Avaliação in vitro da sensibilidade da Corynebacterium pseudotuberculosis frente a diferentes tipos de antissépticos e desinfetantes e determinação de sua curva de crescimento

Potential in vitro action of an adenosine analog and synergism with penicillin against Corynebacterium pseudotuberculosis

Caseous lymphadenitis is a well-known disease caused by Corynebacterium pseudotuberculosis affecting small ruminants with small significance to human health because of its minor zoonotic potential. In both cases, few treatment options are available and conventional antimicrobial therapy is commonly refractory due to development of pyogranulomatous reactions, bringing great interest in discovering novel therapeutics for more suitable approaches. Dideoxynucleotides presented antibacterial action against various bacteria but were never described for C. pseudotuberculosis. Hypothesizing the antimicrobial action of 2',3'-dideoxiadenosine (ddATP) against C. pseudotuberculosis, we performed for the first time an investigation of its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in the ATCC® 19,410 strain and a well-characterized clinical isolate of C. pseudotuberculosis. We also assessed potential synergism with penicillin. ddATP showed a growth delay effect for C. pseudotuberculosis at 2 µmol/mL and a MIC and MBC of 4 µmol/mL against the ATCC® 19,410 strain, but not for the clinical strain. An antimicrobial effect was observed when using concentrations lower than the MIC of ddATP associated with penicillin for both strains tested. Our data suggest the potential of nucleotide analogs, especially adenosine, and its combination with penicillin, as a possible novel treatment for C. pseudotuberculosis-induced infections, and contributes with knowledge regarding alternative drugs to treat C. pseudotuberculosis infections.

NMR insights on nano silver post-surgical treatment of superficial caseous lymphadenitis in small ruminants

Caseous lymphadenitis (CL), caused by a pathogen of the second class of biosafety – Corynebacterium pseudotuberculosis, is a chronic and severe infectious disease that affects small ruminants and requires long, ineffective treatment which generally leads to animal sacrifice so as to stop the disease spreading. The infected animals suffer the excision of affected superficial lymph nodes and post-surgical treatment with iodine (10% solution in ethanol) and, sometimes, prolonged antibiotic use, but only if the sick animals are of great importance to breeding. Herein, we propose a cheap and easy to apply treatment of CL with excellent results using biogenic silver nanoparticles (AgNP) based technology. AgNP antibacterial properties were investigated in vitro against Corynebacterium pseudotuberculosis cells and in vivo on small ruminants with CL. Treatment of surgical wounds resulting from the excision of superficial CL lesions with a AgNP-based cream was compared to the standard post-surgical treatment method by iodine. Also, the effects of AgNP-based cream treatment were evaluated and compared with the effects of the iodine CL treatment by serum NMR-based metabolomics. Serum samples were collected from 29 animals, 9 sheep and 20 goats, during the treatments and analyzed. All animals showed stable serum metabolomes when iodine or AgNP-based cream effects were compared. The AgNP-based cream treatment showed excellent results, especially in accelerating the healing of wounds, which occurred two to three times faster in comparison with the iodine treatment. AgNP-based cream treatment also prevented CL reappearance and did not cause any side effects on animals. This is the first report on very effective post-surgical treatment of superficial CL in small ruminants based on biogenic silver nanoparticles, which might open up the possibility for a safe veterinary application of AgNP-based cream.

Biogenic nanosilver in a pharmaceutical cream for wound healing in animal and human healthcare.

In vivo evaluation of antiseptics and disinfectants on control of Caseous Lymphadenitis: clinical, haematological, serological and microbiological monitoring

The objective of this experiment was to evaluate the efficacy of iodine tincture at 10% and sodium hypochlorite at 2.5% applied into the abscess of animals affected by Caseous Lymphadenitis (CL). Eighteen ewes were used, assorted into three groups: one treated with iodine tincture at 10% (IT), another one with sodium hypochlorite at 2.5% (SH) and the last group underwent the conventional treatment (CT). Conventional treatment was based on surgical drainage and chemical cauterization of the lesion with iodine tincture at 10%. Natural rupture of six abscesses from IT group was observed and in five of them the viability of Corynebacterium pseudotuberculosis was confirmed on the lesion place, after rupture of lymph node. As for the SH group, spontaneous rupture was observed in five out of six abscesses treated, and the microorganism was identified on the lesion of five animals, after rupture. In the sixth animal of this group, abscess involution was noticed. A severe swelling was identified in the region of lymph node treated, resulting in wide lesion in animals from groups IT and SH. No difference (p > 0,05) was found in blood parameters due to treatments. As for the serological monitoring of animals, comparative analysis between months within each group showed that months 1, 2, 3 and 4 were different (p < 0,05) from month 0, for groups IT and SH. For CT group, there was no difference (p > 0,05) between months 1 to 5 and 0. Then, the application of iodine tincture at 10% or sodium hypochlorite at 2.5% into the abscess of animals affected by CL, at stage in which lesions are detected through inspection, is not effective for its control.