New therapy options for MRSA with respiratory infection/pneumonia

Daptomycin for the successful treatment of postoperative methicillin-resistant Staphylococcus aureus empyema: a case report

Empyema is typically treated using pleural space drainage and systemic treatment with antimicrobials, and specific antimicrobial agents in the case of methicillin-resistant Staphylococcus aureus (MRSA) infections. A 57-year-old man underwent segmental resection of the left lung owing to multiple lung metastases and developed MRSA-related empyema postoperatively. Although the patient received chest drainage and linezolid, the inflammation caused by the infection persisted. Consequently, linezolid was replaced by daptomycin, and his empyema was accordingly resolved. Our findings indicate that daptomycin could be an effective treatment for postoperative MRSA-related empyema.

Establishment of a new methicillin resistant Staphylococcus aureus animal model of osteomyelitis

PURPOSE

The increase in methicillin-resistant Staphylococcus aureus (MRSA) infections is currently a major health care problem. Vancomycin is still often the first-line anti-microbiological agent for treating such infections; however, a recent decline in efficacy of vancomycin in MRSA infections has raised concerns and accelerated the search for new antibiotics. The aim of this study was to establish a MRSA peri-implant osteomyelitis animal model for future testing of new anti-microbiological agents under typical MRSA infection conditions.

METHODS

Eighteen randomised NZW-rabbits underwent a standardised surgical procedure with the insertion of a femoral bone implant. Animals were then divided into group 1 (MRSA inoculation, no antibiotics; M/N), group 2 (MRSA inoculation, Vancomyin; M/V), and group 3 (no MRSA inoculation, no antibiotics; N/N). The primary study outcome parameters were animal leucocyte count, animal weight, and animal body temperature at one, seven, and 42 days after surgery. Additionally, a histo-morphometrical score was established and adjusted to a modified histological Smeltzer score.

RESULTS

Macroscopic and histo-morphometrical findings showed a peri-implant osteomyelitis in group 1 with both increased acute and chronic infection parameters in M/N, as compared to M/V and N/N, indicating that vancomycin treatment prevented typical morphological changes of MRSA peri-implant osteomyelitis. Similarly, there was a reduction in animal weight and increase in leucocyte count and body temperature in group 1 (each p < 0.005). Vancomycin treatment again resulted in significantly reduced leucocyte count and body temperature, and increased animal body weight.

CONCLUSIONS

Here we have established a peri-implant MRSA osteomyelitis model that successfully combined clinical and laboratory outcome parameters of infection with histo-morphometrical results; this model appears to be valuable for future experimental use and therapeutic monitoring of new anti-microbiological MRSA drugs.

Antimicrobial activity of geranium oil against clinical strains of Staphylococcus aureus

The aim of this work was to investigate the antibacterial properties of geranium oil obtained from Pelargonium graveolens Ait. (family Geraniaceae), against one standard S. aureus strain ATCC 433000 and seventy clinical S. aureus strains. The agar dilution method was used for assessment of bacterial growth inhibition at various concentrations of geranium oil. Susceptibility testing of the clinical strains to antibiotics was carried out using the disk-diffusion and E-test methods. The results of our experiment showed that the oil from P. graveolens has strong activity against all of the clinical S. aureus isolates—including multidrug resistant strains, MRSA strains and MLS_B-positive strains—exhibiting MIC values of 0.25–2.50 μL/mL.