title: Molecular analysis of human and canine Staphylococcus aureus strains reveals distinct extended-host-spectrum genotypes independent of their methicillin resistance.
abstract: Staphylococcus aureus causes a wide range of infectious diseases in humans and various animal species. Although presumptive host-specific factors have been reported, certain genetic lineages seem to lack specific host tropism, infecting a broad range of hosts. Such Extended-Host-Spectrum Genotypes (EHSGs) have been described in canine infections, caused by common regional human methicillin-resistant S. aureus (MRSA) lineages. However, information is scarce about the occurrence of methicillin-susceptible S. aureus (MSSA) EHSGs. To gain deeper insight into EHSG MSSA and EHSG MRSA of human and canine origin, a comparative molecular study was carried out, including a convenience sample of 120 current S. aureus (70 MRSA and 50 MSSA) isolates obtained from infected dogs. spa typing revealed 48 different spa types belonging to 16 different multilocus sequence typing clonal complexes (MLST-CCs). Based on these results, we further compared a subset of canine (n = 48) and human (n = 14) strains, including isolates of clonal complexes CC5, CC22, CC8, CC398, CC15, CC45, and CC30 by macrorestriction (pulsed-field gel electrophoresis [PFGE]) and DNA-microarray analysis. None of the methods employed was able to differentiate between clusters of human and canine strains independently of their methicillin resistance. In contrast, DNA-microarray analysis revealed 79% of the 48 canine isolates as carriers of the bacteriophage-encoded human-specific immune evasion cluster (IEC). In conclusion, the high degree of similarity between human and canine S. aureus strains regardless of whether they are MRSA or MSSA envisions the existence of common genetic traits that enable these strains as EHSGs, challenging the concept of resistance-driven spillover of MRSA.
authors.affiliation: Institute of Microbiology and Epizootics, Veterinary Faculty, Free University Berlin, Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Vincze
authors.forename: I
authors.initials: I
authors.lastname: Stamm
authors.forename: S
authors.initials: S
authors.lastname: Monecke
authors.forename: P A
authors.initials: PA
authors.lastname: Kopp
authors.forename: T
authors.initials: T
authors.lastname: Semmler
authors.forename: L H
authors.initials: LH
authors.lastname: Wieler
authors.forename: A
authors.initials: A
authors.lastname: Lübke-Becker
authors.forename: B
authors.initials: B
authors.lastname: Walther
mesh_terms: D000818:Animals; D001435:Bacteriophages / Q000235:genetics; D016000:Cluster Analysis; D004285:Dogs; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D058507:Host Specificity; D006801:Humans; D016106:Methicillin Resistance; D046228:Microarray Analysis; D058885:Multilocus Sequence Typing; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology* / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology