Early Warning Systems for Emerging Profiles of Antimicrobial Resistance in Italy: A National Survey

Antimicrobial resistance (AMR) national surveillance systems in Italy lack alert systems for timely detection of emerging profiles of AMR with potential relevance to public health. Furthermore, the existence of early warning systems (EWS) at subnational level is unclear. This study aims at mapping and characterizing EWS for microbiological threats available at regional level in Italy, focusing on emerging AMR, and at outlining potential barriers and facilitators to their development/implementation. To this end, a three-section, web-based survey was developed and administered to all Italian regional AMR representatives from June to August 2022. Twenty out of twenty-one regions and autonomous provinces (95.2%) responded to the survey. Among these, nine (45%) reported the implementation of EWS for microbiological threats at regional level, three (15%) reported that EWS are in the process of being developed, and eight (40%) reported that EWS are not currently available. EWS characteristics varied widely among the identified systems concerning both AMR profiles reported and data flow: the microorganisms most frequently included were extensively drug-resistant (XDR) Enterobacterales, with the lack of a dedicated regional IT platform reported in most cases. The results of this study depict a highly heterogeneous scenario and suggest that more efforts aimed at strengthening national AMR surveillance systems are needed

Turkey rhinotracheitis outbreak in 7 week old turkeys caused by a vaccine derived AMPV

A virus was isolated in association with respiratory disease typical of turkey rhinotracheitis, from turkeys which had been vaccinated with a B subtype Avian Metapneumovirus (AMPV) vaccine. Sequencing of the virus showed that, as in a previous similar report, the virus had originated from a live A subtype vaccine. In this instance the disease was much later, at 50 days of age, and there had been no recent history of use of the vaccine. This may indicate that AMPV vaccines are able to circulate in the environment for longer than was previously envisage

FIELD AVIAN METAPNEUMOVIRUS EVOLUTION AVOIDING VACCINE INDUCED IMMUNITY

Infection of turkeys and chickens with Avian Metapneumovirus (AMPV) leads to disease and serious economic losses in unprotected birds. In the late 1980s, live AMPV vaccines became available in Europe and these largely brought the disease under control. However disease has still been encountered and much of this remains unexplained. There is evidence that in some instances disease might be due to the involvement of another subtype or in some cases the disease may be caused by the vaccine itself. However many disease outbreaks remain unexplained especially in situations where they are observed after apparently successful vaccination with virus of the same subtype. Longitudinal studies were undertaken in Italian turkey farms and demonstrated that subtype B AMPV was frequently detected some period after subtype B vaccination. Sequencing showed that these later viruses were not derived from the previously applied vaccine, and have genome differences in key antigenic regions. An experimental infection of birds was carried out to discover whether the consistent mutations observed in the more recent Italian isolates might allow the viruses to avoid an immune response induced by the common subtype B vaccine, which has virus sequence close to AMPV strains isolated in Italy in the late 80s. The results of the study demonstrated that the more recent field viruses were able to overcome vaccine induced immunity and are consistent with the hypothesis that the field virus has changed in key antigenic regions in order to thrive within a groups of well vaccinated birds

Disease associated with 7 week old isolation of an avian metapneumovirus vaccine derived virus.

A virus was isolated in association with respiratory disease typical of turkey rhinotracheitis, from turkeys which had been vaccinated with a B subtype licensed Avian Metapneumovirus vaccine. Sequencing of the virus showed that, as in a previous similar report, the virus had originated from a licensed live A subtype vaccine. In this instance the disease was much later, at 50 days of age, and there had been no recent history of use of the vaccine. This may indicate that AMPV vaccines are able to circulate in the environment for longer than was previously envisaged