Prevention of periodontal disease in dogs: an experimental approach using an antimicrobial peptide

Funder

Organizational Unit

Publications

Nisin influence on the antimicrobial resistance ability of canine oral enterococci

Publication . Cunha, Eva; Janela, Rita; Costa, Margarida; Tavares, Luís; Veiga, Ana Salomé; Oliveira, Manuela

Periodontal disease (PD) is one of the most common diseases in dogs. Although previous studies have shown the potential of the antimicrobial peptide nisin for PD control, there is no information regarding its influence in the development of antimicrobial resistance or horizontal gene transfer (HGT). Nisin’s mutant prevention concentration (MPC) and selection window (MSW) were determined for a collection of canine oral enterococci. Isolates recovered after the determination of the MPC values were characterized for their antimicrobial profile and its nisin minimum inhibitory and bactericidal concentrations. The potential of vanA HGT between Enterococcus faecium CCGU36804 and nine clinical canine staphylococci and enterococci was evaluated. Nisin MPC values ranged from 400 to more than 600 µg/mL. In comparison with the original enterococci collection, the isolates recovered after the determination of the nisin MPC showed increased resistance towards amoxicillin/clavulanate (5%), vancomycin (5%), enrofloxacin (10%), gentamicin (10%) and imipenem (15%). The HGT of vanA gene was not observed. This work showed that nisin selective pressure may induce changes in the bacteria’s antimicrobial resistance profile but does not influence horizontal transfer of vanA gene. To our knowledge, this is the first report of nisin’s MPC and MSW determination regarding canine enterococci.

2020Journal article

Open access

Commonality of multidrug-resistant klebsiella pneumoniae ST348 isolates in horses and humans in Portugal

Publication . Trigo Da Roza, Filipa; Couto, Natacha; Carneiro, Carla; Cunha, Eva; Rosa, Teresa; Magalhães, Mariana; Tavares, Luis; Novais, Ângela; Peixe, Luísa; Lamas, Luís P.; Oliveira, Manuela

ABSTRACT - Multidrug-resistant (MDR) Klebsiella pneumoniae is considered a major global concern by the World Health Organization. Evidence is growing on the importance of circulation of MDR bacterial populations between animals and humans. Horses have been shown to carry commensal isolates of this bacterial species and can act as human MDR bacteria reservoirs. In this study, we characterized an extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae sequence type (ST) 348 isolate from a horse, an ST reported for the first time in an animal, using next-generation sequencing. We compared it with six other MDR K. pneumoniae ST348 human isolates previously identified in health-care facilities in Portugal using a core genome multi-locus sequence typing approach to evaluate a possible genetic link. The horse isolate was resistant to most of the antimicrobials tested, including 3rd generation cephalosporins, fluoroquinolones, and aminoglycosides, and presented several antimicrobial resistance genes, including blaESBL. Twenty-one allele differences were found between the horse isolate and the most similar human isolate, suggesting a recent common ancestor. Other similarities were observed regarding the content on antimicrobial resistance genes, plasmid incompatibility groups, and capsular and somatic antigens. This study illustrates the relevance of the dissemination of MDR strains, and enhances that identification of these types of bacterial strains in both human and veterinary settings is of significant relevance in order to understand and implement combined control strategies for MDR bacteria in animals and humans.

2019-07-10Journal article

Open access

Periodontal disease in dogs : an experimental approach towards prevention using antimicrobial peptides

Publication . Cunha, Eva; Oliveira, Maria Manuela Castilho Monteiro de; Veiga, Ana Salomé Rocha do Nascimento

ABSTRACT - Periodontal disease (PD) is one of the most widespread inflammatory diseases in dogs. This disease is initiated by a polymicrobial biofilm (dental plaque) in the teeth surface, along with a subsequent local inflammatory response leading to periodontium damage and systemic consequences. Enterococci are opportunistic bacteria that may be found in the plaque biofilm. Their ability to act as reservoirs of resistant determinants and their previously linkage to PD-systemic consequences, makes enterococci an interesting bacterial model for antimicrobial studies. Several strategies can be used for PD control, being the removal and inhibition of dental plaque the keystone for PD prevention. Antimicrobial peptides (AMPs) are promising compounds for the management of bacterial infections with low rate of resistance incidence. Nisin is an AMP with antimicrobial activity against Gram-positive and some Gram-negative bacteria, including periodontal pathogens. Considering PD high prevalence, its consequences, and the urgent need to control antimicrobial resistant (AMR) strains and develop new antimicrobial strategies, the main goal of this project was to evaluate the potential of the AMP nisin A for PD control in dogs. First, the antimicrobial activity of nisin and of nisin incorporated in two delivery systems (guar gum biogel and a veterinary toothpaste) were evaluated against a previously characterized collection of canine oral enterococci (n=20). Nisin and nisin-biogel were able to inhibit and eradicate all isolates tested in both planktonic and biofilm forms. Supplemented toothpaste was able to inhibit 95% of the isolates tested. As such, nisin-biogel was selected for the following assays, being observed that it also presented inhibition and eradication abilities against an in vitro multispecies biofilm. Then, nisin-biogel antimicrobial ability was evaluated in the presence of canine saliva and over a 24-month storage, as well as its safety towards eukaryotic cells. Saliva hampered nisin-biogel activity, but it maintained its antimicrobial activity over the storage period at freezing, cooling and room temperatures. In addition, nisin-biogel showed no cytotoxicity at concentrations up to 200 μg/mL. Later, nisin-biogel influence on the canine oral microbiome was evaluated by next generation sequencing, revealing that one dental application of nisin-biogel promoted a reduction in bacterial diversity. Still, a diversity recovery was detected after three applications, along with a reduction in some PD-related bacterial species. Finally, nisin influence in AMR development was evaluated by determination of the mutant section window, mutants AMR profiles and horizontal gene transfer (HGT). It was observed that nisin selective pressure may induce changes in the bacteria’s AMR profile, but not influencing vanA HGT between enterococci and staphylococci. Together, these results show that nisin-biogel seems to be an appropriate approach for PD control in dogs, being important to test this product in an in vivo controlled clinical trial.

2021-12-14Doctoral thesis

Open access