiratory tract infections (LRTIs, n = 10). Clinical cure was achieved in 28 (75.6%) cases and microbiologically confirmed in all 25 with follow-up cultures. Three (10.7%) of the 28 clinical cures (all BSIs, 2/3 microbiologically confirmed) were followed by in-hospital recurrences after meropenem/vaborbactam was discontinued (median interval: 18 days). All three recurrences were susceptible to meropenem/vaborbactam and successfully managed with meropenem/vaborbactam combined with colistin or fosfomycin. Nine patients (24.3%) (all with BSIs or LRTIs) died in hospital with persistent signs of infection. Most were aged over 60 years, with high comorbidity burdens and INCREMENT scores >= 8. Only one had received meropenem/vaborbactam monotherapy. Six began meropenem/vaborbactam therapy >48 h after infection onset. Outcomes were unrelated to the isolate's ceftazidime/avibactam susceptibility status. The single adverse event observed consisted of severe leukopenia with thrombocytopenia. Conclusions With the well-known limitations of real-life retrospective studies, our results support previous findings indicating that meropenem/vaborbactam therapy will be a safe, effective tool for managing serious KPC-Kp infections, including the increasing proportion displaying resistance to ceftazidime/avibactam.

This study aimed to assess the comparability of in vitro susceptibility testing methods to ceftazidime-avibactam (CZA) and ceftolozane-tazobactam (C/T). Meropenem-resistant and/or carbapenemase-producing clinical isolates of Enterobacterales (Enterobacteriaceae) and Pseudomonas aeruginosa were tested by both bioMérieux ETEST and VITEK-2 AST-N397 card and compared with a Micronaut AST-system broth microdilution (BMD) method. CZA and C/T MICs were interpreted using EUCAST breakpoints. Of the 153 Enterobacteriaceae isolates, 55.6% and 0.0% (VITEK 2) and 56.9% and 0.0% (ETEST and BMD) were susceptible to CZA and C/T, respectively. Of 52 P. aeruginosa isolates, 50.0% and 40.4% (VITEK 2, ETEST, and BMD) were susceptible to CZA and C/T, respectively. The essential agreement (EA) was 96.1% (197/205; VITEK 2 versus BMD) and 95.6% (196/205; ETEST versus BMD) for CZA testing, whereas EA was 98.0% (201/205; VITEK 2 versus BMD) and 96.6% (198/205; ETEST versus BMD) for C/T testing. The categorical agreement (CA) was 98.0% (201/205; VITEK 2 versus BMD) and 100% (ETEST versus BMD) for CZA testing, whereas CA was 100% (VITEK 2 versus BMD) and 100% (ETEST versus BMD) for C/T testing. Categorical errors regarded four Enterobacteriaceae isolates. VITEK 2 and ETEST yielded equivalent CZA and C/T susceptibility testing results, compared to the BMD method, in such a clinical context.

BACKGROUND AND AIM:Antibiotic resistance represents one of the major public health issues, due to the potential future ineffectiveness of available antibiotics. However, epidemiological studies on E. coli antibiotic resistance patterns in the pediatric population are limited.METHODS:We conducted a retrospective analysis on children younger than 18 years of age admitted to the Department of Pediatrics from April 2016 to April 2018 with E. coli isolation on biological materials.RESULTS:205 subjects were included in the study (mean age 1.6 years). We found an overall low rate of resistance of E. coli isolates to Amoxicil-lin/Clavulanate (20%), Cephalosporins (6.3%) and Aminoglycosides (6.3%), while no isolates were resistant to Carbapenems. Presence of invasive devices and intensive care admissions were as-sociated with resistance to Cephalosporines (P < 0.001; OR 9.21, 95% CI 2.7 - 31.39) and Amino-glycosides (P < 0.004; OR 5.42, 95% CI 1.71 - 17.15), while no factors associated with resistance to the other antibiotics were found.CONCLUSIONS:Aminoglycosides and Cephalosporins were frequently used as empiric therapy, whereas targeted therapies aimed at sparing these classes of antibiotics once antibiograms were available have not always been established. These data may inform local antimicrobial stewardship and guide the development of programs aiming at a better use of antibiotics.

