Antibiotic Treatment of Carbapenem-Resistant Acinetobacter baumannii Infections in View of the Newly Developed ß-Lactams: A Narrative Review of the Existing Evidence.

It is estimated that antimicrobial resistance (AMR) is responsible for nearly 5 million human deaths worldwide each year and will reach 10 million by 2050. Carbapenem-resistant Acinetobacter baumannii (CRAB) infections represent the fourth-leading cause of death attributable to antimicrobial resistance globally, but a standardized therapy is still lacking. Among the antibiotics under consideration, Sulbactam/durlobactam seems to be the best candidate to replace current back-bone agents. Cefiderocol could play a pivotal role within combination therapy regimens. Due to toxicity and the pharmacokinetics/pharmacodynamics (PK/PD) limitations, colistin (or polymyxin B) should be used as an alternative agent (when no other options are available). Tigecycline (or minocycline) and fosfomycin could represent suitable partners for both NBLs. Randomized clinical trials (RCTs) are needed to better evaluate the role of NBLs in CRAB infection treatment and to compare the efficacy of tigecycline and fosfomycin as partner antibiotics. Synergism should be tested between NBLs and "old" drugs (rifampicin and trimethoprim/sulfamethoxazole). Huge efforts should be made to accelerate pre-clinical and clinical studies on safer polymyxin candidates with improved lung activity, as well as on the iv rifabutin formulation. In this narrative review, we focused the antibiotic treatment of CRAB infections in view of newly developed ß-lactam agents (NBLs).

Intravenous fosfomycin for treatment of severe infections caused by carbapenem-resistant Acinetobacter baumannii: A multi-centre clinical experience.

BACKGROUND: Severe infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) have been reported increasingly over the past few years. Many in-vivo and in-vitro studies have suggested a possible role of intravenous fosfomycin for the treatment of CRAB infections. METHODS: This multi-centre, retrospective study included patients treated with intravenous fosfomycin for severe infections caused by CRAB admitted consecutively to four hospitals in Italy from December 2017 to December 2022. The primary goal of the study was to evaluate the risk factors associated with 30-day mortality in the study population. A propensity score matched analysis was added to the model. RESULTS: One hundred and two patients with severe infections caused by CRAB treated with an intravenous fosfomycin-containing regimen were enrolled in this study. Ventilator-associated pneumonia (VAP) was diagnosed in 59% of patients, primary bacteraemia in 22% of patients, and central-venous-catheter-related infection in 16% of patients. All patients were treated with a regimen containing intravenous fosfomycin, mainly in combination with cefiderocol (n=54), colistin (n=48) or ampicillin/sulbactam (n=18). Forty-eight (47%) patients died within 30 days. Fifty-eight (57%) patients experienced clinical therapeutic failure. Cox regression analysis showed that diabetes, primary bacteraemia and a colistin-containing regimen were independently associated with 30-day mortality, whereas adequate source control of infection, early 24-h active in-vitro therapy, and a cefiderocol-containing regimen were associated with survival. A colistin-based regimen, A. baumannii colonization and primary bacteraemia were independently associated with clinical failure. Conversely, adequate source control of infection, a cefiderocol-containing regimen, and early 24-h active in-vitro therapy were associated with clinical success. CONCLUSIONS: Different antibiotic regimens containing fosfomycin in combination can be used for treatment of severe infections caused by CRAB.

Persistence of SARS-CoV-2 infection and viral intra- and inter-host evolution in COVID-19 hospitalized patients.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) persistence in COVID-19 patients could play a key role in the emergence of variants of concern. The rapid intra-host evolution of SARS-CoV-2 may result in an increased transmissibility, immune and therapeutic escape which could be a direct consequence of COVID-19 epidemic currents. In this context, a longitudinal retrospective study on eight consecutive COVID-19 patients with persistent SARS-CoV-2 infection, from January 2022 to March 2023, was conducted. To characterize the intra- and inter-host viral evolution, whole genome sequencing and phylogenetic analysis were performed on nasopharyngeal samples collected at different time points. Phylogenetic reconstruction revealed an accelerated SARS-CoV-2 intra-host evolution and emergence of antigenically divergent variants. The Bayesian inference and principal coordinate analysis analysis showed a host-based genomic structuring among antigenically divergent variants, that might reflect the positive effect of containment practices, within the critical hospital area. All longitudinal antigenically divergent isolates shared a wide range of amino acidic (aa) changes, particularly in the Spike (S) glycoprotein, that increased viral transmissibility (K417N, S477N, N501Y and Q498R), enhanced infectivity (R346T, S373P, R408S, T478K, Q498R, Y505H, D614G, H655Y, N679K and P681H), caused host immune escape (S371L, S375F, T376A, K417N, and K444T/R) and displayed partial or complete resistance to treatments (G339D, R346K/T, S371F/L, S375F, T376A, D405N, N440K, G446S, N460K, E484A, F486V, Q493R, G496S and Q498R). These results suggest that multiple novel variants which emerge in the patient during persistent infection, might spread to another individual and continue to evolve. A pro-active genomic surveillance of persistent SARS-CoV-2 infected patients is recommended to identify genetically divergent lineages before their diffusion.

From Spores to Solutions: A Comprehensive Narrative Review on Mucormycosis.

Mucormycosis is an infrequent but fatal illness that mainly affects patients with uncontrolled diabetes mellitus, diabetic ketoacidosis, solid and hematologic neoplasms, organ transplantation, chronic steroid intake, prolonged neutropenia, iron overload states, neonatal prematurity, severe malnutrition, and HIV. Many cases were reported across the world recently following the COVID-19 pandemic. Recent research has led to a better understanding of the pathogenesis of the disease, and global guidelines are now available for managing this serious infection. Herein, we comprehensively review the etiological agents, pathogenesis, clinical presentations, diagnosis, and management of mucormycosis.