Jpn. J. Infect. Dis., 54, 2001

Laboratory and Epidemiology Commumications

Molecular Epidemiology of Methicillin‑Resistant Staphylococcus aureus
in a Tbkyo Hospital in 2001
Tomoko Fujino, Namiko Mori, Akihiko Kawana, Yoshikazu Naiki, Hisashi Kawahata,
Tadatoshi Kuratsuji, Koichiro Kudo, Oichirou Kobori, Yoshio Yazaki and Teruo Kirikae*
In ternational Medical Center ofJapan,
Toyama 1‑21‑1, Shinjuku‑ku, Too,0 162‑8655
Communicated by Hiroshi Yoshikura(Accepted December 1 2, 2001 )Methicillin‑resistant Staphylococcus aureus (MRSA) is aEpidemiological analysts Of MRSA by means of restriction

frequent one (A4) represented 15%, 14%, and 12% of total
isolates, respectively. Distribution of MRSA isolates in thewards is shown in Table 1. The isolates belonglng tO PFGE

fragment length polymorphisms ofgenomic DNA as revealed
by pulsed‑field gel electrophoresis (PFGE) is essential for

pattem A spread over the different wards; more specifically,PFGE pattem A4 was detected in wards 4N, 4S, 8N, 9S, 12S,

major nosocomial pathogen in healthcare facilities (1).

assessment of hospital infection controls (2).

16, and ICU. Two or more different PFGE pattems wereTwo hundred MRSA isolates were obtained from 61 inpa‑tients in October 2001 in a hospital with 27 wards and 925

detected in some of the same wards, such as 7N, 7S, 9S, 12S,and 13N. The isolates with pattem JI contributed to a MRSA

beds in Tbkyo. Sixty‑one of the isolates, each derived丘om aoutbreak in a tuberculosis ward in June 2001 (3).

single patient, Were analyzed for chromosomal DNAtyping

Sensitivityto antibiotics is shown in Table 2. The MRSA

by uslng a contour‑Clamped homogeneous electric field

isolates had a wide spectrum of drug‑resistance; there weresystem (CHEF MapperTM: Bio‑Rad Laboratories, Hercules,

22 different pattems. Those isolates were resistant to 10‑ I 3
drugs of the 17 dmgs tested. All isolates were sensitive toCalif. , U SA),and for antibiotic resistance (WalkAwayTM: DadeBehring, Deerfield, 111･･ USA), enterotox!n serotyping (SET‑vancomycln and streptomycin. All of the three isolates with

RPLA: Denka Seiken Co., Tbkyo), toxIC Shock syndrome
toxin‑ 1 (TSST‑ 1 ) production (TSTIRPLA: Denka Seiken), andcoagulase serotyping (Denka Seiken). Isolates showing theantibiotic pattem u had PFGE pattem Jl. No other co汀ela‑tion was found between antibiotic resistance pattems andPFGE pattems (data not shown).

Among the 61 MRSA isolates, 58 isolates produced

same PFGE pattems were probably of the same ongln.

Thiny different PFGE pattems of SmaI DNA digests werecoagulase type II, and the remaining three pro血ced coagulase

detected (Fig. I ). A band‑based cluster analysis (Moleculartype I, ⅠⅠⅠ, or IV Forty‑seven isolates produced enterotoxin

AnalystTM: Bio‑Rad), in which PFGE‑band similarityexceed‑

type C, four isolates enterotoxin type B, three isolates

lng 70% was used as the criterion of cluster formation,
revealed ll pattem clusters: A, G, J, M, N, 0, P, Q, R, S, andT (Fig. 2A). Frequency distribution ofMRSA of these dimerent
PFGE pattems is shownin Fig. 2B. The most frequent pattem

enterotoxin types B and D, two isolates enterotoxin A, oneisolate enterotoxintypes A and C, one.isolate enterotoxintypes

