The sources of antimicrobial peptides against Gram-positives and Gramnegatives: our research experience.

Antibiotic resistance of Gram-positive and Gramnegative bacteria is becoming increasingly prevalent. For this reason, the search for new molecules that can overcome current resistance and also recover antibiotics that are no longer effective is becoming increasingly urgent. Our research group at the 'Polytechnic University of Marche' managed to study the effectiveness of certain antimicrobial peptides (AMPs). We decided to review our experience with AMPs by classifying them according to their origin and evaluating their effect on Gram-negative and Gram-positive bacteria. AMPs can derive from mammals, amphibians, microorganisms, and insects. In conclusion, our research experience shows that the richest source of AMPs are amphibians. However, the studies done are mainly in vitro or in animal models, requiring further human studies to assess the efficacy and safety of these molecules. AMPs may be a new therapeutic option for infections sustained by multi-resistant micro-organisms and for overcoming the mechanisms of resistance to antibiotics currently used. In particular, combining AMPs with antibiotics, including those with limited antimicrobial activity due to antimicrobial resistance, has often shown a synergistic effect, increasing or restoring their efficacy. The possibility of using manageable and relatively safe antibiotics again is crucial, considering the widespread increase in bacterial resistance in hospitals and the community. Despite a plethora of research on AMPs and their application as potential treatment on infectious diseases, this area needs further exploration. There is evidence that the characteristics of AMPs can seriously improve through structural chemical modifications and different delivery systems to become alternatives drugs to conventional antibiotics. The aim is to provide an overview of the possible sources from which AMPs are extracted, evaluating their action exclusively on Gram-positive and negative bacteria. This is to determine, based on our experience, which might be the most promising sources of AMPs for future research as well.

Candida auris: the new fungal threat.

Candida auris is an emergent fungal pathogen of particular concern. Since its first identification in Japan in 2009, it rapidly spread all over the world, including Italy. The main concern related to the diffusion of this fungus is its antifungal resistance. It is speculated that about 90% of isolates are resistant to fluconazole, 30% to amphotericin B and 5% to echinocandins; furthermore, some cases of pan-antifungal resistance have been described. Critically ill patients are particularly at risk of being colonized by this yeast and person-to-person transmission may generate hospital outbreaks. In fact, C. auris can survive on inanimate surfaces for a long time and commonly used disinfectants are not effective. Additionally, devices such as central venous catheters (CVCs) or urinary catheters are particularly at risk of being colonized, representing a possible source for the development of bloodstream infections caused by C. auris, which carries a high mortality rate. Given its capability to spread in the hospital setting and the limited therapeutic options it is of outmost importance to promptly identify C. auris. However, commonly used biochemical tests frequently misidentify C. auris as other Candida species; currently the best identification techniques are MALDI-TOF and molecular methods, such as PCR of the ITS and D1/D2 regions of the 28s ribosomal DNA. Whole genome sequencing remains the gold standard for the phylogenetic investigation of outbreaks. The majority of cases of colonization by C. albicans will not cause bloodstream infections and contact precautions and surveillance of contacts will be sufficient. When invasive fungal infections occur, echinocandins still represent the first therapeutic choice. A combination therapy or the use of novel antifungals (such as ibrexafungerp or fosmanogepix) would be required for echinocandin resistant strains. In conclusion, C. auris represents a growing threat because of its antifungal resistance characteristics, its difficult identification and its easy spread from person to person. The aim of this mini-review is to summarize the main aspects concerning this pathogen.

The Clinical Characteristics of Bloodstream Infections Due to Candida spp. in Patients Hospitalized in Intensive Care Units during the SARS-CoV-2 Pandemic: The Results of a Multicenter Study.

