[Detection of methicillin-resistant Staphylococcus aureus by polymerase chain reaction].
The low-affinity penicillin-binding protein (PBP 2') is associated with methicillin-resistance of Staphylococcus aureus and its structural gene (mecA) not present in methicillin-susceptible S. aureus could be detected by the polymerase chain reaction (PCR) method, in which a 533 bp region of mecA was amplified and detected by agarose gel electrophoresis. Survey for the mecA gene in 210 clinical isolates of S. aureus revealed that, while there was a gross correlation between the presence of the mecA gene and the resistance level to beta-lactams, three strains of mecA (+) tested showed beta-lactam susceptibility similar to those of mecA (-) strains. These three strains did not produce a detectable amount of PBP 2' constitutively nor inducibly, which was the cause of their high susceptibility to beta-lactams. One of them yielded a typical methicillin-resistant variant at a low frequency with a concomitant recovery of PBP 2' production when the bacterial cells of high density were spread onto an agar plate containing 10 micrograms/ml of oxacillin. These findings suggested that typical methicillin resistant S. aureus occurred during chemotherapy with beta-lactam antibiotics even when resistant strains could not be detected by the susceptibility test and thus all mecA (+) strains including those with high susceptibility should be precisely detected.
Murakami
K
K
Shionogi Research Laboratories, Shionogi & Co., Ltd., Osaka.
Minamide
W
W
Wada
K
K
Nakamura
E
E
Teraoka
H
H
Watanabe
S
S
D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000096:biosynthesis; D005798:Genes, Bacterial; D006602:Hexosyltransferases; D016106:Methicillin Resistance; D002267:Muramoylpentapeptide Carboxypeptidase / Q000096:biosynthesis; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D016133:Polymerase Chain Reaction; D013211:Staphylococcus aureus / Q000235:genetics / Q000302:isolation & purification*
D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase