Rebecca B. Leonard

Rapid lysis of gram-positive cocci for pulsed-field gel electrophoresis using achromopeptidase.

To adapt pulsed-field gel electrophoresis (PFGE) to a busy clinical laboratory, we evaluated the use of achromopeptidase (ACP) as the sole agent for lysis of a variety of gram-positive cocci. Growth in an appropriate broth media was adjusted to a 3.0 McFarland density before aliquotting for washing and plug preparation. ACP incorporated into the agarose plugs, or added to the buffer solution, lysed cells in <1 h when suspended in a Tris-NaCl buffer. Two 30-min washes in a Tris-EDTA buffer were sufficient to remove cellular debris without additional deproteination. Final PFGE results were obtained in ∼48 h, including the initial broth subculturing.

A community pseudo-outbreak of invasive Staphylococcus aureus infection.

Outbreaks of invasive infection caused by methicillin-susceptible and methicillin-resistant Staphylococcus aureus occur in hospitals, long term care institutions, and in patients discharged from these settings. In contrast, epidemic S. aureus infection has not been reported in well persons in the community. Here, we describe a group of healthy young adults who resided in the same neighborhood and participated together in school sports, and who developed serious S. aureus infections within 3 weeks of each other, suggesting a true community outbreak. Timely use of molecular epidemiological tools, however, demonstrated that their illnesses were caused by unrelated bacterial strains.