Jpn. J. Infect. Dis., 53, 2000

Laboratory and Epidemiology Communications
An Ou也reak of Enteritis lnduced by Methicillin‑Resistant

Staphylococcus aureus Produclng Enterotoxin Types A and C,
Toxic Shock Syndrome Toxin‑1 and Coagulase Type II
Aki Kaneko, Tetsuo Mori1, Tomoko Fujino, Akio Nakamura, Yoshikazu Naiki,
Masaki Mutohl, Atsuo Nagatal and Teruo Kirikae*
Department of lnfectious Diseases and TTflOPical Medicine, Research Institute,International Medical Center ofJapan,

Toyama 1‑21‑1, Shinjuku‑ku, Tob70 162‑8655 andJNational Nagano Hospital,Midorigaoka 1‑27‑21, Ueda, Nagano 386‑8610
Communicated by Hiroshi Yoshikura(Accepted November 9, 2000)

Methicillin‑resistant Stapkylococcus au71euS (MRSA) is one of the most common pathogens causlng hospital infections( I ). Enteritis caused by MRSA is a serious problem, especiallyfor postoperative patients (2).

'Corres.ponding author･'Fax: +8 1 ‑3‑320217364, E‑mail: tkirikae@

In a hospital with420 beds, 4 patients successively contracted

ri･imq.goJP

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Jpn. J. Infect. Dis., 53, 2000
522, and 524 produced enterotoxin type C in addition.

serious acute enteritis and 2 patients contracted mild enteritis.

MRSA was isolated from the stools of the patients. TheAs summarized in Table 2, four isolates (Nos. 520‑522 andisolates from patientswith MRSA infection or from its524) from serious enteritis patients in either ward 5E or thecarriers in the same hospltal just befわre the outbreak were

ICU shared the same character with the one (No. 412)

tested for chromosomal DNA typlng by using Pulsed‑fieldobtained befわre the outbreak. They all produced enterotoxin

gel electrpphoresis (PFGE) (CHEF Mapper'": Bio‑Rad
LaboratorleS, Hercules, Calif., USA), plasmid DNA typing

types A and C, TSST‑1, and coagulate type H and had thesame PFGE pattern ofSmaI DNA digests, BglI digests andon agarose gel electrophoresIS, antibiotic resistance pattern

BstXI digests (Fig. 4), tわe same spectrum of antibiotic(WalkAwayTM, Dade Behring, Deerfield, Ill., USA), entero‑susceptibility and the same plasmid patem (no plasmid). The

tox享n serotyping (SET‑RPLA: Denka Seiken Co･, Tokyo),toxic Shock syndrome toxin‑1 (TSSTl1) production (TST‑

RPLA: Denka Seiken), and coagulase seIOtyping (Denka80%Seiken).

90%

100%

Six different PFGE patterns ofSmal DNA digests (Fig･ 1)
were detected. A band‑based cluster ana)ysis of these pattems(Molecular Analyst'M: Bio‑Rad) revealed that pattems B to G

shared more than an 89% similarity, while sharing a relatively
lower similarity with pattem A (Fig. 2). There were threedifferent kinds ofplasmidwith sizes of>10 kb, 5 kb, and 2kb (Fig. 3). Twelve isolates had one, two, or three of them(from the carriage pattem of the plasmids, the isolates wereclassified into four groups), while six had none. Sensitivlty

to antibiotics is shown in Table 1; there were four different
patterns. All isolates produced enterotoxin type C, TSSTll ,and type H coagulase (Table 2). Numbers 407 and 414
produced enterotoxin type B, and Nos. 412, 416, 520, 521,Fig･ 2. Cluster analysis ofMRSA isolates based on PFGE pattems orM1 2345

6

SmaI‑digested genomic DNA.

