- Volume 54, Issue 8, 2005

The roles of the three ORFs HP0208, HP0159 and HP1416 in the biosynthesis of Helicobacter pylori 26695 LPS were investigated in this study. These ORFs represent a paralogous family of genes with homology to the Salmonella enterica serovar Typhimurium (hereafter referred to as S. typhimurium) waaJ gene, which encodes an α-1,2-glycosyltransferase required for core LPS biosynthesis. HP0208 contains multiple tandem repeats of the dimer 5′GA at its 5′ end and its expression is predicted to be subject to phase variation. The number of 5′GA repeats present in this ORF was found to be non-permissive for the expression of HP0208 in the majority of H. pylori strains examined. To determine a role for this ORF in LPS biosynthesis a non-phase-variable, constitutively expressed variant of HP0208 was constructed and introduced into the genome of H. pylori 26695. Analysis of the LPS profile of this strain by Tricine-SDS-PAGE and immunoblotting with anti-Lewis Y antigen (Ley) mAbs confirmed a role for HP0208 in the biosynthesis of core LPS. A role for HP0159 and HP1416 in the biosynthesis of core LPS was also established. Although homologous to waaJ, H. pylori HP0208, HP0159 and HP1416 failed to complement an S. typhimurium waaJ mutant, suggesting that these ORFs encode functionally different enzymes.

Milk contains a wide variety of host protective factors against infectious microbes. Among these protective factors, lactoferrin (LF) and lactoperoxidase (LPO) have been reported to exhibit antiviral activities as well as immuno-modulatory effects. In the present study, the effects of orally administered LF and LPO were assessed in a mouse influenza virus infection model. BALB/c mice were intranasally infected with 6.6 × 102 p.f.u. of influenza virus A/PR/8/34(H1N1). Bovine LF or LPO was administered once daily at a dose of 62.5 mg per mouse by gavage, starting 1 day before infection. Mice given LF or LPO showed a significantly lower lung consolidation score on day 6 after infection compared with the control mice that were given water instead. Concurrently, the number of infiltrated leukocytes recovered from bronchoalveolar lavage fluid (BALF) on day 6 was significantly lower in mice given LF or LPO. However, the virus yield in the BALF was not affected by these treatments. The serum level of IL-6, a pro-inflammatory cytokine, positively correlated with the lung consolidation score in each group and was significantly lower on day 6 in the mice given LPO. These results suggest the potential of oral administration of LF or LPO to attenuate pneumonia in influenza-virus-infected mice through the suppression of infiltration of inflammatory cells in the lung.

Multiple colonies of Trichophyton rubrum were isolated from single skin specimens from 10 patients with tinea pedis and were typed using a PCR-based analysis of repeats in the rRNA intergenic spacer. In each case only a single strain type of T. rubrum was isolated, suggesting a monotypic aetiology of tinea pedis. This is in contrast to the multiple strains previously shown to be involved in many cases of onychomycosis.

The objective of this study was to determine the pharmacodynamic (PD) activity of moxifloxacin against four selected Bacteroides fragilis strains (three strains with low MICs and one strain with a high MIC) and two Escherichia coli strains (one strain with a low MIC and one strain with a high MIC) in a pharmacokinetic (PK) in vitro model in pure cultures as well as in mixed cultures. PK/PD assays of moxifloxacin were carried out with an initial maximum concentration of 4.0 mg l−1 and a half-life of 13 h. The E. coli strain with the low MIC was rapidly killed in both pure and mixed cultures in the in vitro PK/PD model, while the E. coli strain with the high MIC was not killed. None of the B. fragilis strains were rapidly killed in pure or mixed cultures. The bacterial numbers of the B. fragilis strains with low MICs were reduced by about one to two logs after 12 h in pure cultures. The presence of an E. coli strain with a low or a high MIC in the mixed culture reduced this effect even further.

