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Characterization of indole-positive Proteus mirabilis
Abstract:
Thirteen indole-producing, swarming strains of Proteus were identified by additional biochemical testing as being Proteus mirabilis. These strains were characterized by 40 biochemical tests and by susceptibility testing to 11 antibiotics. All produced ornithine decarboxylase and were susceptible to members of the penicillin-cephalosporin groups of antibiotics. These indole-positive strains are similar to indole-negative P. mirabilis and are distinctly different from P. vulgaris. For greatest accuracy and to insure greatest clinical relevancy, P. mirabilis and P. vulgaris should be distinguished from one another in the laboratory by performing both the indole and ornithine decarboxylase tests.
Insights
Indole-producing Proteus mirabilis strains were identified using biochemical tests. Distinguishing P. mirabilis from P. vulgaris is crucial for clinical accuracy, requiring indole and ornithine decarboxylase tests.
Area of Science:
- Microbiology
- Clinical Diagnostics
- Bacterial Identification
Background:
- Accurate identification of Proteus species is essential for effective clinical management.
- Proteus mirabilis and Proteus vulgaris are distinct species with differing clinical significance.
- Indole production is a key differentiator, but exceptions exist.
Purpose of the Study:
- To characterize indole-producing Proteus strains and determine their species.
- To evaluate the utility of biochemical tests, including ornithine decarboxylase, in differentiating Proteus species.
- To assess antibiotic susceptibility patterns of identified strains.
Main Methods:
- Isolation and biochemical characterization of thirteen indole-producing, swarming Proteus strains.
- Performance of 40 biochemical tests and antibiotic susceptibility testing against 11 antibiotics.
- Utilized indole and ornithine decarboxylase tests for species differentiation.
Main Results:
- All thirteen strains were identified as Proteus mirabilis.
- All identified P. mirabilis strains produced ornithine decarboxylase.
- Strains were susceptible to penicillin and cephalosporin antibiotics.
- Indole-positive P. mirabilis strains exhibited biochemical profiles distinct from P. vulgaris.
Conclusions:
- Indole-positive Proteus strains in this study were confirmed as P. mirabilis.
- Performing both indole and ornithine decarboxylase tests is recommended for accurate differentiation of P. mirabilis and P. vulgaris.
- This differentiation is critical for clinical relevance and appropriate patient treatment.