Therapeutic potential of low-molecular weight lignin model polymer fractions for treating skin lesions in animals: a pilot study.

Bacterial infections and resistance to antibiotics are increasingly severe problems. In recent years, Staphylococcus species have emerged as important pathogens in animals and humans. Current therapeutic methods against these species have serious disadvantages; therefore new agents with antibacterial potential, such as plant-based substances, are very important in therapy. We report a pilot study with new method of fractioning the dehydrogenate polymer DHP obtained from coniferyl alcohol and application of the low-MW fractions of 200-3000 Da for antibacterial activity in healing animal lesions. In vivo experiments were conducted on the dogs having a skin lesion. Dogs were treated with the suspension containing the low-MW DHP fractions as the active ingredient, in combination with alginate for 7 days. Cytological smears and microbiological analyses of the affected area were performed. Staphylococcus spp. was isolated from lesions in all dogs from our research. The results show that the low-MW DHP suspension in alginate promotes skin healing and reduction of the infection of the lesions in the affected animals. Pharmaceutical composition containing the low-MW DHP fractions exerts a soothing effect on the subject in wound treatment. Reduction in the number of bacteria by 30% and more were noticed in 6 dogs, while in 4 dogs this percentage is above 50%. No side effects were noticed. Synthesized lignin oligomers may have a significant place as antimicrobial and skin healing agents, especially since an increasing number of multidrug-resistant staphylococci are found on the skin lesions in animals.

Genotypes and virulence factors in Staphylococcus aureus isolated from dairy cows with subclinical mastitis in Serbia.

This study aimed to determine the prevalence of Staphylococcus aureus subclinical mastitis and to genotype the S. aureus isolates using the 16S-23S rRNA intergenic spacer (RS-PCR) method. In addition, the genes responsible for adherence, biofilm formation, host evasion, tissue necrosis, methicillin resistance, and enterotoxin production of S. aureus were investigated. The overall prevalence of S. aureus subclinical mastitis in lactating cows was 5.4% (95% confidence interval, CI=4.7-6.1%). An increased risk of S. aureus intramammary infection was observed on small family farms (odds ratio, OR=4.2, 95% CI=2.6-6.6, P < 0.001) and medium-sized farms (OR=3.5, 95% CI=2.2-5.7, P < 0.001). The RS-PCR analysis revealed 44 genotypes and genotype variants, of which 15 new genotypes and five new variants were detected within small and medium-sized farms. S. aureus isolates of new genotypes and genotype variants carried the clfA gene responsible for adherence at a lower frequency (64.8%) and enterotoxin-producing genes sea (20.4%), seb (14.8%) and sec (14.8%) at a higher frequency than the other known genotypes (P < 0.001), and were confirmed to carry the sej and sep genes. The spa gene was detected in all S. aureus isolates, whereas none harbored bap, ser, or tsst-1 genes. Methicillin-resistant strains of S. aureus (MRSA) were also detected, with a higher prevalence (19.2%) on large farms with more than 50 cows (P < 0.001). Using molecular techniques as diagnostic tools provides a better understanding of intramammary staphylococcal infections' occurrence, spread, and eradication.

Genetic analysis reveals multiple intergenic region and central variable region in the African swine fever virus variants circulating in Serbia.

This study provides the first comprehensive report on the molecular characteristics of African swine fever virus (ASFV) variants in Serbia between 2019 and 2022. Since its first observation in July 2019, the disease has been found in wild boar and domestic swine. The study involved the analysis of 95 ASFV-positive samples collected from 12 infected administrative districts in Serbia. Partial four genomic regions were genetically characterized, including B646L, E183L, B602L, and the intergenic region (IGR) between the I73R-I329L genes. The results of the study suggest that multiple ASFV strains belonging to genotype II are circulating in Serbia, as evidenced by the analysis of the IGR between I73R-I329L genes that showed the most differences. Furthermore, the phylogenetic analysis of the B602L gene showed three different clades within the CVR I group of ASFV strains. Regarding the IGR, 98.4% were grouped into IGR II, with only one positive sample grouped into the IGR III group. These findings provide essential insights into the molecular characteristics of ASFV variants in Serbia and contribute to the knowledge of circulating strains of ASFV in Europe. However, further research is necessary to gain a better understanding of ASFV spread and evolution.

Molecular Characterization of Multidrug-Resistant Escherichia coli Isolates from Bovine Clinical Mastitis and Pigs in the Vojvodina Province, Serbia.

The aim of the study was to characterize multidrug-resistant (MDR) Escherichia coli isolates collected in Serbia from bovine clinical mastitis cases and diseased pigs, mainly with molecular methods. A total of 48 E. coli isolates was collected during the years 2013-2014, of which 22 were MDR and were included in further analysis. Phylogenetic typing showed that 17 isolates belonged to group A, while two isolates were classified in group B1 and a single one in group D. All isolates showed unique macrorestriction patterns. Phenotypic susceptibility testing revealed resistances of the isolates against up to 13 antimicrobial agents, including resistance to fluoroquinolones. A wide variety of resistance genes was detected by PCR amplification and sequencing of amplicons. Sequence analysis of the quinolone resistance determining regions of topoisomerase genes revealed mutations in gyrA, parC, and/or parE. Plasmid-mediated quinolone resistance genes were detected in two porcine (aac-6'-Ib-cr and qnrS, respectively) isolates and a single bovine (aac-6'-Ib-cr) isolate. Resistance genes were found to be located on conjugative plasmids in 16 cases, many of which conferred a multidrug resistance phenotype. In conclusion, the plentitude of resistance genes located on conjugative plasmids and integrons in E. coli from cows and pigs in Vojvodina, Serbia, pose a high risk for horizontal gene transfer in bacteria from livestock husbandry.