7MM

12

3

45Mー>10kb

ー5kb
ー2kb

Fig･ 3, Agarose gel electrophoresis ofplasmid DNA.
Fig･ I ･ Pulsed‑fleld gel electrophoresis ofSmaI‑digested genomic DNA

Bands of four different sizes were found. A band of the second largest

from MRSA isolates.
Lane 1: PFGEpattemA, 1ane2: B, lane 3: C, 1ane4: D, lane 5: E,

from different plasmids. Lane I : MRSA with no plasmid, lanes 2‑5:

size was derived from fragments of genomic DNA and other bands

lane 6: F, lane 7: G, M: low‑range PFG Marker.

plasmid pattems I‑ⅠV respectively. M: molecular marker.

Table I ･ Antibiotic pattern classified by antibiotic pattem of 1 8 antibiotics against MRSA
Antibiotics Antibiotics listed

CLDM

GMMINOABKVCM

ST

SSR良R

ISIIS

SSSSS

SSSSS

SSSSS

pattem in footnote#aabcd

R良RRR

良氏RS良

" Listed antibiotics are amplCillin, benzyl‑penicillin, cefmetazole, cefotiam, erythromycln, Cefazolin,fosfomycin, nomoxef, imlpenem/cilastatin, levonoxacin, oxacillin, and piperacillin.

CLDM: clindamycin, GM: gentamicin, MINO: minocycline, ABK: arbekacin, VCM: vancomycln,ST: streptomycin, 良: resistant, S: susceptible, 1: intemediate.

213

Jpn. J. Infect. Dis., 53, 2000
BgIlβ∫/ XIM 1 23456

M1 27M

34567

M

Fig. 4. Pulsed‑fleld gel electrophoresis ofBglI‑digested or BstXI‑digested genomic DNA from MRSA isolates producing
enterotoxins A and C.

Lanes 1 to 6: enterotoxin A/C producing MRSANos. 412, 416, 520‑522, and 524. Lane 7: enterotoxin B producing MRSANo. 525. M: low range PFG Marker.

Table 2. Phenotypic and genotypic characterization of the S. aureus isolates%ol:aTbo,onf symptoms i慧乙toefs ward ･solationpan SpsaF;GeaHniittioiic P,1aatst:id Enterotoxin ,SST‑1 Coatyg,uiase
Julycame一407

3W

408

409
4ICU

1041

141

2

Ccavity

C+lI

D+

Il

pus

B+

ⅠⅠabdomen

A+

ⅠⅠ+

ICU

sputum3E

1CU

sputum

E

4I

42W

sputumF

5W

tracheaG

6E

trachea

AfecesA

6520

ⅠⅠpharynx

5E

5+ccc ACc

3IBCB

14‑Ⅳ1日ⅢbCdacaaa

sputum441August watery diarrhea

nasal

4W

5E,ICU+BCbIl一Ca++I

11+

HaAC+lIlI

52

5E

feces

AaAC+watelY diarrhea

522

5E,ICU

feces

AaAC+

mild dia汀hea

523

4W

feces

watery diarrhea

524

1CU

feces

mild dia汀hea

525

6W

feces

a a JulIC

IVBC+

AC

results indicated that an enterotoxins A and C‑ and TSST‑1‑HIl

ACwatery diarrhea

1ⅠⅠ++Il

ⅠI

1l

IlSemin. Perinato1., 22, 25‑32.

producing MRSA strain caused enteritis in the ou他reak. Tわxin

2. Kodama, T., Santo, T., Yokoyama, T., Takesue, Y.,production is a use凡ll marker in predicting MRSA enteritis

Hiyama, E., Imamura, Y., Murakami, Y., Tsumura, H.,
Shinbara, K., Tatsumoto, N. and Matsuura, Y. (1997):

outbreak.

Postoperative enteritis caused by methicillin‑resistant

Staphylococcus aureus. Surg. Today, 27, 8 1 6‑825.

REFERENCES

1. Baltimore, R. S. (1998): Neonatalnosocomial infections.

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