Staphylococci are common pathogens in dogs, causing a variety of dermatological problems. This study aimed to characterize the prevalence, antibiotic resistance, and biofilm-forming potential of Staphylococcus species isolated from the skin of shelter dogs. Overall, 108 samples were collected from the hairless skin areas of dogs in a shelter over one year. Isolates were cultured using standard microbiological methods and identified through biochemical testing, MALDI-TOF MS, and multiplex PCR. A total of 67 Staphylococcus isolates were identified, with S. pseudintermedius being the most prevalent. Antibiotic susceptibility was assessed using disk diffusion and MIC methods, revealing high resistance to ampicillin, erythromycin, and tetracycline. Notably, 12 multidrug-resistant SIG (S. intermedius group; S. pseudintermedius) and 4 CoNS strains (coagulase-negative staphylococci; S. equorum) were identified. Biofilm production was evaluated using a crystal violet assay, showing variable biofilm-forming capabilities among isolates and PCR, to confirm genes associated with biofilm formation. These findings highlight the presence of multidrug-resistant Staphylococcus species in shelter dogs, emphasizing the need for careful monitoring and antibiotic stewardship to manage potential risks to both animal and human health.

The conditions in livestock housing are suitable for the survival of airborne microorganisms, mainly due to high temperatures, humidity, and the presence of organic material. The total count of airborne bacteria concentrations in cattle farms ranged from 3.01 log₁₀ CFU/mL to 6.90 log₁₀ CFU/mL; for coliform bacteria, they were from 2.18 log₁₀ CFU/mL to 3.34 log₁₀ CFU/mL; and for molds, they ranged from 3.00 log₁₀ CFU/mL to 4.57 log₁₀ CFU/mL. Bacteria resistant to antimicrobial substances and resistance genes can be spread on animal farms. Antimicrobial resistance in ubiquitous Escherichia coli isolated from cattle feces was investigated. Minimum inhibitory concentration (MIC) testing was utilized to identify phenotypic resistance profiles, and the PCR method was employed to detect the presence of resistant genes. A higher percentage of resistance was found to amikacin (65%), tetracycline (61%), streptomycin (56%), ampicillin (55%), and nalidixic acid (45%). Multidrug resistance was determined in up to 64.3% of the isolates studied. The most widespread resistance genes were bla_TEM (85.7%), sul2 (66.7%), tetB (52.38%), and sul1 (47.6%). We found that 4.8% of the E. coli isolates had the bla_CMY gene. We found that, despite phenotypic resistance, E. coli isolates do not necessarily carry genes conferring resistance to that particular antimicrobial agent.

Methicillin-resistant coagulase-negative staphylococci (MRCoNS) are a major cause of infectious diseases, owing to their ability to form biofilms and colonize community and hospital environments. MRCoNS strains were identified using biochemical tests, an MALDI-TOF MS analyzer, and PCR-based 16S rRNA gene confirmation. This study was designed to assess antibiotic resistance and biofilm-forming capacity and to determine the presence of the mecA, mecC, agrA, srtA, icaABCD, bap, fnbAB, and clfAB genes in MRCoNS isolates. From patients undergoing random screening during hospitalization in the Orthopedics Clinic in Slovakia, 28 strains of MRCoNS were identified: S. epidermidis (n = 10), S. hominis (n = 8), S. haemolyticus (n = 4), S. lugdunensis (n = 3), while S. simulans, S. pasteuri, and S. warneri were detected only once. The highest rates of resistance were observed for ampicillin, oxacillin, rifampicin, trimethoprim (100%), and erythromycin (62%). The mecA gene was detected in 12 analyzed isolates. In 12 isolates, MDR, strong efflux pump activity, and strong or moderate biofilm formation were simultaneously detected. Our findings highlight the problems posed by biofilm-forming, resistant CoNS in hospitalized patients and the importance of diagnostics, separation, rapid treatment, and proper hospital hygiene.

