An epidemiologic survey of methicillin-resistant Staphylococcus aureus by combined use of mec-HVR genotyping and toxin genotyping in a university hospital in Japan.
OBJECTIVE
To evaluate the usefulness of an assay using two polymerase chain reaction-based genotyping methods in the practical surveillance of methicillin-resistant Staphylococcus aureus (MRSA).


METHODS
Nosocomial infection and colonization were surveyed monthly in a university hospital in Japan for 20 months. Genotyping with mec-HVR is based on the size of the mec-associated hypervariable region amplified by polymerase chain reaction. Toxin genotyping uses a multiplex polymerase chain reaction method to amplify eight staphylococcal toxin genes.


RESULTS
Eight hundred nine MRSA isolates were classified into 49 genotypes. We observed differing prevalences of genotypes for different hospital wards, and could rapidly demonstrate the similarity of genotype for outbreak isolates. The incidence of genotype D: SEC/TSST1 was significantly higher in isolates causing nosocomial infections (49.5%; 48 of 97) than in nasal isolates (31.4%; 54 of 172) (P = .004), suggesting that this genotype may represent the nosocomial strains.


CONCLUSIONS
The combined use of these two genotyping methods resulted in improved discriminatory ability and should be further investigated.
Nishi
Junichiro
J
Kagoshima University Hospital, Infection Control Team, Japan.
Yoshinaga
Masao
M
Miyanohara
Hiroaki
H
Kawahara
Motoshi
M
Kawabata
Masaharu
M
Motoya
Toshiro
T
Owaki
Tetsuhiro
T
Oiso
Shigeru
S
Kawakami
Masayuki
M
Kamewari
Shigeko
S
Koyama
Yumiko
Y
Wakimoto
Naoko
N
Tokuda
Koichi
K
Manago
Kunihiro
K
Maruyama
Ikuro
I
D001427:Bacterial Toxins / Q000235:genetics*; D015373:Bacterial Typing Techniques / Q000379:methods* / Q000592:standards; D002353:Carrier State / Q000453:epidemiology / Q000382:microbiology; D022801:Complementarity Determining Regions / Q000235:genetics; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics*; D016002:Discriminant Analysis; D004196:Disease Outbreaks / Q000706:statistics & numerical data; D004768:Enterotoxins / Q000235:genetics; D005083:Exfoliatins / Q000235:genetics; D005838:Genotype; D006785:Hospitals, University; D006801:Humans; D015994:Incidence; D017053:Infection Control / Q000379:methods; D007564:Japan / Q000453:epidemiology; D016106:Methicillin Resistance / Q000235:genetics*; D009666:Nose / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods* / Q000592:standards; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000235:genetics*; D018089:Superantigens
D001427:Bacterial Toxins; D022801:Complementarity Determining Regions; D004269:DNA, Bacterial; D004768:Enterotoxins; D005083:Exfoliatins; D018089:Superantigens; C030107:enterotoxin F, Staphylococcal