Isao Haraga

The effects of vancomycin and beta-lactam antibiotics on vancomycin-resistant Staphylococcus aureus

To the Editor: First Sieradzki et al.1 and then Climo et al.2 presented evidence that combinations of vancomycin and β-lactam antibiotics were synergistic in vitro and in vivo against vancomycin-re...

Modification of the gluteus maximus V-Y advancement flap for sacral ulcers: the gluteal fasciocutaneous flap method.

&NA; We designed a modified gluteus maximus V‐Y advancement flap method for closing a sacral ulcer. The purposes of our method were to simplify the surgical procedure and to avoid a functional deficit of the gluteus maximus muscle that was sacrificed by the conventional method. After excising the sacral ulcer, the V‐Y advancement flap is marked on the bilateral buttock. Fascial incision of the gluteus maximus is made at the same incision in the skin. One‐third of each medial flap is elevated as a fasciocutaneous flap by dissecting the layer between the fascia and the muscle at the parasacral region. The flaps are then moved medially and sutured. We operated on 24 patients with sacral ulcers using this technique. The patients included 19 with a sacral pressure sore and 5 with a radiation ulcer on the sacrum. Eighteen ambulatory patients also were included in this group. The results showed no flap necrosis in any patient. No functional deficit of the gluteus maximus muscle was observed postoperatively in the ambulatory patients. Average blood loss was 250 ml during the procedure. We conclude that the gluteus V‐Y advancement flap as a fasciocutaneous flap is superior to the conventional musculocutaneous flap method.

Emergence of vancomycin resistance during therapy against methicillin-resistant Staphylococcus aureus in a burn patient—importance of low-level resistance to vancomycin

OBJECTIVES Staphylococcus aureus with low-level resistance to vancomycin (VLSA) which could develop into vancomycin-resistant S. aureus (VRSA) is most important. However, VLSA is difficult to detect by standard laboratory methods. We describe here improved methods to detect VLSA. METHODS Three methicillin-resistant S. aureus (MRSA) strains, designated Fu6, Fu10, and Fu18, were sequentially isolated from the burn wound site of a patient, during vancomycin therapy. The properties of these strains were compared with those of reference strains Mu3 and Mu50 (previous resistant isolates from other patients). RESULTS The isolated strains, Fu10 and Fu18, had identical phenotypes and genotypes. The vancomycin resistance of Fu10 was equivalent to that of strain Mu3, whereas Fu18 had much higher vancomycin resistance than Fu10 and Mu3, although reaching the level of Mu50. Fu18 showed similar growth to Mu50 on gradient gels and on Mu3 medium. CONCLUSIONS Our data indicate that the VLSA developed vancomycin resistance during exposure to vancomycin in vivo. The population analysis of tested VLSA and vancomycin intermediately resistant S. aureus (VISA) indicates that a penem at relatively low concentrations induced a significant increase in the number of vancomycin-resistant subpopulations. Furthermore, we confirmed that gradient gel analysis and Mu3 medium are simple and useful methods for the detection of VLSA judged as VSSA by its conventional MIC alone.

Increased biofilm formation ability and accelerated transport of Staphylococcus aureus along a catheter during reciprocal movements

Staphylococcus spp. is a major cause of device-related infections. However, the mechanisms of deep-tissue infection by staphylococci from the skin surface remain unclear. We performed in vitro experiments to determine how staphylococci are transferred from the surface to the deeper layers of agar along the catheter for different strains of Staphylococcus aureus with respect to bacterial concentrations, catheter movements, and biofilm formation. We found that when 5-mm reciprocal movements of the catheter were repeated every 8h, all catheter samples of S. aureus penetrated the typical distance of 50mm from the skin to the epidural space. The number of reciprocal catheter movements and the depth of bacterial growth were correlated. A greater regression coefficient for different strains implied faster bacterial growth. Enhanced biofilm formation by different strains implied larger regression coefficients. Increased biofilm formation ability may accelerate S. aureus transport along a catheter due to physical movements by patients.

Drill-hole guide for internal fixation of fractures of the mandibular condyle.

We have developed a drill-hole guide valuable in accurately positioning the fracture of the mandibular ramus. It operates by introducing a Kirschner wire through the fracture stump from the mandibular angle to the condyle. A 2.0- to 2.4-mm-diameter Kirschner wire is drilled into the ramus from below and proceeds up to the condylar fragment through the stump of the fracture. With this guide, 15 patients with 23 subcondylar fractures underwent open reduction with Kirschner wire fixation. In each case, wire, by means of a pinning technique, was inserted accurately from the mandibular angle to the repositioned condyle.

Bacterial contamination upon the opening of injection needles

IntroductionTwo opening methods are used for injection needle products: the “peel-apart method” where the adhesive surface of the packaging mount is peeled off, and the “push-off top method,” where the needle hub is pressed against the mount to break it. However, the risks of bacterial contamination as a result of opening method remain unknown. The aim of our study was to evaluate the bacterial contamination of needle hubs upon the opening of injection needles by the peel-apart or push-off top method under various conditions.MethodsBacterial contamination upon the opening of injection needles was examined in two materials, paper and plastic. Various concentrations of Staphylococcus aureus were applied to the mount and were maintained under wet or dry conditions. Injection needles were opened using the peel-apart or push-off top method. Needle hub contamination was examined using agar medium colony counting. Clinically assumed conditions (the hands and saliva of anesthesiologists) were also evaluated. Data were statistically examined using the Cochran-Mantel-Haenszel, Jonckheere, and Fisher’s exact tests.ResultsThe lateral surfaces of needle hubs were contaminated using the push-off top method, but not by the peel-apart method, in a manner that was dependent on S. aureus concentrations. No significant differences were observed between mount materials. Needle hub contamination was significantly more severe for the wet than for the dry opening portion. The clinically assumed condition study revealed that the lateral and bottom surfaces of the needle hub were contaminated significantly more in the saliva contamination group than in the dry and wet hand groups.ConclusionsThe bacterial contamination of needle hubs may occur upon the opening of injection needles when the push-off top method is used and may be affected by hands contaminated with saliva under clinical conditions.