A high resistance rate (47.9%) to gatifloxacin (GAT; 8-methoxy fluoroquinolone) in Helicobacter pylori (H. pylori) strains from 48 Japanese patients is observed after unsuccessful H. pylori eradication. A significant association between MICs for GAT equal to or above 1 g/ml and mutations of the gyrA gene of H. pylori was demonstrated.Resistance to antibiotics is the major cause of the failure to eradicate Helicobacter pylori. For such cases, alternative regimens need to be developed.Perri et al. have reported an unacceptable low eradication rate of only 68% with a 7-day regimen of levofloxacin (LVX), amoxicillin (AMX), and pantoprazole (12). However, Sharara et al. have recently reported an excellent eradication rate of 92% with a 7-day regimen of gatifloxacin (GAT), AMX, and rabeprazole (14). It is important to note the superior in vitro activity of GAT over that of LVX against H. pylori (1). Therefore, GAT-based triple therapy might be a promising option for an alternative treatment regimen.Several studies have shown that the "quinolone resistancedetermining region" (QRDR) of the gyrA gene plays a critical role in the resistance of H. pylori to ciprofloxacin (CIP) (8,15). H. pylori does not contain genes for topoisomerase IV, an important fluoroquinolone target in other bacteria (15). The present study demonstrated a correlation between MICs to GAT and mutations of the gyrA and gyrB genes in H. pylori isolated from Japanese patients after unsuccessful eradication of infection.A total of 48 patients (32 males and 16 females; mean age, 57.8) with H. pylori infection after treatment failure were enrolled at Keio University Hospital between September 2004 and June 2005. Of the total, 42 patients had one treatment failure, 4 patients had two treatment failures, and 2 patients had three treatment failures (first-line treatment, triple therapy with clarithromycin [CLR], AMX, and proton pump inhibitor [PPI]; second-line treatment, triple therapy with metronidazole [MNZ], AMX, and PPI; and third-line treatment, triple therapy with LVX, AMX, and PPI). All patients underwent upper gastrointestinal endoscopy and gastric biopsy at Keio University Hospital.The susceptibility of H. pylori isolates to CRL, GAT, and MNZ was determined by the agar dilution method according to the guidelines established by the CLSI (formerly NCCLS) (9). Isolates were considered resistant to MNZ if the MIC of the drug was Ն8 g/ml and resistant to CLR and GAT if the MIC of these drugs was Ն1 g/ml (3, 7, 10). The resistance rates to GAT, CLR, and MNZ were 47.9%, 79.2%, and 6.3%, respectively. The GAT resistance rates were 22.2% (2/9) in the strains susceptible to both CLR and MNZ, 50% (18/36) in the strains resistant to CLR but susceptible to MNZ, 100% (1/1) in the strains resistant to MNZ but susceptible to CLR, and 100% (2/2) in the strains resistant to both CLR and MNZ.Studies in Europe have suggested that the primary resistance rate might be as low as 8% for CIP (2, 16) and that only 9% of the isolates show resistance to CIP after failure of pr...

Although fosfomycin is an old antibiotic, it has resurfaced with particular interest. The antibiotic is still effective against many pathogens that are resistant to other commonly used antibiotics. We have found that fosfomycin resistance of enterohemorrhagic Escherichia coli (EHEC) O157:H7 is controlled by the bacterial two-component signal transduction system CpxAR. A cpxA mutant lacking its phosphatase activity results in constitutive activation of its cognate response regulator, CpxR, and fosfomycin resistance. We have shown that fosfomycin resistance requires CpxR because deletion of the cpxR gene in the cpxA mutant restores fosfomycin sensitivity. We have also shown that CpxR directly represses the expression of two genes, glpT and uhpT, which encode transporters that cotransport fosfomycin with their native substrates glycerol-3-phosphate and glucose-6-phosphate, and repression of these genes leads to a decrease in fosfomycin transport into the cpxA mutant. However, the cpxA mutant had an impaired growth phenotype when cultured with glycerol-3-phosphate or glucose-6-phosphate as a sole carbon substrate and was outcompeted by the parent strain, even in nutrient-rich medium. This suggests a trade-off between fosfomycin resistance and the biological fitness associated with carbon substrate uptake. We propose a role for the CpxAR system in the reversible control of fosfomycin resistance. This may be a beneficial strategy for bacteria to relieve the fitness burden that results from fosfomycin resistance in the absence of fosfomycin.

Oral administration of urease-specific IgY not only inhibited H. pylori disease activity in H. pylori-infected gerbils, but also prevented H. pylori colonization in those not yet infected. These encouraging results may pave the way for a novel therapeutic and prophylactic approach in the management of H. pylori-associated gastroduodenal disease.

