Yonago Acta medica 1996;39:109–112

Antibiotic Susceptibility of Staphylococcus spp. Collected from theEntrance Hall of the New Dispensary at Tottori University Hospital
Yoshinori Tanaka, Akiko Adachi, Tomofumi Ogoshi, Yoshiki Ohnishi, Naoto
Kobayashi and Yasuhide Fukatsu
Department of Bacteriology, Faculty of Medicine, Tottori University, Yonago 683 Japan
Fifty-three strains of Staphylococcus were isolated from the entrance hall of the dispensary at the university hospital. The frequencies of S. aureus, MRSA in S. aureus, andDMPPC-resistant strains in all the strains of Staphylococcus isolated were 17%, 22%
and 30%, respectively. In relation to our previous studies, these results fall between
those from healthy individuals and those from a hospital ward.
Key words: epidemiology; methicillin-resistant Staphylococcus aureus (MRSA); nosocomial infection

Nosocomial infection with Staphylococcus
aureus has become as troublesome as it used to
be in the 1980s. One of the reasons for this is
the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistantstrains of coagulase-negative staphylococci(CNS). In 1991 we investigated the occurrenceof Staphylococcus spp. in the new ward of auniversity hospital over a 10 month period(Tanaka et al., 1992). Last November, a dispensary was opened at Tottori University Hospital,
and we collected bacteria samples from theentrance hall to monitor drug-resistant strainsof Staphylococcus.

and gram-positive cocci were selected byoxidation-fermentation, and then identified
using the N-IDtest • SP-18 (Nissui Seiyaku Co.
Ltd., Tokyo, Japan). The Staphylococcus aureus
identified was finally confirmed to be coagulasepositive.
Antibiotic susceptibility was performed by
the disk method using ampicillin (ABPC),methicillin (DMPPC), cefmetazole (CMZ),
erythromycin (EM), gentamicin (GM), tetracycline (TC), minocycline (MINO), and lomefloxacin (LFLX) (Showa disc; Showa Yakuhin
Kako Co. Ltd., Tokyo). Antibiotic disk breakpoint zone sizes for resistance and susceptibility were set according to the manufacturer’sinstructions. The strains giving an intermediateor equivocal test result by the methicillin disk
method were analyzed further by the dilution
method.

Materials and Methods
Staphylococcus specimens were collected fromthe entrance hall of Tottori University Hospitalon January 11 and February 14, 1996. Sterilized swabs were rubbed on the surface of handrails, doors, the service counter, and on the floorof the hall. These swabs were put directly on tonutrient agar plates and mannitol salt agar
plates, which were incubated for 2 days at 37°C.
Several colonies were selected at random fromeach plate and the bacteria were gram-stained,

Results
Fifty-three strains of Staphylococcus wereisolated from the entrance hall of the university
hospital. Twenty-six strains were isolated on
January 11, and 27 strains were isolated on
February 14, as shown in Table 1. Pathogenic

Abbreviations: ABPC, ampicillin; CMZ, cefmetazole; CNS, coagulase-negative staphylococci; DMPPC,methicillin; EM, erythromycin; GM, gentamicin; LFLX, lomefloxacin; MRSA, methicillin-resistant
Staphylococcus; MINO, minocycline; TC, tetracycline.

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Y. Tanaka et al.

Table 1. Isolation of Staphylococcus fromthe entrance hall of Tottori University
Hospital on January 11 and February 14,1996
SpeciesNo. of strains isolated on:Jan. 11 Feb. 14and S. lugdunensis do not inhabit humans. Thesespecies of Staphylococcus are often found in thesoil.
The drug susceptibility of isolated staphylococci is shown in Table 2. Forty-five per centof all the isolates were ABPC-resistant, and30% were DMPPC-resistant. Six strains ofDMPPC-resistant S. haemolyticus were themost common strains isolated. S. haemolyticus
and S. aureus had a high frequency of drug
resistant factors (0.40 and 0.25, respectively).
Only 2 strains were MINO-resistant.

Total (%)

S. aureus
S. capitis
S. caprae
S. epidermidis
S. haemolyticus
S. hominis
S. intermedius
S. kloosii
S. lugdunensis
S. saprophyticus
S. warneri
S. xylosis

194080
1100
208
2072
100
2
122

9 ( 17.0)
11 ( 20.8)
4 ( 7.5)
7 ( 13.2)
10 ( 18.9)
1 ( 1.9)1 ( 1.9)1 ( 1.9)2 ( 3.8)
1 ( 1.9)
4 ( 7.5)
2 ( 3.8)

Total

26

27

53 (100 )Discussion
According to Bergey’s Manual of Determinative Bacteriology, Staphylococcus has beenclassified into 28 species and 4 subspecies (Holtet al.,1994). The N-IDtest • SP-18 system can beused to separate the genus Staphylococcus into
26 species, however it cannot identify S. filisand S. saccharolyticus. In January, many strainsof S. capitis and S. haemolyticus were isolated,and S. aureus and S. epidermidis were found inFebruary. The reason this segregation occurred
is unclear. Among the 12 species isolated, S.
aureus, S. capitis, S. epidermidis, S. haemo-strains of S. aureus (17%), opportunistic pathogens of S. capitis (21%) and S. epidermidis (13%),and nonpathogenic strains of S. haemolyticus(19%) were found. These 4 species and S. hominis, S. saprophyticus, S. warneri and S. xylosis
are known to inhabit humans and are often
isolated from clinical specimens (Schleifer andKoos, 1986). S. caprae, S. intermedius, S. kloosii

Table 2. The susceptibility of the 53 isolates to antibiotics
SpeciesS. aureus
S. capitis
S. caprae
S. epidermidis
S. haemolyticus
S. hominis
S. intermedius
S. kloosii
S. lugdunensis
S. saprophyticus
S. warneri
S. xylosis

No. ofNo. of strains resistant to:strain ABPC DMPPC CMZ EM
GM MINO TC
91147101
11214291127100002122126000
200
123
102
0000001221160
100000

Total

210
1
3000000001
10000000000112
30000000

Total*
LFLX
11115000100018 (0.25)
12 (0.14)
7 (0.22)9 (0.16)32 (0.40)
1 (0.13)1 (0.13)0 (0 )
3 (0.19)0 (0 )
2 (0.06)
3 (0.19)

53
24
16913
727
10
88 (0.21)(100)(45.3) (30.2) (17.0) (24.5) (13.2) (3.8) (13.2) (18.9)*The average number of resistant factors is shown in parenthesis, and was calculated by dividing the total
number of resistant factors by the number of strains and number of drugs used.

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Staphylococcus spp. in the dispensary

Rate of S. aureus
isolation
Average rate ofdrug-resistance
ABPC-resistant
DMPPC-resistant
CMZ-resistantEM-resistantGM-resistantTC-resistant
01020304050(%)

Fig. 1. The isolation of
antibiotic-resistant Staphylococcus aureus strains fromhealthy individuals, the entrance hall and from the hospital environment.
The white column ( ) represents the healthy individuals, the dotted column ( ) represents the entrance hall, andthe shaded column ( ) represents the ward environment.

The rates of isolation

lyticus, S. hominis, S. saprophyticus, S. warneriand S. xylosis inhabit humans, and are often isolated from clinical specimens (Schleifer andKoos, 1986). At the same time S. capitis, S. epidermidis, S. saprophyticus and S. xylosis are opportunistic pathogens to humans.
MRSA are known to be found in the hospitalenvironment (Kusano and Nakasone, 1989; Hedin
and Hambraeus, 1991; Ndawula and Brown,1991; Kjolen and Andersen, 1992; Omori et al.,
1992; Hedin, 1993; Richards et al., 1993; Mehtar,1994; Cox et al., 1995; Layton et al., 1995).
The frequency of MRSA in S. aureus was 55–
80% (Kusano and Nakasone, 1989). We isolated MRSA from a ward environment for a periodof a year just after the ward opened, and foundthat MRSA was isolated at a frequency of 20%,and the frequency of DMPPC-resistant
Staphylococcus in all of the strains of Staphylococcus isolated was 48%. In this study, thefrequency of MRSA isolation was 22%, andthat of DMPPC-resistant Staphylococcus was30% (Table 2). The frequency with which
DMPPC-resistant strains were isolated was notas high as that of Staphylococcus in the ward.
However, DMPPC-resistant strains of Staphylococcus clearly started to inhabit the new entrance hall.
In another of our experiments, Staphylococcus was isolated from young healthy students (Tanaka et al.,1993). Drug-resistantstrains of S. aureus isolated from healthy
individuals, the dispensary entrance hall, and award of the university hospital are shown in
Fig.1. The frequency of isolating S. aureus in
the genus Staphylococcus was almost the samein the 3 groups, but there were a lot of differences in the drug-resistance between the 3 groupsof S. aureus. Efforts to reduce the number ofdrug-resistant strains of Staphylococcus are required to lower the risk of nosocomial infection.

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(Received April 22, Accepted June 6, 1996)

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