Aerosolic Application of Phages Against S. infantis on Plates and Chicken Skin.

Phages are known as a promising method to combat antimicrobial resistance (AMR) in the human and veterinary sector. Use of phage aerosols enormously increases the application field, although the impact on the infectivity of phages during nebulization needs to be evaluated. In this study S. infantis was treated on plates and chicken skin with nebulized phage particles of the Myoviridae type, identified by transmission electron microscopy, using a commercial nebulizer primarily used for H2O2 disinfection. The reduction of bacterial number by aerosol applied phage particles was evaluated. It could clearly be shown that the phage particles were able to infect Salmonella after being nebulized using ultrasound technology. Further studies on other types of phages as well as other conditions must be performed to standardize the aerosolic application of phages.

Assessment of microbial quality in poultry drinking water on farms in Austria.

The quality of poultry drinking water has a significant effect on broiler health and performance. This study conducted an analysis of aerobic mesophilic counts (AMC), Enterobacteriaceae (EB), Pseudomonadaceae (PS), and screened for the presence of Campylobacter spp. in water samples collected from a total of 14 farms in Austria, with either a public or private water source. The efficacy of two water line treatment methods was evaluated: a chemical treatment of the water lines with 4.0 ppm ClO2 (T1) and a combined chemical (4.0 ppm active ClO2 and 3.0% peracetic acid) and mechanical treatment (purging of the water lines with a high-pressure air pump; T2). However, both the T1 and T2 treatments failed to reduce the AMC counts below the maximum acceptable microbial limit of 4.0 log10 CFU/ml in water samples. In addition, no significant reduction in EB and PS counts was observed in water samples after either T1 or T2 water line treatment. The water samples showed a high level of microbial diversity with 18 to 26 different genera. The genus Pseudomonas was most frequently isolated across all poultry farms, while Campylobacter jejuni was identified in a single sample collected before water line treatment. Isolate analysis revealed the presence of opportunistic pathogens in water samples both before (T1 43.1%, T2 30.9%) and after (T1 36.3%, T2 33.3%) water line treatment. Opportunistic pathogens belonging to genera including Pseudomonas spp., Stenotrophomonas spp., and Ochrobactrum spp., were most frequently isolated from poultry drinking water. These isolates exhibited multidrug resistance and resistance phenotypes to antimicrobials commonly used in Austrian poultry farms. The findings of this study emphasize the potential risk of exposure to opportunistic pathogens for poultry and personnel, underscoring the importance of efficient water line management.

Genetic diversity of pestivirus isolates in cattle from Western Austria.

The genetic diversity of bovine viral diarrhoea virus (BVDV) isolates in infected cattle from Tyrol and Vorarlberg (Austria) was investigated. Blood samples were collected within the compulsory Austrian BVDV control programme during 2005 and 2006. The 5'-untranslated region (5'-UTR) and partially the N-terminal autoprotease (N(pro)) were amplified by one-step reverse transcriptase-polymerase chain reaction (RT-PCR) and the PCR products were subsequently sequenced. Phylogenetic analysis based on 5'-UTR and N(pro) sequences demonstrated that almost all isolates (307/310) were of the BVDV-1 genotype. They were clustered into eight different subtypes, here listed by their frequency of occurrence: BVDV-1h (143), BVDV-1f (79), BVDV-1b (41), BVDV-1d (28), BVDV-1e (6), BVDV-1a (4), BVDV-1g (3) and BVDV1-k (3). Two pestivirus isolates were typed as BVDV-2 and one isolate as BDV closely related to Gifhorn strain (BDV-3). Correlation among isolates could only be observed at the farm level, i.e., within a herd. However, no correlation between the genetic and geographical distances could be observed above the farm level. Because of the wide distribution of certain BVDV-1 subtypes and the low prevalence of herd-specific strains, a determination of tracing routes of infection was not possible. Furthermore, recombination events were not detected.

Estimating sensitivity and specificity of a PCR for boot socks to detect Campylobacter in broiler primary production using Bayesian latent class analysis.

The present study compares three different assays for sample collection and detection of Campylobacter spp. in broiler flocks, based on (i) the collection of faecal samples from intestinal organs (caecum), (ii) individual faecal droppings collected from the bedding and (iii) faecal material collected by socks placed on the outside of a pair of boots (boot socks) and used for walking around in the flock. The two first methods are examined for Campylobacter using a culture method (ISO-10272-2:2006), while the boot socks are tested using PCR. The PCR-assay is a genus specific multiplex PCR with primers targeting 16S rDNA in Campylobacter and primers targeting Yersinia ruckerii. Sixty-seven broiler flocks from Austria and 83 broiler flocks from Denmark were included in this prospective study and 89 of these were found to be positive in at least one method (AT: 49 samples, DK: 40 samples) whereas 61 of these were negative in all assays. In Austria samples for the three assays were collected simultaneously, which facilitates a direct comparison of the diagnostic test performance. In Denmark, however, boot socks and faecal droppings were collected three days before slaughter while caecum samples were collected at slaughter. The results were evaluated in the absence of a gold standard using a Bayesian latent class model. Austrian results showed higher sensitivity for PCR detection in sock samples (0.98; Bayesian credible interval (BCI) [0.93-1]) than for culture of faecal droppings (0.86; BCI [0.76-0.91]) or caecal samples (0.92; BCI [0.85-0.97]). The potential impact of Campylobacter introduction within the final three days before slaughter was observed in Denmark, where four flocks were tested negative three days before slaughter, but were detected positive at the slaughterhouse. Therefore the model results for the PCR sensitivity (0.88; BCI [0.83-0.97]) and cultural ISO-method in faecal samples (0.84; BCI [0.76-0.92]) are lower than for caecal samples (0.93; BCI [0.85-0.98]). In our study, PCR detection on boot sock samples is more sensitive than conventional culture. In view of the advantage of rapid results before slaughter and low costs for sampling, especially in combination with existing Salmonella surveillance systems (just another pair of boot socks needed), this method-matrix combination could be a valuable surveillance tool in the broiler primary production.

Monitoring for bovine viral diarrhea virus in Austrian red deer (Cervus elaphus elaphus) by using ear-notch samples.

During 2007-09, ear-notch samples from free-living (n=527) and farmed (n=237) Austrian red deer (Cervus elaphus elaphus) were tested for bovine viral diarrhea virus type 1 (BVDV-1) and type 2 (BVDV-2) by enzyme-linked immunosorbent assay and single-tube real-time reverse transcription PCR. Ear-notch samples were collected by applying modified ear tags from randomly selected hunter-harvested red deer and from individuals originating from deer holdings. All samples tested negative for BVDV-1 and BVDV-2. Results of this study show no evidence of persistently infected animals. They indicate further that BVDV is playing a minor role in free-living and farmed red deer in Austria. Ear-notch samples are an effective tool for in vivo and postmortem detection of BVDV in wildlife. This sample collection technique can be easily used in combination with tagging individual wild animals kept in captivity.