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Aims: To determine if antibiotics associated with conventional pig farming have a direct role in altering the populations of key soil micro‐organisms isolated from piggery environments with and without exposure to antibiotics. Methods and Results: Fluorescent Pseudomonas sp. and the Bacillus cereus group from soils adjacent to four conventional piggeries (use of antibiotics) exposed to effluent (via irrigation) and two organic piggeries (non‐use of antibiotics) were assessed against nine relevant antibiotics using disc diffusion. The focus of the study was not to determine antibiotic resistance (or sensitivity) of isolates based on the manufacturer‐defined sensitive break point, instead this point was used as the interpretation point to compare the populations (i.e. farm/organism combination) for the antibiotics tested. Each population was statistically analysed to determine whether the mean diameters were significantly above this selected interpretation point. Bacterial species from both environments did not show a distinct population pattern linked to the antibiotics. Conclusions: Antibiotics associated with conventional pig farming do not have a direct role in altering the environmental populations of Pseudomonas and Bacillus sp. when assessed by population shifts. Significance and Impact of the Study: This study confirms that an understanding of the resident soil microbiota, as compared to the transient bacteria of pig origin, is important in addressing the impact of antibiotic usage on the food‐chain as a consequence of effluent re‐use in, and around, pig farms. [ABSTRACT FROM AUTHOR]

The levels of two key pathogens, Salmonella and Campylobacter, are assessed along with the indicator organism Escherichia coli in aerosols within and outside poultry sheds. The studies have shown that the public health risk from these organisms in poultry environments via the aerosol pathway is very minimal.

Abstract: This study has examined the dynamics (in terms of levels and serovar diversity) of Salmonella in the “dual litter environment” that occurs within a single shed as a result of a management practice common in Australia. The study also looked at the physical parameters of the litter (pH, moisture content, water activity and litter temperature) as a means of understanding the Salmonella dynamics in these litter environments. The Australian practice results in the brooder end of the shed having new litter each cycle while the grow-out end has re-used litter (a “dual litter environment”). Two farms that adopted this partial litter re-use practice were studied over one full broiler cycle each. Litter was sampled weekly for the levels (and serovars) of Salmonella during a farming cycle. There was a trend for lower levels of Salmonella (and a lower Salmonella serovar) diversity in the re-used litter environment as compared with the new litter environment. Of the physical parameters examined, it would appear that the lower water activity associated with the re-used litter may contribute to the Salmonella dynamics in the dual environment. [Copyright &y& Elsevier]

1. Litter samples were collected at the end of the production cycle from spread litter in a single shed from each of 28 farms distributed across the three Eastern seaboard States of Australia. 2. The geometric mean for Salmonella was 44 Most Probable Number (MPN)/g for the 20 positive samples. Five samples were between 100 and 1000 MPN/g and one at 105 MPN/g, indicating a range of factors are contributing to these varying loads of this organism in litter. 3. The geometric mean for Campylobacter was 30 MPN/g for the 10 positive samples, with 7 of these samples being <100 MPN/g. The low prevalence and incidence of Campylobacter were possibly due to the rapid die-off of this organism. 4. E. coli values were markedly higher than the two key pathogens (geometric mean 2⋅0 × 105 colony forming units (cfu)/g) with overall values being more or less within the same range across all samples in the trial, suggesting a uniform contribution pattern of these organisms in litter. 5. Listeria monocytogenes was absent in all samples and this organism appears not to be an issue in litter. 6. The dominant (70% of the isolates) Salmonella serovar was S. Sofia (a common serovar isolated from chickens in Australia) and was isolated across all regions. Other major serovars were S. Virchow and S. Chester (at 10%) and S. Bovismorbificans and S. Infantis (at 8%) with these serovars demonstrating a spatial distribution across the major regions tested. 7. There is potential to re-use litter in the environment depending on end use and the support of relevant application practices and guidelines. [ABSTRACT FROM AUTHOR]

Aims: To investigate the occurrence and levels of Arcobacter spp. in pig effluent ponds and effluent-treated soil. Methods and Results: A Most Probable Number (MPN) method was developed to assess the levels of Arcobacter spp. in seven pig effluent ponds and six effluent-treated soils, immediately after effluent irrigation. Arcobacter spp. levels in the effluent ponds varied from 6·5 × 105 to 1·1 × 108 MPN 100 ml−1 and in freshly irrigated soils from 9·5 × 102 to 2·8 × 104 MPN g−1 in all piggery environments tested. Eighty-three Arcobacter isolates were subjected to an abbreviated phenotypic test scheme and examined using a multiplex polymerase chain reaction (PCR). The PCR identified 35% of these isolates as Arcobacter butzleri, 49% as Arcobacter cryaerophilus while 16% gave no band. All 13 nonreactive isolates were subjected to partial 16S rDNA sequencing and showed a high similarity (>99%) to Arcobacter cibarius. Conclusions: A. butzleri, A. cryaerophilus and A. cibarius were isolated from both piggery effluent and effluent-irrigated soil, at levels suggestive of good survival in the effluent pond. Significance and Impact of the Study: This is the first study to provide quantitative information on Arcobacter spp. levels in piggery effluent and to associate A. cibarius with pigs and piggery effluent environments. [ABSTRACT FROM AUTHOR]

h.n. chinivasagam and p.j. blackall. 2005.To investigate methods for the recovery of airborne bacteria within pig sheds and to then use the appropriate methods to determine the levels of heterotrophs andEscherichia coliin the air within sheds.AGI-30 impingers and a six-stage Andersen multi-stage sampler (AMS) were used for the collection of aerosols. Betaine and catalase were added to impinger collection fluid and the agar plates used in the AMS. Suitable media for enumeratingE. coliwith the Andersen sampler were also evaluated. The addition of betaine and catalase gave no marked increase in the recovery of heterotrophs orE. coli. No marked differences were found in the media used for enumeration ofE. coli. The levels of heterotrophs andE. coliin three piggeries, during normal pig activities, were 2·2 × 105 and 21 CFU m−3 respectively.The failure of the additives to improve the recovery of either heterotrophs orE. colisuggests that these organisms are not stressed in the piggery environment. The levels of heterotrophs in the air inside the three Queensland piggeries investigated are consistent with those previously reported in other studies. Flushing with ponded effluent had no marked or consistent effect on the heterotroph orE. colilevels.Our work suggests that levels of airborne heterotrophs andE. coliinside pig sheds have no strong link with effluent flushing. It would seem unlikely that any single management activity within a pig shed has a dominant influence on levels of airborne heterotrophs andE. coli. [ABSTRACT FROM AUTHOR]

h.n. chinivasagam, r.j. thomas, k. casey, e. mcgahan, e.a. gardner, m. rafiee and p.j. blackall. , and 2004.To assist in the development of safe piggery effluent re-use guidelines by determining the level of selected pathogens and indicator organisms in the effluent ponds of 13 south-east Queensland piggeries.The numbers of thermotolerant coliforms,Campylobacter jejuni/coli,Erysipelothrix rhusiopathiae,Escherichia coli,Salmonellaand rotavirus were determined in 29 samples derived from the 13 piggeries. The study demonstrated that the 13 final effluent ponds contained an average of 1·2 × 105 colony-forming units (CFU) 100 ml−1 of thermotolerant coliforms and 1·03 × 105 CFU 100 ml−1 ofE. coli. TheCampylobacterlevel varied from none detectable (two of 13 piggeries) to a maximum of 930 most probable number (MPN) 100 ml−1 (two of 13 piggeries).Salmonellawas detected in the final ponds of only four of the 13 piggeries and then only at a low level (highest level being 51 MPN 100 ml−1). No rotavirus and noErysip. rhusiopathiaewere detected. The average log10 reductions across the ponding systems to the final irrigation pond were 1·77 for thermotolerant coliforms, 1·71 forE. coliand 1·04 forCampylobacter.This study has provided a baseline knowledge on the levels of indicator organisms and selected pathogens in piggery effluent.The knowledge gained in this study will assist in the development of guidelines to ensure the safe and sustainable re-use of piggery effluent. [ABSTRACT FROM AUTHOR]