No abstract

Although nasal carriage has been described as a risk factor for Staphylococcus aureus infections in humans, there is a scarcity of studies about S. aureus nasal carriers in animals. In rabbits, S. aureus is one of the most important pathogens responsible for a number of different types of infections. This study was designed to determine the extent of staphylococcal nasal carriage and to establish whether a relationship exists between nasal carriage and development of lesions. One hundred and sixteen rabbits with and without chronic signs of staphylococcosis from 6 industrial rabbitries were monitored. Nasal swabs for microbiological assessments were obtained from all animals. Microbiological results showed that 56% of the animals carried S. aureus in their nasal cavities with significantly higher incidence in animals with staphylococcal-related lesions (84.2%) compared to apparently healthy animals (28.8%). Additionally, the S. aureus strains isolated from the nasal cavity and lesions were clonally related in 91.7% of animals. This suggests that nasal carriage of S. aureus in rabbits could be a risk for development of clinical infections.

Staphylococcus aureus is an opportunistic multi-host pathogen that threatens both human and animal health. Animals can act as a reservoir of S. aureus for humans, but very little is known about wild animals’ epidemiological role. Therefore, in this study, we performed a genomic characterization of S. aureus isolates from wildlife, hunters, and their auxiliary hunting animals of Eastern Spain. Of 20 different species, 242 wild animals were examined, of which 28.1% were S. aureus carriers. The common genet, the Iberian ibex, and the European hedgehog were the species with the highest S. aureus carriage. We identified 30 different sequence types (STs), including lineages associated with wild animals such as ST49 and ST581, multispecies lineages such as ST130, ST398, and ST425, and lineages commonly isolated from humans, including ST1 and ST5. The hunters and the single positive ferret shared ST5, ST398, or ST425 with wild animals. In wildlife isolates, the highest resistance levels were found for penicillin (32.8%). For virulence factors, 26.2% of them carried superantigens, while 14.8% harbored the immune evasion cluster (IEC), which indicates probable human origin. Our findings suggest that wild animals are a reservoir of clinically relevant genes and lineages that could have the potential to be transmitted to humans. These data support the notion that wildlife surveillance is necessary to better understand the epidemiology of S. aureus as a pathogen that circulates among humans, animals, and the environment.

Mycobacteriosis is an important disease that affects captive and wild aquatic fish. Syngnathids are susceptible to infection by non-tuberculous mycobacteria. The aim of this study was to describe clinical signs, and macroscopic and histological lesions in 25 syngnathids and the molecular characterization of the causative mycobacteria. Clinical presentation ranged from sudden death to non-specific signs, including anorexia, poor body condition, weight loss and marked dyspnea with increased respiratory effort and rate. Gross lesions were mostly ulcers on the tail and small white nodules in the liver, coelomic cavity and inside the eye. The most affected organs were gills, liver, intestine and coelomic mesentery. Microscopic lesions consisted of areas of multifocal to diffuse granulomatous inflammation and bacterial emboli with numerous intralesional acid-fast bacilli. Epithelioid cells, multinucleated giant cells, lymphocytes and fibrous connective tissue, which are commonly observed in granulomatous inflammation, were not observed here. In the real-time PCR, M. fortuitum, M. chelonae and M. marinum common primers, Mycobacterium spp. were detected in 4, 7 and 14 individuals, respectively. In addition, this is the first description of mycobacteriosis found in Syngnathus acus.