B and C, and three isolates enterotoxln Other thantypes A, B,C, or D･ Pony‑n享ne isolates produced TSST‑1 , and the other 12

did not. CollectlVely, among 61 MRSA isolates, 47 isolates(Al), the second most frequent one (A3), and the third mostM 1 23456789101112131415161718192021222324252627282930M

Fig･ 1 ･ Pulsed‑field gel electrophoresis ofSmaI‑digested genomic DNA from MRSA isolates･ M: low range PFG Marker･Lanes I to 30: MRSA isolates with different PFGE pattems Al to T shown in Fig･ 2B･*Corres.ponding author: Fax: +8 1 13 13202‑7364, E‑mail: tkirikae@
ri.imq.goJp240

Jpn. J. Infect. Dis., 54, 2001

produced coagulasetype II, enterotoxintype C, and TSST‑1.
PFGE‑based MRSA surveillance was conducted in theA3, A4, A5, All, Gl, and G3 Were detected in the present
study and in that conducted in December 2000. PFGE pattems

same hospital in December 2000. PFGE pattems A 1 , A2(M l ),A14to 17,M2to4,N,01 to4,P,Q,R,S,Jl,J3,J4,andT
were newly detected the present study. Rapid turnover ofMRSA as well as persistence or some other MRSA strains
3.0

4.0

5.0

6.0

7.0

8.0

9.0

occumd in the hospital.

1?0(%)

Phenotyplng based on antibiotic sensitivities and other bi0‑

Al ●‑
A3 ●‑

10glCal properties was fわund unsuitable f♭r assesslng MRSA

AH●‑

epidemiology in healthcare facilities.

A相:･u 5.,もIfi

A!,ちA17
A4 ◆‑

A少●‑

A5‑
M 1(A2)●‑.tlTユM3汚′日(.oN)S37tFtOSt

ヽ0l8よV4i.)203
OJG3●‑Gl●‑PcyI /)=お山T

首号音音響o"on等群発官職好守ob88 4Y舛帆BFig. 2. Clusteranalysis ofMRSA isolates based on PFGE pattems.
MRSA isolates indicated in bold and arrows were also detected in the previous surveillance (3).

Table 1. Distribution ofMRSA in a hospital
PFGE patternA13榔哨洲粥帥鵬Ⅷ乃附的州娼ー｡Nl S…朋12N ‑S1 N朋̲‑ ̲6K

42 159ll13G
141516

∫
1713

M
1N

341023P4q12氏34〟11421

211121I1U#Number or patients wi仇MRSA

241

1ST

Jpn. J. Infect. Dis., 54, 2001
Table 2･ Antibiotic patternclassfied by antibiotic pattern of 17 antibiotics agalnSt MRSA
Antibiotic

PattemcdgilkIm0pqu>WxyZ組曲∝adEM
臥良R 良 良 良 R良 良 良 良氏良 s

LVFX
R良I R良1 良 良1 良 良 IS

Antibiotics

1

CLDM

FOMGM良 良s良R良氏良 s R良s良s 良 s良氏良 良 良 良sIS1良s良sR良1IS良R良氏良s s 良s良 R良s s良s

ABKM N0VC M

STS S S S R良s s s

IS ■1S ･ 1SI‑lt T▲

SSSSSSSSSSSSH日日All the isolates were resistant to PCG, MPIPC, ABPC, CEZ, CTM, CFDN, FMOX, IPM.
PCG:benzyl‑Penicillin, MPIPC: oxacillin, ABPC: ampicillin, CEZ: cefazolin, CTM: cefotiam,
CFDN: cefdinir, FMOX: flomoxef, IPM: imlPenem/cilastatln, EM: erythromycirL, LVFX.Alevonoxacin, CLDM: clindamycin, FOM: fosfomycin, GM: gentamicin, ABK: arbekacin, MINO:
minocyclin, VCM: vancomycln, ST: streptomycin, R: resistant, S: susceptible, hntermediate.

Staphylococcus aureus in a Tokyo hospital in 2000. Jpn.

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Semin. Perinato1., 22, 25‑32.

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