Staphylococcus aureus (S. aureus) is one of the most clinically important inflammation-inducing pathogens, while Staphylococcus epidermidis (S. epidermidis) is nonpathogenic and hardly causes inflammation on skin. β-defensins, antimicrobial peptides, are secreted from keratinocytes constitutively or upon induction by various microorganisms. However, the difference between S. aureus and S. epidermidis is still unclear in terms of their influences on the production of β-defensins. In this study, we focused on the influences of S. aureus and S. epidermidis on the keratinocyte innate immune response. Pathogenic S. aureus mainly induced human β-defensin (hBD) 1 and hBD3, but not hBD2, and nonpathogenic S. epidermidis mainly induced hBD2 from human keratinocytes. Molecular weight fractions of >10 kDa prepared from S. aureus supernatants induced the production of hBD1 and hBD3. On the other hand, molecular weight fraction of >100 kDa prepared from S. epidermidis supernatants induced the production of hBD2.Furthermore, the secreted products of S. epidermidis used the toll-like receptor (TLR) 2 pathway in the induction of hBD2 production. The secreted products of S. aureus and S. epidermidis differentially induced subtypes of hBD through different receptors, which may be associated with the difference in virulence between these two bacteria.

Sub-MIC levels of macrolides down-regulate bacterial virulence factors and suppress inflammatory processes. The ability of macrolides to reduce the production of pneumolysin has been shown to explain the discrepancy between in vitro resistance and outcomes with macrolides against macrolide-resistant Streptococcus pneumoniae. In this study, we determined whether the ability of macrolides to regulate inflammatory processes is beneficial for innate resistance to macrolide-resistant pneumococci in a murine pneumonia model. Among the macrolides tested, only roxithromycin did not affect in vitro pneumococcal virulence factors at sub-MIC levels. Roxithromycin (1.25 to 10 mg/kg of body weight/day) was administered to mice by oral gavage for 3 days before infection with a resistant strain of S. pneumoniae. We evaluated the efficacy of the treatment by determining mouse survival curves and by measuring bacterial burdens and several inflammatory parameters in the airways. Pneumolysin and PspA in infected lungs were examined by Western blot assay. Roxithromycin at doses of >5 mg/kg/day increased the median survival time and retarded bacteremia without suppressing the production of pneumolysin and PspA in infected lungs. This treatment reduced matrix metalloproteinase-7 expression and activation and keratinocyte-derived chemokine production in the lungs, while it increased mononuclear cell responses in the lungs, with enhanced bacterial clearance. Concentrations of roxithromycin in plasma and tissues were below the MICs for the inoculated strain during infection. The treatment also reduced inflammatory responses to killed pneumococci in the lungs. These results suggest that the modification by roxithromycin of airway inflammatory responses, including those of matrix metalloproteinase-7 and phagocytes, is beneficial for initial resistance to macrolide-resistant pneumococci.Streptococcus pneumoniae is the most prevalent pathogen associated with community-acquired pneumonia, and the emergence of antibiotic resistance among pneumococcal isolates linked to community-acquired pneumonia has been of great concern. Especially, the incidence of macrolide-resistant S. pneumoniae is rapidly increasing (11,22). Nevertheless, macrolide compounds have been empirically among the firstline drugs for the treatment of outpatients with communityacquired pneumonia. Such empirical therapy is likely to involve the risk of exacerbating the disease in cases of infection with macrolide-resistant S. pneumoniae (31, 32). However, despite the appreciable level of macrolide resistance, concordance between in vitro macrolide susceptibility and clinical outcomes among patients with community-acquired pneumonia is lacking (5, 34); the exact clinical relevance of in vitro findings has yet to be determined. A recent report (12) has shown that the ability of macrolides to reduce pneumococcal virulence factors may account for the discordance between the in vitro resistance of pneumococci and the conservative clinical effects of macrolides. In addition to the su...

