Development of a bacteriophage-typing set for Staphylococcus epidermidis

Area of Science:

• Microbiology
• Bacteriology
• Virology

Background:

• Accurate typing of Staphylococcus epidermidis is crucial for clinical and epidemiological studies.
• Previous phage typing sets had limitations in identifying a significant portion of S. epidermidis isolates.
• The need for improved phage typing strategies for S. epidermidis was evident.

Purpose of the Study:

• To evaluate the efficacy of a new set of six bacteriophages for typing Staphylococcus epidermidis.
• To compare the typability of S. epidermidis using the new phage set versus an existing set of 13 phages.
• To determine the combined effectiveness of both phage sets for enhancing S. epidermidis identification.

Main Methods:

• Six novel phages were isolated from lysogenic Staphylococcus epidermidis cultures.
• Typability was assessed using the new phage set, the original set of 13 phages, and a combination of both.
• Clinical isolates from various geographic locations and previously untypable strains were included in the study.

Main Results:

• The new set of 6 phages achieved 39.9% typability for 203 cultures, compared to 36.0% with the original 13 phages.
• Combining both phage sets increased overall typability to 49.9% for 425 cultures, a significant improvement over the original set (35.7%).
• For biotype 1 S. epidermidis, the combined set improved typability to 58.2% from 39.5% with the original set.

Conclusions:

• A new set of six phages significantly enhances the typability of Staphylococcus epidermidis.
• Combining the new phage set with the original set offers a more comprehensive approach to S. epidermidis phage typing.
• A provisional set of 11 phages, derived from the combined set, is proposed for routine use due to its high efficiency.