Characterization of a bacteriocin-like substance produced by a vaginal Lactobacillus salivarius strain.
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A novel bacteriocin-like substance produced by vaginal Lactobacillus salivarius subsp. salivarius CRL 1328 with activity against Enterococcus faecalis, Enterococcus faecium, and Neisseria gonorrhoeae was characterized. The highest level of production of this heat-resistant peptide or protein occurred during the late exponential phase. Its mode of action was shown to be bactericidal. L. salivarius subsp. salivarius CRL 1328 could be used for the design of a probiotic to prevent urogenital infections. (+info)
Structural and immunochemical characterization of a Neisseria gonorrhoeae epitope defined by a monoclonal antibody 2C7; the antibody recognizes a conserved epitope on specific lipo-oligosaccharides in spite of the presence of human carbohydrate epitopes.
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Lipo-oligosaccharides (LOS) produced by Neisseria gonorrhoeae are important antigenic and immunogenic components of the outer membrane complex. Previously, we showed that murine monoclonal antibody (mAb) 2C7 did not cross-react with human glycosphingolipids but identified the LOS epitope that is widely expressed in vivo and in vitro (Gulati, S., McQuillen, D. P., Mandrell, R. E., Jani, D. B., and Rice, P. A. (1996) J. Infect. Dis. 174, 1223-1237). In the present study, we analyzed the structure of gonococcal strain WG LOS containing the 2C7 epitope and investigated the structural requirements for expression of the epitope. We determined that the WG LOS components are Hep[1]-elongated forms of 15253 LOS that have a lactose on both Hep[1] and Hep[2] (Yamasaki, R., Kerwood, D. E., Schneider, H., Quinn, K. P., Griffiss, J. M., and Mandrell, R. E. (1994) J. Biol. Chem. 269, 30345-30351). In addition, we found that expression of the 2C7 epitope within the LOS is blocked when the Hep[2]-lactose is elongated. Based on the structural data of these LOS and the results obtained from immunochemical analyses, we conclude the following: 1) mAb 2C7 requires both the 15253 OS minimum structure and the N-linked fatty acids in the lipoidal moiety for expression of the epitope; 2) mAb 2C7 binds to the LOS that elongates the lactose on Hep[1] of the 15253 OS, but not the one on Hep[2]; and 3) the 2C7 epitope is expressed on gonococcal LOS despite the presence of human carbohydrate epitopes such as a lactosamine or its N-acetylgalactosaminylated (globo) form. Our study shows that the conserved epitope defined by mAb 2C7 could potentially be used as a safe site for the development of a vaccine candidate. (+info)
Susceptibilities of Neisseria gonorrhoeae isolates containing amino acid substitutions in GyrA, with or without substitutions in ParC, to newer fluoroquinolones and other antibiotics.
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We examined the antimicrobial susceptibilities of 85 Neisseria gonorrhoeae isolates, classified according to the presence of amino acid substitutions in the GyrA and ParC proteins, to 12 fluoroquinolones and 7 other antibiotics. Sitafloxacin and HSR-903 showed excellent activity against N. gonorrhoeae, including strains with both GyrA and ParC substitutions. Among the strains with various GyrA substitutions, strains with a serine-91-to-phenylalanine mutation required the highest MICs of all of the fluoroquinolones tested and were cross-resistant to structurally unrelated beta-lactams. (+info)
Rapid micro-carbohydrate test for confirmation of Neisseria gonorrhoeae.
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A rapid carbohydrate utilization procedure for the confirmation of Neisseria gonorrhoeae and identification of other Neisseria species has been developed. This method utilizes both preformed enzymes, introduced in a heavy inoculum, and enzymes formed by the microorganisms as a result of growth in a small volume of super-enriched medium. Expected carbohydrate reactions were produced by 383 clinical isolates of neisseriae and were clearly visible within 4 h of incubation. The combined use of disposable glass tubes (6 by 50 mm) and microamounts of media (0.05 ml) make this method not only rapid, but also low in cost. (+info)
Rapid diagnosis of septic arthritis by quantitative analysis of joint fluid lactic acid with a monotest lactate kit.
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The Monotest Lactate Kit (MLT) was compared with gas-liquid chromatography (GLC) for the rapid detection of septic arthritis. A total of 36 joint fluids were tested. Specimens were obtained from patients with septic arthritis (17 cases), inflammatory arthritis (18 cases), and degenerative arthritis (1 case). Specimens from 15 patients with bacterial arthritis had lactate levels above 65 mg/dl (mean, 318 mg/dl with the GLC method and 378 mg/dl with the MLT method). Three specimens from patients with gonococcal arthritis had levels that were not above 30 mg/dl (mean, 21 mg/dl with either the GLC or the MLT methods). Patients with inflammatory or degenerative disease yielded levels lower than 65 mg/dl (mean, 48 mg/dl with the GLC method and 46 mg/dl with the MLT method). Both methods proved to be equallly reliable in detecting septic arthritis, except for the gonococcal cases. Both methods are fast and easily adaptable to clinical laboratories; however, MLT was more definitive when quantitation was needed, required less fluid per speciment, and could be readily done at the bedside. (+info)
Opa expression correlates with elevated transformation rates in Neisseria gonorrhoeae.
