The escalating global concern of antimicrobial resistance in human and veterinary medicine is exacerbated by the inappropriate prescription of antibiotics for bacterial infections in companion animals. This study aimed to determine the distribution of coagulase-positive staphylococci causing clinical skin and ear infections in dogs and to determine methicillin-resistant isolates. A total of 78 staphylococcal strains were isolated from clinical samples taken from patients at the Dermatology Clinic at the Faculty of Veterinary Medicine in Belgrade, Serbia. Multiplex PCR was used for species-specific identification, and mecA and mecC genes were used to determine methicillin resistance, in addition to phenotypic determination, MIC values and detection of PBP2a. Out of the 78 samples analyzed, 65.8% were identified as Staphylococcus pseudintermedius , 22.4% as S. aureus , 7.9% as S. coagulans , and 3.9% as S. intermedius . Four S. aureus isolates exhibited methicillin resistance confirmed by cefoxitin disk diffusion, while five were confirmed with MIC testing and latex agglutination. MecA gene was detected in 29.4% of S. aureus and 30% of S. pseudintermedius isolates. These isolates were classified as methicillin-resistant S. aureus (MRSA) and methicillin-resistant S. pseudintermedius (MRSP), respectively. No isolates carried the mecC gene. This study provides insights into the prevalence of CoPS species and methicillin resistance in isolates from dogs. Continued surveillance is essential to monitor and understand the emergence and dissemination of antimicrobial resistance in veterinary medicine and the results of this study accent the need for establishment of a continuous antimicrobial resistance surveillance program in the Republic of Serbia.

Wild boars are one of the widest-ranging mammals worldwide and represent reservoirs for many important viruses. Disease outbreaks in domestic swine are often described as a consequence of contact with wild boars, and traditional rearing conditions are a particular risk factor. Examples of such diseases include classical swine fever (CSF), African swine fever (ASF), Aujeszky?s disease (AD), and diseases caused by porcine circoviruses and parvoviruses. Some viral infections causing high mortality rates are easily noticeable and thus reported, though many viruses infecting wildlife are insidious impacting survival rates and reproduction in wild animals. Samples from wild boars for laboratory testing are usually collected postmortem and include various tissues or blood sera. The recovery of viable viruses during virus isolation depends on the virus species and the condition of the sample. Since this method does not yield timely results, most diagnostic procedures are based on PCR or antigen detection methods. Serological surveys are inexpensive and appropriate for prevalence studies. When interpreting the results of diagnostic tests, both virus and host characteristics, and the epizootiological situation must be accounted for. Disease control techniques such as fencing or feeding wild boars cause animal aggregation and give rise to population density which favors pathogen maintenance in the environment. Hunting reduces the number of susceptible animals and is helpful as an additional control measure and for sampling. Available data on infectious disease dynamics in wild boars is scarce, and constant knowledge improvement on pathogenesis, clinical symptoms, risk factors, and adequate control measures are required.

Background: Canine skin and ear infections are common in small-animal practice and increasingly complicated by multidrug resistance (MDR), yet data from Serbia are limited. This study aimed to describe the bacterial etiology and antimicrobial resistance patterns in canine otitis externa and pyoderma. Methods: We retrospectively reviewed laboratory records from the Clinical Bacteriology and Mycology Laboratory, Faculty of Veterinary Medicine, University of Belgrade (January 2017–August 2024). A total of 422 non-invasive swabs from clinically ill dogs were included (ears: n = 210; skin: n = 212). Bacterial identification used conventional methods and commercial systems, and disk-diffusion susceptibility testing followed CLSI/EUCAST guidance. Methicillin resistance in staphylococci was assessed by cefoxitin/oxacillin screening; MRSA was confirmed by PCR and PBP2a detection. Resistance trends were compared between 2017–2020 and 2021–2024. Results: The leading pathogens were Staphylococcus pseudintermedius (ears 48.1%; skin 79.7%) and Pseudomonas aeruginosa (ears 29.1%; skin 7.6%). Staphylococci showed high resistance to macrolides, clindamycin, tetracycline, and first-line β-lactams (amoxicillin–clavulanate, cephalexin), with the highest susceptibilities to amikacin, florfenicol, and rifampicin. P. aeruginosa remained most susceptible to amikacin, polymyxin B, and imipenem. Between the two periods, S. pseudintermedius resistance increased to amikacin, fusidic acid, and cephalexin, while resistance to florfenicol decreased. P. aeruginosa resistance to imipenem increased. The prevalence of methicillin-resistant S. pseudintermedius (MRSP) was 27.4% (74/270). MDR S. pseudintermedius and MDR P. aeruginosa were identified in 38.5% and 53.3% of isolates, respectively. One isolate of each species was resistant to all tested drugs. Conclusions: These findings confirm high levels of antimicrobial resistance in major canine skin and ear pathogens and emphasize the need for susceptibility-based therapy, rational antimicrobial use, and ongoing surveillance in small-animal practice.

