BRIEF REPORT
Antimicrobial resistance and molecular characterization
of Staphylococcus haemolyticus in a Chinese hospital
M.-H. Yu
&
Y.-G. Chen
&
Y.-S. Yu
&
C.-L. Chen
&
L.-J. Li
Received: 2 February 2010 / Accepted: 15 February 2010 / Published online: 4 March 2010
#
Springer-Verlag 2010
Abstract The aim of this study was to perform the
molecular characterization of methicillin-resistant Staphy-
lococcus haemolyticus (MRSH) from clinical specimens of
patients in a Chinese hospital. One hundred and thirty-three
strains of S. haemolyticus collected from April 2002 to
April 2003 were analyzed. Antimicrobial susceptibility to
15 antimicrobial agents was determined by the broth
microdilution method. The resistant rates to penicillin G
and oxacillin were higher than 90%. There were no isolates
resistant to linezolid or vancomycin, and only 6.0% of the
strains were resistant to teicoplanin. The positivity rate for
mecA genes was 90.2% by polymerase chain reaction
(PCR). Ninety MRSH (isolated from inpatients and mecA-
gene-positive) were genotyped by pulsed-field gel electro-
phoresis (PFGE) after SmaI digestion. Twenty-five different
PFGE patterns (A∼Y) were found and a major clone (type
A; n=36) with five subtypes was identified. Clone A was
detected during a 1-year period. Identical PFGE types were
found in different wards and patients. The results of this
study suggest the clonal spread of MRSH within our
hospital. This emphasizes the need for control and
prevention measures.
Although previously regarded as harmless commensal
bacteria, the coagulase-negative staphylococci (CNS) are
increasing in importance as the cause of hospital-acquired
infections. These are generally associated with the use of
medical devices in seriously ill and immunocompromised
patients [1]. Staphylococcus haemolyticus is a prominent
species of CNS [2–4]. S. haemolyticus is second in
frequency only to S. epidermidis among clinical isolates
of CNS and, today, it represents the third most common
organism among clinical isolates of methicillin-resistant
staphylococci [4]. Some recent reports have recognized S.
haemolyticus as the cause of severe infections, including
meningitis, skin and skin structure infections, prosthetic
joint infections, bacteremia, and even endocarditis [2].
All methicillin-resistant S. haemolyticus (MRSH) have
been shown to contain the mecA gene and which may spread
to other methicillin-susceptible S. haemolyticus (MSSH),
probably through transposition [5]. MRSH are resistant to all
other penicillins, carbapenems, cephems, and beta-lactam/
beta-lactamase inhibitor combinations [7]. Consequently,
these antibiotics should not be used for the treatment of
MRSH infections [6]. In fact, S. haemolyticus, besides its
tendency to develop multiple resistance, was the first Gram-
positive pathogen able to acquire glycopeptide resistance [8].
The extensive use of glycopeptides has been related to
decreased susceptibility to these agents [3]. This condition
has led S. haemolyticus to become a serious health problem
that medical practitioners should be concerned about.
The purpose of this study was to report the antimicrobial
resistance of S. haemolyticus and the prevalence of MRSH
from a large teaching hospital in China, over a 1-year period.
In this study, we investigated the local epidemiology of the
multiresistant isolates of S. haemolyticus in our hospital.
One hundred and thirty-three non-replicate
S. haemoly-
ticus isolates were collected from clinical specimens of the
patients (94 inpatients, 39 outpatients) in The First
Affiliated Hospital, College of Medicine, Zhejiang Univer-
M.-H. Yu
:
Y.-G. Chen
:
Y.-S. Yu (*)
:
C.-L. Chen
:
L.-J. Li
State Key Laboratory for Diagnosis and Treatment of Infectious
Diseases, The First Affiliated Hospital,
College of Medicine, Zhejiang University,
No. 79 Qing Chun Road,
Hangzhou, Zhejiang Province 310003,
People’s Republic of China
e-mail: y8m8h@163.com
Eur J Clin Microbiol Infect Dis (2010) 29:613–616
DOI 10.1007/s10096-010-0893-3