Anomalous but helpful findings from the BBL Crystal ID kit with Haemophilus spp

Area of Science:

• Microbiology
• Clinical Diagnostics
• Bacterial Identification

Background:

• Accurate identification of bacterial species is crucial for effective clinical management.
• Commercial identification kits are widely used but can exhibit limitations in accuracy.
• Haemophilus species are clinically significant pathogens, and their misidentification can lead to inappropriate treatment.

Purpose of the Study:

• To evaluate the performance of the BBL Crystal ID Enteric/Nonfermenter kit in identifying Haemophilus species.
• To compare the BBL Crystal kit's accuracy with API 20E and API 20NE kits for Haemophilus identification.
• To determine if the BBL kit misidentifies Haemophilus spp. as Pasteurella spp., similar to potential API kit errors.

Main Methods:

• Fourteen Haemophilus strains (12 H. influenzae, 1 H. parainfluenzae, 1 H. aphrophilus) were tested.
• Identification was performed using BBL Crystal ID Enteric/Nonfermenter, API 20E, and API 20NE kits.
• Results were analyzed for accuracy and types of misidentification.

Main Results:

• The BBL Crystal kit yielded uninterpretable color reactions for 13 out of 14 Haemophilus strains, indicating an inappropriate test.
• API 20E and API 20NE kits frequently misidentified Haemophilus species as Pasteurella species.
• The API kits provided confident identifications without signaling the misidentification.

Conclusions:

• The BBL Crystal ID Enteric/Nonfermenter kit is unsuitable for the identification of Haemophilus species due to uninterpretable results.
• API 20E and API 20NE kits demonstrate a significant tendency to misidentify Haemophilus as Pasteurella, posing a risk in clinical settings.
• Clinicians and laboratories should be aware of these limitations when using these identification kits for Haemophilus.