Urinary tracts infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a common infectious disease. With the shortage of new antimicrobial agents, the increase in UPEC resistance to commonly used drugs, such as fluoroquinolones and β-lactams including carbapenems is a critical issue. UPEC invades urinary tract cells, where it aggregates, and subsequently, forms biofilm-like multicellular colonies termed intracellular bacterial communities (IBCs). This process allows the bacteria to establish infections and so may be a good potential target for new drugs to treat infections. Here, we show that deletion of the tolB gene, encoding a protein of the Tol-Pal system that was originally characterized as a protein complex for colicin uptake and maintenance of the outer membrane, decreases the level of bacterial internalization into and aggregation within cultured bladder epithelial cells and also inhibits the colonization of mice urinary tracts. The tolB mutant also exhibited defective motility because of impaired flagellum syntheses. The fliC and motA mutants, which are non-motile strains, also exhibited lower levels of bacterial internalization and aggregation than their wild-type parent. Additional deletion of tolB in the fliC mutant did not further decrease these, suggesting that the attenuated virulence of the tolB mutant is a result of defective motility. The tolA , tolQ , tolR , and pal mutants that lack other members of the Tol-Pal system also exhibited lower levels of motility and aggregation within bladder epithelial cells compared to their wild-type parent. These combined results suggest another role of the Tol-Pal system, i.e., that it is responsible for optimal internalization, aggregation followed by IBC formation within urinary tract cells, and bacterial motility.

Uropathogenic Escherichia coli (UPEC) is a major pathogen that causes urinary tract infections (UTIs). This bacterium adheres to and invades the host cells in the bladder, where it forms biofilm-like polymicrobial structures termed intracellular bacterial communities (IBCs) that protect UPEC from antimicrobial agents and the host immune systems. Using genetic screening, we found that deletion of the fur gene, which encodes an iron-binding transcriptional repressor for iron uptake systems, elevated the expression of type I fimbriae and motility when UPEC was grown under iron-rich conditions, and it led to an increased number of UPEC cells adhering to and internalized in bladder epithelial cells. Consequently, the IBC colonies that the fur mutant formed in host cells were denser and larger than those formed by the wild-type parent strain. Fur is inactivated under iron-restricted conditions. When iron was depleted from the bacterial cultures, wild-type UPEC adhesion, invasion, and motility increased, similar to the case with the fur mutant. The purified Fur protein bound to regions upstream of fimA and flhD, which encode type I fimbriae and an activator of flagellar expression that contributes to motility, respectively. These results suggest that Fur is a repressor of fimA and flhD and that its repression is abolished under iron-depleted conditions. Based on our in vitro experiments, we conclude that UPEC adhesion, invasion, IBC formation, and motility are suppressed by Fur under iron-rich conditions but derepressed under iron-restricted conditions, such as in patients with UTIs.

IntroductionWe have developed an implant-type tissue-engineered cartilage using a poly-l-lactide scaffold. In a clinical study, it was inserted into subcutaneous areas of nasal dorsum in three patients, to correct cleft lip–nose deformity. The aim of this study was to helping evaluation on the efficacy of the regenerative cartilage.Methods3D data of nasal shapes were compared between before and after surgery in computed tomography (CT) images. Morphological and qualitative changes of transplants in the body were also evaluated on MRI, for one year.ResultsThe 3D data from CT images showed effective augmentation (>2 mm) of nasal dorsum in almost whole length, observed on the medial line of faces. It was maintained by 1 year post-surgery in all patients, while affected curves of nasal dorsum was not detected throughout the observation period. In magnetic resonance imaging (MRI), the images of transplanted cartilage had been observed until 1 year post-surgery. Those images were seemingly not straight when viewed from the longitudinal plain, and may have shown gentle adaptation to the surrounding nasal bones and alar cartilage tissues.ConclusionThose findings suggested the potential efficacy of this cartilage on improvement of cleft lip–nose deformity. A clinical trial is now being performed for industrialization.

Ghrelin secretion triggered by H pylori infection might be suppressed by IL-1beta, the release of which is also induced by the infection, resulting in the body weight loss of mice with H pylori infection.

Because a shortage of new antimicrobial agents is a critical issue at present, and with the spread of multidrug-resistant (MDR) pathogens, the use of fosfomycin to treat infections is being revisited as a "last-resort option." This drug offers a particular benefit in that it is more effective against bacteria growing under oxygen-limited conditions, unlike other commonly used antimicrobials, such as fluoroquinolones and aminoglycosides. In this study, we showed that Escherichia coli strains, including enterohemorrhagic E. coli (EHEC), were more susceptible to fosfomycin when grown anaerobically than when grown aerobically, and we investigated how the activity of this drug was enhanced during anaerobic growth of E. coli. Our quantitative PCR analysis and a transport assay showed that E. coli cells grown under anaerobic conditions had higher levels of expression of glpT and uhpT, encoding proteins that transport fosfomycin into cells with their native substrates, i.e., glycerol-3-phosphate and glucose-6-phosphate, and led to increased intracellular accumulation of the drug. Elevation of expression of these genes during anaerobic growth requires FNR, a global transcriptional regulator that is activated under anaerobic conditions. Purified FNR bound to DNA fragments from regions upstream of glpT and uhpT, suggesting that it is an activator of expression of glpT and uhpT during anaerobic growth. We concluded that the increased antibacterial activity of fosfomycin toward E. coli under anaerobic conditions can be attributed to elevated expression of GlpT and UhpT following activation of FNR, leading to increased uptake of the drug.