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Evaluation of the sodium polyanethol sulfonate disk test for the identification of Peptostreptococcus anaerobius
Abstract:
The previously reported sodium polyanethol sulfonate disk test for the identification of Peptostreptococcus anaerobius (Graves et al., 1974) was evaluated, with modifications. Three bands of brucella agar, three inoculum sizes, and two inoculum sources were compared. Nine stock cultures of P. anaerobius (eight normal flora isolates and ATCC 27337) and 16 fresh clinical isolates were used. All cultures of P. anaerobius showed inhibition zones of 12 to 30 mm in diameter, regardless of test conditions. Out of 103 clinical isolates of other species of anaerobic gram-positive cocci tested, only two had an inhibition zone size in this range (one P. micros of 11 studied had a zone of 12 mm and one P. prevotii of 14 studied had a zone of 16). The test had an overall accuracy of 98% in the identification of P. anaerobius from clinical specimens. Since P. anaerobius accounts for one-fifth to one-third of all anaerobic gram-positive cocci encountered in clinical specimens, this simple and rapid technique can be very useful for presumptive identification.
Insights
The sodium polyanethol sulfonate disk test accurately identifies Peptostreptococcus anaerobius in clinical samples. This rapid method shows 98% accuracy for this common anaerobic gram-positive cocci.
Area of Science:
- Microbiology
- Clinical Diagnostics
- Bacteriology
Background:
- Peptostreptococcus anaerobius is a significant anaerobic gram-positive cocci in clinical specimens.
- Accurate and rapid identification of P. anaerobius is crucial for patient management.
Purpose of the Study:
- To evaluate and optimize the sodium polyanethol sulfonate disk test for identifying Peptostreptococcus anaerobius.
- To assess the test's accuracy and utility in clinical settings.
Main Methods:
- Comparison of brucella agar formulations, inoculum sizes, and inoculum sources.
- Testing of nine stock cultures and 16 fresh clinical isolates of P. anaerobius.
- Evaluation of 103 clinical isolates of other anaerobic gram-positive cocci.
Main Results:
- All P. anaerobius cultures exhibited inhibition zones between 12-30 mm, irrespective of test conditions.
- Only two non-P. anaerobius isolates showed zones within this range (P. micros and P. prevotii).
- The test achieved 98% overall accuracy for P. anaerobius identification.
Conclusions:
- The modified sodium polyanethol sulfonate disk test is a reliable and efficient method for presumptive identification of Peptostreptococcus anaerobius.
- This simple technique can aid in the clinical laboratory's workflow for anaerobic gram-positive cocci detection.