Detection, evolution and outcome of the first case of Vancomycin Resistant Staphylococcus aureus (VRSA) infection in Europe
In Portugal, in May 2013 a VRSA strain (MRSA with vancomycin MIC = 1024 mg/l) was isolated from pus of a toe amputation wound of a 74 year-old female patient with chronic renal failure requiring haemodialysis, diabetes mellitus and peripheral vascular disease. The patient was under treatment with vancomycin for a methicillin-resistant Staphylococcus aureus (MRSA) local infection. Vancomycin-resistant Enterococcus faecalis (VRE) and Pseudomonas aeruginosa were also isolated from the wound.
Antibiotic therapy with daptomycin, rifampicin and amikacin was administered for 6 weeks. Control precautions were reinforced. The strain was characterized and an epidemiological survey to monitor its possible dissemination was carried out. All isolates were characterized by multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE) profiling, and the structure of the SCCmec element of all MRSA isolates was determined.
The VRSA strain was no longer found in the wound after 3 weeks, and the VRE strain after 5 weeks. Nasal swabs from 53 close contacts (2 household members (HHM), 47 healthcare workers (HCW), 4 patients) did not reveal VRSA. Methicillin susceptible Staphylococcus aureus (MSSA) were recovered from 14 HCW, and 5 MRSA isolates were recovered from 3 HCW, 1 HHM and 1 patient. S. aureus isolates presented high genetic diversity, most of them belonging to clones previously identified in Portugal.
The VRSA strain harboured vanA, was ST105-II and belonged to CC5, as in 12 of the 13 cases detected in the USA. vanA-positive VRE may have been the donor of the vanA into a MRSA during co-infection and therapy with vancomycin. Transmission of the strain to contacts was not detected.
In countries with increase in CC5-associated clones and high prevalence of MRSA and VRE, such as Portugal, VRSA may arise more frequently in the near future.
Pfizer: Consultant, Grant Investigator and Speaker's Bureau, Consulting fee, Research grant and Speaker honorarium
Gilead: Speaker's Bureau, Speaker honorarium
GlaxoSmithKline: Consultant, Consulting fee
A. Friaes, None
C. Resina, None
V. Manuel, None
L. Lito, None