Carbapenem-resistant Enterobacteriaceae (CRE) strains have become globally distributed in the past decade, resulting in concern over the control of hospital infections and antimicrobial therapies (1, 2). The majority of CRE isolates are carbapenemase-producing Enterobacteriaceae (CPE) strains, so early detection of CPE strains is essential for providing optimal antimicrobial therapies and preventing horizontal transmission. In 2015, van der Zwaluw et al. reported the carbapenem inactivation method (CIM), a new method for detecting carbapenemase producers with high sensitivity and specificity (3). However, it was unclear whether CIM can identify IMP producers with a low carbapenem MIC or non-CPE strains that are highly carbapenem resistant. In this study, we evaluated whether CIM can identify CPE strains independently of their carbapenem MICs.Were used 233 CPE and 51 non-CPE strains isolated in general hospitals across Japan from 2012 to 2016 and stocked in our laboratory. The strains were collected from blood, sputum, wounds, urine, and feces. Their antibiotic susceptibilities were determined by the agar dilution method in accordance with the recommendations of the CLSI (4). The CPE strains included 191 IMP, 20 KPC, 17 NDM, and 5 OXA-48-like (OXA-48 and OXA-244) producers. The non-CPE strains included 31 extended-spectrum beta-lactamase (CTX-M, SHV, and TEM) producers and 5 plasmid-mediated AmpC ␤-lactamase (DHA, CMY, and CFE) producers. They were identified by DNA sequence amplification as previously described (5-10). Of the non-CPE strains, 13 highly carbapenem-resistant strains were identified as producing cephalosporinases and lacking porin function by SDS-PAGE, DNA sequencing, and quantitative reverse transcription-PCR (11).The CIM was conducted as previously described (3). The isolates were cultured on Mueller-Hinton agar (MHA) plates. A full 10-l inoculation loop of each strain was suspended in 400 l of sterile distilled water, and a 10-g meropenem (MEM) susceptibilitytesting disk (E-DF85; EIKEN) was immersed in the solution. After incubation at 35°C for 2 h, the disk was removed and placed on an MHA plate inoculated with a 0.5 McFarland standard of Escherichia coli strain ATCC 25922 with a sterile cotton swab. Finally, the plate was incubated overnight at 35°C and the inhibition zone around each disk was measured. Inhibition circles Ͻ10 mm in diameter were judged to indicate CIM positivity.The CIM showed a sensitivity of 100% (233/233) for CPE strains and a specificity of 96.1% (49/51) for non-CPE strains (Table 1). The MICs of MEM for the 191 IMP producers ranged from 0.125 to 32 g/ml (MIC 50 ϭ 0.5 g/ml, MIC 90 ϭ 2 g/ml), and those of imipenem (IPM) ranged from 0.06 to 8 g/ml (MIC 50 ϭ 0.125 g/ml, MIC 90 ϭ 0.5

Fructan-hydrolyzing enzyme from Streptococcus salivarius KTA-19 isolated from human dental plaque was investigated. The enzyme was purified by ammonium sulfate precipitation, acetone fractionation, and column chromatography on Bio-Gel and DEAE-cellulose. The purified enzyme showed a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing. Its molecular weight was 100,000 as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme exhibited an optimum pH of 6.5 and decreased its activity from pH 6.0 and especially below pH 5.5. The optimum temperature was 40 to 50°C, and enzyme activity was reduced by 90% at 55°C. Enzyme activity was markedly inhibited by Hg2+, Ag+, Cu2+, and pchloromercuribenzoate at a concentration of 10-3 M, but not by other metal ions or chemical effectors. Fructose was the only by-product of the enzyme action on levan. These results indicated that the levanase of S. salivarius KTA-19 is an exo

Spectrophotometric photodynamic detection involving extracorporeal treatment with HAL for bladder cancer cells in voided urine showed high accuracy. This bladder cancer detection method is easy and cost-effective, and has the potential for clinical use.