IntroductionUreaplasma (U.) and Mycoplasma (M.) species have been related to pregnancy complications (including preterm birth) and worse neonatal outcomes. The aim of our work is to evaluate neurodevelopmental outcomes in preterm infants born to mothers with Ureaplasma/Mycoplasma colonization during pregnancy.MethodsPreterm infants with gestational age (GA) of ≤ 30 weeks were included in a retrospective follow-up study. To evaluate the effects of maternal vaginal colonization, we divided preterm infants into two groups: exposed and unexposed infants. All infants were assessed at 24 ± 3 months of age using Griffith’s Mental Developmental Scales (GMDS).ResultsAmong 254 preterm infants, only 32 infants (12.6%) were exposed to U. /M. colonization during pregnancy. Exposed infants and unexposed ones had a similar Griffith′s Developmental Quotient (106 ± 27.2 vs. 108.9 ± 19.5, respectively), without significant differences (p = 0.46). However, exposed infants had a significantly poorer outcome than their unexposed peers in terms of locomotor abilities (100.7 ± 28.3 exposed vs. 111.5 ± 26.1 unexposed, p = 0.03).ConclusionFor visual and hearing impairment, exposed and unexposed infants had similar incidences of cognitive and motor impairment. However, exposed infants had significantly lower locomotor scores than unexposed peers.

Objective The study aimed to report a novel coronavirus disease 2019 (COVID-19)-associated multisystem inflammatory syndrome in children (MIS-C) in a neonate found to have an atypical diffuse thickening in coronary artery walls whose diagnosis required a multi-imaging approach. Study Design A neonate presented at birth with multiple organ involvement and coronary artery anomalies. A diagnosis of MIS-C associated with COVID-19 was supported by maternal severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection during pregnancy, and by the presence of both immunoglobulin (Ig)-G against SARS-CoV-2 and spike-specific memory B-cells response in the neonatal blood. Other plausible causes of the multiple organ involvement were excluded. Result At admission, a severe coronary artery dilatation was identified on echocardiography, supporting the diagnosis of the MIS-C Kawasaki-like disease; however, coronary artery internal diameters were found to be normal using cardiac computed tomography angiography. At discharge, comparing the two imaging techniques each other, the correct diagnosis resulted to be an abnormal thickening in coronary arterial walls. These findings suggest that the inflammatory process affecting the coronary arterial wall in MIS-C could result not only in typical coronary artery lesions such as dilatation of the lumen or aneurysms development but also in abnormal thickening of the coronary artery wall. Conclusion Our case provides an alert for pediatric cardiologists about the complexity to assess coronary artery involvement in MIS-C and raises the question that whether an abnormal vascular remodeling, with normal inner diameters, is to be considered like coronary artery dilatation for risk stratification.

Sir, Recently, EUCAST developed a rapid antimicrobial susceptibility testing (RAST) method for direct use on positive blood culture (BC) samples, which relies on EUCAST standard disc diffusion (DD) methodology and allows inhibition zone reading within 4–8 h of BC positivity. Shortly after the first description of the method in 20181 and before its publication at the beginning of 2020,2 we concertedly began to familiarize ourselves with RAST in the clinical microbiology laboratories of three large hospitals from Northern or Central Italy. Although RAST is applicable to most important bloodstream infection (BSI) pathogens (including Gram-negative and Gram-positive species) against a definite (albeit clinically comprehensive) number of antimicrobial agents,2 we focused on Escherichia coli and Klebsiella pneumoniae, because both species represent the bulk of BSI aetiologies (with highly diversified antimicrobial resistance mechanisms) encountered in clinical settings. We herein report on EUCAST RAST results for BCs consecutively collected between...

