Affiliation:
1. Microbiology Research Unit, Department of Oral Surgery, Oral Medicine and Pathology, School of Dental Science, Trinity College, University of Dublin, Ireland
2. National MRSA Reference Laboratory, St. James's Hospital, Dublin, Ireland
3. Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
Abstract
ABSTRACT
Methicillin-resistant
Staphylococcus aureus
(MRSA) isolates recovered in Irish hospitals between 1971 and 2002 were characterized using multilocus sequence typing (MLST) (
n
= 130) and SCC
mec
typing (
n
= 172). Where atypical SCC
mec
typing results were obtained, PCR amplification of entire SCC
mec
elements, analysis of amplimer mobility, and nucleotide sequencing were undertaken. MLST revealed that 129/130 isolates had the same genotypes as internationally spread MRSA clones, including ST239, ST247, ST250, ST5, ST22, ST36, and ST8. A novel genotype, ST496, was identified in one isolate. Half of the isolates (86/172) had SCC
mec
type I, IA, II, III, or IV. The remaining 86 isolates harbored novel SCC
mec
variants in three distinct genetic backgrounds: (i) 74/86 had genotype ST8 and either one of five novel SCC
mec
II (IIA, IIB, IIC, IID, and IIE) or one of two novel SCC
mec
IV (IVE and IVF) variants; (ii) 3/86 had genotype ST239 and a novel SCC
mec
III variant; (iii) 9/86 had a novel SCC
mec
I variant associated with ST250. SCC
mec
IVE and IVF were similar to SCC
mec
IVc and IVb, respectively, but differed in the region downstream of
mecA
. The five SCC
mec
II variants were similar to SCC
mec
IVb in the region upstream of the
ccr
complex but otherwise were similar to SCC
mec
II, except for the following regions: SCC
mec
IIA and IID had a novel
mec
complex, A.4 (Δ
mecI
-IS
1182-
Δ
mecI-mecR1-mecA-
IS
431mec
); SCC
mec
IIC and IIE had a novel
mec
complex, A.3 (IS
1182
-Δ
mecI
-
mecR1-mecA-
IS
431mec
); SCC
mec
IID and IIE lacked pUB110; SCC
mec
IIC and IIE lacked a region of DNA between Tn
554
and the
mec
complex; and SCC
mec
IIB lacked Tn
554
. This study has demonstrated a hitherto-undescribed degree of diversity within SCC
mec
.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Pharmacology (medical),Pharmacology
Cited by
144 articles.
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