Candidemia is a serious health threat. Whether this infection has a greater incidence and a higher mortality rate in patients with COVID-19 is still debated. In this multicenter, retrospective, observational study, we aimed to identify the clinical characteristics associated with the 30-day mortality in critically ill patients with candidemia and to define the differences in candidemic patients with and without COVID-19. Over a three-year period (2019-2021), we identified 53 critically ill patients with candidemia, 18 of whom (34%) had COVID-19 and were hospitalized in four ICUs. The most frequent comorbidities were cardiovascular (42%), neurological (17%), chronic pulmonary diseases, chronic kidney failure, and solid tumors (13% each). A significantly higher proportion of COVID-19 patients had pneumonia, ARDS, septic shock, and were undergoing an ECMO procedure. On the contrary, non-COVID-19 patients had undergone previous surgeries and had used TPN more frequently. The mortality rate in the overall population was 43%: 39% and 46% in the COVID-19 and non-COVID-19 patients, respectively. The independent risk factors associated with a higher mortality were CVVH (HR 29.08 [CI 95% 3.37-250]) and a Charlson's score of > 3 (HR 9.346 [CI 95% 1.054-82.861]). In conclusion, we demonstrated that candidemia still has a high mortality rate in patients admitted to ICUs, irrespective of infection due to SARS-CoV-2.

Antifungal Combinations against Candida Species: From Bench to Bedside.

Candida spp. is the major causative agent of fungal infections in hospitalized patients and the fourth most common cause of nosocomial bloodstream infection (BSI). The availability of standardized methods for testing the in vitro activity of antifungals along with the expanding of antifungal armamentarium, the rising of drug-resistance and the persistence of a high mortality rate in systemic candidiasis have led to an increased interest in combination therapy. Therefore, we aimed to review the scientific literature concerning the antifungal combinations against Candida. A literature search performed in PubMed yielded 92 studies published from 2000 to 2021: 29 articles referring to in vitro studies, six articles referring to either in vitro and in vivo (i.e., animal models) studies and 57 clinical articles. Pre-clinical studies involved 735 isolates of Candida species and 12 unique types of antifungal combination approaches including azoles plus echinocandins (19%), polyenes plus echinocandins (16%), polyenes plus azoles (13%), polyenes plus 5-flucytosine ([5-FC], 13%), azoles plus 5-FC (11%) and other types of combinations (28%). Results varied greatly, often being species-, drug- and methodology-dependent. Some combinatorial regimens exerted a synergistic effect against difficult-to-treat Candida species (i.e., azoles plus echinocandins; polyenes plus 5-FC) or they were more effective than monotherapy in prevent or reducing biofilm formation and in speeding the clearance of infected tissues (i.e., polyenes plus echinocandins). In 283 patients with documented Candida infections (>90% systemic candidiasis/BSI), an antifungal combination approach could be evaluated. Combinations included: azoles plus echinocandins (36%), 5-FC-combination therapies (24%), polyenes plus azoles (18%), polyenes plus echinocandins (16%) and other types of combination therapy (6%). Case reports describing combination therapies yielded favorable response in most cases, including difficult-to-treat fungal infections (i.e., endocarditis, osteoarticular infections, CNS infections) or difficult-to-treat fungal pathogens. The only randomized trial comparing amphotericin-B deoxycholate (AMB) plus FLU vs. AMB alone for treatment of BSI in nonneutropenic patients showed that the combination trended toward improved success and more-rapid clearance from the bloodstream. In summary, antifungal combinations against Candida have produced great interest in the past two decades. To establish whether this approach can become a reliable treatment option, additional in vitro and clinical data are warranted.

In Vitro Activity of Novel Lipopeptides against Triazole-Resistant Aspergillus fumigatus.

Aspergillosis, which is mainly sustained by Aspergillus fumigatus, includes a broad spectrum of diseases. They are usually severe in patients with co-morbidities. The first-line therapy includes triazoles, for which an increasing incidence of drug resistance has been lately described. As a consequence of this, the need for new and alternative antifungal molecules is absolutely necessary. As peptides represent promising antimicrobial molecules, two lipopeptides (C14-NleRR-NH2, C14-WRR-NH2) were tested to assess the antifungal activity against azole-resistant A. fumigatus. Antifungal activity was evaluated by determination of minimum inhibitory concentrations (MICs), time-kill curves, XTT assay, optical microscopy, and checkerboard combination with isavuconazole. Both lipopeptides showed antifungal activity, with MICs ranging from 8 mg/L to 16 mg/L, and a dose-dependent effect was confirmed by both time-kill curves and XTT assays. Microscopy showed that hyphae growth was hampered at concentrations equal to or higher than MICs. The rising antifungal resistance highlights the usefulness of novel compounds to treat severe fungal infections. Although further studies assessing the activity of lipopeptides are necessary, these molecules could be effective antifungal alternatives that overcome the current resistances.

