Genotypes and phenotypes of Staphylococcus lugdunensis isolates recovered from bacteremia
Sung-Pin Tseng, Yu-Tzu Lin, Jui-Chang Tsai, Wei-Chun Hung, Hsiao-Jan Chen, Pi-Fang Chen, Po-Ren Hsueh, Lee-Jene Teng
Received: July 1, 2013 Revised: November 12, 2013 Accepted: January 2, 2014
Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan
Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
Corresponding author. Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Number 1, Chang-Te Street, Taipei 100, Taiwan.
Background and purpose:
Staphylococcus lugdunensis is a member of coagulase-negative staphylococci, which has the potential to cause serious infections, such as endocarditis, bone and joint infections, and septicemia. Differences in phenotypic/genotypic characterization may be linked to different diseases.
Genotypes of 11 S. lugdunensis isolates from bacteremia were determined by pulsed field gel electrophoresis and accessory gene regulator (agr) typing. The SCCmec elements in two oxacillin-resistant isolates were sequenced. Phenotypes were tested by antimicrobial susceptibility testing, biofilm formation assessments, and virulence factor analysis (hemolytic and protease activities).
Among the 11 isolates, six pulsotypes were found, and seven isolates belonged to two major pulsotypes. Two agr types (agr-1sl or agr-2sl) were found. The 11 isolates were susceptible to most antimicrobial agents tested. The SCCmec elements in two oxacillin-resistant isolates belonged to the SCCmec type V, but with additional ccrAB2 genes. The agr-2sl isolates (n = 7) displayed higher hemolytic and protease activities than the agr-1sl isolates. All isolates contained the icaA gene but with variable biofilm activities. The results suggest that protein might play an important part in S. lugdunensis biofilms, possibly through an ica-independent pathway. Of the 11 patients with S. lugdunensis bacteremia, one patient had a community-onset infection, and others had a hospital-acquired infection, which were mostly central venous catheter-related infections.
The 11 S. lugdunensis bacteremia isolates displayed various genotypes and phenotypes. Two oxacillin-resistant isolates contained SCCmec type V and carried additional ccrAB2 genes. Correlation of genotypes and phenotypes with infections needs further studies.
Accessory gene regulator typing, Bacteremia, Biofilm, SCCmec, Staphylococcus lugdunensis