Pathogenicity and virulence of coagulase negative staphylococci in relation to adherence, hydrophobicity, and toxin production in vitro.
OBJECTIVE
To study the pathogenicity and virulence characteristics of Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus sapro-phyticus.


METHODS
BALB/c mice were challenged intraperitoneally with graded doses of three strains belonging to each species. LD50s were measured for each strain. Haemolysin (alpha- and delta-) and enzyme (DNAase, lipase, and esterase) production in vitro were measured qualitatively and quantitatively. Adhesion to plastic was measured and related to cell surface hydrophobicity among the strains.


RESULTS
S saprophyticus proved the most virulent (LD50 = 2.7-2.9 x 10(7) cfu/g body weight) while S epidermidis was the least virulent (LD50 = 6-8 x 10(7) cfu/g body weight). An enlarged spleen was the most common macroscopic pathological feature. Kidney, liver, and more rarely peritoneal abscesses were also seen in the infected animals. No direct correlation was found between adherence in vitro, cell surface hydrophobicity, or toxin/enzyme biosynthesis and virulence in mice.


CONCLUSIONS
The results show that coagulase negative staphylococci are pathogenic in BALB/c mice. It is clear that these bacteria can cause invasive disease. However, the in vitro characteristics of coagulase negative staphylococci are not related to the pathogenicity of the organisms in mice.
Department of Clinical Chemistry, University of Debrecen, Hungary.
C
C
Molnàr
Z
Z
Hevessy
F
F
Rozgonyi
C G
CG
Gemmell
D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology*; D001427:Bacterial Toxins / Q000096:biosynthesis*; D002847:Chromatography, Agarose; D003030:Coagulase / Q000378:metabolism; D003851:Deoxyribonucleases / Q000096:biosynthesis; D004950:Esterases / Q000096:biosynthesis; D005260:Female; D006460:Hemolysin Proteins / Q000096:biosynthesis; D007928:Lethal Dose 50; D008049:Lipase / Q000096:biosynthesis; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D013210:Staphylococcus / Q000472:pathogenicity* / Q000502:physiology; D013212:Staphylococcus epidermidis / Q000472:pathogenicity; D014774:Virulence
D001427:Bacterial Toxins; D003030:Coagulase; D006460:Hemolysin Proteins; D003851:Deoxyribonucleases; D004950:Esterases; D008049:Lipase