Jpn. J. Infect. Dis., 55, 2002

Laboratory and Epidemiology Communications

Molecular Epidemiology of Methicillin‑Resistant Staphylococcus aureus
in a Kumamoto Hospital in 2001
Fumio Kawano*, Hisayoshi Miyazaki, Jun‑ichi Takami, Tomoko Fujinol,
Katsutoshi Sarutal and TeruO Kirikael
Kumamoto National Hospital,
Ninomaru ll5, Kumamoto 860‑0008 andJInternational Medical Center ofJapan,

Toyama 1‑21‑1, Shinjuku‑ku,乃b)0 162‑8655

Communicated by Hiroshi Yoshikura(Accepted April 3, 2002)

Methicillin‑resistant Staphylococcus aureus (MRSA) is a

isolates had a spectrum of drug‑resistance showlng Seven

major nosocPmial pathogen in healthcare facilities (1)･

different pattems. Those isolates were resistant to 7‑9 0f 1 1

EpidemiologlCal analysts Of MRSA isolates present in atested dmgs. No isolate was resistant to either vancomycln Or

hospital, assisted such as by restriction fragment lengtharbekacin. No correlation was fわund between the antibiotic

polymorphisms of genomic DNA uslng Pulsed‑field gelelectrophoresis (PFGE), is essential for assessment of hospital

pattems and PFGE pattems (data not shown).

infection controls (2).

type II, and two isolates produced coagulase type III. Twenty‑

Among 29 MRSA isolates, 27 isolates produced coagulase

Fifty‑six MRSA isolates were obtained from 22 inpatientseach derived from a slngle patient, Were analyzed forsix isolates produced enterotoxin type C, three isolates
enterotoxin type B, three isoletes enterotoxin types B and D,
and three isolates enterotoxin other than types A, B, C, andD. Twenty‑six isolates produced TSST‑1, but three did notchromosomal DNA typlng by uslng a COntOur‑Clamped

produce it. Collectively, among 29 MRSA isolates, 26 iso‑fTrom October 2001 in a hospital with ll wards and 550 bedsin Kumamoto Prefecture. Among these isolates, 22 isolates,

homogeneous electric field system (CHEF MapperTM: BioI

lates produced coagulase type II, enterotoxin type C, andRad Laboratories, Hercules, Calif･, USA), antibiotic resistan?e

TSST‑I, i.e., most of the isolates shared common character‑(VITEKTM: bioMerieux, Marcy‑1'Etoile, France), enterotoxln

istics regarding these parameters.

Pattems Al, A6, and A2 (Ml) detected in this hospital had

serotyping (SETJRPLA: Denka Seiken Co., Tokyo), toxic
shock syndrome toxin‑1 (TSSTll) production (TSTIRPLA:Denka Seiken), and coagulase serPtyping (Denka Seiken)A In

been detected in a hospital in Tokyo (Fig. 3) (2,3). Amongthese patterns, pattern AI was the most frequent in boththe present study,也e isolates showlng the same PFGE pattems

hospitals (Fig. 2B) (2,3). The data indicate血e clonal expansion

were considered to have the same orlgln.

of MRSA not only within hospitals but also nationwide.

Ten different PFGE patterns of SmaI DNA digests weredetected (Fig. 1 ). A band‑based cluster analysis ofmese pattems(MolecularAnalystTM : BioIRad) revealed five clusters (clustersM 1 2

34567

8

9 10M

A/U, M, V, 0, and W) (a cluster was defined as a group ofpatterns with more than 70% similarity) (Fig. 2A). A
frequency distribution of MRSA isolates based on PFGE
pattems is shown in Fig. 2B. The most frequent pattern(Al)represented 45.5% of the total isolates. The top丘Ve clusters,Al,A6, Ul, U2, andA2, made up 77.3 % of the total isolates.
A geogr叩hic distribution ofMRSA isolates in the hospital isshown in Table 1. The two, two, four, and two isolates fromwards el, e2, e3, and wl, respectively, belonged to the samecluster, Al , suggestlng a quite extensive spread by secondary

infections. Moderate spread was observed for MRSA in clustergroups Ul and U2, i.e., two isolates from wards a3 and a5
belonged to the same cluster, Ul , and two isolates from wards
el and a6 to the same cluster, U2. Two isolates belonglng tOcluster A6 were isolated from the ward wl, suggestlng aspread within the ward. Isolates with pattems A2, M5, M6,05, V2, and W appeared to be limited to wards e3, a6, el, al,a5, and a2, respectively.

Sensitivity to antibiotics is shown in Table 2. The MRSA
Fig. 1. Pulsed‑field gel electrophoresis ofSmaI‑digested genomic DNA

from MRSA isolates. M: low range PFG Marker. Lanes 1 to 10:*Corresponding author: Fax: +8 1‑96‑325‑25 19, E‑mail: f‑kawano

MRSA isolateswith different PFGE pattemsAl to W shown in Fig.

@sa2.so‑net.ne.jp

2A.

29

Jpn. J. Infect. Dis., 55, 2002

A5060709080

1 0 0 円1%

Table 1. Distribution ofMRSA in a hospitalヽ■/A l朋舶=1mM Ⅵ0 5We12#A l舶舶M M o 5U 1 SⅥW

22W

31231235624 12■●11つエ一 O#Number of patients with MRSA(.oN)saTt!TOStQC▲U420

Table 2. Antibiotic patternclassfied by antibiotic patternof 1 1 antibiotics

agalnSt MRSA
Antibiotic pattem

a一b C d e flAI

A6UIU2A2M5M605

V2Antibiotics

EM良良良良良RI

GMMINO

RR良sssR

良sI良siSABKSSSSSSSVCM
SSSSSSSW

Fig･ 2･ Cluster analysュs OrMRSA isolates based on PFGE pattems.

弧40l

印

00.

F.

8I

2110■ 0%nJ.JU

ヽ■/K一〇 〇T一〇 〇 〇 〇 〇 〇 〇 〇A A A A A A 1 3 1 5 ′b 1 1 1 4 0ノ l

#All the isolates were resistant to MPIPC, ABPC, PIPC, CEZ, CMZ,
1 4 5 ′0 3IPM.
MPIPC: oxacillin, ABPC: ampicillin, PIPC: piperacillin, CEZ: cefazolin,
CMZ: cefmetazole, IPM: imipenem/cilastatin, EM: erythromycin, GM:gentamicin, MINO: minocyclin, ABK: arbekacin, VCM: vancomycln,
良: resistant, S: susceptible, Ⅰ: intemediate.

A17

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A18(M2)
A19(M3)
M4
M5〇〇〇〇M6

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Fig･ 3･ Cluster analysts Of MRSA isolates based on PFGE pattems.
K: Kumamoto hospltal, T: Tokyo hospltal.

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