Colibacillosis, caused by avian pathogenic Escherichia coli (APEC), is one of the most prevalent and economically damaging bacterial diseases affecting poultry globally. Managing colibacillosis is difficult and frequently ineffective because APEC strains have developed widespread resistance to antibiotics, and the strict regulations and public concerns towards using antimicrobial agents in poultry further complicate the situation. This study aimed to evaluate the antibacterial properties of hydrolysable (sweet chestnut extract) and condensed (quebracho extract) tannins on Escherichia coli ( E. coli) isolates from poultry, exploring their potential as antibiotic alternatives in managing colibacillosis. E. coli was isolated from the internal organs of deceased poultry across 18 farms, including layers, broilers, and broiler breeders. Each isolate was assessed for the presence of APEC strain predictors (virulence genes iutA , hlyF , iss , iroN , and ompT ), antimicrobial resistance to 14 antibiotics using the disc diffusion method, and the presence of resistance genes for specific antibiotics (ampicillin, gentamicin, tetracycline, and quinolones). Out of 43 isolates, 27 (62.8%) were classified as APEC, 30 (69.8%) showed resistance to three or more antibiotic classes, and 32 (74.4%) carried at least one AMR gene. The minimum inhibitory concentrations (MICs) for the hydrolysable tannins from sweet chestnut extract ( Castanea sativa Mill.) (SwCh) ranged from 0.5 to 3 mg/mL, while for the condensed tannins from quebracho extract ( Schinopsis lorentzii ) (Que), the MICs ranged from 1.5 to 4.5 mg/mL. The results indicate that both hydrolysable and condensed tannins possess significant in vitro antimicrobial activity against APEC, offering a potentially valuable alternative for controlling colibacillosis in the poultry industry.

Porcine circoviruses 2 and 3 (PCV2 and PCV3) are known agents of diseases in domestic pigs and wild boars. PCV2 is an economically important pathogen causing porcine circovirus-associated diseases (PCVAD), while the recently discovered PCV3 is associated with similar disorders. Wild boars can serve as a PCV reservoir for domestic pigs, which is a particular risk for pig farms with low biosecurity. Reports of these infections in Serbia are sporadic, and this study was intended as a follow-up to an earlier study. Our aim was to assess the prevalence and genetic characteristics of PCVs circulating in wild boars in a region in north-eastern Serbia with extensive hunting areas. In our study of 103 samples, 17.48% tested positive for PCV2 and 15.53% for PCV3. The low co-infection rates in 2.94% of the PCR-positive samples, suggests these viruses circulate independently. PCV2 prevalence was lower than in our previous study (40.32% out of 124 samples), but the genetic stability of circulating strains was detected with a clear genotype shift towards PCV2d-2. Moreover, this is the first report of PCV3 occurrence in wild boar in Serbia, and the detected strains were grouped into two genotypes: PCV3-1 and PCV3-3c. The PCV3-1 sequences were clustered with German strains, indicating the prevalence of this genotype in Europe. However, no further geographical correlation could be established, as the PCV3-3c representative was separated within the cluster containing Chinese and Indian strains. Furthermore, there was no correlation between PCV positivity and pathological findings in the sampled animals indicating subclinical infection.

Salmonella spp. infections pose a significant threat to both animal and public health, with various serotypes affecting a wide range of hosts. This case report investigates an outbreak of salmonellosis on a chinchilla farm in Serbia, focusing on the clinical, pathological, and microbiological aspects of the infection. Two chinchilla cadavers were brought to the Faculty of Veterinary Medicine, University of Belgrade. The animals on the farm exhibited anorexia, apathy, diarrhea, and abortions before succumbing to the infection. Pathohistological findings revealed severe necrohaemorrhagic metritis and placentitis, along with multifocal randomly dispersed areas of necrosis in the liver. Conventional microbiological analysis revealed the presence of Salmonella Typhimurium which was confirmed by serological typing. Antimicrobial susceptibility analysis showed that bacteria were susceptible to all tested antibiotics. The outbreak could maybe attributed to inadequate husbandry practices and stress, particularly among gravid females. This report underscores the importance of proper husbandry, judicious antibiotic use based on susceptibility testing and implementation of preventive measures to mitigate the recurrence and spread of salmonellosis in chinchilla populations, both in farm and pet settings.