Methicillin-resistant coagulase-negative staphylococci in the community: high homology of SCCmec IVa between Staphylococcus epidermidis and major clones of methicillin-resistant Staphylococcus aureus.
BACKGROUND
Data on community spread of methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are scarce. We assessed their potential role as a reservoir of staphylococcal cassette chromosome mec (SCCmec) IVa, the leading SCCmec subtype in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA).


METHODS
Nasal carriage of MR-CoNS was prospectively investigated in 291 adults at hospital admission. MR-CoNS were characterized by SCCmec typing, long-range polymerase chain reaction (PCR) for SCCmec IV, and multiple-locus variable-number tandem repeat analysis (MLVA) for Staphylococcus epidermidis (MRSE) strains. Three SCCmec IVa elements were fully sequenced.


RESULTS
The carriage rate of MR-CoNS was 19.2% (25.9% and 16.5% in patients with and patients without previous exposure to the health care system, respectively; P = .09). MR-CoNS strains (n = 83, including 58 MRSE strains with highly heterogeneous MLVA patterns) carried SCCmec type IVa (n = 9, all MRSE), other SCCmec IV subtypes (n = 9, including 7 MRSE), other SCCmec types (n = 15), and nontypeable SCCmec (n = 50). Long-range PCR indicated structural homology between SCCmec IV in MRSE and that in MRSA. Complete sequences of SCCmec IVa from 3 MRSE strains were highly homologous to those available for CA-MRSA, including major clones USA300 and USA400.


CONCLUSIONS
MR-CoNS are probably disseminated in the community, notably in subjects without previous exposure to the health care system. MRSE, the most prevalent species, may act as a reservoir of SCCmec IVa for CA-MRSA.
Barbier
François
F
Bacteriology Unit and National Reference Center for Emergence of Resistance in Commensal Flora, 2EA 3964, Bichat-Claude Bernard Hospital, Assistance Publique-Hôpitaux de Paris and Xavier Bichat Medical School, Denis Diderot-Paris 7 University, Paris, France.
Ruppé
Etienne
E
Hernandez
David
D
Lebeaux
David
D
Francois
Patrice
P
Felix
Benjamin
B
Desprez
Adeline
A
Maiga
Aminata
A
Woerther
Paul-Louis
PL
Gaillard
Kevin
K
Jeanrot
Cécile
C
Wolff
Michel
M
Schrenzel
Jacques
J
Andremont
Antoine
A
Ruimy
Raymond
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D002999:Clone Cells; D003030:Coagulase / Q000172:deficiency / Q000235:genetics*; D017931:DNA Primers; D004197:Disease Reservoirs / Q000382:microbiology; D024881:Drug Resistance, Bacterial / Q000276:immunology; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007126:Immunoglobulin Allotypes; D008297:Male; D016106:Methicillin Resistance / Q000235:genetics / Q000502:physiology*; D008875:Middle Aged; D009666:Nose / Q000382:microbiology; D016133:Polymerase Chain Reaction; D006435:Renal Dialysis; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000276:immunology / Q000635:transmission; D013212:Staphylococcus epidermidis / Q000201:enzymology* / Q000235:genetics*
D003030:Coagulase; D017931:DNA Primers; D007126:Immunoglobulin Allotypes