Characterization of Listeria monocytogenes Strains Isolated in Palermo (Sicily and Italy) during the Years 2018-2020 from Severe Cases of Listeriosis.

Listeria monocytogenes (LM), the etiological agent of listeriosis, can cause foodborne zoonosis. In this study, we characterized 23 strains that caused human severe listeriosis in Palermo (Sicily, Italy) during the period of 2018-2020. In addition, we assessed the phenotypic susceptibility of clinical isolates to antibiotics in accordance with EUCAST guidelines. The serogroup was determined through the use of PCR, while MLST and MVLST were identified through the sequencing of housekeeping genes. Finally, susceptibility to antibiotics was assessed by means of the Phoenix automatic system. Patients hospitalized with listeriosis were predominantly males (56% vs. 44% of females). The cases not associated with pregnancy included patients >65 years of age (60%), two of whom were affected by cancer, while cases associated with pregnancy included two pregnant women and three preterm infants. The data collected showed that the main pathologies shown by patients were meningitis (60.9%) and bacteremia (39.1%). The LM strains were isolated from the blood (52%), cerebrospinal fluid (26%), cerebrospinal fluid + blood (13%), blood + a nasal swab (4%), and ascitic fluid (4%). The predominant serogroup was IVb (96%), whereas only one strain belonged to serogroup IIa (4%). Among the strains with serotypes 4b, 4d, and 4e, ST2/VT21 (92%) and ST6/VT19 (4%) were determined, while only isolates with serotypes 1/2a and3a show ST155/VT45 (CC155). This study reveals the widespread circulation of a clinical strain (ST2/VT21) associated with suspected food contamination, demonstrating the importance of carrying out molecular epidemiological surveillance. Our clinical isolates were susceptible to the beta-lactams assayed, in agreement with the literature data.

Editorial: Special Issue: "Legionella pneumophila: A Microorganism with a Thousand Faces".

Legionella pneumophila is a microorganism that is able to contaminate the freshwater environment and, consequently, human-made water systems [...].

Multicomponent Antibiofilm Lipid Nanoparticles as Novel Platform to Ameliorate Resveratrol Properties: Preliminary Outcomes on Fibroblast Proliferation and Migration.

The well-being of skin and mucous membranes is fundamental for the homeostasis of the body and thus it is imperative to treat any lesion quickly and correctly. In this view, polyphenols might assist and enhance a successful wound healing process by reducing the inflammatory cascade and the production of free radicals. However, they suffer from disadvantageous physico-chemical properties, leading to restricted clinical use. In this work, a complex mixture of PEGylated lipid, Glyceryl monoester, 18-ß-Glycyrrhetinic Acid and Menthol was designed to entrap Resveratrol (RSV) as the active ingredient and further produce lipid nanoparticles (LNPs) by homogenization followed by high-frequency sonication. The nanosystem was properly characterized in terms of particle size (DLS, SEM), zeta potential, drug loading, antioxidant power (DPPH), release behaviour, cytocompatibility, wound healing and antibiofilm properties. The optimized lipid mixture was homogeneous, melted at 57-61 °C and encapsulated amorphous RSV (4.56 ± 0.04% w/w). The RSV-loaded LNPs were almost monodispersed (PDI: 0.267 ± 0.010), with nanometric size (162.86 ± 3.12 nm), scavenger properties and suitable DR% and LE% values (96.82 ± 1.34% and 95.17 ± 0.25%, respectively). The release studies were performed to simulate the wound conditions: 1-octanol to mimic the lipophilic domains of biological tissues (where the First Order kinetic was observed) and citrate buffer pH 5.5 according to the inflammatory wound exudate (where the Korsmeyer-Peppas kinetic was followed). The biological and microbiological evaluations highlighted fibroblast proliferation and migration effects as well as antibiofilm properties at extremely low doses (LNPs: 22 µg/mL, corresponding to RSV 5 µM). Thus, the proposed multicomponent LNPs could represent a valuable RSV delivery platform for wound healing purposes.

Multicentre Surveillance of Candida Species from Blood Cultures during the SARS-CoV-2 Pandemic in Southern Europe (CANCoVEU Project).

