Indentification of Ruminal Enterococcal and Streptococcal Flora of Sheep

The isolation of rumen enterococci strains along with high potential utilizing cyanide

Cyanogenic glycosides in forage species and the possibility of cyanide (CN) poisoning can have undesirable effects on ruminants. The literature estimates that unknown rumen bacteria with rhodanese activity are key factors in the animal detoxification of cyanogenic glycosides, as they are capable of transforming CN into the less toxic thiocyanate. Therefore, identifying these bacteria will enhance our understanding of how to improve animal health with this natural CN detoxification process. In this study, a rhodanese activity screening assay revealed 6 of 44 candidate rumen bacterial strains isolated from domestic buffalo, dairy cattle, and beef cattle, each with a different colony morphology. These strains were identified as belonging to the species Enterococcus faecium and E. gallinarum by 16S ribosomal DNA sequence analysis. A CN-thiocyanate transformation assay showed that the thiocyanate formation capacity of the strains after a 12 h incubation ranged from 4.42 to 25.49 mg hydrogen CN equivalent/L. In addition, thiocyanate degradation resulted in the production of ammonia nitrogen and acetic acid in different strains. This study showed that certain strains of enterococci substantially contribute to CN metabolism in ruminants. Our results may serve as a starting point for research aimed at improving ruminant production systems in relation to CN metabolism.

Novel ulcerative leg lesions in yearling lambs: Clinical features, microbiology and histopathology

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An outbreak of an infectious dermatological disorder of unknown aetiology in a flock of yearling lambs was investigated.

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Lesions occurred on the distal limb between the coronary band and carpel joint as a circular ulcerative dermatitis.

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Treponema spp., Dichelobacter nodosus, Staphylococcus aureus, Dermatophilus congolensis and poxvirus screens were negative.

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Fusobacterium necrophorum and Streptococcus dysgalactiae were detected in the majority of lesions examined.

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An aetiology involving bacterial infection with F. necrophorum and S. dysgalactiae was implicated.

Here we report an outbreak of an atypical, ulcerative dermatitis in North Country mule lambs, located in South Gloucestershire, UK. The lesions, which appeared to be contagious, occured between the coronary band and the carpal joint as a focal, well demarcated, circular, ulcerative dermatitis. Histopathological examination of the lesion biopsies revealed areas of ulceration, epidermal hyperplasia, suppurative dermatitis and granulation tissue. Clumped keratohyalin granules and intracellular keratinocyte oedema (ballooning degeneration) were evident within lesion biopsies, consistent with an underlying viral aetiology. A PCR-based microbiological investigation failed to detect bovine digital dermatitis-associated treponeme phylogroups, Dichelobacter nodosus, Staphylococcus aureus, Dermatophilus congolensis or Chordopoxvirinae virus DNA. However, 3 of the 10 (30 %) and 6 of 10 (60 %) lesion samples were positive for Fusobacterium necrophorum and Streptococcus dysgalactiae DNA, respectively. Contralateral limb swabs were negative by all standard PCR assays. To better define the involvement of F. necrophorum in the aetiology of these lesions, a qPCR targeting the rpoB gene was employed and confirmed the presence of F. necrophorum DNA in both the control and lesions swab samples, although the mean F. necrophorum genome copy number detected in the lesion swab samples was ∼19-fold higher than detected in the contralateral control swab samples (245 versus 4752 genome copies/μl, respectively; P < 0.001). Although we have not been able to conclusively define an aetiological agent, the presence of both F. necrophorum and S. dysgalactiae in the majority of lesions assayed supports their role in the aetiopathogenesis of these lesions.

Comparison of nisin and monensin effects on ciliate and selected bacterial populations in artificial rumen

The effect of daily supplementation of nisin (2 mg/L), monensin (5.88 mg/L) and nisin and monensin (2 + 5.88 mg/L) on ovine ruminal ciliates and bacteria was investigated using the artificial rumen RUSITEC. Major groups in RUSITEC were Entodinium spp. and Dasytricha ruminantium. The supplementation of nisin significantly increased the population of both major ciliate groups. The supplementation of monensin significantly decreased the population of both groups. The combined effect of nisin and monensin was similar to the effect of monensin. Monensin had strong antiprotozoic effects in contrast to the stimulatory effects of nisin. D. ruminantium followed by Entodinium spp. appeared more resistant to tested compounds than other rumen ciliates. Tested additives did not significantly influence the presence and growth of amylolytic streptococci and enterococci but nisin showed a tendency to decreasing the concentration of Escherichia coli and lactobacilli.

Oral application ofEnterococcus faecium strain EE3 in healthy dogs

The ability of canine strain Enterococcus faecium EE3 to survive in healthy dogs and its effect on microbiological and biochemical parameters was determined. The strain was individually applied to 11 dogs per os at a dose of 10(9) CFU/mL (differed from 2 to 3 mL) for 1 week and persisted in feces for 3 months after cessation of its administration (reaching average concentration of 6.83 +/- 0.95 log CFU/g). Seven d after administration, a decrease in staphylococci and a significant decrease in Pseudomonas-like bacteria was observed. On the other hand, concentration of lactic acid bacteria increased but the growth of E. coli was not influenced. In the blood samples of dogs after 0-1 d (before application) and the blood samples 1 week after application, total lipids decreased in 8 dogs; the total protein also decreased. The levels of cholesterol were brought to the physiological level, i.e. in blood samples with low cholesterol values it increased to the physiological level and in those with high levels it decreased; cholesterol was not influenced in 3 dogs.

Production of bacteriocins by different enterococcal isolates

Bacteriocins produced by ruminal as well as environmental isolates were found to be heat-stable antimicrobial substances with a broad inhibitory spectrum (including Gram-negative species and sanitary-important species). The exponential phase of growth and pH 4-7 were optimal for their production. After purification, some of them were sequenced and specified.

Inhibition of ruminal staphylococci and enterococci by nisin in vitro

A collection of 59 ureolytic and lactic acid-producing ruminal staphylococci and enterococci, isolates from domestic and wild ruminants, were tested for sensitivity or resistance to lantibiotic nisin. All strains tested were sensitive with zones of inhibition, around wells containing 250 micrograms nisin, from 6 to 26 mm. 74.6% of isolates had zones of inhibition more than 10 mm and 11.1% more than 20 mm. Nisin was more effective against enterococci than staphylococci. Sensitivity of ruminal isolates to nisin may be used to control bacterial growth during the colonization of the rumen or to study the role of antibacterial activity in microbial interactions. Results obtained can be also used in experiments on gnotobiotic animals.