Crossing of interspecies barriers by microorganisms is observed. In recent years, Staphylococcus pseudintermedius-a species formerly thought to be animal-has also been isolated from human clinical materials. Many virulence factors are responsible for the colonization, which is the first step an infection, of the new host organism. We analyzed the factors influencing this colonization as well as susceptibility to antibiotics in fourteen S. pseudintermedius strains isolated from clinical cases from humans and animals. The occurrence of genes responsible for binding elastin, fibronectin, and fibrinogen and some phenotypic features, although different between strains, is comparable in both groups. However, the animal isolates had more genes coding for virulence factors. All isolates tested had the exfoliating toxin gene and the leukotoxin determining genes, but only the human strains had enterotoxin genes. The assessment of antibiotic resistance of strains of both groups indicates their broad resistance to antibiotics commonly used in veterinary medicine. Antibiotic resistance was more common among animal isolates. The multilocus sequence typing analysis of the studied strains was performed. The results indicated a large diversity of the S. pseudintermedius population in both studied groups of strains. Equipped with important virulence factors, they showed the ability to infect animals and humans. The clonal differentiation of the methicillin-susceptible strains and the multidrug resistance of the strains of both studied groups should be emphasized. The considerable genetic diversity of strains from a limited geographical area indicates the processes of change taking place within this species. Thus, careful observation of the ongoing process of variation is necessary, as they may lead to the selection of S. pseudintermedius, which will pose a significant threat to humans.

• Keywords
• Bacterial adhesions, Methicillin resistance, Staphylococcal infections, Staphylococcus, Zoonotic infections,
• MeSH
• Anti-Bacterial Agents * pharmacology   MeSH
• Drug Resistance, Bacterial MeSH
• Virulence Factors genetics   MeSH
• Humans MeSH
• Microbial Sensitivity Tests MeSH
• Staphylococcal Infections * veterinary   epidemiology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Anti-Bacterial Agents * MeSH
• Virulence Factors MeSH

A group of 59 putative strains of Staphylococcus intermedius/Staphylococcus pseudintermedius deposited in the Czech National Collection of Type Cultures (CNCTC, National Institute for Public Health, Prague, Czech Republic) and the National Reference Laboratory for Staphylococci (NRL for Staphylococci, National Institute for Public Health, Prague, Czech Republic) was reclassified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). There the biggest human collection of S. pseudintermedius in Europe was analysed; 44 samples (75%) were of human origin. Twenty-two percent (n = 13) of the strains were isolated from animals, and two staphylococci were of unknown origin. This study revealed the prevalence of Staphylococcus pseudintermedius (94%, n = 53) vs. Staphylococcus intermedius (6%, n = 6) in the collection of human and veterinary staphylococci after reclassification. Results of PCR-RFLP analysis were verified by comparison with a repetitive element sequence-based polymerase chain reaction (Rep-PCR) analysis on 26 (44%) randomly selected strains. Due to a low-resolution ability of PCR-RFLP to separate Staphylococcus intermedius from Staphylococcus delphini, four isolates of Staphylococcus intermedius were biochemically verified further to exclude the presence of Staphylococcus delphini in the collection. Our results indicate that S. intermedius and S. pseudintermedius have occurred independently over an age-long period of their co-evolution.

• MeSH
• Bacterial Proteins genetics   MeSH
• Bacteriological Techniques MeSH
• Biological Evolution * MeSH
• DNA, Bacterial genetics   MeSH
• Humans MeSH
• Polymerase Chain Reaction MeSH
• Polymorphism, Restriction Fragment Length MeSH
• Repetitive Sequences, Nucleic Acid genetics   MeSH
• Sequence Analysis, DNA MeSH
• Staphylococcal Infections microbiology   veterinary   MeSH
• Staphylococcus intermedius classification   genetics   isolation & purification   MeSH
• Staphylococcus classification   genetics   isolation & purification   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Bacterial Proteins MeSH
• DNA, Bacterial MeSH