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Reasons for Performing Study: The intestinal microbiota is a complex polymicrobial ecosystem that exerts extremely important roles in the development and maintenance of health. Recently, as new sequencing technologies have become more available, there has been a revolution in the understanding of the equine intestinal microbiota. However, studies characterising the pioneer intestinal bacteria colonising foals and its development over time are still limited., Objectives: The objectives of this study were to characterise the intestinal bacterial colonisation of newborn foals and to follow individual animals over time until age 9 months., Study Design: Longitudinal study., Methods: Eleven pregnant mares from one farm were enrolled and faecal samples were collected longitudinally from mares and foals during their first day post partum and again periodically until foals were age 9 months. The V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq platform., Results: Newborn foals had a rich and diverse bacterial community, which was mainly comprised of the Firmicutes phylum with several low abundant genera being unique at this age. Foals aged 2-30 days had significantly decreased diversity compared to older animals, with the majority of organisms classified as Akkermansia spp. After 60 days of life, the intestinal microbiota structure tended to remain stable, but differences in community membership were still present between 9-month-old animals and mature mares. Several differences at the phylum level were observed between different ages, including a higher abundance of Fibrobacteres after weaning., Conclusions: The intestinal microbiota of the equine newborn is already complex by the first day of life. Microbiota adaptation occurs during the first month and the microbiota of foals older than 60 days resemble the mother's microbiota, although differences in community membership are still present., (© 2015 EVJ Ltd.)

Reasons for Performing the Study: The microbiota plays a key role in health and disease. Probiotics are a potential way to therapeutically modify the intestinal microbiota and prevent disease., Objectives: The aim of this study was to investigate the effects of probiotics on the bacterial microbiota of foals during and after administration., Study Design: Randomised placebo controlled field trial., Methods: Thirty-eight healthy neonatal foals enrolled in a previous study were selected. The foals had received a multi-strain probiotic (four Lactobacillus spp. 3-4 × 10 3 colony-forming units (cfu)/g each, Bifidobacterium animalis spp. lactis, 1 × 10 3-4 cfu/g) or placebo once daily for 3 weeks. A total of 3 faecal samples were collected from each foal at 2-week intervals and assessed via metagenomic sequencing. The Wilcoxon test was used to compare data between treatment groups., Results: There were no changes on the phylum, order or class level between treatment groups at any age (all P>0.05) but some significant changes in relative abundance of families. Probiotic administration did not result in an increased relative abundance of lactobacilli or bifidobacteria at any age (Lactobacillus: P = 0.9, P = 0.1 and P = 0.2, Bifidobacterium: P = 0.3, P = 0.6 and P = 0.1 for Weeks 2, 4 and 6, respectively). Lactobacillus was enriched in the probiotic group at Week 6 on LEfSe analysis (linear discriminant analysis score 0.34, P = 0 .02). There was no effect on alpha diversity (all P>0.2) or community structure when parsimony and unifrac analysis were applied (all P>0.6)., Conclusions: There were limited effects of probiotic treatment on the bacterial microbiota of foals. The studied probiotic based on lactobacilli and bifidobacteria has a limited potential for therapeutic modification of the gastrointestinal microbiota., (© 2015 EVJ Ltd.)

Reasons for Performing Study: The intestinal microbiota is important for health and disease. Factors that disturb the equine intestinal microbiota need further investigation., Objectives: To determine the effects of transport, fasting and anaesthesia on the faecal microbiota of healthy adult horses using next-generation sequencing., Study Design: Experimental trial., Methods: Faecal samples were taken from 8 horses at baseline, after transport, 12 h of fasting and 24, 48 and 72 h after a 6 h anaesthesia. Next generation sequencing of the V4 region of the 16S rRNA gene was used to assess the microbial composition of faeces. Alpha diversity, phylogenetic structures and beta diversity were assessed., Results: There were significant changes in the relative abundances of phyla, classes, orders and families after transport, fasting and anaesthesia. Most notably horses had a significantly lower abundance of Clostridiales after transport compared with baseline (P = 0.03) and a decreased abundance of Rickettsiales after fasting (P = 0.024). Alpha diversity was not significantly different between time points (all P>0.21). When parsimony analysis was applied, anaesthesia had a significant effect on community membership and structure (Jaccard index and Yue and Clayton index both P = 0.02)., Conclusions: There was some effect of transport, fasting and anaesthesia on the composition and structure of the microbiota of healthy horses. This indicates these are potentially stress factors for the equine intestinal microbiota. Further investigation is required to look at the potential impact of changes in the microbiota on the development of disease in the post anaesthetic period., (© 2015 EVJ Ltd.)

