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Volume 16, Number 7—July 2010

Endocarditis Caused by Actinobaculum schaalii, Austria

Martin Hoenigl, Eva Leitner, Thomas Valentin, Gernot Zarfel, Helmut J.F. Salzer, Robert Krause, and Andrea J. GrisoldComments to Author 
Author affiliations: Medical University of Graz, Graz, Austria

Main Article


Comparison of isolated Actinobaculum schaalii with related human pathogens reported in the literature

Characteristic Isolate that caused endocarditis
Reaction of (reference)*
A. schaalii (1,2) Actinobaculum massiliae (3) Actinobaculum urinale (4) Arcanobacterium pyogenes Actinomyces turicensis (1,2)
A. schaalii†
Catalase reaction
β-hemolysis on sheep blood agar –/w‡ w + w
Nitrate reduction
Pyrazinamidase V +
Pyrrolidonyl arylamidase + + +
Alkaline phosphatase + –§ V
β-glucuroniadase + +
β-galactosidase +
α-glucosidase + + + + +
N-acetyl-β-glucosaminidase V
Esculin hydrolysis –§
Urease activity +
Gelatin hydrolysis


Acid from
Glucose V + + + +
Ribose + + + + + +
Xylose + V + + +
Maltose + + + + + V
Lactose +
Sucrose + V + V +
Glycogen + V

*API Coryne system (bioMérieux, Craponne, France) profile for our isolate was compared with those described in the references (Actinobaculum schaalii [14 strains], A. massiliae [1 strain], A. urinale [1 strain], A. turicensis [43 strains]) and those in the manufacturer´s database for Arcanobacterium pyogenes. +, >90% of strains positive; –, >90% strains negative; V, variable; w, weak.
†In API Coryne, the strain gave the profile number 4110621 (unacceptable profile because of lack of specificity).
A. schaalii was described as nonhemolytic for 5 patients (1) and as showing weak β-hemolysis only after 2–5 d in 9 cases (2).
§Reported as positive for 1 of 14 strains.

Main Article

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Main Article

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