Comparison of virulence factors and biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections.
The aim of this study was to find different prevalence of genes involved in the biofilm formation process and to assess the phenotypic and genotypic markers of biofilm formation among Staphylococcus aureus strains isolated from human and bovine infections. In this study, 215 S. aureus strains were collected from human and dairy cow's infections. The biofilm forming capacity of the strains was evaluated using a colorimetric microtiter plate assay. The genes encoding microbial surface components, recognizing adhesive matrix molecules (MSCRAMMs) (ebpS, eno, fib, fnbA, fnbB, cna and bap), and the intracellular adhesion (ica) genes (icaA, and icaD) were targeted by polymerase chain reaction (PCR)-based method. Approximately 70% of the isolates produced biofilm. Among these, 59.3% were producers of weakly adherent biofilms while 34.8% and 5.8% produced moderate and strong biofilms, respectively. The most prevalent gene was icaD found in 88.4% of the isolates, followed by icaA, fib and eno found in 87.9%, 75.8% and 75.3% of the isolates, respectively. The bap gene was not detected in any of the isolates. The prevalence of ebpS and fnbA genes among bovine isolates were significantly higher than those in human isolates, whilst the prevalence of cna gene was significantly higher in the human isolates. In this study, a high prevalence of biofilm production was found among S. aureus strains isolated from human and bovine infections. Most biofilm producing isolates were positive for MSCRAMM, icaA, and icaD genes.
Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran.
Babak
B
Khoramian
Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Fereshteh
F
Jabalameli
Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
Amir
A
Niasari-Naslaji
Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.
Morovat
M
Taherikalani
Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Electronic address: emaneini@tums.ac.ir.
Mohammad
M
Emaneini
D018829:Adhesins, Bacterial / Q000235:genetics; D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D006801:Humans; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000382:microbiology* / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology*; D037521:Virulence Factors / Q000235:genetics*
D018829:Adhesins, Bacterial; D037521:Virulence Factors
Biofilm; MSCRAMMs genes; Staphylococcus aureus; ica genes