Anaerobes belonging to the genera Propionibacterium, Bacteroides, Peptococcus, Peptostreptococcus, Eubacterium, Streptococcus and Lactobacillus, which are commonly isolated from the human urogenital flora, were tested for their ability to inhibit the in vitro growth of Neisseria gonorrhoeae strains. / The antigonococcal effect of the anaerobic bacterial strains tested was found not to be due to nutrient depletion and pH change of the media which had supported their growth. This inhibition was not an all-or-none phenomenon since an inhibitory strain did not necessarily interfere with all the gonococcal strains tested. / All the 23 lactobacilli strains tested were found to inhibit the in vitro growth of N. gonorrhoeae. This inhibition was found to be dependent on the composition of the culture medium. In comparison to the gonococcus (GC) and dextrose starch agar (DSA) media, a modified deMan, Rogosa et Sharpe (MRS) medium was more appropriate to support both the growth of lactobacilli and the production of their antigonococcal activity. / For the other 32 anaerobic bacterial strains tested, six were selected for their large antigonococcal spectrum of activity. These strains were Peptostreptococcus anaerobius (Pc9,Ps11B,Ps11C), Bacteroides fragilis (B1A), Bacteroides ovatus (B24) and Eubacterium limosum (Ps11A). The antigonococcal activity produced by these six strains appeared to be specific to the gonococcus since a variety of anaerobes and aerobes were not generally inhibited. / E. limosum and B. fragilis strains were further selected to evaluate the production of their antigonococcal activity in liquid medium. E. limosum Ps11A strain produced its inhibitory activity in prereduced brain heart infusion (BHI) broth during the mid-logarithmic phase of growth, when no inhibitory concentration of short-chain fatty acids was detected in the culture medium. Furthermore, when the amounts of short-chain fatty acids produced by E. limosum increased, its antigonococcal activity decreased. Based on these results and on the individual amount of short-chain fatty acids excreted by E. limosum strains, it was concluded that the observed antigonococcal activity was not due to the presence of these acids. However, B. fragilis strains excreted propionic acid in amount reported to be inhibitory to the gonococcus. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI

No description available.

Bacterial species of the genus Neisseria include pathogens that are responsible for diseases of humans including bacterial meningitis (Neisseria meningitidis) and the sexually transmitted disease gonorrhea (Neisseria gonorrhoeae). These diseases are often characterized by a massive influx and activation of neutrophils, white blood cells involved in the early/innate immune response to pathogens, at the infection site. Neisseria spp. bind to and activate neutrophils via their Opacity-associated (Opa) outer membrane proteins, which interact with some members of the human carcinoembryonic antigen-related cellular adhesion molecule (CEACAM) family. One of these CEACAMs, CEACAM3 (CD66d), is unique in its restriction to neutrophils and its expression of a cytoplasmic immunoreceptor tyrosine-based activation motif (ITAM; YxxL/Ix6-8YxxL/I). In the course of my thesis work, I have shown that this motif is critically dependent for the activation of the neutrophil response to Neisseria, through the coupling of neisserial binding to activation of the tyrosine kinase, Syk, which initiates downstream signaling responsible for the antimicrobial responses of neutrophils. These data contribute to the knowledge of how seemingly unrelated receptors of neutrophils (such as the IgG-binding Fcγ receptors, the fungal receptor Dectin-1, and the bacterial-binding CEACAM3) converge functionally on the presence of the ITAM.

This study examined the adherence of Neisseria meningitidis to human buccal epithelial cells (BEC). Past studies have utilized microscopic assays which are tedious and are, at high bacterial concentrations, relatively inaccurate. This study developed a rapid radioactive assay for bacterial adherence which gave results comparable to the microscopic assay. This new assay system was used, then, to examine the kinetics and specificity of meningococcal adherence. Adherence, which increased linearly as a function of multiplicity of infection, reached maximal values within 5 minutes. Adherence was mediated by a bacterial surface protein; pronase-treated meningococcidid not adhere well to BEC. Unlike other adherent Neisseria, adherent meningococci did not exhibit pill. Removal of the capsule with saccharolytic agents greatly increased adherence. These results suggest that Neisseria meningitidis may adhere to human BEC via a non-pilus surface protein which is partially masked by the capsule. The BEC receptor for this protein was examined but remains unidentified.

