Dissemination of intestinal pathogens between lambs and puppies in sheep farms

[Influence of breed and herd size on the intra-herd prevalence of Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7) in sheep]

SUBJECT AND AIM

At present, only little information is available on the within-flock prevalence of Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7) (SASd) in sheep flocks in Germany as well as their possible influencing factors. The aim of the study was to investigate relationships between flock size, breed and within-flock prevalence.

MATERIAL AND METHODS

A total of 1610 clinically healthy ewes from 14 sheep flocks of 9 different breeds aged 2 to 12 years were microbiologically tested for SASd by nasal swab and fecal samples. Linear multivariable models were used to analyse the associations between within-flock prevalence and farm factors (flock size, breed) or detection frequencies in fecal or nasal swabs.

RESULTS

SASd was detected in all sheep flocks examined, with 75% of adults having at least one positive nasal or fecal result. In comparison to the 11 flocks in which commercial breeds were kept, the 3 flocks of landraces had a lower apparent within-flock prevalence (p=0.01). No association with herd size was evident. With respect to the age of the ewes, there was a negative relationship (p=0.05) with the frequency of detection of SASd in the nasal swab but not in the fecal swab. The health status and fertility performance of the flocks were in line with a normal range for commercial sheep flocks, with lambing losses of 5% to 10% and lambing scores of 130% to 158%.

CONCLUSIONS

Despite the high prevalence of SASd infections particularly within commercial breeds, there was no evidence of a relevant risk to sheep health. Compared with commercial breed flocks, a lower spread of SASd within flocks keeping landraces was evident.

CLINICAL RELEVANCE

Despite a high prevalence, infections with SASd are very unlikely to lead to clinical symptoms or disease. Regulation and monitoring of SASd in sheep are of low priority for animal health authorities.

A review of the predictors of antimicrobial use and resistance in European food animal production

Antimicrobial resistance (AMR) is a major threat to global health and a key One Health challenge linking humans, animals, and the environment. Livestock are a key target for moderation of antimicrobial use (AMU), which is a major driver of AMR in these species. While some studies have assessed AMU and AMR in individual production systems, the evidence regarding predictors of AMU and AMR in livestock is fragmented, with significant research gaps in identifying the predictors of AMU and AMR common across farming systems. This review summarizes existing knowledge to identify key practices and critical control points determining on-farm AMU/AMR determinants for pigs, layer and broiler hens, beef and dairy cattle, sheep, turkeys, and farmed salmon in Europe. The quality and quantity of evidence differed between livestock types, with sheep, beef cattle, laying hens, turkeys and salmon underrepresented. Interventions to mitigate both AMU and/or AMR highlighted in these studies included biosecurity and herd health plans. Organic production typically showed significantly lower AMU across species, but even in antibiotic-free systems, varying AMR levels were identified in livestock microflora. Although vaccination is frequently implemented as part of herd health plans, its effects on AMU/AMR remain unclear at farm level. Social and behavioral factors were identified as important influences on AMU. The study fills a conspicuous gap in the existing AMR and One Health literatures examining links between farm management practices and AMU and AMR in European livestock production.

[Longitudinal study on the time of infection of sheep lambs with Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7)]

OBJECTIVE

Infections with Salmonella enterica subspecies diarizonae serovar 61: k: 1, 5, (7) (SASd) are widespread in sheep. SASd is considered as host associated with low virulence. The aim of the study was to determine the time of infection of lambs after birth with consideration of the Salmonella status of the mother.

MATERIAL AND METHODS

Fecal and nasal swabs from 88 ewes of a flock with known SASd status but unknown intraherd prevalence were examined for SASd in the period of 6 weeks before the beginning of the lambing period. Fecal and nasal swabs from one female lamb from each of these ewes were also examined for SASd at 4-6 time points between the 4th and 50th day of life and at 7, 30 and 40 months of age.

RESULTS

In the first two weeks after birth, significantly more lambs were positive in the nasal swab than in the fecal swab. SASd positive nasal swabs were mainly found in lambs originating from ewes also positive in nasal swabs. 43 lambs remained SASd-negative until day 50 of age. There was no correlation between the SASd status of ewes and their off-spring. At 7 months of age, the number of animals with a positive detection of SASd increased significantly. 32% of the nasal swabs and 62% of the fecal samples were positive for SASd.

CONCLUSIONS

There is no rapid and intensive transmission of SASd from ewes to their offspring. Most likely, the infection begins by colonising the nasal mucosa of the lambs and does not cause any clinical symptoms.

CLINICAL RELEVANCE

Even with a high intraherd prevalence, infections with SASd are very unlikely to cause clinical symptoms.

