Laboratory and EpidemiOlogy Communications

ls There a Relation between the Antibiotic Sensitivity of Methicillin‑Resistant

Staphylococcus aureus and the Consumption of Antibiotics in a Hospital?:a Study from April 1993‑March 1999
Junko Kizu, Motoki Arakawa and Kenji Yamamotol,2*Kyoritsu College of Pharmacy,
Shibakoen 1‑∫‑30, Minato‑ku, To砂0 105‑8512,

lDepartment ofMedical Ecology and lnformatics, Research Institute, International Medical Center ofJapan,

Toyama 1‑21‑1, Shinjuku‑ku, Too)0 162‑8655,
2Department of Chemical System Enginering, Faculo, of Engineering, Universio, of To砂0,

Hongo 7‑3‑1, Bunk)0‑ku. Too)0 113‑8656
Communicated by Hiroshi Ybshikura(Accepted June 1 1, 2002)

We investigated a possible relation between antibioticusetion (MIC) was measured using the micro‑liquid‑dilution

and the development of resistance to each antibiotic inmethod (1). The isolates were grouped into three groups,

methicillin‑resistant Staphylococcus a㌢"'eus (MRSA) ･susceptive (SHntemediate (Ⅰ), and resistant (良), according

The percentage OfMRSA isolates resistant tO eaChantibiotic

to the MIC value (1).

and amount of the antibiotic prescribed were fわllowed in a

Each graph in Figure l shows the follow‑up of annual

hospital with 245 beds from April 1993 to March 1999. Anti‑
biotic sensitivity in terms of minimum inhibitory concentra‑

consumption of an antibiotic and the frequency of MRSAs
classified according to the grade of resistance tothe same
antibiotic. Based onthis data, the correlation coefficient*Corresponding author: E‑mail: backen@ri.imcj.go.jp

between the total amount of an antibiotic used in each year65

Jpn. J. Infect. Dis., 55, 2002
Table 1. The correlation coefrlCient between the doseper year and theand the舟equency of the isolates resistant to the antibiotic insusceptibil ity

the same year was calculated (Table 1). Only imipenem/

antibiotic correlation coefficient P value cilastatin (IPM) showed a significant positive correlationwith
imipenem/cilastatin (lPM)

0.937

0.006

sulbactam/ampicillin (SBT/ABPC)

0.960

o.856

antibiotics, no correlation was seen between the development

10.520o.290

0f antibiotic resistance and the amount of the antibiotic used.

Namely, lnCreaSed use of IPM may result in the development

cefazolin
cefbtiam(CEZ)

cefepime

0.

132

0.804

‑0.

122

o.819

0f resistance to this drug, but, for other antibiotics, an0.5

1o.298increase or decrease of their use did not result in the increase(CTM)

cefmetazole(CMZ)(CFPM)

minocycline (MINO)
fosfomycin(TOM)

levofloxacin

a correlation coefrlCient ofO.93 (P value ‑ 0.006). For other3o. 1 67

0r decrease of their resistant strains, respectively. In the case63o.757

0f minocycline (MINO), decreased use did not result in the‑0.257

o,623

decrease of the resistant stralnS though the resistant strains

10.6450.

(LVFX)

1

continued to increase (Fig. 1), For vancomycin (VCM),
desplte the increase of its use, resistant MRSA has not yet

The correlation coefficient between the total amount of an antibiotic
used in each year and the frequency of the isolates resistant to theappeared.

antibiotics in the same year was calculated,

The process of the development of antibiotic resistance is,M 円 PC
2 2 1 1 5 (U 5 nVnV ∩> 0 0

SBT/ABPC12000

1 20000000

1 0000

1 叩 80 60

1 o 8 6 4 20 0 0 0 0^lH!qIldBSne^)!I!qI.Id85SnC^t![!qudeDSnの糾印4nV nV 0000

りSOP

10000

1 O 8 6 40 0 nU 0

8000

GrのOPq)6000 doて)
44000

20 0

2000
000

1993 1994 1995 1996 1997 1998

1993 1994 1995 1996 1997 1998

CEZ

CTM

1993 1994 1995 1996 1997 1998

CMZ
454 035苅25201 51 050

rlro m仰o m o 叩045 04 035｡刑25｡2 0 1 5 01 0｡脚oo o 即 60 4 0 21^)!r!q!)d￠uSnSnV 8 6 4 20 0 (UO O0 0 0 0 (U倉Hq!】daDSnの申SOP

1993 1994 1995 1996 1997 1998

CFPM
4一4 3 3 2 2 1 1 5 n0U 5 0 L ' 0 5 0 0

中のOP

1993 1994 1995 1996 1997 1998

1993 1994 1995 1996 1997 1998

MINO戸OM

相関印o 伽叩o m o

500
nrL

1 0 0 8 0 60 40 2 010 8 6 40 0 0 000000

400^lt[!q!]d8SnS

着(!q!td3SnS

着一!qItdGpDSnの∩) 8 6 4 23OO o

中SOPtI)

0200て〉

1000

1993 1994 1995 1996 1997 1998

1993 1994 1995 1996 1997 1998

1993 1994 1995 1996 1997 1998

VCM

ABK

LVFX
12000
｢l (U 8 6 4 2100
^l!ニqtldeDSnS1 000000000^芸!qltdBのnS

808000のSOP￠

606800 冒
1⊃404000

202000001993 1994 1995 1996 1997 1998□s E])

団R

Fig. 1. A consumption Of an antibiotic and the frequency of MRSAsclassified according to the grade of resistance(S: susceptive, I: intemediate, 氏: resistallt) to the same antibiotics.

IPM: imlPenem/cilastatin, MPIPC: oxacillin, SBT/ABPC: sulbactam/ampicillin, CEZ: cefazolin, CTM: cefotiam,
CMZ: cefmetazo】e, CFPM: cefephlle, MINO:minocycline, FOM: fosfomycin, VCM: vancomycin, ABK: arbekacin sulfate,

LVFX: levofloxacin.

66Jpn. J. Infect. Dis., 55, 2002
therefore, very complex. For most of the antibiotics studied,

REFEREN CE

no simple relation, such as decreased use resulting in the

1. National Committee for Clinical Laboratory Standards

decreased kequency of the bacteria resistant to the antibiotic.

Cross‑resistance due to multidrug resistance plasmids, transfer(2000): Methods fb∫ dilution antimicrobial susceptibilityof genes among bacteria, complex processes of selection,

tests fb∫ bacteria that grow aerobically. Approvedinteraction of antibiotics, etc. may come into play.

Standards, 5th ed. National Committee fb∫ ClinicalLaboratory Standards. Villanova, Pa.

67