Chromosomal mediated antimicrobial resistance in Neisseria gonorrhoeae can develop as a result of three main processes including the alteration of target enzymes, changes in transmembrane transport channels and active efflux pump function. Single nucleotide polymorphisms (SNPs) of target genes such as DNA gyrase (gyrA) and topoisomerase (parC), together with mutations in the promoter regions of the efflux pumps norM and mtr can confer resistance to the macrolides, penicillins and fluoroquinolones. These SNPs were analyzed using the SNaPshot method to allow for rapid detection of resistant isolates. Oligonucleotides were developed in the 5’ to the 3’ direction, ending one nucleotide adjacent to the specific SNP of interest. Single base extension reactions were performed and were detected using capillary electrophoresis. The SNaPshot procedure from Applied Biosystems employed in this study adds a single fluorescently-labelled nucleotide complementary to this SNP at the 3’ end by a primer extension polymerase reaction. Then using capillary electrophoresis, the labelled nucleotide is detected, enabling differentiation between A, C, T, or G. SNP results obtained were verified using DNA sequencing and both single and multiplexed reactions were carried out to increase the efficiency of the procedure. Spiked urine samples were also observed to determine if SNPs could be detected clinically. Single reactions enabled the characterization of all confirmed and relevant SNPs. With multiplex primer extension, multiple peaks were observed, each corresponding to one of the SNPs in the gene. This technique was explored for its applicability to detect SNPs of gyrA and parC mutations. Observable SNP detection limits were seen in spiked urine samples at 108 cells/mL in as early as 4 hours. DNA sequencing results confirmed the SNPs identity in each case. Thus, capillary electrophoresis using the SNaPshot protocol is another way to rapidly identify clinically resistant strains of Neisseria gonorrhoeae. This technique has also been shown to reduce analysis time compared to DNA sequencing and produces the same results.

Chromosomal mediated antimicrobial resistance in Neisseria gonorrhoeae can develop as a result of three main processes including the alteration of target enzymes, changes in transmembrane transport channels and active efflux pump function. Single nucleotide polymorphisms (SNPs) of target genes such as DNA gyrase (gyrA) and topoisomerase (parC), together with mutations in the promoter regions of the efflux pumps norM and mtr can confer resistance to the macrolides, penicillins and fluoroquinolones. These SNPs were analyzed using the SNaPshot method to allow for rapid detection of resistant isolates. Oligonucleotides were developed in the 5’ to the 3’ direction, ending one nucleotide adjacent to the specific SNP of interest. Single base extension reactions were performed and were detected using capillary electrophoresis. The SNaPshot procedure from Applied Biosystems employed in this study adds a single fluorescently-labelled nucleotide complementary to this SNP at the 3’ end by a primer extension polymerase reaction. Then using capillary electrophoresis, the labelled nucleotide is detected, enabling differentiation between A, C, T, or G. SNP results obtained were verified using DNA sequencing and both single and multiplexed reactions were carried out to increase the efficiency of the procedure. Spiked urine samples were also observed to determine if SNPs could be detected clinically. Single reactions enabled the characterization of all confirmed and relevant SNPs. With multiplex primer extension, multiple peaks were observed, each corresponding to one of the SNPs in the gene. This technique was explored for its applicability to detect SNPs of gyrA and parC mutations. Observable SNP detection limits were seen in spiked urine samples at 108 cells/mL in as early as 4 hours. DNA sequencing results confirmed the SNPs identity in each case. Thus, capillary electrophoresis using the SNaPshot protocol is another way to rapidly identify clinically resistant strains of Neisseria gonorrhoeae. This technique has also been shown to reduce analysis time compared to DNA sequencing and produces the same results.

Proefschrift Universiteit van Amsterdam. / Auteursnaam op omslag: Frits de Vries. Met lit. opg. - Met samenvatting in het Nederlands.

Universiẗat, Diss., 2006--Würzburg. / Erscheinungsjahr an der Haupttitelstelle: 2005.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.