Escherichia coli isolates from intensive poultry production are associated with antimicrobial resistance and worldwide health problems. The aim of the study was to detect and evaluate the phenotypic and genotypic antimicrobial resistance, biofilm formation, phylogenetic typing, and virulence factors in E. coli isolates from the rectal swabs of chickens from two farms and swabs of chicken meat purchased from Slovakian food markets. Interpretative readings of minimal inhibitory concentration (MIC) revealed dominant resistance to ampicillin (>50%) in both groups. We also detected higher resistance to ciprofloxacin (45%), tetracycline, ampicillin + sulbactam, and trimethoprim + sulfonamide (each >30%). Here, 28.57% of the strains studied were multidrug-resistant (MDR). The formation of weak biofilms was confirmed in 8.8% of E. coli, while one of the strains obtained from chicken cloacal swabs was classified as a strong biofilm producer. The most frequently confirmed phylogenetic groups in E. coli were B₁ and A₁ in all groups. PCR detection revealed the presence of genes encoding tetracycline resistance (tetAB) and plasmid-mediated quinolone resistance (qnrABS), and Int1 (52.9%), Tn3 (76.5%), kpsMT II (8.8%), fimA (97.1%), cvaC (38.2%), and iutA (76.5%) genes in the strains studied. Our results demonstrate that chickens and chicken meat were the source of antibiotic-resistant, biofilm-forming, and virulent E. coli, representing a potential risk from the point of view of the One Health concept.

Background: Staphylococci, recognized for their virulence and antibiotic resistance, are important in both human and veterinary medicine. Loss of sensitivity to beta-lactam antibiotics, such as ampicillin, complicates therapy, prompting the search for alternative antibacterials or ways to increase drug efficacy. Silver and gold nanoparticles (AgNPs, AuNPs) are promising on their own or in combination with antibiotics. Methods: The aim of this study is to compare the biological activity of pure, washed AgNPs and AuNPs with biosynthesized nanoparticles from Alchemilla vulgaris (AgNPs-Av and AuNPs-Av). Their antibacterial, antibiofilm, and biofilm-eradication effects on the tested antibiotic-resistant, biofilm-forming staphylococci (Methicillin-resistant Staphylococcus aureus (MRSA) and multiresistant Non-aureus staphylococci and mammaliicocci (NASM)) were evaluated using in vitro microdilution methods. Results: AgNPs-Av and AuNPs-Av inhibited bacterial growth at 50 μg/mL, while a significant suppression of biofilm formation was observed at just 25 μg/mL. Our research showed that neither AuNPs-Av nor AuNPs disrupts bacterial biofilm. AgNPs-Av effectively eradicated the biofilm at 50 μg/mL. NPs and ampicillin at subinhibitory antibiotic concentrations against the tested staphylococci. The results showed significant antibacterial and antibiofilm effects (p = 0.001). Partially, biofilm-eradication activity and strong antibiotic potentiation were also detected. Conclusions: These findings highlight the importance of rational combination therapy to improve antibiotic effectiveness and reduce bacterial resistance.

Staphylococcus aureus is an important human pathogen known for its versatility and ability to cause a wide range of infections. The aim of this study was to isolate and identify S. aureus from skin lesions from human patients, to determine antimicrobial resistance and biofilm formation potential at phenotypic and genotypic levels, as well as to verify the activity of efflux pump production. Out of 51 samples collected from skin lesions of various etiologies, 13 isolates were identified as S. aureus. All isolates showed the ability to form biofilms, which correlated with the presence of the icaABCD, agrA, srtA, clfAB, and fnbAB genes, while the bap gene was absent. The highest rates of resistance were observed for ampicillin (69.2%) and gentamicin (46.2%), as well as for erythromycin and clindamycin (38.5%). The mecA gene was present in two isolates, but phenotypic resistance to methicillin was confirmed in only one of them, suggesting possible heterogeneous expression or regulated activity of resistance mechanisms. The mecC gene was not present in any isolate. Efflux pump production was observed in only three isolates, showing weak to intermediate levels. These findings indicate the high biofilm potential and variable antimicrobial resistance of S. aureus clinical isolates, which pose a challenge for the treatment of emerging skin infections.