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Due to its large surface area, the skin is susceptible to various injuries, possibly accompanied by the entrance of infective agents into the body. Commensal organisms that constitute the skin microbiota play important roles in the orchestration of cutaneous homeostasis and immune competence. The opportunistic pathogen Staphylococcus aureus is present as part of the normal biota of the skin and mucous membranes in both humans and animals, but can cause disease when it invades the body either due to trauma or because of the impaired immune response of the host. Colonization of livestock skin by S. aureus is a precursor for majority of bacterial skin infections, which range from boils to sepsis, with the best-characterized being bovine mastitis. Antibiotic treatment of these infections can contribute to the promotion of resistant bacterial strains and even to multidrug resistance. The development of antibiotic resistance to currently available antibiotics is a worldwide problem. Considering the increasing ability of bacteria to effectively resist antibacterial agents, it is important to reduce the livestock consumption of antibiotics to preserve antibiotic effectiveness in the future. Plants are recognized as sources of various bioactive substances, including antibacterial activity towards clinically important microorganisms. This review provides an overview of the current knowledge on the major groups of phytochemicals with antibacterial activity and their modes of action. It also provides a list of currently known and used plant species aimed at treating or preventing bacterial skin infections in livestock.

Ultra-high performance liquid chromatography/mass spectrometry showed soyasaponin I and the isoflavones daidzein, genistein, and glycitein to be the main components of the methanolic extract of the Korean soybean fermented product doenjang, which is known to be a rich source of naturally occurring bioactive substances, at average contents of 515.40, 236.30, 131.23, and 29.00 ng/mg, respectively. The antimicrobial activity of the methanolic extract of doenjang against nine Staphylococcusaureus strains was determined in vitro by the broth microdilution method to investigate its potential to serve as an alternative antibacterial compound. The results suggest that the extract is an effective antistaphylococcal agent at concentrations of 2048–4096 µg/mL. Moreover, the tested extract also showed the ability to inhibit the growth of both methicillin-sensitive and methicillin-resistant animal and clinical S. aureus isolates. The growth kinetics of the chosen strains of S. aureus at the minimum inhibitory concentration of the methanolic extract of doenjang support the idea that the tested extract acts as an antibacterial compound. To the best of our knowledge, this is the first report on the antistaphylococcal action of the methanolic extract of doenjang thus, additional studies including in vivo testing are necessary to confirm this hypothesis.

Antibiotic resistance represents a serious threat worldwide. When considering the increasing ability of bacteria to effectively resist antibacterial agents, it is necessary to reduce the consumption of antibiotic substances in animal production in order to preserve their effectiveness in the future. Attention should be paid to the multidrug resistant microorganisms’ occurrence, which can be very exhausting for the breeder not only from the economic point of view. Therefore, alternative sources of antibacterials should be considered due to the limited possibilities of using conventional antibiotics in animal breeding, e.g. application of various substances including organic acids, clay minerals, etc. Nowadays, the research in this field also focuses on the combinatory effect of such compounds, which can also find the perspective for use in animal breeding. This article provides an overview of problems connected with the resistance of diverse bacteria to antibiotic treatment in livestock breeding. It emphasises the need for alternate resources usage with the aim to lower the environmental burden caused by overuse of antimicrobials used in subclinical doses in the past and with the expanding bacterial resistance.

Bacterial skin diseases of livestock could be a serious global threat, especially in association with overcoming bacterial resistance. Combinatory action of antimicrobial agents proves to be an effective strategy to overcome the problem of increasing antibiotic resistance of microorganisms. In this study, the in vitro combined effect of zinc pyrithione with gentamicin against bacterial skin pathogens of livestock (Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae) was evaluated according to the sum of fractional inhibitory concentration indices (FICI) obtained by checkerboard method. The results showed that a combination of zinc pyrithione with gentamicin produced a strong synergistic effect (p < 0.001) against all tested streptococcal strains (with FICI values ranging from 0.20 to 0.42). Compared to that, only three out of eight S. aureus strains were highly susceptible to the combination of antimicrobial agents at single concentration (0.25 µg/mL) of zinc pyrithione with range of FICI 0.35–0.43. These findings suggest that interference between agents tested in this study can be used for the development of future veterinary pharmaceutical preparations for the treatment of bacterial skin infections of livestock.

Outdoor access is an important part of organic and free-range poultry production, yet limited information exists on the effect of various housing and production systems on the growth performance and colonization of food-borne pathogens. Therefore, the primary purpose of the current study was to evaluate the influence of different housing systems (particularly fixed versus small, portable houses, with and without outdoor access to pasture) and different broiler genotypes on the gastrointestinal bacteria in broilers. The fundamental factor studied was the presence of any quantitative changes in common gastrointestinal microbiota, including pathogenic genera such as Campylobacter sp. and Salmonella sp. The results showed differences in intestinal microbiota and confirmed lowered counts of caecal coliforms in pasture-reared broilers.