| Summary: | Staphylococcus aureus is the causative agent of clinical or subclinical mastitis
in dairy cow. The bacteria cause also several diseases in human. The case of
methicillin resistant Staphylococcus aureus (MRSA) increase frequently, and this
strain was resistant to several antibiotics. The aim of the study were to identify the
resistance of S. aureus to methicillin and the clonal association between dairy cow
and human isolates.
Staphylococcus aureus strains used in this study were isolated from human
skin infections of RSUP Dr. Sardjito Yogyakarta (10 isolates) and from dairy cows
milk (10 isolates) originated from Yogyakarta, Solo and Boyolali. Bacterial
identifications were performed based on the growth of bacteria on blood agar plate
(BAP) media, Gram staining, MSA fermentation, catalase, coagulase and clumping
factor test, and amplification of specific section of the 23S rRNA gene. The
resistancy assay of S.aureus to methicillin were performed by the disc diffusion
method and the detection of mecA genes by using polymerase chain reaction (PCR)
with specific primers. Determination of the genetic relationships between S. aureus
isolated from dairy cow and human used single enzyme amplified fragment length
polymorphism (AFLP) technique and sequencing of mecA genes of MRSA strains
were analysed by phylogenetic tree.
The results showed that all isolates from human and dairy cow (21 isolates)
were S. aureus based on the phenotypic and genotypic identification. The bacteria
were resistant to methicillin for 7 (33.3%) isolates by disc diffusion test, but there
were 9 (42.9%) isolates expressed mecA gene. Seven S. aureus isolates methicillin
resistant, there were 5 isolates expressed mecA gene and 2 isolates without
expression of mecA gene. On the other hand, there were 4 S. aureus isolates
sensitive to methicillin, expressed mecA gene. A single enzyme AFLP analysis
revealed 15 patterns named A to O and could be clustered into 7 clusters (I to VII).
Staphylococcus aureus isolated from dairy cow wich location is close to each other
in Boyolali and Solo, grouped in one cluster (exept 1 dairy cow isolate from
Yogyakarta), dairy cow and human isolates in Yogyakarta grouped into several
clusters. Each cluster could be detected MRSA strains. Based on the phylogenetic
tree analysis of the sequence of 9 S. aureus were positive mecA gene (6 human
isolates and 3 dairy cow isolates), there were grouped into 3 types of MRSA. In
conclusion, the molecular technique was more sensitive method in detecting MRSA
compared to the classical disc diffusion method. The genotypic analysis of the
present stydy might help to understand the distribution of S. aureus clones between
human and dairy cow isolates and might help to control MRSA infection.
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