Wild Duck (Anas platyrhynchos) as a Source of Antibiotic-Resistant Salmonella enterica subsp. diarizonae O58—The First Report in Poland

The “One Health” approach increasingly demonstrates the global spread of pathogenic microorganisms and their antimicrobial resistance in the environment, both in animals and humans. Salmonella enterica subsp. diarizonae is nowadays very often isolated from cold-blooded reptiles to a lesser extent from sheep, but unfortunately more and more often from humans. However, there are a few studies describing the isolation of Salmonella enterica subsp. diarizonae from migratory wild birds. The mallard duck (Anas platyrhynchos), a wild animal that traverses the continent of Eurasia, can be an excellent indicator of the spread of intestinal microbes as well as their resistance to antibiotics. This is the first report of the Salmonella enterica subsp. diarizonae detection in Poland in a migrating mallard duck. This research presented the identification difficulties associated with the isolation of Salmonella enterica subsp. diarizonae using three different biochemical tests and advanced serology tests. At the same time, we detected very high antimicrobial resistance in the isolated strain. By using the minimum inhibitory concentration (MIC) method, it was found that the isolated strain of S. enterica subsp. diarizonae has high antibiotic resistance against 14 of the 33 tested antimicrobials agents. The resistance genes that have been identified in S. enterica subsp. diarizonae include aadA, strA/strB, and bla_TEM.

Pet husbandry as a risk factor for colonization or infection with MDR organisms: a systematic meta-analysis

BACKGROUND

MDR organisms (MDROs) pose a relevant risk for patients in modern healthcare. Although ownership of pet animals is common and owners and pets commonly live in close contact, it is still unclear whether pet ownership may be considered as a risk factor for MDRO acquisition prior to hospitalization.

METHODS

We performed three separate meta-analyses in accordance with the PRISMA guidelines, assessing contact to pets as a risk factor for acquisition of MRSA, VRE and MDR Gram-negatives [namely third-generation cephalosporin-resistant Enterobacterales (3GCRE) and carbapenem-resistant Enterobacterales (CRE)].

RESULTS

We calculated an increased risk of MRSA carriage for dog owners [risk ratio (RR) 2.28, 95% CI 1.47-3.56]. Meta-analysis did not show a significantly higher risk for 3GCRE colonization among owners of different pet species compared with non-pet owners (RR 1.18, 95% CI 0.83-1.68 for pet owners in general, RR 0.88, 95% CI 0.56-1.40 for dog owners, RR 1.16, 95% CI 0.58-2.34 for cat owners, RR 1.34, 95% CI 0.43-4.18 for rodent owners, RR 0.91, 95% CI 0.38-2.18 for bird owners, and RR 2.34, 95% CI 0.33-16.63 for lizard/frog owners). For VRE, there were insufficient data to perform a meta-analysis.

CONCLUSIONS

Our analyses suggest contact to pet animals is a risk factor for MRSA, but not for 3GCRE/CRE acquisition. Evaluation of the underlying literature suggested a possible role of pet animals as: (i) vectors for the transmission of MDROs between livestock and humans; as well as (ii) a reservoir for MDROs. Pets, therefore, may promote transmission and reinfection of humans.

Experimental Study of the Potential Role of Salmonella enterica subsp. diarizonae in the Diarrhoeic Syndrome of Lambs

The objectives of this experimental work were the evaluation of the potential role of Salmonella enterica subsp. diarizonae in diarrhoeic syndrome in lambs and the investigation of facets of the pathogenesis of the infection. In total, 12 lambs were challenged orally on the first day of life, with a S. enterica subsp. diarizonae isolate from a clinical case of diarrhoeic syndrome. Sequential blood, faecal and buccal samples were collected from lambs and faecal and milk samples were taken from their dams. Lambs were euthanised 1, 2, 4, 7, 10, 14 and 21 days after challenge. Samples were processed for recovery of the challenge organism; they were also subjected to examination by PCR for detection of the invA gene. Tissue samples from lambs were also examined as above and histopathologically. S. enterica subsp. diarizonae was recovered from faecal samples of all lambs, in total, from 45/77 samples (median duration: 2.4 days post-inoculation). It was also recovered from buccal samples (10/77) from seven lambs (median duration: 0.8 days), and from tissue samples (small intestine, abomasum, liver, gallbladder) of nine lambs. It was recovered from two consecutive milk samples from the same ewe, but not from any faecal sample from ewes. The invA gene was detected in samples from all lambs (median duration: 5.5 days in faecal and 1.3 days in buccal samples), as well as in milk samples from three ewes. Histopathological findings included abomasitis with subepithelial presence of eosinophils, lymphocytes and plasma cells, consistently observed in all lambs. In the small intestine, salient lesions initially included distension and oedema of intestinal villi, leucocytic infiltration and hyperplasia of lymphoid nodules with apparent germinal centres; this was followed at later stages by atrophy and/or degeneration of the lymphoid tissue of the intestine with marked subepithelial infiltration of lymphocytes, plasma cells and eosinophils.