Reasons for Performing Study: Disruptions in the gastrointestinal microbiota may trigger development of post partum colic., Objectives: To determine the effects of the periparturient period on the faecal microbiome and identify associations between the faecal microbiota and post partum colic., Study Design: Longitudinal case-control study., Methods: Pre- and post partum faecal samples were collected from mares on 3 farms in central Kentucky. Next generation sequencing of the V4 region of the 16S rRNA gene was performed on samples from 13 mares that developed colic, 13 mares that did not display colic and 5 nonpregnant controls., Results: There were 4,523,727 sequences from 85 samples evaluated (mean ± s.d. 53,220 ± 29,160, range 8442-122,535). Twenty-five phyla were identified, although only Firmicutes, Verrucomicrobia, Actinobacteria and Proteobacteria were present at a relative abundance of 1% or greater. The faecal microbiota of late-term mares differed from nonpregnant mares, with differences in microbial community membership and structure but not the relative abundance of major phyla. There was limited impact of foaling and the post partum period on the faecal microbiome. Faecal samples obtained from mares prior to episodes of colic had significantly higher relative abundance of Proteobacteria (8.2%, P = 0.0006) compared with samples from mares that did not display colic (3.7%). All samples with a relative abundance of Firmicutes of ≤50% preceded colic, as did 6/7 (86%) samples with >4% Proteobacteria. Differences in microbiota membership and structure were also present between mares that developed large colon volvulus and matched controls that did not have colic. Sixty-one indicator operational taxon units were identified for the control (vs. volvulus) samples, and these were dominated by Lachnospiraceae (n = 38) and Ruminococcaceae (n = 8)., Conclusions: Foaling had minimal effects on the mares' faecal microbiota. Numerous differences in the faecal microbiota preceded colic. Associations between Firmicutes (particularly Lachnospiraceae and Ruminococcaceae) and Proteobacteria and development of colic could lead to measures to predict and prevent colic. The Summary is available in Chinese - see Supporting information., (© 2014 EVJ Ltd.)

Reasons for Performing Study: Methods that can be used to estimate rates of healthcare-associated infections and other nosocomial events have not been well established for use in equine hospitals. Traditional laboratory-based surveillance is expensive and cannot be applied in all of these settings., Objectives: To evaluate the use of a syndromic surveillance system for estimating rates of occurrence of healthcare-associated infections among hospitalised equine cases., Study Design: Multicentre, prospective longitudinal study., Methods: This study included weaned equids (n = 297) that were admitted for gastrointestinal disorders at one of 5 participating veterinary referral hospitals during a 12-week period in 2006. A survey form was completed by the primary clinician to summarise basic case information, procedures and treatments the horse received, and whether one or more of 7 predefined nosocomial syndromes were recognised at any point during hospitalisation. Adjusted rates of nosocomial events were estimated using Poisson regression. Risk factors associated with the risk of developing a nosocomial event were analysed using multivariable logistic regression., Results: Among the study population, 95 nosocomial events were reported to have occurred in 65 horses. Controlling for differences among hospitals, 19.7% (95% confidence interval, 14.5-26.7) of the study population was reported to have had at least one nosocomial event recognised during hospitalisation. The most commonly reported nosocomial syndromes that were unrelated to the reason for hospitalisation were surgical site inflammation and i.v. catheter site inflammation., Conclusions: Syndromic surveillance systems can be standardised successfully for use across multiple hospitals without interfering with established organisational structures, in order to provide useful estimates of rates related to healthcare-associated infections., (© 2013 EVJ Ltd.)

