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.

Autoclaving as a Routine Method for the Decontamination of Animal Carcasses in a Biosafety Level 3 Facility.

Introduction: Carcasses from animal experiments with RG-3 pathogens should be decontaminated onsite in Austria. Objective: The aim of this study was to find out if the use of pass-through autoclaves for the decontamination of animal carcasses (up to 40 kg of weight) could serve as a routine method for smaller laboratories, as the installation of special carcass decontamination plants may be cost prohibitive. Methods: Biological indicators (BIs) were implanted into the carcasses of animals of different sizes and species with a novel method using stainless steel pipes. The bodies were placed in autoclavable plastic bags and equipped with thermal probes by insertion through the rectum. Subsequently a factory default autoclave cycle for liquids was performed, which holds a core temperature of 121°C for 20 min. Results: The weight of the carcasses ranged from 1 to 42 kg, the duration of the individual cycles reached from 2.2 to 17.23 h. Decontamination was successful every single time as shown by the BIs. The application through the natural orifices with the help of the application tools seems to offer a reliable alternative for implanting the BIs into the carcasses without creating new openings. Insulation properties did not pose substantial challenges to the process. Limitations on the packaging procedure were identified in carcasses larger than 30 kg. Conclusion: Based on the results of this study, using pass-through autoclaves represents an option as a routine method for the decontamination of animal carcasses up to at least 40 kg.

Resilience of agricultural soils to antibiotic resistance genes introduced by agricultural management practices.

Antimicrobial resistance (AR) represents a global threat in human and veterinary medicine. In that regard, AR proliferation and dissemination in agricultural soils after manure application raises concerns on the enrichment of endogenous soil bacterial population with allochthonous antibiotic resistance genes (ARGs). Natural resilience of agricultural soils and background concentrations of ARGs play key roles in the mitigation of AR propagation in natural environments. In the present study, we carried out a longitudinal sampling campaign for two crop vegetation periods to monitor spatial and temporal changes in the abundance of seven clinically relevant ARGs (sul1, ermB, vanA, aph(3')-IIa, aph(3')-IIIa, blaTEM-1 and tet(W)) and ribosomal 16S RNA. The absolute and relative abundances of the selected ARGs were quantified in total community DNA extracted from agricultural (manured and non-manured) and forest soils, fresh pig faeces and manure slurry. We observed that ARG concentrations return to background levels after manure-induced exposure within a crop growing season, highlighting the resilience capacity of soil. Naturally occurring high background concentrations of ARGs can be found in forest soil in due distance under low anthropogenic influences. It was observed that pesticide application increases the concentrations of three out of seven ARGs tested (ermB, aph(3')-IIIa and tet(W)). Moreover, we noticed that the absolute abundances of sul1, vanA, ermB and blaTEM-1 resistance genes show an increase by 100- to 10,000- fold, from maturation of fresh pig faeces to manure. Outcomes of our study suggest that agricultural soil environments show a strong capacity to alleviate externally induced disturbances in endogenous ARG concentrations. Naturally occurring high concentrations of ARGs are present also in low human impacted environments represented by the indigenous resistome.