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

Laboratory and Epidemiology Communications

Molecular Epidemiology of Methicillin‑Resistant Staphylococcus aureus
in a Communlty Hospital in Hiroshima
Junko Kawasaki, Tomoko Fujinol, Yoshikazu Naiki., Namiko Mori.,
Rie Sasaki, Norikazu Shigeto and TeruO Kirikael *National Hataka Hospital,
Hataka 2‑1411, Aki, HiflOShima 736‑0088 andJlnternational Medical Center ofJapan,

Toyama 1‑21‑1, Shinjuku‑ku, Too)0 16218655
Communicated by Hiroshi Yoshikura(Accepted June 20, 2001)

Methicillin‑resistant Staphylococcus.aureus (MRSA) is amajor nosocomial pathogen in hospitals, Including community
hospitals with relatively small number of beds ( 1 )･ Restriction

fragment length polymorphism analysis Of genomic DNA
using pulsed‑field gel electrophoresis (PFGE) is a powerfultool for assessment of hospital infection controls (2).

The present study was conducted in a hospital in Hiroshima

with two wards and 100 beds. In August 2000, MRSA was
isolated from five patients'sputa in ward I and three patients'

sputa and one patient's stool specimen in ward II. In December,
MRSA was isolated丘om five patients'sputa and one patient's

pus in ward 1 and two patients'sputa in ward II. At the time,a MRSA survey of the hospital persormel was perfomed andfive camiers were detected, including a doctor and four nurses,

Fig. 1 a. Pulsed‑field gel electrophoresis ofgenomic DNA from MRSA

isolates. Upper panel: Smal‑digested genomic DNA. Lane 1 : MRSA

among eight doctors and foれy‑three nurses. The isolates fromthe patients and the carriers were tested for chromosomal DNA

isolateNo. 395, lane 2: No. 397, lane 3: No. 635, 1ane4: No. 401,
lane 5: No. 399, 1ane6: No. 627, Iane 7: No. 396, lane 8: No. 636,

typing by using a contour‑clamped homogeneou.s electric fieldIane9: No. 629, 1aneIO: No. 634, lane ll: No. 623, lane I2: No. 630,

system (CHEF MapperTM, Bio‑R礼d LaboratorleS, Hercules,

lane 13: No. 398, lane 14: No.404, 1ane 15: No. 628. M: lowrange

Calif., USA), enterotoxin serotyping (SET‑RPLA, Denka
Seiken Co., Tokyo), toxic shock syndrome toxin‑1 (TSST‑ 1 )PFG Marker.

production (TST‑RPLA, Denka Seiken), and coagulase
serotyping (Denka Seiken).
FiReen different PFGE pattems of Smal DNA digests were50

6070detected (Fig. la). Band‑based cluster analysis of these80q山心 14加rI<舶A1O胡BCDl比Epattems (MolecularAnalystTM, Bio‑Rad) revealed five clusters
A to E (Fig. lb) (pattems sharing a similarityof70% Or higher
were grouped into a cluster). Pattems 良 and C exhibited morethan 60% similarityto pattems A and D. E shared less similarity
with the others (Fig. lb). MRSA isolates with PFGE pattem
A (Nos. 395, 396, 397, 399, 400, 401, 402, 624, 625, 626,627, 629, 633, 634, 635, 636, and 641), and isolates withpattems 良 (No. 623) and C (No. 630) produced enterotoxin

type C, TSST‑1, and coagulasetype II (Table 1)･ Isolates withPFGE pattem D (Nos. 398 and 404) produced enterotoxin
type B and coagulase type II, but did not produce TSST‑1(Table 1). An isolate with pattem E (No. 628) produced
enterotoxin D and nontypable enterotoxin other than types
A, B, C, orD (Table 1).

All of the five MRSA isolatesfrom ward I in August wereof cluster type A and producers of enterotoxin type C, TSST‑
1, and coagulase type ll. Four of six isolates from the sameward in December were of the same type, and all the clinicalFig. lb. Cluster analysis orMRSA isolates based on PFGE pattcms or*Corresponding author: Fax: +8 1 ‑3‑3202‑7364, E‑mail: tkirikae

Smal‑digested genomic DNA.

@ri.imcj.go.jp
117Jpn. J. Infect. Dis., 54, 2001
Table I. Phenotypic and gcnotypic characterization of the S. aweus isolates
Isolatemonth

WardPatient(P)/Isolate

No.

2000

MedicalIsolation

PFGE

part

二二二二August

TSST‑1

Coagulase
typ cSptl tum

AI

1399

SPutumA5ll

Ⅰ400

Spu tum

AIll

1401

Spu tum

A4ll

1402

SputumAI日

11396

Sputum

A7II

11397

feces

A2

II

1Ⅰ

398

Spu tum

DIII

1404

sputumD2ll

1

DecCmbcr

nr nr Dl nr nr nr nr nrEnterotoxin

Pa ttern

personncl(M)3195‑ 2 つJ 4 5 ′hY 7 史U

P9

CCCCCCCBB+++++++ll623

P

10sputum

a1624

P11sputum

AI+

1625

P

12sputum

AI+

lI

Ⅰ626

P

13sputumAI+

111627

P 1 4spu山mA6+

1628

P1511629

PI

6sputum

A9+

11630

P

17sputum

C+

11+

ⅠⅠ

1‑ーI t･mu 一

Illl

NTEpus

M 1 nasal cavity A 1
M M M M2 tJ 4 5

CCCCCDCC

CCCCC

ll

nasal cavity+

11

nasalcavity+

ⅠⅠnasal cavity+

ⅠⅠnasal cavity+

ⅠⅠ

NT: nontypable

personnel (Ml‑M5) carried MRSA of the same type. MRSAK･, FunlmOtO, A･, Kobayashi, S., Sato, A. and Nagatake,of the same type was isolated in ward II inAugust ( Nos. 396and 397) and December (No. 629). The above observation

T･ (200 I ): Emergence and spread of low‑level mupirocin

appears to suggest that the main MRSAinfections during theobservation period were initiated by a slngle MRSA strain

isolated from a community hospitalin Japan. J. Hosp.

which mainly spread in ward I through medical personnel or

2. Fujino, T., Mori, N., Kawana, A., Kawabata, H., KuratsuJl,T., Kudo, K., Kobori, 0., Yazaki, Y. and Kirikae, T.

resistance in methicillin‑resistant Staphylococcus aureus
Infect., 47, 2941300.

other vehicles.

(200 1 ): Molecular epidemiology or methicillin‑resistant
Staphylococcus aweus in a Tokyo hospital in 2000. Jpn.

REFERENCES

J. Infect. Dis., 54, 91‑93.

1. Watanabe, H., Masaki, H.,Asoh, N., Watanabe, K., Oishi,118