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Neisseria gonorrhoeae is naturally competent for DNA transformation. Under most conditions encountered in vivo, gonococci express one or more opacity (Opa) proteins on their surfaces. Recently, it was shown that DNA preferentially binds to the surfaces of Opa-expressing organisms compared to those of isogenic Opa-negative strains, presumably due to the numerous cationic residues in the predicted surface-exposed loops of the Opa protein. This study examined whether Opa-DNA interactions actually influence DNA transformation of the gonococcus. The data show that Opa-expressing gonococci are more efficient recipients of DNA for transformation and are more susceptible to exogenous DNase I treatment at early stages during the DNA transformation process than non-Opa expressors. Furthermore, inhibition of the transformation process was demonstrable for Opa(+) populations when either nonspecific DNA or the polyanion heparin was used. Overall, the data suggest that Opa expression, with its presumptive positive surface charge contribution, promotes DNA transformation by causing a more prolonged sequestration of donor DNA at the cell surface, which translates into more efficient transformation over time. (+info)
Peripheral blood T cell proliferative response to chlamydial organisms in gonococcal and non-gonococcal urethritis and presumed pelvic inflammatory disease.
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OBJECTIVE: To study peripheral blood mononuclear cell (PBMC) proliferative response to Chlamydia trachomatis elementary bodies in (a) controls, (b) various stages of gonococcal (c) and non-gonococcal urethritis, and (d) women with a clinical diagnosis of pelvic inflammatory disease (PID). METHODS: We categorised 102 men presenting to a GUM clinic with urethritis by organisms (C trachomatis (CT) or Neisseria gonorrhoeae (NG) (both by culture), and whether it was their first (urethritis naive) or subsequent (urethritis experienced) attack. 23 women presenting to the clinic with a clinical diagnosis of PID were also investigated. We measured PBMC proliferative responses to C trachomatis (DK20--an oculogenital strain, serovar E), lysate of McCoy cells (used to propagate chlamydiae), and the recall antigen PPD. Controls were 37 men and women without present or past history of urethritis or chlamydial infection. Results were expressed as the ratio of the stimulation index (SI) obtained with DK20 compared with McCoy cells (DK index), and the ratio of the SI obtained with DK20 compared with PPD (PPD index). RESULTS: The median SI to DK20 in the urethritis was 12.7 which was significantly higher than the controls (7.6, p < 0.003). The median SI to the recall antigen PPD was similar in the urethritis patients (17.4) and the controls (22.4). All urethritis patient subgroups had a significantly higher DK index and PPD index than the controls. There was no difference in the PPD and DK index between urethritis naive and urethritis experienced patients and between the culture positive and culture negative urethritis subgroups. In PID patients only the PPD index was significantly higher than the controls. CONCLUSION: Men presenting with urethritis and women presenting with PID both have significantly greater peripheral blood mononuclear cell proliferative responses to the DK20 strain of C trachomatis than controls. A similar T cell proliferative response pattern in urethritis naive patients with either gonococcal or non-gonococcal urethritis could be because low sensitivity of CT culture failed to diagnose some cases of C trachomatis. However, it may also signify earlier exposure of the patients to chlamydial antigens (for example, C pneumoniae), cross reacting antigens such as heat shock proteins from other microbial species, or a "bystander" activation of chlamydia specific memory T cells trafficking through mucosal lymphoid tissue during urethritis. These results suggest evidence of T cell mediated response to C trachomatis cannot be used as a diagnostic tool. (+info)
Use of heme compounds as iron sources by pathogenic neisseriae requires the product of the hemO gene.
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Heme compounds are an important source of iron for neisseriae. We have identified a neisserial gene, hemO, that is essential for heme, hemoglobin (Hb), and haptoglobin-Hb utilization. The hemO gene is located 178 bp upstream of the hmbR Hb receptor gene in Neisseria meningitidis isolates. The product of the hemO gene is homologous to enzymes that degrade heme; 21% of its amino acid residues are identical, and 44% are similar, to those of the human heme oxygenase-1. DNA sequences homologous to hemO were ubiquitous in commensal and pathogenic neisseriae. HemO genetic knockout strains of Neisseria gonorrhoeae and N. meningitidis were unable to use any heme source, while the assimilation of transferrin-iron and iron-citrate complexes was unaffected. A phenotypic characterization of a conditional hemO mutant, constructed by inserting an isopropyl-beta-D-thiogalactopyranoside (IPTG)-regulated promoter upstream of the ribosomal binding site of hemO, confirmed the indispensability of the HemO protein in heme utilization. The expression of HemO also protected N. meningitidis cells against heme toxicity. hemO mutants were still able to transport heme into the cell, since both heme and Hb could complement an N. meningitidis hemA hemO double mutant for growth. The expression of the HmbR receptor was reduced significantly by the inactivation of the hemO gene, suggesting that hemO and hmbR are transcriptionally linked. The expression of the unlinked Hb receptor, HpuAB, was not altered. Comparison of the polypeptide patterns of the wild type and the hemO mutant led to detection of six protein spots with an altered expression pattern, suggesting a more general role of HemO in the regulation of gene expression in Neisseriae. (+info)