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Phenotypic and genotypic characterisation of blood isolates of coagulase‐negative staphylococci in the newborn
Author(s) -
Björkqvist Maria,
Söderquist Bo,
Törnqvist Eva,
Sjöberg Lennart,
Fredlund Hans,
Kühn Inger,
ColqueNavarro Patricia,
Schollin Jens
Publication year - 2002
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1034/j.1600-0463.2002.100408.x
Subject(s) - staphylococcus epidermidis , coagulase , sepsis , genotype , microbiology and biotechnology , biology , genotyping , pulsed field gel electrophoresis , blood culture , typing , neonatal intensive care unit , staphylococcus , immunology , medicine , bacteria , staphylococcus aureus , genetics , antibiotics , gene , pediatrics
Coagulase‐negative staphylococci (CNS) are the leading cause of late‐onset sepsis in newborns (>72 h of age). Our aim was to determine whether phenotypic and/or genotypic differences existed between blood isolates of CNS regarded as inducers of sepsis or as contaminants. Ninety‐seven bloodisolates of CNS recovered from newborns at the neonatal intensive care unit, Örebro, Sweden in 1983–1997 were analysed. Twenty‐nine of them (30%) were classified as sepsis isolates and 68 (70%) as contaminants. The most prevalent species was Staphylococcus epidermidis (n=59). Staphylococcus haemolyticus (n=16) was most often isolated from newborns with the lowest gestational age and birth weight. Biochemical typing using the Phene Plate system (PhP) and genotyping using pulsed‐field gel electrophoresis (PFGE) showed that the S. epidermidis isolates regarded as inducers of sepsis (n=16) were more homogeneous than isolates considered contaminants (n=37). One main genotypic group, representing seven (44%) isolates, was identified among the sepsis isolates. Phenotypically the S. epidermidis sepsis isolates comprised three major clusters. In contrast, among the S. epidermidis contaminants, eight genotypic groups and two phenotypic clusters were identified. The dominating genotypic group among the sepsis isolates of S. epidermidis may represent strains with higher invasive capacity.