Detection of elements of the staphylococcal cassette chromosome (SCC) in a methicillin-susceptible (mecA gene negative) homologue of a fucidin-resistant MRSA.
OBJECTIVE
To determine the DNA relatedness of an outbreak of community-acquired fucidin-resistant methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) isolated from intravenous drug users (IVDUs).


METHODS
Relatedness was determined by PFGE analysis of macro-restricted chromosome, together with a variety of PCR methods, to determine polymorphisms in the accessory gene regulator (agr) locus, the structure of the staphylococcal cassette chromosome (SCCmec) and the presence or absence of the gene encoding Panton-Valentine leucocidin (PVL).


RESULTS
Clonality of the MRSA and MSSA was established by PFGE, a finding further supported by agr analysis. By PCR, the MRSA contained the typical genetic organization of SCCmec type-1. However, the MSSA, though mecA-negative, contained certain fragments of the SCC. Genes encoding PVL were not detected.


CONCLUSIONS
This outbreak involved a community-acquired fucidin-resistant MRSA and its methicillin-susceptible homologue. The MSSA did not contain the mecA gene but did contain elements of the mobile type-I SCC. The MSSA were associated with a change in PFGE pattern with a deletion in fragment size of approximately 215-195 kb.
Corkill
John E
JE
Royal Liverpool University Hospital, Department of Medical Microbiology, Prescot Street, Liverpool L7 8XP, UK.
Anson
James J
JJ
Griffiths
Paul
P
Hart
C Anthony
CA
D016470:Bacteremia / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics; D002876:Chromosomes, Bacterial / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D005098:Exotoxins; D016680:Genome, Bacterial; D006460:Hemolysin Proteins; D007956:Leukocidins / Q000737:chemistry; D016106:Methicillin Resistance / Q000235:genetics*; D046915:Penicillin-Binding Proteins; D012150:Polymorphism, Restriction Fragment Length; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000235:genetics*
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D005098:Exotoxins; D006460:Hemolysin Proteins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D046915:Penicillin-Binding Proteins; C037956:gamma-hemolysin, Staphylococcus aureus; C487789:mecA protein, Staphylococcus aureus