Læknablaðið - 15.01.1994, Blaðsíða 56

46
LÆKNABLAÐIÐ 1994; 80: 46
NÝR DOKTOR í LÆKNISFRÆÐI
KARL GÚSTAF KRISTINSSON
Þann 12. júní síðastliðinn var Karli G.
Kristinssyni veitt doktorsnafnbót við
háskólann í Sheffield í Englandi. Ritgerðin
nefnist á frummáli: Coagulase negative
staphylococci and foreign body associated
infections. Fer ágrip hér á eftir.
Infections caused by coagulase negative
staphylococci (CNS) have increased in
recent years and are now amongst the most
common nosocomial infections. Originally
the CNS were only considered bothersome
contaminants in clinical specimens but
we now know they can cause significant
morbidity. The aim of these studies was
to learn about the factors that make a
”harmless” commensal an important pathogen
in infections associated with implanted foreign
bodies, by studying potential virulence factors
and some of the main infections.
The effects of extracellular slime production
on opsonophagocytosis was studied by
neutrophil chemiluminescence and bacterial
killing assays and its effects on antimicrobial
activity by ATP bioluminescence and
agar/broth dilutions. The ability of the
CNS to adhere to and colonise polymer
substances was investigated by novel ATP
bioluminescence methods, quantitative cultures
and scanning electron microscopy. Infections
associated with continuous ambulatory
peritoneal dialysis, intravascular catheters and
prosthetic hip joints were investigated both
clinically and by various laboratory methods.
Efficient opsonisation of CNS was dependent
on complement, and slime production did
not have significant anti-opsonic properties
in solution. There was wide variation in
adherence and colonisation of CNS. Certain
slime producing strains adhered strongly to
polymers and once colonised could not be
killed by vancomycin. CNS showed wide
range of hydrophobicity which was highly
dependent on the growth conditions. They
were the commonest causative organisms of
the infections studied. Slime production was
not a useful marker in differentiating infecting
from contaminating strains, but was more
often associated with complicated peritonitis.
Multiple CNS strains were common in
infections associated with prosthetic hips,
necessitating the examination of multiple
specintens for diagnosis.
A single virulence factor could not explain the
propensity of CNS for foreign bodies. Several
properties they have developed for existence
on the skin may also benefit them on polymer
surfaces.