Direct and indirect causal effects of heterozygosity on fitness-related traits in Alpine ibex

Heterozygosity–fitness correlations (HFCs) are a useful tool to investigate the effects of inbreeding in wild populations, but are not informative in distinguishing between direct and indirect effects of heterozygosity on fitness-related traits. We tested HFCs in male Alpine ibex (Capra ibex) in a free-ranging population (which suffered a severe bottleneck at the end of the eighteenth century) and used confirmatory path analysis to disentangle the causal relationships between heterozygosity and fitness-related traits. We tested HFCs in 149 male individuals born between 1985 and 2009. We found that standardized multi-locus heterozygosity (MLH), calculated from 37 microsatellite loci, was related to body mass and horn growth, which are known to be important fitness-related traits, and to faecal egg counts (FECs) of nematode eggs, a proxy of parasite resistance. Then, using confirmatory path analysis, we were able to show that the effect of MLH on horn growth was not direct but mediated by body mass and FEC. HFCs do not necessarily imply direct genetic effects on fitness-related traits, which instead can be mediated by other traits in complex and unexpected ways

Table 6: Results of changing reference categories of categorical variables included in the final model presented in Table 5.

BACKGROUND. Staphylococci are commensals of the mucosal surface and skin of humans and animals, but have been implicated in infections such as otitis externa, pyoderma, urinary tract infections and post-surgical complications. Laboratory records provide useful information to help investigate these infections. Therefore, the objective of this study was to investigate the burdens of these infections and use multinomial regression to examine the associations between various Staphylococcus infections and demographic and temporal factors among dogs admitted to an academic veterinary hospital in South Africa. METHODS. Records of 1,497 clinical canine samples submitted to the bacteriology laboratory at a veterinary academic hospital between 2007 and 2012 were included in this study. Proportions of staphylococcal positive samples were calculated, and a multinomial logistic regression model was used to identify predictors of staphylococcal infections. RESULTS. Twenty-seven percent of the samples tested positive for Staphylococcus spp. The species of Staphylococcus identified were S. pseudintermedius (19.0%), S. aureus (3.8%), S. epidermidis (0.7%) and S. felis (0.1%). The remaining 2.87% consisted of unspeciated Staphylococcus. Distribution of the species by age of dog showed that S. pseudintermedius was the most common (25.6%) in dogs aged 2 4 years while S. aureus was most frequent (6.3%) in dogs aged 5 6 years. S. pseudintermedius (34.1%) and S. aureus (35.1%) were the most frequently isolated species from skin samples. The results of the multivariable multinomial logistic regression model identified specimen, year and age of the dog as significant predictors of the risk of infection with Staphylococcus. There >8 years of age. Similarly, dogs between 2 8 years of age were significantly more likely to test positive for S. pseudintermedius than those >8 years of age. In addition, dogs 2 4 years of age (RRR D 1.83; 1.09 3.06) were significantly more likely to test positive for S. pseudintermedius compared to those <2 years of age. The risk of infection with S. pseudintermedius or S. aureus was significantly higher in ear canal and skin specimens compared to other specimens. CONCLUSIONS. The findings suggest that S. pseudintermedius and S. aureus were the most commonly isolated species from dogs presented at the study hospital. Age of the dog and the location of infection were significant predictors of infection with both Staphylococcus species investigated. Significant increasing temporal trend was observed for S. pseudintermedius but not S. aureus. This information is useful for guiding clinical decisions as well as future research.https://peerj.comam2017Paraclinical Science

What has changed in canine pyoderma? A narrative review

Canine pyoderma is a common presentation in small animal practice and frequently leads to prescription of systemic antimicrobial agents. A good foundation of knowledge on pyoderma was established during the 1970s and 1980s, when treatment of infection provided relatively few challenges. However, the ability to treat canine pyoderma effectively is now limited substantially by the emergence of multidrug-resistant, methicillin-resistant staphylococci (MRS) and, in some countries, by restrictions on antimicrobial prescribing for pets. The threat from rising antimicrobial resistance and the zoonotic potential of MRS add a new dimension of public health implications to the management of canine pyoderma and necessitate a revisit and the search for new best management strategies. This narrative review focusses on the impact of MRS on how canine pyoderma is managed and how traditional treatment recommendations need to be updated in the interest of good antimicrobial stewardship. Background information on clinical characteristics, pathogens, and appropriate clinical and microbiological diagnostic techniques, are reviewed in so far as they can support early identification of multidrug-resistant pathogens. The potential of new approaches for the control and treatment of bacterial skin infections is examined and the role of owner education and hygiene is highlighted. Dogs with pyoderma offer opportunities for good antimicrobial stewardship by making use of the unique accessibility of the skin through cytology, bacterial culture and topical therapy. In order to achieve long term success and to limit the spread of multidrug resistance, there is a need to focus on identification and correction of underlying diseases that trigger pyoderma in order to avoid repeated treatment

