Unusual presence of the immune evasion gene cluster in livestock-associated MRSA of lineage CC398 causing peridural and psoas abscesses in a poultry farmer.
OBJECTIVE
To characterize a methicillin-resistant Staphylococcus aureus (MRSA) isolate responsible for an aggressive infection (peridural and psoas abscess secondary to haematogenous septic arthritis) in a poultry farmer.


METHODS
Molecular characterization was performed, including spa- and multilocus sequence typing of the isolate, assessment of its resistance phenotype and detection of tetracycline resistance and of virulence and immune evasion cluster (IEC) genes were performed.


RESULTS
The MRSA isolate was tetracycline- and fluorquinolone-resistant, and was ascribed to CC398, spa-t1451. The isolate harboured tet(M) (distinctive of livestock-associated (LA) MRSA-CC398 clade) and IEC-type B system (characteristic of the methicillin-susceptible human lineage, but typically absent in LA-MRSA-CC398 strains), and lacked toxin-coding genes lukF/lukS-PV, tsst-1, eta and etb.


CONCLUSIONS
IEC re-acquisition by LA-MRSA-CC398-LA strains is an unusual finding, but could constitute an emerging public health problem. It would represent an evolutionary step towards LA-MRSA-CC398's adaptation to human hosts, and might enhance its invasiveness and ability to be transmitted to humans.
Laboratori Clínic ICS-Terres de l'Ebre (Área de microbiología), Hospital de Tortosa Verge de la Cinta, Tortosa (Tarragona), Spain; Institut d'Investigació Sanitària Pere Virgili (IISPV), Spain. Electronic address: moperez.ebre.ics@gencat.cat.
Mar Olga
MO
Pérez-Moreno
Laboratori Clínic ICS-Terres de l'Ebre (Área de microbiología), Hospital de Tortosa Verge de la Cinta, Tortosa (Tarragona), Spain; Institut d'Investigació Sanitària Pere Virgili (IISPV), Spain.
María José
MJ
Centelles-Serrano
Servicio de Cirugía Ortopédica y Traumatología, Hospital de Tortosa Verge de la Cinta, Tortosa (Tarragona), Spain.
Julio
J
Nogales-López
Servicio de Medicina Preventiva, Hospital de Tortosa Verge de la Cinta, Tortosa (Tarragona), Spain.
Marie France
MF
Domenech-Spanedda
Centro de Investigación Biomédica de la Rioja, Área de Microbiología Molecular, Logroño, Spain.
Carmen
C
Lozano
Facultad de Ciencia y Tecnología, Área de Bioquímica y Biología Molecular, Universidad de la Rioja, Logroño, Spain.
Carmen
C
Torres
D000038:Abscess / Q000382:microbiology*; D000822:Animal Husbandry; D000818:Animals; D001170:Arthritis, Infectious / Q000382:microbiology*; D015373:Bacterial Typing Techniques; D000077684:Cauda Equina Syndrome / Q000209:etiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D006801:Humans; D057131:Immune Evasion / Q000235:genetics*; D008159:Lumbar Vertebrae / Q000382:microbiology; D008297:Male; D008581:Meningitis / Q000150:complications / Q000382:microbiology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D008875:Middle Aged; D009784:Occupational Diseases / Q000382:microbiology*; D011200:Poultry / Q000382:microbiology*; D016659:Psoas Abscess / Q000382:microbiology; D012008:Recurrence; D013166:Spondylitis / Q000150:complications / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000382:microbiology* / Q000635:transmission; D014946:Wound Infection / Q000382:microbiology; D015047:Zoonoses; D021801:Zygapophyseal Joint / Q000382:microbiology
Absceso epidural y de psoas; Artritis séptica hematógena; Haematogenous septic arthritis; Immune evasion cluster; Livestock-associated MRSA-CC398; Peridural and psoas abscess; SARM-CC398 asociado al ganado; Sistema de evasión inmune