Culture-negative primary sternal osteomyelitis in a patient with uncontrolled type 2 diabetes mellitus.

Primary sternal osteomyelitis (PSO) is a rare condition defined as an infection of the sternal bone marrow with no contiguous source of infection. The overlap in symptoms of PSO with other cutaneous and malignant pathologies often leads to misdiagnosis and delay of appropriate care. In this case report, we outline the presentation of PSO in a 30 year-old male patient who was newly diagnosed with type 2 diabetes mellitus. The patient was successfully treated with antibiotic therapy alone, without need for surgical intervention. Interestingly, the patient's workup returned with negative microbial cultures. To our knowledge, this patient represents the first reported case of a spontaneously presenting, culture-negative PSO.

Granulysin-derived peptides demonstrate antimicrobial and anti-inflammatory effects against Propionibacterium acnes.

Propionibacterium acnes is a key therapeutic target in acne, yet this bacterium has become resistant to standard antibiotic agents. We investigated whether the human antimicrobial protein granulysin is a potential candidate for the treatment of acne. Granulysin and synthetic granulysin-derived peptides possessing a helix-loop-helix motif killed P. acnes in vitro. Modification of a helix-loop-helix peptide, 31-50, by substitution of a tryptophan for the valine at amino acid 44 (peptide 31-50v44w) to increase its interaction with bacterial surfaces also increased its antimicrobial activity. Moreover, when synthesized with D- rather than L-type amino acids, this peptide (D-31-50v44w) became less susceptible to degradation by proteases and more effective in killing P. acnes. Granulysin peptides were bactericidal, demonstrating an advantage over standard bacteriostatic antibiotics in their control of P. acnes. Moreover, peptide D-31-50v44w killed P. acnes in isolated human microcomedone preparations. Importantly, peptides 31-50, 31-50v44w, and D-31-50v44w also have potential anti-inflammatory effects, as demonstrated by suppression of P. acnes-stimulated cytokine release. Taken together, these data suggest that granulysin peptides may be useful as topical therapeutic agents, providing alternatives to current acne therapies.