Rapid identification of Staphylococcus aureus in blood cultures by thermonuclease testing

Madison, Bereneice; Baselski, Vickie S.

doi:10.1128/jcm.18.3.722-724.1983

Cited by 40 publications

(16 citation statements)

References 23 publications

(18 reference statements)

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“…Previously, we have tested additional non-S. aureus isolates, some of which were also positive in the thermonuclease test (4,5,9). Although the thermonuclease test has been used to identify S. aureus isolates from human and veterinary clinical specimens, including same-day identification of blood culture isolates (21,24), environmental or dietary product isolates (14, 23), our results substantiate the lack of specificity of this test for S. aureus. Furthermore, the seroinhibition test based on polyclonal anti-TNase serum failed to confirm the species S. aureus, since this antiserum also inhibited the activity of non-S. aureus TNases to a considerable extent.…”

Section: Discussionmentioning

confidence: 59%

“…The thermonuclease test for DNA degradation by the thermostable nuclease (TNase) produced by S. aureus, originally described by Lachica et al (19), is regarded as reliable for identification of this bacterium by direct examination of blood cultures (21,24). However, strains of the species S. schleiferi, S. carnosus, S. intermedius, S. hyicus, S. caprae, and S, capitis may produce TNases (10,17,18).…”

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confidence: 99%

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Comparison of tests designed to identify Staphylococcus aureus thermostable nuclease

Brakstad

Mæland²,

Chesneau

1995

APMIS

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The thermonuclease test has been employed for same‐day identification of Staphylococcus aureus in blood cultures and a seroinhibition test to confirm S. aureus thermonuclease (TNase) by using polyclonal anti‐S. aureus TNase antiserum. However, strains of non‐S. aureus staphylococci may produce TNases which are neutralized by the antiserum. This study evaluated alternative reagents and confirmatory tests for the S. aureus TNase. The tests included seroinhibition by a monoclonal antibody (MAb) against S. aureus TNase, MAb‐based detection of the TNase in a sandwich ELISA, and a polymerase chain reaction for amplification of the nuc gene encoding the S. aureus TNase. All these tests discriminated between TNase produced by S. aureus and TNase produced by strains of the species S. caprae, S. carnosus, S. simulans, S. capitis, and S. intermedius. Specificity for the S. aureus TNase was confirmed by an inhibition ELISA for two out of three MAbs tested. Thus, the MAb‐and nwobased tests will be useful to discriminate between TNases from S. aureus and non‐S. aureus staphylococci.

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Section: Discussionmentioning

confidence: 59%

mentioning

confidence: 99%

Comparison of tests designed to identify Staphylococcus aureus thermostable nuclease

Brakstad

Mæland²,

Chesneau

1995

APMIS

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“…Direct detection of ORSA in blood cultures. The blood culture vials showing growth of gram-positive cocci and demonstrating thermonuclease activities indicated that there were S. aureus cells in these vials (17). A total of 96 such blood cultures were used for direct detection of ORSA by the impedance method.…”

Section: Effect Of Oxacillin Concentration On Impedance Curvesmentioning

confidence: 99%

Rapid detection of oxacillin-resistant Staphylococcus aureus in blood cultures by an impedance method

Huang

Dai

et al. 1997

J Clin Microbiol

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The feasibility of using an impedance method for direct detection of oxacillin-resistant Staphylococcus aureus (ORSA) in blood cultures was evaluated. An aliquot (0.1 ml) of the positive blood culture, which showed growth of gram-positive cocci and demonstrated thermonuclease activity, was inoculated into the module well of a Bactometer incubator (bioMerieux Vitek, Hazelwood, Mo.) containing 0.6 ml of Mueller-Hinton agar supplemented with oxacillin (2 g/ml). The modules were incubated at 37°C, and the change in impedance in each well was continuously monitored by the instrument at 6-min intervals for 24 h. ORSA strains from blood cultures could multiply in the oxacillin-containing medium, and a time point (detection time [DT]) at which an accelerating change of impedance occurred in the medium was obtained, with an average of 5.5 h. The growth of oxacillin-sensitive S. aureus (OSSA) strains was largely inhibited, and no DT was obtained for these strains within an incubation period of 24 h. For 96 positive blood cultures (38 ORSA and 58 OSSA) tested, 36 and 57 were found to be oxacillin resistant and oxacillin sensitive, respectively, by the impedance method. The impedance method had a sensitivity and specificity of 94.7 and 98.3%, respectively, for the detection of ORSA and had an agreement of 96.9% with the disc diffusion method. Comparable results were obtained by the testing of 235 clinical stock cultures of S. aureus (149 ORSA and 86 OSSA). The impedance test is simple for detecting ORSA in blood cultures and may allow proper antimicrobial treatment almost 36 h before the results of the conventional culture methods are available.

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“…The susceptibility of S. aureus to lysostaphin was reported to be an excellent way to distinguish this organism from CNS (157,158). Subsequently, testing with thermonuclease, a heat-stable DNase produced by S. aureus, was reported to be a rapid, accurate identification method (102,137). The test could be performed from either standard blood culture broths or BACTEC bottles with a positive growth index (144).…”

Section: Biochemical Testsmentioning

confidence: 99%

Update on detection of bacteremia and fungemia.

Reimer

Wilson

Weinstein

1997

Clinical Microbiology Reviews

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Rapid identification of Staphylococcus aureus in blood cultures by thermonuclease testing

Cited by 40 publications

References 23 publications

Comparison of tests designed to identify Staphylococcus aureus thermostable nuclease

Comparison of tests designed to identify Staphylococcus aureus thermostable nuclease

Rapid detection of oxacillin-resistant Staphylococcus aureus in blood cultures by an impedance method

Update on detection of bacteremia and fungemia.

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