Inhibition of sialidase activity and cellular invasion by the bacterial vaginosis pathogen Gardnerella vaginalis.

Bacterial vaginosis is a genital tract infection, thought to be caused by transformation of a lactobacillus-rich flora to a dysbiotic microbiota enriched in mixed anaerobes. The most prominent of these is Gardnerella vaginalis (GV), an anaerobic pathogen that produces sialidase enzyme to cleave terminal sialic acid residues from human glycans. Notably, high sialidase activity is associated with preterm birth and low birthweight. We explored the potential of the sialidase inhibitor Zanamavir against GV whole cell sialidase activity using methyl-umbelliferyl neuraminic acid (MU-NANA) cleavage assays, with Zanamavir causing a 30% reduction in whole cell GV sialidase activity (p < 0.05). Furthermore, cellular invasion assays using HeLa cervical epithelial cells, infected with GV, demonstrated that Zanamivir elicited a 50% reduction in cell association and invasion (p < 0.05). Our data thus highlight that pharmacological sialidase inhibitors are able to modify BV-associated sialidase activity and influence host-pathogen interactions and may represent novel therapeutic adjuncts.

Biotypes and virulence factors of Gardnerella vaginalis isolated from cases of bacterial vaginosis.

The present study was conducted to correlate the biotypes of Gardnerella vaginalis strains isolated from cases of bacterial vaginosis and their virulence factors. Thirty-two strains of G. vaginalis isolated from cases of bacterial vaginosis were biotyped. Adherence to vaginal epithelial cells, biofilm production, surface hydrophobicity, phospholipase C and protease activity were tested on these isolates. Biotype 1 was the most prevalent (8; 25%), followed by biotype 2 (7; 21.9%) and biotypes 5 and 8 (5; 15.6%). We did not find any statistical correlation between G. vaginalis biotypes and its virulence factors. Virulence factors expressed by G. vaginalis were not associated with a single biotype.

Determination of immunoglobulin A against Gardnerella vaginalis hemolysin, sialidase, and prolidase activities in vaginal fluid: implications for adverse pregnancy outcomes.

A nested case-control study of low birth weight and preterm delivery was performed with singleton women. Immunoglobulin A (IgA) against the Gardnerella vaginalis hemolysin (anti-Gvh IgA) and sialidase and prolidase activities were determined in vaginal fluid at 17 weeks of gestation. Sialidase positivity and bacterial vaginosis with high prolidase activity were associated with 2- and 11-fold increased risks for low birth weight, respectively. No woman with bacterial vaginosis plus a strong anti-Gvh IgA response had an adverse outcome.

Development of a species-specific polymerase chain reaction assay for Gardnerella vaginalis.

The nucleotide sequence of the region between the 16S and 23S rRNA genes of the facultative anaerobic bacterium Gardnerella vaginalis has been determined, together with the 5' proximal 500 nucleotides of the 23S rRNA gene. Regions suited for the development of specific, probe-confirmable polymerase chain reaction (PCR) assays were selected. PCR assays were evaluated with respect to sensitivity and specificity, the latter in comparison with a number of G. vaginalis reference strains and closely related species like Bifidobacterium spp. In an initial diagnostic study it appeared that the PCR test detected G. vaginalis in 40% of women irrespective of their clinical status. Ten out of 11 patients suffering from bacterial vaginosis as defined on the basis of clinical parameters were carrying G. vaginalis.

[A new zoonosis--investigation of Gardnerella vaginalis disease of fox. II. Identification of pathogenic bacteria].

16 strains isolated from aborted foetus and vaginal exeretions of foxes were used for examination of cell morphology including fine structure of the cell wall and septa, test for homolysis, biochemical reactions and analysis of G+C content of the bacterial DNA. The cells are pleomorphic bacilli and coccobacilli, Gram stain reaction appear positive to variable, catalse and oxidase-negative, with a fermentative type of glucose metabolism, giving acetic and lactic acid as the major end products of fermentation. It's differentiated from the human strains of G. vaginalis by its less fastidious in growth requirements and being facultatively anaerobic to aerobic. We propose the name: a new subspecies--Gardnerella vaginalis subsp. fox, the type strain is U80.