Male-biased gastrointestinal parasitism in a nearly monomorphic mountain ungulate

Background: Pyrenean chamois (Rupicapra pyrenaica pyrenaica) is a nearly monomorphic mountain ungulate with an unbiased sex-specific overwinter adult survival. Few differences in gastrointestinal parasitism have been reported by coprology as yet. This study aims to assess diversity, prevalence, intensity of infection and aggregation of gastrointestinal nematodes in male and female adult chamois. We expect no differences in the parasite infection rates between sexes. Findings: Gastrointestinal tracts of 28 harvested Pyrenean chamois in the Catalan Pyrenees (autumn 2012 and 2013) were necropsied and sexual differences in the diversity and structure of parasite community, prevalence, intensity of infection, and richness were investigated. We found 25 helminth species belonging to 13 different genera. Conclusions: Contrary to our expectations, male chamois showed different parasite communities, higher prevalence, intensity of infection and richness than females. Such sexual differences were clear irrespective of age of individuals. Hence, male chamois must cope with a more diverse and abundant parasite community than females, without apparent biological cost. Further research will be required to confirm this hypothesis

Epidemiology of multi-drug resistant staphylococci in cats, dogs and people in Switzerland

Background: The human relationship with cats and dogs has been suggested to be of potential concern to public health because of the possible role of pets as reservoir of antibiotic resistant microorganisms. Here I suggest the “One Health” interdisciplinary approach to be helpful towards the understanding of the role of pets in antibiotic resistance spreading, considering also the socio-emotional context of the human-pet relationship. Methods: I investigated the presence of multi-drug resistant (MDR) staphylococci in cats, dogs and people in the nursing homes and in the community of four Swiss Cantons (Berne, Ticino, Vaud and Zurich). The study received ethical clearance from the responsible Cantonal Ethical Committees and authorization for animal experimentation from the Cantonal and Federal Veterinary Offices. Between March 2008 and December 2009 I collected nasal swabs from 978 people and nasal and ear swabs from 256 dogs and 277 cats and checked them for the presence of staphylococci. Isolated bacteria were identified and their phenotypic antibiotic resistance profile evaluated. Questionnaires on demographic information, health status and human–pet contact were completed by each participant and for each animal investigated. Results: Rapid and reliable identification of staphylococci by matrix assisted laser desorption ionisation – time of flight mass spectrometry (MALDI-TOF MS) was a pre-requisite to understand the distribution of Staphylococcus spp. in people and pets, also to differentiate among phylogenetically close related species such as S. delphini, S. intermedius, and S. pseudintermedius. The analysis of the staphylococcal population composition of healthy cats and dogs revealed that S. pseudintermedius was present in 27 % (70/256) of healthy dogs and 3 % (8/277) of healthy cats, whereas S. felis was isolated only from cats and represented 31 % of their coagulase-negative staphylococcal isolates. About 17 % (92/533) of pets carried MDR Staphylococcus spp. strains. Previous hospitalisation (stay in a veterinary clinic during at least one night) was identified as a risk factor for the carriage of these strains in nostril and ear of cats and dogs. However, although a relevant proportion of pets and nursing home residents was found to be carrier of MDR staphylococci, the residents had no increased risk of being carriers of these strains when living in homes with pets or having contact with these animals at least once a week. Findings suggested limited strain transmission between pets and humans. I could show strong physical closeness of pets with their owners in households and the high emotional importance of this relationship, but I did not observe any evident impact of pets on carriage of MDR staphylococci in their owners. At the end of my study I also analysed the clinical implications of methicillin-resistant S. pseudintermedius (MRSP) infections using as an example the isolation of this microorganism from a pyoderma lesion in a dog that underwent various antibiotic treatments before the correct diagnosis was made and an appropriate antibiotic treatment was administered. Discussion and conclusions: MDR staphylococci were recovered in relevant proportions from healthy pets and people. I could document the potential for exchange of strains due to close physical contact between their hosts. My results, however, indicated negligible rates of MDR staphylococcal transmission between human and pets. In evaluating the role of pets as reservoir of antibiotic resistant staphylococci, the network of contacts and their physical intensity, together with information on multi-drug resistance carriage in humans and pets should be considered for a correct estimation of the transmission and distribution of antibiotic resistant strains among different hosts

Identification of Staphylococcus intermedius Group by MALDI-TOF MS

The Staphylococcus intermedius Group includes S. intermedius, S. pseudintermedius and S. delphini,coagulase-positive bacteria commonly isolated from animals. The identification of organisms belonging to this group is presently carried out using molecular methods. This study assessed the suitability of MALDI-TOF MS for their identification. 69 strains of different biological and geographic origins, identified by partial hsp60 gene sequencing as S. intermedius (n = 15), S. pseudintermedius (n = 32) and S. delphini (n = 22), were analyzed by MALDI-TOF MS. The estimated sensitivity, specificity and efficiency were calculated. In addition we computed the agreement between the outcome of MALDI-TOF MS identification and partial hsp60 gene sequencing. The sensitivity of MALDI-TOF MS was higher for S. intermedius [0.95 (95% CI: 0.68–0.99)], than for S. pseudintermedius [0.78 (95% CI: 0.60–0.90)] and S. delphini [0.64 (95% CI: 0.41–0.83)], whereas the specificity was 1 for S. intermedius and S. delphini and 0.97 (95% CI: 0.86–0.99) for S. pseudintermedius. The Cohen’s kappa coefficient indicated almost perfect agreement between MALDITOF MS and hsp60 gene sequencing for the identification of S. intermedius [0.96 (95% CI: 0.87–1.04)], and substantial agreement for S. delphini and S. pseudintermedius [0.70 (95% CI: 0.52–0.89) and 0.76 (95% CI: 0.616–0.92), respectively]. The overall efficiency of the proteomic identification ranged between 0.88 (95% CI: 0.78–0.95) for S. pseudintermedius and S. delphini and 0.99 (95% CI: 0.92–0.99) for S. intermedius. MALDI-TOF MS is thus a valuable and reliable tool for the rapid and accurate identification of bacteria belonging to the S. intermedius Group

Testosterone is positively related to the output of nematode eggs in male alpine ibex (Capra ibex) faeces

Question: Does testosterone suppress the immune system of males in a strongly sexually dimorphic and long-lived ungulate? Immunocompetence handicap hypothesis: Testosterone promotes the development of secondary sexual characteristics and simultaneously suppresses immunological defence. Organisms: Free-ranging and individually identifiable male Alpine ibex (Capra ibex). Methods: In faecal samples, measure testosterone levels (ng · g−1) and the number of parasite eggs per gram of faeces (faecal egg counts). Determine social dominance by observing the outcomes of agonistic interactions in the field. Weigh males at a salt-lick scale. Data analysis: Path analysis to examine the relationships between testosterone levels, dominance, body mass, age, and faecal egg counts. Conclusions: We found a strong positive effect of testosterone on the amount of parasite eggs in the faeces of males. The level of parasite infection did not depend on any other tested variable. Testosterone therefore has an immunosuppressive effect in male Alpine ibex, as suggested by the immunocompetence handicap hypothesis

Extended-spectrum β-lactamase-producing Enterobacteriaceae in healthy companion animals living in nursing homes and in the community

Animals could be reservoirs of extended-spectrum β-lactamases (ESBL) strains, but epidemiologic data on ESBL-producing bacteria in healthy pets are missing. We determined the prevalence of ESBL-producing Enterobacteriaceae in pets living in nursing homes and in households to investigate the potential role of companion animals as carriers of ESBL.; Three hundred seventy-six rectal swabs were taken from cats and dogs visiting or living in 68 randomly selected nursing homes or brought to 26 veterinary practices in Switzerland for routine mandatory vaccination. Isolates were identified by matrix-assisted laser desorption ionization time of flight mass spectrometry. Confirmatory tests were performed on the isolated Enterobacteriaceae. Phenotypic ESBL isolates were investigated for genetic determinants of resistance.; The overall prevalence of ESBL isolates, adjusted for clustering, was 2.5% (95% confidence interval: 1.3-4.6). Pets that received an antibiotic treatment in the 3 months prior to the study had a higher risk to be carriers of these microorganisms (Adjusted odds ratio, 7.8; 95% confidence interval: 2.2-26.9).; ESBL-producing Enterobacteriaceae were present in healthy cats and dogs, particularly from those with a history of antibiotic treatment. These animals could become ESBL reservoirs. Investigations are needed to assess the possible transmission of these microorganisms between pets and humans