Ceftazidime-Avibactam for the Treatment of Multidrug-Resistant Pathogens: A Retrospective, Single Center Study.

Background: Ceftazidime/avibactam is a new cephalosporin/beta-lactamase inhibitor combination approved in 2015 by the FDA for the treatment of complicated intra-abdominal and urinary tract infection, hospital-acquired pneumoniae and Gram-negative infections with limited treatment options. Methods: In this retrospective study, we evaluate the efficacy of ceftazidime/avibactam treatment in 81 patients with Gram-negative infection treated in our center from January 2018 to December 2019. The outcome evaluated was 30-days survival or relapse of infection after the first positive blood culture. Results: the majority of patients were 56 male (69%), with median age of 67. Charlson's Comorbidity Index was >3 in 58 patients. In total, 46% of the patients were admitted into the medical unit, 41% in the ICU, and 14% in the surgical ward. Of the patients, 78% had nosocomial infections, and 22% had healthcare-related infections. The clinical failure rate was 35%: 13 patients died within 30 days from the onset of infection. The outcome was influenced by the clinical condition of the patients: solid organ transplantation (p = 0.003) emerged as an independent predictor of mortality; non-survival patients most frequently had pneumonia (p = 0.009) or mechanical ventilation (p = 0.049). Conclusion: Ceftazidime−avibactam showed high efficacy in infections caused by MDR Gram-negative pathogens with limited therapeutic options.

Candidemia in Internal Medicine: Facing the New Challenge.

Candidemia is an alarming problem in critically ill patients including those admitted in Internal Medicine Wards (IMWs). Here, we analyzed all cases of candidemia in adult patients hospitalized over nine years (2010-2018) in IMWs of a 980-bedded University Hospital of Ancona, Italy. During the study period, 218/505 (43%) episodes of candidemia occurred in IMWs patients. The cumulative incidence was 2.5/1000 hospital admission and increased significantly over time (p = 0.013). Patients were predominantly male, with a median age of 68 years. Cardiovascular diseases and solid tumors were the most frequent comorbidities. Candida albicans accounted for 51% of the cases, followed by C. parapsilosis (25%), C. tropicalis (9%) and C. glabrata (7%). Thirty-day mortality was 28% and did not increased significantly over time. By multivariate logistic regression analysis, the presence of neutropenia (OR 7.247 [CI95% 1,368-38,400; p = 0.020]), pneumonia (OR 2.323 [CI95% 1,105-4,884; p = 0.026]), and being infected with C. albicans (OR 2.642 [95% CI 1,223-5,708; p = 0.013) emerged as independent predictors of mortality. The type of antifungal therapy did not influence the outcome. Overall, these data indicate that patients admitted to IMWs are increasingly at higher risk of developing candidemia. Mortality rate remains high and significantly associated with both microbiologic- and host-related factors.

Use of Dalbavancin in Skin, Bone and Joint Infections: A Real-Life Experience in an Italian Center.

Dalbavancin is a lipoglycopeptide approved for the treatment of acute bacterial skin and skin structure infections (ABSSSI). The aim of the study was to evaluate the efficacy and safety in all patients who received at least one administration of dalbavancin. METHODS: We carried out a retrospective study of the use of dalbavancin in 55 patients at the Azienda Ospedaliera Ospedali Riuniti Umberto I (Ancona, Italy) from February 2017 to May 2020 and compared "on label" and "off label" use of dalbavancin in ABSSSI and non-ABSSSI. RESULTS: A total of 55 patients were included in the study. The median age was 61 years; 51% had ABSSSI; 24% had prosthetic joint infections, and 14% had osteomyelitis. A total of 53% received a single 1500 mg infusion of dalbavancin, and 18% received a second dose 14 days later; 24% of patients received further doses at 14-day intervals. In 91% of cases, patients achieved clinical objectives with dalbavancin: 96% of patients with ABSSSI and 69% of those with prosthetic joint infections. CONCLUSIONS: Dalbavancin was shown to have an excellent tolerability profile and to be a highly successful therapeutic approach even in those cases treated "off-label".

Bloodstream infections in the COVID-19 era: results from an Italian multi-centre study.

BACKGROUND: Correlation between coronavirus disease 2019 (COVID-19) and superinfections has been investigated, but remains to be fully assessed. This multi-centre study reports the impact of the pandemic on bloodstream infections (BSIs). METHODS: This study included all patients with BSIs admitted to four Italian hospitals between 1 January and 30 June 2020. Clinical, demographic and microbiologic data were compared with data for patients hospitalized during the same period in 2019. RESULTS: Among 26,012 patients admitted between 1 January and 30 June 2020, 1182 had COVID-19. Among the patients with COVID-19, 107 BSIs were observed, with an incidence rate of 8.19 episodes per 1000 patient-days. The incidence of BSI was significantly higher in these patients compared with patients without COVID-19 (2.72/1000 patient-days) and patients admitted in 2019 (2.76/1000 patient-days). In comparison with patients without COVID-19, BSI onset in patients with COVID-19 was delayed during the course of hospitalization (16.0 vs 5 days, respectively). Thirty-day mortality among patients with COVID-19 was 40.2%, which was significantly higher compared with patients without COVID-19 (23.7%). BSIs in patients with COVID-19 were frequently caused by multi-drug-resistant pathogens, which were often centre-dependent. CONCLUSIONS: BSIs are a common secondary infection in patients with COVID-19, characterized by increased risk during hospitalization and potentially burdened with high mortality.

Integrated strategies for allogeneic blood saving in major elective surgery.

BACKGROUND: Large use of allogeneic red blood cell concentrates (RBCc), albeit necessary in major surgery, may influence patients' outcome. DESIGN AND METHODS: We introduced an integrated strategy including patients' evaluation and supplementation associated with autologous blood collection and saving to support major elective surgery at our hospital since 2008. After 2 years of stabilization of this approach, we analyzed the results obtained in 2010 in terms of allogeneic blood usage and reduction of transfusion of stored RBCc. RESULTS: Analyzing 2010 results we found that usage of total autologous RBCc units was increased by 2.2 folds, of "not stored" autologous RBCc units by 2.4 folds and of allogeneic RBCc unit transfusion reduced by 65%. The significant reduction in the number of transfused allogeneic RBCc units associated with the use of "fresher" blood could prevent patients' complications due to immunomodulation and biologic/metabolic disregulation.

The incidence of hip, forearm, humeral, ankle, and vertebral fragility fractures in Italy: results from a 3-year multicenter study.

INTRODUCTION: We aimed to assess the incidence and hospitalization rate of hip and "minor" fragility fractures in the Italian population. METHODS: We carried out a 3-year survey at 10 major Italian emergency departments to evaluate the hospitalization rate of hip, forearm, humeral, ankle, and vertebral fragility fractures in people 45 years or older between 2004 and 2006, both men and women. These data were compared with those recorded in the national hospitalizations database (SDO) to assess the overall incidence of fragility fractures occurring at hip and other sites, including also those events not resulting in hospital admissions. RESULTS: We observed 29,017 fractures across 3 years, with hospitalization rates of 93.0% for hip fractures, 36.3% for humeral fractures, 31.3% for ankle fractures, 22.6% for forearm/wrist fractures, and 27.6% for clinical vertebral fractures. According to the analyses performed with the Italian hospitalization database in year 2006, we estimated an annual incidence of 87,000 hip, 48,000 humeral, 36,000 ankle, 85,000 wrist, and 155,000 vertebral fragility fractures in people aged 45 years or older (thus resulting in almost 410,000 new fractures per year). Clinical vertebral fractures were recorded in 47,000 events per year. CONCLUSIONS: The burden of fragility fractures in the Italian population is very high and calls for effective preventive strategies.