Prevalence of Salmonella enterica subsp. diarizonae serotype 61:k:1:5:(7) in nasal secretions and stool of sheep flocks with and without cases of chronic proliferative rhinitis

Salmonella enterica subsp. diarizonae serotype 61: k: 1,5, (7) (SED) is a microorganism well adapted to sheep; however, it has also been described producing chronic proliferative rhinitis (CPR) in ovine. CPR causes a proliferative inflammation of the ventral nasal turbinates that may totally obstruct the nasal cavity. The main objective of the present study was to investigate the prevalence of SED in nostrils and stool of sheep without CPR clinical signs in commercial sheep farms of Spain with and without previous clinical cases of CPR. Five samplings were performed in 10 commercial sheep farms for one year. Samples from nostrils and faeces were taken from four animals without CPR visible clinical signs that belonged to four different age ranges at each farm visit. The prevalence of positive animals was 45.3 %, and the number of positive samples in nostrils was higher than in faeces (38.5 % vs 22.5 %). Only on one farm was no positive result obtained in the entire study. In almost all positive farms, sheep belonging to the youngest age ranges accounted for more than 50 % of positive isolates. Finally, farms with a previous diagnosis of CPR were 1.784 times more likely to have an animal with positive isolation than farms without a previous diagnosis. This could suggest that the infection pressure in the farm might favour the occurrence of clinical cases of the disease. However, further studies will be necessary to unravel why this saprophytic bacterium is able to cross the epithelial barrier causing severe rhinitis in certain animals.

Nontyphoid Salmonella Prevalence, Serovar Distribution and Antimicrobial Resistance in Slaughter Sheep

This study aimed to determine the current prevalence, serovar distribution and antimicrobial resistance rate and patterns of nontyphoid Salmonella (NTS) in slaughter sheep and their edible offal. While filling the gap of up to date related information in Turkey, data presented is also of significance since contamination of ovine meat, its products and offal with this pathogen is threat to public health due to their considerably high consumption rates in our country. Current NTS carriage in 200 apparently healthy slaughter sheep by ISO 6579:2002, 6579:2002/A1:2007 standard bacteriology (ISO) was 5% (10/200) (4 fecal content - 2%, 3 mesenterial lymph node - 1.5%, 3 kidney - 1.5%) out of 1,400 samples (0.7%), with no isolation from carcass, liver, gallbladder, spleen. Real-time PCR was in substantial agreement to ISO in confirming Salmonella-suspect isolates (Relative Trueness: 93.6%). S. Newport (40%) was the predominant serovar, followed by the second prevalent serovars as S. Typhimurium and S. Kentucky (20%), and by S. Umbilo and S. Corvallis (10%). Four and 6 out of 10 NTS isolates were susceptible (40%) and resistant (60%) to 18 antimicrobials, respectively. S. Typhimurium isolates were multidrug resistant (MDR) to tigecycline and sulphamethoxazole/trimethoprim, with one also resistant to cefepime. S. Corvallis was MDR to ampicillin, ciprofloxacin, norfloxacin and pefloxacin. The predominance of S. Newport and first isolation of S. Corvallis in sheep in the world; first time isolations of Newport, Kentucky, Corvallis, Umbilo serovars from sheep in Turkey; and high antimicrobial resistance rates obtained in majority of the isolates highlights study findings.

Salmonella prevalence and serovar distribution in healthy slaughter sheep and cattle determined by ISO 6579 and VIDAS UP Salmonella methods

Prevalence of Salmonella in slaughter sheep and cattle was determined by International Organization for Standardization Method 6579 (ISO) and Vitek Immunodiagnostic Assay System UP Salmonella Phage Technology (VIDAS UP Salmonella SPT-VIDAS UP). A total of 400 healthy slaughter sheep (n = 200) and cattle (n = 200) carcass (C), fecal content (FC), mesenteric lymph node (MLN), liver (L), kidney (K), spleen (S) and gall bladder (GB) were randomly sampled and analysed. ISO and VIDAS UP results indicated 13 (3.25%) and 17 (4.25%) of 400 animals carried Salmonella, respectively, regardless of sample type. There was no isolation from L, S, GB, while 2 C (0.5%), 6 FC (1.5%), 7 MLN (1.75%), 3 K (0.75%) were contaminated with Salmonella. S. Typhimurium (27.8%), S. Enteritidis (22.2%), S. Newport (22.2%) were the three dominant serovars, followed by S. Kentucky (11.1%), S. Umbilo (5.6%), S. Corvallis (5.6%), and S. Albany (5.6%). Overall prevalence in 2800 samples was 0.46% by ISO and 0.61% by VIDAS UP. High relative trueness (RT: 99.79%) of VIDAS UP with a substantial agreement to ISO (κ value: 0.80) indicated its efficiency to accompany ISO to monitor Salmonella in slaughter animals. As the first report to evaluate ISO and VIDAS UP in detecting Salmonella from slaughter sheep and cattle, this current prevalence signifies a risk for public health in red-meat and related products in Turkey.