Reasons for Performing Study: Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging equine and zoonotic pathogen. Infection control protocols can be used to control MRSA in human hospitals, but measures to eradicate MRSA on horse farms have not been evaluated., Objectives: To describe an MRSA eradication programme that was used to attempt to eliminate MRSA colonisation among horses and horse personnel on 2 equine farms., Methods: Active surveillance cultures and infection control protocols were implemented on 2 farms with endemic MRSA., Results: Active screening and strict implementation of infection control protocols resulted in a rapid decrease in number of colonised horses on both farms. The majority of horses eliminated MRSA without antimicrobial treatment. On one farm colonisation was eradicated, while only 2 (3%) colonised horses remained on the other farm at the end of the study., Conclusions: Although at this stage the benefit of eradication of MRSA from populations of horses and cost-benefit studies have not been established, this study illustrates that short-term eradication can be achieved with a policy of segregation, enhanced infection control precautions and repeated testing of groups of animals., Potential Relevance: Infection control practices should form the basis of MRSA control. Antimicrobial therapy does not appear to be required for eradication of MRSA colonisation in horses and control of MRSA on farms. In appropriate circumstances, these methods may be useful for controlling the spread of this potentially serious pathogen.

Reasons for Performing Study: Probiotics have not been demonstrated to provide any beneficial health effects in horses, possibly because of improper selection of probiotic organisms. This study was designed to identify lactic acid bacteria of equine origin with predetermined beneficial properties which might make them useful as therapeutic probiotics., Hypothesis: A small percentage of lactic acid bacteria that are native to the intestinal tract of horses possess properties that may be useful in the treatment and/or prevention of gastrointestinal disease in horses., Methods: Faecal samples were collected from healthy mature horses and foals. Lactic acid bacteria were isolated and tested for the ability to grow in acid and bile environments, aerotolerance and in vitro inhibition of enteropathogens. One isolate that possessed these properties was administered orally to healthy mature horses and foals and gastrointestinal survival was assessed., Results: Of the 47 tested organisms, 18 were deemed to be adequately acid- and bile-tolerant. All were aerotolerant. Four organisms markedly inhibited Salmonella spp. One isolate, Lactobacillus pentosus WE7, was subjectively superior and chosen for further study. It was also inhibitory against E. coli, moderately inhibitory against S. zooepidemicus and C. difficile and mildly inhibitory against C. perfringens. After oral administration, this isolate was recovered from the faeces of 8/9 (89%) foals and 7/8 (87.5%) mature horses., Conclusions: Lactobacillus pentosus WE7 possesses in vitro and in vivo properties that may be useful for the prevention and treatment of enteric disease in horses., Potential Relevance: The beneficial in vitro and in vivo properties that L. pentosus WE7 possesses indicate that randomised, blinded, placebo-controlled efficacy studies are warranted.

Faecal samples from adult horses and from foals with diarrhoea or with normal faeces were evaluated for the presence of Clostridium difficile, C. difficile toxins, C. perfringens enterotoxin (CPE) and C. perfringens spore counts. Clostridium difficile was isolated from 7/55 horses (12.7%) and 11/31 foals (35.5%) with colitis, but from 1/255 normal adults (0.4%) and 0/47 normal foals (P<0.001). Clostridium difficile toxins A and/or B were detected in 12/55 diarrhoeic adults (21.8%) and 5/30 diarrhoeic foals (16.7%) but in only 1/83 adults (1.2%) and 0/21 foals with normal faeces (P<0.001 and P<0.05, respectively). Clostridium perfringens enterotoxin was detected in 9/47 diarrhoeic adults (19%) and 8/28 diarrhoeic foals (28.6%), but was not detected in 47 adult horses (P<0.002) or 4 foals (P = 0.22) with normal faeces. The positive predictive value of isolation of C. perfringens with respect to the presence of CPE was only 60% in adult horses and 64% in foals. There was no association between total C. perfringens spore count and CPE in the faeces. The overall mortality rate from colitis was 22% for adult horses and 18% for foals. Clostridium difficile toxin-positive adult horses with colitis were less likely to survive than C. difficile-negative horses with colitis (P = 0.03). This study provides further evidence that C. difficile and enterotoxigenic C. perfringens are associated with equine enterocolitis.