Detection of methicillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene in wild small mammals in Spain.
OBJECTIVE
To determine the rate of Staphylococcus aureus faecal carriage in 101 wild small mammals in Spain and to characterize the isolates obtained.


METHODS
Faecal samples were seeded on mannitol salt agar and ORSAB plates. The presence of the resistance genes mecA, mecC and blaZ and the new blaZ allotype associated with staphylococcal cassette chromosome mec (SCCmec) XI (blaZ-SCCmecXI) was studied by PCR. S. aureus isolates were characterized by spa typing, agr typing and multilocus sequence typing. The presence of immune evasion cluster (IEC) genes and virulence genes was analysed by PCR.


RESULTS
S. aureus was detected in 13/101 studied faecal samples and one isolate per positive sample was further studied. Two S. aureus isolates were methicillin-resistant S. aureus (MRSA) (recovered from wood mice, Apodemus sylvaticus) and 11 were methicillin-susceptible S. aureus (MSSA). Both MRSA isolates harboured the mecC gene and the novel blaZ-SCCmecXI, were typed as spa-t1535/agrIII/ST1945(CC130)/SCCmecXI (where ST stands for sequence type and CC stands for clonal complex), carried the exfoliative toxin etd2 gene and were IEC type E. Eight different spa types were identified among the 11 MSSA isolates (five new) and six different sequence types were identified (two new). All MSSA strains were susceptible to the antibiotics tested except one blaZ-positive penicillin-resistant isolate (spa-t120/agrII/ST15). MSSA isolates were ascribed to the CCs (number of strains) CC5 (1), CC1956 (4) and singleton (6). Nine of 11 MSSA isolates carried the cna virulence gene. Only one MSSA isolate carried IEC genes (type C).


CONCLUSIONS
This is the first report of MRSA carrying mecC in faecal samples of wild small mammals in Spain. These resistant isolates carried genes of the IEC system, unusual in S. aureus from animals. Wild small mammals could be a reservoir of the mecC gene with important implications for public health.
Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain.
Paula
P
Gómez
SaBio group, IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain.
David
D
González-Barrio
Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain.
Daniel
D
Benito
Ecology group, IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain.
Jesús T
JT
García
Ecology group, IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain.
Javier
J
Viñuela
Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain.
Myriam
M
Zarazaga
SaBio group, IREC (CSIC-UCLM-JCCM), Ciudad Real, Spain.
Francisco
F
Ruiz-Fons
Area of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain carmen.torres@unirioja.es.
Carmen
C
Torres
D000818:Animals; D000835:Animals, Wild / Q000382:microbiology; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000235:genetics; D005243:Feces / Q000382:microbiology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D051379:Mice; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D046330:Myoxidae / Q000382:microbiology; D046915:Penicillin-Binding Proteins / Q000235:genetics*; D051381:Rats; D012788:Shrews / Q000382:microbiology; D013030:Spain; D037521:Virulence Factors / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*
D004269:DNA, Bacterial; D046915:Penicillin-Binding Proteins; D037521:Virulence Factors; D001618:beta-Lactamases
CC30; ST1945; clonal complex 30; sequence type 1945; wood mouse