The proposed qualitative endoscopic activity score for canine IBD meets the following requirements as described for human endoscopic indices: (1) it is well correlated with the endoscopist\’s overall assessment of abnormal mucosal appearance; (2) the quality of the assessment is consistent when evaluated in a set of patients different than that used for its development; (3) it incorporates mucosal parameters intuitively considered as important by experienced endoscopists; (4) it incorporates mucosal parameters previously shown to be reproducibly collected, and is itself reproducible; and (5) it is simple to calculate. Importantly, this validated endoscopic index should be correlated with clinical indices and laboratory biomarkers of inflammation in future studies (Mary and Modigliani, 1989).
Conflict of interest statement
Porcine tonsils and the nasal cavity can act as a site of colonisation by opportunistic pathogens, including staphylococcal bacteria (Weese et al., 2014). In Belgium, methicillin-resistant Staphylococcus epidermidis (MRSE) has been found to be a major constituent of the methicillin-resistant non-Staphylococcus aureus staphylococci (MRNAS) flora in pig nostrils (Vanderhaeghen et al., 2012).
S. epidermidis colonises the skin and mucous membranes of mammalian species and is acknowledged as an important opportunistic pathogen in humans (Otto, 2009). Approximately 70–95% of the S. epidermidis strains circulating in human hospitals have been estimated to be methicillin-resistant, and most also display resistance to other 4-ap of antimicrobial drugs (Otto, 2009). In staphylococci, methicillin resistance is mediated by acquisition of mecA or mecC genes, located on the mobile genetic element staphylococcal cassette chromosome mec (SCCmec) (García-Álvarez et al., 2011). In some S. epidermidis strains, SCCmec has been found to be associated with the arginine catabolic element (ACME), a genomic island which might contribute to enhanced fitness and an ability to colonise the host (Barbier et al., 2011).
In veterinary medicine, S. epidermidis is one of the main aetiological agents of intra-mammary infections in ruminants (Vanderhaeghen et al., 2014) and can also be involved in various types of infectious disease in companion animals (Kern and Perreten, 2013). The aim of the present study was to investigate the prevalence, genetic diversity, virulence and antimicrobial resistance characteristics of S. epidermidis in pigs, as well as to determine the role that pigs might play as potential reservoirs of zoonotic S. epidermidis for the human population.
Materials and methods
Humans living or working on pig farms have been reported to have an increased risk of colonisation or infection with livestock-associated MRSA (Crombé et al., 2013). Pigs are also a potential reservoir of other staphylococci, including CoNS, such as S. epidermidis, which is one of the most frequent causes of nosocomial infections in humans, especially those associated with indwelling medical devices (Otto, 2009).
In the present study, approximately one-quarter of the healthy pigs tested carried S. epidermidis, with MRSE prevalence of 13.5%. In other published studies, MRSE has been infrequently or not detected in farmed pigs (Zhang et al., 2009; Bhargava and Zhang, 2012). Similarly, in poultry (Zhang et al., 2009; Bhargava and Zhang, 2012) and cattle (Vanderhaeghen et al., 2013) relatively few MRSE isolates have been identified in healthy populations. Conversely, S. epidermidis is one of the main CoNS causing ruminant intramammary infections (Vanderhaeghen et al., 2014), with similar methicillin-resistance rates as reported in the current study (Sampimon et al., 2011; Frey et al., 2013). It has been suggested that the S. epidermidis strains that cause mastitis originate from humans (Watts and Owens, 1989), and some evidence for cis configuration has come from studies, comparing organisms found in milk with strains of S. epidermidis isolated from humans working with those animals (Thorberg et al., 2006; Jaglic et al., 2010).