Vancomycin resistant enterococcus risk factors for hospital colonization in hematological patients: a matched case-control study.

BACKGROUND: Vancomycin-resistant enterococcus (VRE) was the fastest growing pathogen in Europe in 2022 (+ 21%) but its clinical relevance is still unclear. We aim to identify risk factors for acquired VRE rectal colonization in hematological patients and evaluate the clinical impact of VRE colonization on subsequent infection, and 30- and 90-day overall mortality rates, compared to a matched control group. METHODS: A retrospective, single center, case-control matched study (ratio 1:1) was conducted in a hematological department from January 2017 to December 2020. Case patients with nosocomial isolation of VRE from rectal swab screening (≥ 48 h) were matched to controls by age, sex, ethnicity, and hematologic disease. Univariate and multivariate logistic regression compared risk factors for colonization. RESULTS: A total of 83 cases were matched with 83 controls. Risk factors for VRE colonization were febrile neutropenia, bone marrow transplant, central venous catheter, bedsores, reduced mobility, altered bowel habits, cachexia, previous hospitalization and antibiotic treatments before and during hospitalization. VRE bacteraemia and Clostridioides difficile infection (CDI) occurred more frequently among cases without any impact on 30 and 90-days overall mortality. Vancomycin administration and altered bowel habits were the only independent risk factors for VRE colonization at multivariate analysis (OR: 3.53 and 3.1; respectively). CONCLUSIONS: Antimicrobial stewardship strategies to reduce inappropriate Gram-positive coverage in hematological patients is urgently required, as independent risk factors for VRE nosocomial colonization identified in this study include any use of vancomycin and altered bowel habits. VRE colonization and infection did not influence 30- and 90-day mortality. There was a strong correlation between CDI and VRE, which deserves further investigation to target new therapeutic approaches.

A proposal for a comprehensive approach to infections across the surgical pathway.

Despite evidence supporting the effectiveness of best practices in infection prevention and management, many healthcare workers fail to implement them and evidence-based practices tend to be underused in routine practice. Prevention and management of infections across the surgical pathway should always focus on collaboration among all healthcare workers sharing knowledge of best practices. To clarify key issues in the prevention and management of infections across the surgical pathway, a multidisciplinary task force of experts convened in Ancona, Italy, on May 31, 2019, for a national meeting. This document represents the executive summary of the final statements approved by the expert panel.

Italian field survey reveals a high diffusion of avian metapneumovirus subtype B in layers and weaknesses in the vaccination strategy applied.

The current information on the prevalence of avian metapneumovirus (aMPV) infection in layers is fragmentary and its true impact on egg production often remains unknown or unclear. In order to draw an epidemiologic picture of aMPV presence in layer flocks in Italy, a survey was performed on 19 flocks of pullets and layers based on longitudinal studies or sporadic samplings. aMPV was detected by reverse transcription (RT)-PCR, and blood samples were collected for serology by aMPV ELISA. Occurrences of respiratory signs and a drop in egg production were recorded. Possible involvement of infectious bronchitis (IB) and egg drop syndrome (EDS) viruses that could have caused loss of egg production we ruled out for IB virus by RT-PCR, and EDS virus was ruled out by hemagglutination-inhibition (HI). Only subtype B of aMPV was found in both pullet and layer farms. Surveys of pullets showed that most groups became infected prior to the onset of lay without showing clear respiratory signs. At the point of lay, these groups were serologically positive to aMPV. In two layer flocks, egg drops were observed and could be strongly linked to the presence of aMPV infection. Results were correlated with aMPV vaccination programs applied to the birds in three flocks on the same farm. Only a vaccination program which included two live and one killed vaccines gave complete protection from aMPV infection to the birds, while a single live vaccine application was not efficacious. The current study gives an inside view of field aMPV diffusion in Italy and its control in layers.

Avian metapneumovirus (AMPV) attachment protein involvement in probable virus evolution concurrent with mass live vaccine introduction.

Avian metapneumoviruses detected in Northern Italy between 1987 and 2007 were sequenced in their fusion (F) and attachment (G) genes together with the same genes from isolates collected throughout western European prior to 1994. Fusion protein genes sequences were highly conserved while G protein sequences showed much greater heterogeneity. Phylogenetic studies based on both genes clearly showed that later Italian viruses were significantly different to all earlier virus detections, including early detections from Italy. Furthermore a serine residue in the G proteins and lysine residue in the fusion protein were exclusive to Italian viruses, indicating that later viruses probably arose within the country and the notion that these later viruses evolved from earlier Italian progenitors cannot be discounted. Biocomputing analysis applied to F and G proteins of later Italian viruses predicted that only G contained altered T cell epitopes. It appears likely that Italian field viruses evolved in response to selection pressure from vaccine induced immunity.

Identification of two regions within the subtype A avian metapneumovirus fusion protein (amino acids 211-310 and 336-479) recognized by neutralizing antibodies.

The fusion (F) protein of a subtype A AMPV was expressed in sections in Escherichia coli. Six genome sections were selected which encoded the majority of the protein. These were cloned then expressed from a His tag expression plasmid and, following purification on nickel columns, identities were confirmed by Western blot analysis. The interactions of each fragment with AMPV neutralizing antisera were determined. Purified fragments were mixed with AMPV sera raised against A-C subtypes by a natural route, in order to determine any reduction in their neutralizing capacities. Two fragments covering regions of the F ectodomain reduced neutralizing capacities of both subtype A and B antisera to a highly significant degree (p<0.001) while no effects were seen with subtype C antiserum. Previous studies of similar viruses had identified neutralization as being associated with equivalent F regions. Findings are likely to be useful in guiding future vaccine design.