Long-term molecular epidemiology of Staphylococcus epidermidis blood culture isolates from patients with haematological malignancies

• Staphylococcus epidermidis is an important cause of bloodstream infections in patients with haematological malignancies. Knowledge of the long-term epidemiology of these infections is limited. We surveyed all S. epidermidis blood culture isolates from patients treated for haematological malignancies at the University Hospital of Örebro, Sweden from 1980 to 2009. A total of 373 S. epidermidis isolates were identified and multilocus sequence typing and standard antibiotic susceptibility testing were employed to characterize these isolates. The majority of the isolates 361/373 (97%) belonged to clonal complex 2, and the 373 isolates were divided into 45 sequence types (STs); Simpson’s Diversity Index was 0.56. The most prevalent STs were ST2 (243/373, 65%) and ST215 (28/373, 8%). These two STs were isolated during the entire study period, and together caused temporal peaks in the incidence of positive blood cultures of S. epidermidis. Methicillin resistance was detected in 213/273 (78%) of all isolates. In the two predominating STs, ST2 and ST215, the proportion of methicillin resistance was 257/271 (95%); 234/271 (86%) displayed a multidrug-resistant phenotype. In conclusion, in this long-term study of patients with haematological malignancies, we demonstrate a predominance of methicillin-resistant ST2 among S. epidermidis blood culture isolates.

Nyckelord

Staphylococcus epidermidis

Bloodstream infection

Haematological malignancy

Multilocus sequence typing

Coagulase-negative staphylococci

Molecular epidemiology

Healthcare-associated infection

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)