Introduction: Surveillance of Candida species isolates from blood cultures (BCs) in Europe is considered fragmented, unable to allow the definition of targets of antifungal stewardship recommendations especially during the SARS-CoV-2 pandemic. Methods: We performed a multicentric retrospective study including all consecutive BC Candida isolates from six Southern European tertiary hospitals (1st January 2020 to 31st December 2021). Etiology, antifungal susceptibility patterns, and clinical setting were analyzed and compared. Results: C. albicans was the dominant species (45.1%), while C. auris was undetected. Candida species positive BC events increased significantly in COVID-19 ICUs in 2021 but decreased in other ICUs. Resistance to azole increased significantly and remained very high in C. albicans (fluconazole from 0.7% to 4.5%, p = 0.03) and C. parapsilosis complex (fluconazole up to 24.5% and voriconazole up to 8.9%), respectively. Resistance to caspofungin was remarkable in C. tropicalis (10%) and C. krusei (20%), while resistance to at least one echinocandin increased in 2021, especially in C. parapsilosis complex (from 0.8% to 5.1%, p = 0.05). Although no significant differences were observed over the study period, fluconazole and echinocandin resistance increased in COVID-19 ICUs by up to 14% and 5.8%, respectively, but remained undetected in non-intensive COVID-19 wards. Conclusions: Antifungal stewardship activities aimed at monitoring resistance to echinocandin in C. tropicalis and C. krusei, and against the spread of fluconazole resistant C. parapsilosis complex isolates are highly desirable. In COVID-19 patients, antifungal resistance was mostly present when the illness had a critical course.

Multicenter study on the prevalence of colonization due to carbapenem-resistant Enterobacterales strains before and during the first year of COVID-19, Italy 2018-2020.

Background: Among multidrug-resistant (MDR) bacteria able to threaten human health, carbapenem-resistant Enterobacterales (CRE) have become a major public health threat globally. National and international guidelines point out the importance of active routine surveillance policies to prevent CRE transmission. Therefore, defining lines of intervention and strategies capable of containing and controlling the spread of CRE is considered determinant. CRE screening is one of the main actions to curb transmission and control outbreaks, outlining the presence and also the prevalence and types of carbapenemase enzymes circulating locally. Objective: The purpose of this study was to outline the epidemiology of CRE colonization in Italy, detecting CRE-colonized patients at admission and during hospitalization, before and during the first year of COVID-19. Materials and methods: A total of 11,063 patients admitted to seven different hospitals (Bologna, Catania, Florence, Genoa, Naples, Palermo, and Turin) in Intensive Care Units (ICU) and other wards (non-ICU) located in the North, Center, and South of Italy were enrolled and screened for CRE carriage at admission (T0) and during the first 3 weeks of hospitalization (T1-T3). The study spanned two periods, before (September 2018-Septemeber 2019, I observational period) and during the COVID-19 pandemic (October 2019-September 2020, II observational period). Results: Overall, the prevalence of CRE-colonized patients at admission in ICU or in other ward, ranged from 3.9 to 11.5%, while a percentage from 5.1 to 15.5% of patients acquired CRE during hospital stay. There were large differences between the I and II period of study according to the different geographical areas and enrolling centers. Overall, comparison of prevalence of CRE-positive patients showed a significant increased trend between I and II observational periods both in ICU and non-ICU wards, mostly in the Southern participating centers. KPC-producing Klebsiella pneumoniae was the most frequent CRE species-carbapenemase combination reported in this study. In particular, the presence of KPC-producing K. pneumoniae was reported in period I during hospitalization in all the CRE-positive patients enrolled in ICU in Turin (North Italy), while in period II at admission in all the CRE-positive patients enrolled in ICU in Catania and in 58.3% of non-ICU CRE-positive patients in Naples (both centers in South Italy). Conclusion: The prevalence of CRE in Italy highly increased during the COVID-19 pandemic, mostly in the Southern hospital centers. KPC-producing K. pneumoniae was the most frequent colonizing CRE species reported. The results of our study confirmed the crucial value of active surveillance as well as the importance of multicenter studies representing diverse geographical areas even in endemic countries. Differences in CRE colonization prevalence among centers suggest the need for diversified and center-specific interventions as well as for strengthening efforts in infection prevention and control practices and policies.

Four-Year Environmental Surveillance Program of Legionella spp. in One of Palermo's Largest Hospitals.

Legionella is a ubiquitous bacterium that lives in freshwater environments and colonizes human-made water systems. Legionella pneumophila is the most virulent species, and risk factors for Legionnaires' disease include increasing age, smoking, chronic diseases, and immunodeficiency. For this reason, it is very important to assess and monitor hospital water systems in order to prevent legionellosis. We have monitored a large hospital in Palermo for four years. To determine the presence of microorganisms, according to national guidelines, we used the culture method, which is considered the gold standard for Legionella detection. Sampling was divided into five macro-areas, and a total of 251 samples were collected during the period of investigation, 49% of which were Legionella spp.-positive and 51% were Legionella spp.-negative. Positive samples with L. pneumophila. sgr 2-15 were most frequent in the Underground (55.6%, p = 0.0184), Medicine (42.9%, p = 0.0184) and Other (63.2%, p = 0.002) areas; while positive samples for L. pneumophila sgr 1 were less frequent in the Underground (0.0%, p = 0.0184) and Surgery areas (4.5%, p = 0.033), and for Legionella anisa, were less frequent in the Medicine (4.1%, p = 0.021), Oncohematology (0.0%, p = 0.0282), and Other (0.0%, p = 0.016) areas. Finally, no significant differences were observed among the areas for each isolate considered. The surveillance carried out in these years demonstrates the importance of monitoring, which allows us to analyze the conditions of hospital facilities and, therefore, prevent Legionella spp. infections.

