Trends of arbekacin-resistant MRSA strains in Japanese hospitals (1979 to 2000).
A total of 472 clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated in Japan between 1979 and 2000 were investigated for resistance to 8 aminoglycosides, 4 aminoglycoside-modifying enzyme gene profiles, and AluI-restriction fragment length polymorphism of the coagulase gene determined by polymerase chain reaction assay. The majority of MRSA strains tested belonged to 4 groups based on coa-RFLP: L21, L22, L31, and M22. About 90% of recent isolates belonged to type L21, indicating the spread of a specific type of MRSA in Japan. Of the type L21 strains, 41.9% included the aac(6')/aph(2") gene, which was one of the risk factors of arbekacin (ABK) resistance, but only 5.5% were resistant to ABK. In contrast, all of the type M22 strains carried aac(6')/aph(2") and 70.1% showed ABK resistance. Among the other types, less than 20% of strains showed ABK resistance. These results suggested that ABK has maintained potent activity. If the predominance of type L21 continues, there will be no progression to ABK resistance in MRSA. However, it may be necessary to monitor the trends in type M22 continuously.
Tsuchizaki
Naofumi
N
Department of Bioactive Molecules, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo 162-8640, Japan.
Ishino
Keiko
K
Saito
Fumiko
F
Ishikawa
Jun
J
Nakajima
Mutsuyasu
M
Hotta
Kunimoto
K
D000617:Aminoglycosides / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D003030:Coagulase / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D003982:Dibekacin / Q000031:analogs & derivatives* / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D004798:Enzymes / Q000235:genetics; D006761:Hospitals; D006801:Humans; D007564:Japan; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003030:Coagulase; D004269:DNA, Bacterial; D004798:Enzymes; D003982:Dibekacin; C024669:endodeoxyribonuclease AluI; D015252:Deoxyribonucleases, Type II Site-Specific; C031986:arbekacin