[Rapid Identification Method Positive Blood Culture Bottles with MALDI Biotyper].

Identification method positive blood culture bottles with MALDI Biotyper is the most important test on precisely and rapidly, for detamination the bacterial name in sepsis and bacteremia is very significant for decision a cure. This time, we devised a new method "blend" to identify the mixture hypostasis that were come into being by centrifuging blood culture broths and 70% formic acid with MALDI Biotyper (Bruker). This time, we identified 65 samples rapidly with MALDI biotyper by "on plate" and "blend," and verified their effectivity. As a result of six ways (on plate, blend-3, blend-6, blend-9, blend-12, blend-15), the highest detection rate was Gram negative rods: blend-15 (74.1%), Gram positive cocci: blend-9 (56.3%), total: blend-9 (55.4%). Moreover, we confirmed that the detection rate raised to 85.2% (GNR), 71.0% (GPC) and 77.6% (total), and the usefully was suggested. Our invented method is more excellently than recommended on Gram negative rods, especially Enterobacteriaceae, Staphylococcus aureus, and Enterococcus spp.

[Staphylococcal cassette chromosome mec types and antimicrobial susceptibilities of methicillin-resistant Staphylococcus aureus isolated from our hospital].

Reports of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections have recently increased in Japan. To determine the status of MRSA infections in our hospital, we investigated their Staphylococcal cassette chromosome mec (SCCmec) types and prevalence of Panton-Valentine leukocidin (PVL). In addition, we investigated the relation between their SCCmec and antimicrobial susceptibility. The 191 strains were isolated from January to July in 2011 and were classified as SCCmec type I (2, 1.0％), type II (136, 71.2％), type IV (36, 18.8％), type V (4, 2.1％) and type VIII (2, 1.0％). Eleven isolates (5.8％) were designated as nontypable. No isolates were PVL-positive in this study. The SCCmec type IV strains were more susceptible to imipenem (MIC90, 0.25 µg/ml) than SCCmec type II strains (MIC90, >16 µg/ml). This difference was also observed between SCCmec type IV and SCCmec type II in susceptibility levels to clarithromycin, clindamycin, minocycline, and levofloxacin, but not to gentamicin. In particular, SCCmec type IV strains were susceptible to imipenem and minocycline. The result indicates these susceptibility is useful to discriminate CA-MRSA from Hospital-associated MRSA (HA-MRSA).

Bacteriological characteristics of Arcanobacterium haemolyticum isolated from seven patients with skin and soft-tissue infections.

Bacteriological examinations were conducted for seven Arcanobacterium haemolyticum strains isolated from elderly patients with skin and soft-tissue infections, such as cellulitis and skin ulcers. Streptococcus dysgalactiae or Gram-positive cocci were isolated together with A. haemolyticum from all patients. The strains were identified as A. haemolyticum based on their being catalase negative, reverse Christie, Atkins and Munch-Petersen (CAMP) positive and phospholipase D gene positive in respective tests. Moreover, API Coryne and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry confirmed the identification of A. haemolyticum. All strains showed good susceptibility to minocycline, vancomycin and ß-lactam antibiotics, but several strains were resistant to gentamicin and levofloxacin.