Evaluation of spa typing for the classification of clinical methicillin-resistant Staphylococcus aureus isolates.

We evaluated the utility of typing the spa gene, which encodes protein A of Staphylococcus aureus, for analyzing methicillin-resistant S. aureus (MRSA) isolates from patients with health care-associated infections by comparing the results of spa typing with those of pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA). We analyzed 78 clinical MRSA isolates collected at our hospital over a period of 2 months.

Genetic diversity of enterococci harboring the high-level gentamicin resistance gene aac(6')-Ie-aph(2'')-Ia or aph(2'')-Ie in a Japanese hospital.

Prevalence of high-level gentamicin resistance genes aac(6')-Ie-aph(2'')-Ia and aph(2'')-Ie, which encode distinct aminoglycoside-modifying enzymes, was analyzed for a total of 1128 clinical isolates of enterococci obtained in a Japanese hospital during a period between 1997 and 2007. The aac(6')-Ie-aph(2'')-Ia was detected in 40.1%, 12.

Genetic diversity of the low-level vancomycin resistance gene vanC-2/vanC-3 and identification of a novel vanC subtype (vanC-4) in Enterococcus casseliflavus.

An intrinsic low-level vancomycin resistance (VanC phenotype) in Enterococcus casseliflavus is conferred by either of two subtypes of vanC genes, that is, vanC-2 or vanC-3, which are genetically closely related. To know genetic diversity of vanC-2/C-3 genes among E. casseliflavus, nucleotide sequences of vanC-2/C-3 and other genetic components in vanC gene cluster (vanXYc, vanTc, vanRc, and vanSc) were analyzed for nine clinical isolates and four standard strains that showed low-level vancomycin resistance.

[Nationwide susceptibility surveillance of ciprofloxacin and various parenteral antimicrobials against bacteria isolated from patients with severe infections--third ciproxan injection special survey (2005)].

We conducted 3 nationwide surveillance studies between 2001 and 2005 at 39 participating institutions throughout Japan according to the special survey plan to investigate susceptibility to ciprofloxacin (CPFX) and various parenteral antimicrobials using clinical isolates from patients with severe infection during the reexamination period of parenteral CPFX. Results of the first special survey (2001) were already reported in this journal. The current third special survey (2005) was conducted at 34 participating institutions throughout Japan to determine susceptibility to CPFX and 22 various parenteral antimicrobials with the use of the microdilution method with respect to 1696 strains isolated and identified from various clinical specimens between January and June 2005.

Diversity of staphylocoagulase and identification of novel variants of staphylocoagulase gene in Staphylococcus aureus.

Staphylocoagulase (SC) is a major phenotypic determinant of Staphylococcus aureus. Serotype of SC (coagulase type) is used as an epidemiological marker and 10 types (I-X) have been discriminated so far. To clarify genetic diversity of SC within a single and among different serotype(s), we determined approximately 1500 bp-nucleotide sequences of SC gene encoding D1, D2, and central regions (N-terminal half and central regions of SC; SC(NC)) for a total of 33 S.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2006].

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 876 strains of Gram-positive bacteria, 1764 strains of Gram-negative bacteria, and 198 strains of anaerobic bacteria obtained from 30 medical institutions during 2006 was measured. The results were as follows; 1. MEPM was more active than the other carbapenem antibiotics tested against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2004].

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 907 strains of Gram-positive bacteria, 1790 strains of Gram-negative bacteria, and 192 strains of anaerobic bacteria obtained from 30 medical institutions during 2004 was measured. The results were as follows; 1. MIC90 of MEPM for almost all of enterobacteriaceae and Haemophilus influenzae were 4-fold to 32-fold lower than those of other carbapenems.

Detection of a novel aph(2") allele (aph[2"]-Ie) conferring high-level gentamicin resistance and a spectinomycin resistance gene ant(9)-Ia (aad 9) in clinical isolates of enterococci.

Aminoglycoside-modifying enzymes (AMEs) are major factors that confer aminoglycoside resistance to enterococci. In an epidemiologic study on distribution of 12 AME genes in 534 recent clinical strains isolated from a Japanese hospital, two uncommon AME genes, ant(9)-Ia and a novel aph(2") allele, aph(2")-Ie, were detected. ant(9)-Ia had been reported only in Staphylococcus aureus and encodes spectinomycin adenylyltransferase ANT(9)-I, which confers resistance to spectinomycin.

Analysis of the prevalence of tetracycline resistance genes in clinical isolates of Enterococcus faecalis and Enterococcus faecium in a Japanese hospital.

Prevalence of seven tetracycline resistance (TC(R)) genes--tet(L), tet(M), tet(K), tet(O), tet(S), tet(T), and tet(U)--which are known to be distributed to gram-positive cocci was analyzed for 224 Enterococcus faecalis and 46 Enterococcus faecium clinical isolates obtained in a Japanese hospital. Any of the TC(R) genes was detected in 75.9% of all the enterococcal strains.

[Nationwide surveillance of parenteral antibiotics containing meropenem activities against clinically isolated strains in 2002].

The antibacterial activity of meropenem (MEPM) and other parenteral antibiotics against clinical isolates of 899 strains of Gram-positive bacteria, 1500 strains of Gram-negative bacteria, and 158 strains of anaerobic bacteria obtained from 28 medical institutions during 2002 was measured. The results were as follows; 1. MEPM was more active than other carbapenem antibiotics against Gram-negative bacteria, especially against enterobacteriaceae and Haemophilus influenzae.

[Nationwide sensitivity surveillance of ciprofloxacin and various parenteral antibiotics against bacteria isolated from patients with severe infections--the first Ciproxan IV special investigation in 2001].

The parenteral injection of ciprofloxacin (CPFX), a fluoroquinolone antimicrobial drug, was approved in September 2000 and a re-examination period of 6 years was set at that time. As a special investigation to apply for re-examination of this drug, it has been planned to conduct 3 nationwide surveillances during the re-examination period by collecting clinically isolated bacteria from patients with severe infections, to whom the drug was mainly indicated, and examining drug susceptibilities of the bacteria to various parenteral antimicrobial drugs including CPFX. This time, we determined the minimum inhibitory concentrations (MICs) of various parenteral antimicrobial drugs including CPFX against 1,220 strains isolated from patients with severe infections by the micro-liquid dilution method and compared susceptibilities of various clinically isolated bacteria to CPFX with those to other antimicrobial drugs.

Analysis on distribution and genomic diversity of high-level antiseptic resistance genes qacA and qacB in human clinical isolates of Staphylococcus aureus.

High-level antiseptic resistance of Staphylococcus aureus is mediated by multidrug efflux pumps encoded by qacA and qacB genes. We investigated distribution and genomic diversity of these antiseptic resistance genes in a total of 522 clinical strains of S. aureus isolated recently in a Japanese hospital.

Endogenous reactive oxygen species is an important mediator of miconazole antifungal effect.

We investigated the significance of endogenous reactive oxygen species (ROS) produced by fungi treated with miconazole. ROS production in Candida albicans was measured by a real-time fluorogenic assay. The level of ROS production was increased by miconazole at the MIC (0.