Heterogeneously vancomycin-intermediate Staphylococcus aureus (hVISA) emerged before the clinical introduction of vancomycin in Japan: a retrospective study.
Vancomycin-intermediate Staphylococcus aureus (VISA) and its precursor, heterogeneous VISA (hVISA), are increasingly the cause of vancomycin treatment failure. Prolonged glycopeptide treatment causes the emergence of these pathogens. However, we recently reported that hVISA can be generated by methicillin-resistant S. aureus (MRSA) exposure to imipenem (Katayama et al., Antimicrob Agents Chemother. 53:3190-6). We report here a retrospective prevalence study of VISA and hVISA on 750 MRSA clinical strains isolated from 31 Japanese national university hospitals in 1990, the year before the introduction of injectable vancomycin into clinical use in Japan in 1991. No VISA strain was identified, but population analysis identified 38 hVISA strains (5.1%) from 19 hospitals. We also determined the nucleotide sequences of vraSR, walRK,                         clpP, and rpoB genes whose mutations are known to be associated with vancomycin resistance. When compared with vancomycin-susceptible MRSA strain N315, six of the 38 hVISA strains possessed nonsynonymous mutations in vraSR, seven in walRK, and two in rpoB genes, Thirteen of 38 (34.2%) hVISA strains possessed at least one of these mutations. Results were consistent with our hypothesis that hVISA was present in Japanese hospitals before the clinical introduction of vancomycin.
Department of Orthopaedic Surgery, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Jun
J
Yamakawa
Mayumi
M
Aminaka
Katsuko
K
Okuzumi
Hiroyoshi
H
Kobayashi
Yuki
Y
Katayama
Shigemi
S
Kondo
Ayako
A
Nakamura
Toyoko
T
Oguri
Satoshi
S
Hori
Longzhu
L
Cui
Teruyo
T
Ito
Jingxun
J
Jin
Hisashi
H
Kurosawa
Kazuo
K
Kaneko
Keiichi
K
Hiramatsu
D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D021821:Communicable Diseases, Emerging / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D015378:Imipenem / Q000494:pharmacology / Q000627:therapeutic use; D007564:Japan / Q000453:epidemiology; D012189:Retrospective Studies; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D014640:Vancomycin / Q000494:pharmacology / Q000627:therapeutic use; D020713:Vancomycin Resistance
D000900:Anti-Bacterial Agents; D014640:Vancomycin; D015378:Imipenem