Transfusion-Transmitted Malaria of Plasmodium malariae in Palermo, Sicily.

Transfusion-transmitted malaria (TTM) is a rare occurrence with serious consequences for the recipient. In non-endemic areas, the incidence of transmission of malaria by transfusion is very low. We report a clinical case of transfusion-transmitted malaria due to Plasmodium malariae, which happened in a patient with acute hemorrhagic gastropathy.Case presentation: In April 2019, a 70-year-old Italian man with recurrent spiking fever for four days was diagnosed with a P. malariae infection, as confirmed using microscopy and real-time PCR. The patient had never been abroad, but about two months before, he had received a red blood cell transfusion for anemia. Regarding the donor, we revealed that they were a missionary priest who often went to tropical regions. Plasmodium spp. PCR was also used on donor blood to confirm the causal link. Discussion and Conclusions: The donations of asymptomatic blood donors who are predominantly "semi-immune" with very low parasitic loads are an issue. The main problem is related to transfusion-transmitted malaria. Our case suggests that P. malariae infections in semi-immune asymptomatic donors are a threat to transfusion safety. Currently, microscopy is considered the gold standard for the diagnosis of malaria but has limited sensitivity to detect low levels of parasitemia. Screening using serological tests and molecular tests, combined with the donor's questionnaire, should be used to reduce the cases of TTM.

Potential Activity of Albino Grifola frondosa Mushroom Extract against Biofilm of Meticillin-Resistant Staphylococcus aureus.

Mushroom extracts are a rich source of natural compounds with antimicrobial properties, which are able to prevent, to some extent, the growth of foodborne pathogens. The aim of this study was to investigate the potential of extracts from albino Grifola frondosa (GF), commonly known as maitake, to inhibit the growth of some bacteria and the biofilm production by Staphylococcus aureus. We obtained not only a significant reduction of OD score between biofilm and biofilm plus albino G. frondosa extract group, but also a reduction of category of biofilm. In addition, we observed a significant presence of isolates with strong category for the biofilm group and a significant presence of isolates with absent category for the biofilm plus albino G. frondosa extract group. These results confirm that the use of albino G. frondosa extract reduces in significant way the presence of biofilm. Our results suggest and confirm that albino G. frondosa extracts could be employed as functional food and could be used as a natural additive for food process control and food safety.

Draft Genome Sequence and Biofilm Production of a Carbapenemase-Producing Klebsiella pneumoniae (KpR405) Sequence Type 405 Strain Isolated in Italy.

Rapid identification and characterization of multidrug-resistant Klebsiella pneumoniae strains is essential to diagnose severe infections in patients. In clinical routine practice, K. pneumoniae is frequently identified and characterized for outbreak investigation. Pulsed-field gel electrophoresis or multilocus sequence typing could be used, but, unfortunately, these methods are time-consuming, laborious, expensive, and do not provide any information about the presence of resistance and virulence genes. In recent years, the decreasing cost of next-generation sequencing and its easy use have led to it being considered a useful method, not only for outbreak surveillance but also for rapid identification and evaluation, in a single step, of virulence factors and resistance genes. Carbapenem-resistant strains of K. pneumoniae have become endemic in Italy, and in these strains the ability to form biofilms, communities of bacteria fixed in an extracellular matrix, can defend the pathogen from the host immune response as well as from antibiotics, improving its persistence in epithelial tissues and on medical device surfaces.

Improvement of a rapid direct blood culture microbial identification protocol using MALDI-TOF MS and performance comparison with SepsiTyper kit.

Fast diagnosis of pathogens is critical to guarantee the most adequate therapy for infections; bacterial culture methods, which constitute the actual gold standard, are precise and sensitive but rather slow. Today, new methods have been made available to enable faster diagnosis, with the Matrix-Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometry (MALDI-TOF MS) technique being the most promising. Even if simpler and faster than traditional bacterial culture methods, analysis of positive blood cultures via MALDI-TOF MS requires a preliminary extraction process of samples. In this study, we compared two extraction protocols for bacterial identification directly from positive blood cultures using the Bruker MALDI Biotyper system (Bruker Daltonics, Billerica, MA). In particular, we evaluated the time employed and the overall performance for their accurate identification. In this work, the performances of a commercial extraction kit, named SepsiTyper™ Kit, and those of the protocol developed by Treibmann et al. were evaluated and proven to be similar. However, the SELTERS method represents the best compromise price/performance. Lastly, an in-house developed analysis protocol has been tested, and the introduced optimizations granted a performance level equal if not better than the SepsiTyper kit, a reduced processing time and reduced costs.