The majority of the keratitis-causing Acanthamoeba isolates are genotype T4. In an attempt to determine whether predominance of T4 isolates in Acanthamoeba keratitis is due to greater virulence or greater prevalence of this genotype, Acanthamoeba genotypes were determined for 13 keratitis isolates and 12 environmental isolates from Iran. Among 13 clinical isolates, eight (61.5 %) belonged to T4, two (15.3 %) belonged to T3 and three (23 %) belonged to the T2 genotype. In contrast, the majority of 12 environmental isolates tested in the present study belonged to T2 (7/12, 58.3 %), followed by 4/12 T4 isolates (33.3 %). In addition, the genotypes of six new Acanthamoeba isolates from UK keratitis cases were determined. Of these, five (83.3 %) belonged to T4 and one was T3 (16.6 %), supporting the expected high frequency of T4 in Acanthamoeba keratitis. In total, the genotypes of 24 Acanthamoeba keratitis isolates from the UK and Iran were determined. Of these, 17 belonged to T4 (70.8 %), three belonged to T2 (12.5 %), three belonged to T3 (12.5 %) and one belonged to T11 (4.1 %), confirming that T4 is the predominant genotype (S2 = 4.167; P = 0.0412) in Acanthamoeba keratitis.

The purpose of this investigation was to quantify the concentration of endotoxin in necrotic root canals and investigate the possible relationship between the concentration of endotoxin and endodontic signs and symptoms. Samples were collected from root canals of 50 patients requiring endodontic treatment due to necrosis of the pulpal tissue. Anaerobic techniques were used to determine the number of c.f.u. in each sample. A quantitative chromogenic Limulus amoebocyte lysate assay was used to measure the concentration of endotoxin in each sample. The presence of c.f.u. was detected by culture in all samples (range 102–5 × 106). In samples from cases of patients with spontaneous pain, the mean c.f.u. was 1.43 × 106 while in asymptomatic cases it was 9.1 × 104. Endotoxin was present in all the samples studied [range 2390.0−22100.0 endotoxin units (EU) ml−1]. The mean concentration of endotoxin in samples from patients with spontaneous pain was 18540.0 EU ml−1 while in asymptomatic cases it was 12030.0 EU ml−1. Asymptomatic cases generally had lower levels of endotoxin (i.e. a negative association). A positive association was found between endotoxin and symptomatic cases (e.g. spontaneous pain, tenderness to percussion, pain on palpation, swelling and purulent exudates). This study showed that endotoxin is present in high concentrations in root canals of symptomatic teeth. There was a positive correlation between the concentration of endotoxin in the root canal and the presence of endodontic signs and symptoms.

Group A streptococcus (GAS) infection can cause severe invasive diseases, including necrotizing fasciitis and streptococcal toxic shock syndrome. Cordyceps sinensis, a Chinese herbal medicine, is an immunomodulator. In this study the air-pouch bacterial inoculation model was used to investigate the protective efficacy of C. sinensis mycelium extract against GAS infection. Force-feeding mice with C. sinensis mycelium extract for 3 consecutive days before GAS infection increased the survival rate and reduced local skin-tissue injury compared with mice fed PBS. Bacterial numbers in the air pouch exudates from C. sinensis-treated mice were lower than those from PBS-treated mice. Blood and organs in PBS-treated mice showed bacterial dissemination, but those in C. sinensis-treated mice did not. Three days of pretreatment with C. sinensis extract followed by C. sinensis treatment every other day after GAS infection resulted in 100 % survival. The post-GAS-infection levels of aspartate aminotransferase, alanine aminotransferase and blood urea nitrogen in the sera of C. sinensis-treated mice were lower than those of PBS-treated mice. Taken together, these results show that C. sinensis mycelium extract protects by decreasing bacterial growth and dissemination, thereby increasing mouse survival rate. IL-12 and IFN-γ expression and macrophage phagocytic activity also increased after C. sinensis treatment.

This paper reports a case of S. constellatus chorioamnionitis in a pregnant Crohn's disease patient who was taking azathioprine. Chorioamnionitis is a major cause of perinatal morbidity. Azathioprine, an immunosuppressive antimetabolite, is widely used to treat inflammatory bowel disease. Streptococcus constellatus is a Gram-positive bacterium that has not previously been associated with chorioamnionitis. A high index of suspicion for chorioamnionitis and unusual pathogens should be maintained in the management of obstetric patients on immunosuppressive agents.