Introduction/Background* The purpose of this paper is to analyze data related to infections of patients suffering from gynecological malignancies, particularly after surgical procedures. Furthermore, we performed an economic analysis to provide an overview of HAIs-related costs. Methodology We retrospectively collected data of the culture samples, collected in the microbiology laboratory, of patients recovered in the Oncological Gynecology Department of the Fondazione Policlinico "Agostino Gemelli" IRCCS, from 1st January 2017 to 31th December 2018. The data concerned both ordinary and emergency hospitalizations. For each patient, we collected data on germs responsible of infection and on the site of the infection Result(s)* 323 gynecological cancer patients with HAIs were identified. 249 patients had undergone surgery in the previous 30 days and 74 were on chemotherapy treatment or in the follow-up phase. The most common HAIs were urinary infections (57.9%), surgical wound infections were present in 42.1%. 14.5% had central venous catheter infection and 21.7% of patients blood stream infections. The median length of stay for patients with post-operative infection or with an infective event during chemotherapy was 25 days. After discharge, 22% of patients were readmitted to the hospital due to new infection and were hospitalized for 22 days on average. The total cost that our hospital paid for the treatment of infected patients was 4.598391 $. Conclusion* Bowel resection appears to be the procedure most associated with the development of HAIs. An important method of reducing the risk of infections is careful screening of patients and risk factors before admission.

Background. A growing body of observational evidence supports the value of ceftazidime-avibactam (CAZ-AVI) in managing infections caused by carbapenem-resistant Enterobacteriaceae. Methods. We retrospectively analyzed observational data on use and outcomes of CAZ-AVI therapy for infections caused by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) strains. Multivariate regression analysis was used to identify variables independently associated with 30-day mortality. Results were adjusted for propensity score for receipt of CAZ-AVI combination regimens versus CAZ-AVI monotherapy. Results. The cohort comprised 577 adults with bloodstream infections (n = 391) or nonbacteremic infections involving mainly the urinary tract, lower respiratory tract, and intra-abdominal structures. All received treatment with CAZ-AVI alone (n = 165) or with >= 1 other active antimicrobials (n = 412). The all-cause mortality rate 30 days after infection onset was 25% (146/577). There was no significant difference in mortality between patients managed with CAZ-AVI alone and those treated with combination regimens (26.1% vs 25.0%, P = .79). In multivariate analysis, mortality was positively associated with presence at infection onset of septic shock (P = .002), neutropenia (P < .001), or an INCREMENT score >= 8 (P = .01); with lower respiratory tract infection (LRTI) (P = .04); and with CAZ-AVI dose adjustment for renal function (P = .01). Mortality was negatively associated with CAZ-AVI administration by prolonged infusion (P = .006). All associations remained significant after propensity score adjustment. Conclusions. CAZ-AVI is an important option for treating serious KPC-Kp infections, even when used alone. Further study is needed to explore the drug's seemingly more limited efficacy in LRTIs and potential survival benefits of prolonging CAZ-AVI infusions to >= 3 hours.

Our prospective study assesses the role of detailed lung ultrasound (LUS) features to discriminate the etiological diagnosis of acute lower respiratory tract infection (ALRTI) in children. We analyzed patients aged from 1 month to 17 years admitted between March 2018 and April 2020 who were hospitalized for ALRTI. For all patients, history, clinical parameters, microbiological data, and lung ultrasound data were collected. Patients were stratified into three main groups (“bacterial”, “viral”, “atypical”) according to the presumed microbial etiology and LUS findings evaluated according to the etiological group. Nasopharyngeal swabs were obtained from all patients. A qualitative diagnostic test developed by Nurex S.r.l. was used for identification of bacterial and fungal DNA in respiratory samples. The Seegene Allplex™ Respiratory assays were used for the molecular diagnosis of viral respiratory pathogens. In addition, bacterial culture of blood and respiratory samples were performed, when indicated. A total of 186 children with suspected ALRTI (44% female) with an average age of 6 were enrolled in the study. We found that some ultrasound findings as size, number and distribution of consolidations, the position and motion of air bronchograms, pleural effusions and distribution of vertical artifacts significantly differ (p < 0.05) in children with bacterial, viral and atypical ALRTI. Our study provides a detailed analysis of LUS features able to predict the ALRTI ethology in children. These findings may help the physicians to better manage a child with ALRTI and to offer personalized approach, from diagnosis to treatment and follow-up.