Phagocytosis and killing of Gardnerella vaginalis by human neutrophils.

Easmon, C. S. F.; Clark, L; Crane, J. P.; Green, R

doi:10.1136/jcp.38.7.747

Cited by 7 publications

(10 citation statements)

References 8 publications

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“…Gardnerella vaginalis is found in the amniotic cavity of women with polymicrobial infection and can induce a strong pro‐inflammatory response in the chorioamniotic membranes . Amniotic fluid neutrophils could rapidly phagocytize this Gram‐variable bacillus, a process likely mediated by the activation of the alternative pathway of the complement system . The current study also provides evidence that amniotic fluid neutrophils can phagocytize Gram‐negative bacillus, including B. fragilis , Prevotella spp., and E. coli .…”

Section: Discussionsupporting

confidence: 53%

Amniotic fluid neutrophils can phagocytize bacteria: A mechanism for microbial killing in the amniotic cavity

Gomez‐Lopez

Romero

Garcia‐Flores

et al. 2017

American J Rep Immunol

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Problem Neutrophils are capable of performing phagocytosis, a primary mechanism for microbial killing. Intra-amniotic infection is characterized by an influx of neutrophils into the amniotic cavity. Herein, we investigated whether amniotic fluid neutrophils could phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection. Methods Amniotic fluid neutrophils from women with intra-amniotic infection were visualized by transmission electron microscopy (n=6). The phagocytic activity of amniotic fluid neutrophils from women with intra-amniotic infection and/or inflammation (n=10) or peripheral neutrophils from healthy individuals (controls, n=3) was tested using ex vivo phagocytosis assays coupled with live imaging. Phagocytosis by amniotic fluid neutrophils was also visualized by confocal microscopy (n=10) as well as scanning and transmission electron microscopy (n=5). Results 1) Intra-amniotic infection-related bacteria including cocci (e.g. Streptococcus agalactiae), bacilli (e.g. Bacteriodes fragilis and Prevotella spp.), and small bacteria without a cell wall (e.g. Ureaplasma urealyticum) were found inside of amniotic fluid neutrophils; 2) peripheral neutrophils (controls) rapidly phagocytized Streptococcus agalactiae, Ureaplasma urealyticum, Gardnerella vaginalis, and Escherichia coli; 3) amniotic fluid neutrophils can rapidly phagocytize Streptococcus agalactiae and Gardnerella vaginalis; and 4) amniotic fluid neutrophils can slowly phagocytize Ureaplasma urealyticum and Escherichia coli; yet, the process of phagocytosis of the genital mycoplasma was lengthier. Conclusions Amniotic fluid neutrophils can phagocytize bacteria found in the amniotic cavity of women with intra-amniotic infection, namely Streptococcus agalactiae, Ureaplasma urealyticum, Gardnerella vaginalis, and Escherichia coli. Yet, differences in the rapidity of phagocytosis were observed among the studied microorganisms. These findings provide a host defense mechanism whereby amniotic fluid neutrophils can kill microbes invading the amniotic cavity.

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Section: Discussionsupporting

confidence: 53%

Amniotic fluid neutrophils can phagocytize bacteria: A mechanism for microbial killing in the amniotic cavity

Gomez‐Lopez

Romero

Garcia‐Flores

et al. 2017

American J Rep Immunol

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“…vaginalis is opsonized for phagocytosis and killing by human neutrophils in the presence of normal human serum in a process primarily mediated by complement activated by the alternative pathway (57). However, the organism is resistant to killing by human serum plus complement or by mouse antiserum (19,57).…”

Section: Transmission Of Bacteria Associated With Vaginosismentioning

confidence: 96%

“…When considering the design of serological tests, it is important to recognize that G. vaginalis strains isolated from different patients exhibit antigenic differences (20,57,60,76,100 Impaired immunity has been suggested as a factor in the association between G. vaginalis and urinary tract infections of kidney transplant patients (69,169) and between G. vaginalis and vaginitis emphysematosa (112).…”

Section: Transmission Of Bacteria Associated With Vaginosismentioning

confidence: 99%

Gardnerella vaginalis: characteristics, clinical considerations, and controversies

1992

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The clinical significance, Gram stain reaction, and genus affiliation of Gardnerella vaginalis have been controversial since Gardner and Dukes described the organism as the cause of "nonspecific vaginitis," a common disease of women which is now called bacterial vaginosis. The organism was named G. vaginalis when taxonomic studies showed that it was unrelated to bacteria in various genera including Haemophilus and Corynebacterium. Electron microscopy and chemical analyses have elucidated the organism's gram-variable reaction. Controversy over the etiology of bacterial vaginosis was largely resolved by (i) studies using improved media and methods for the isolation and identification of bacteria in vaginal fluids and (ii) standardization of criteria for clinical and laboratory diagnosis. Besides G. vaginalis, Mobiluncus spp., Mycoplasma hominis, and certain obligate anaerobes are now acknowledged as participants in bacterial vaginosis. The finding that G. vaginalis, Mobiluncus spp., and M. hominis inhabit the rectum indicates a potential source of autoinfection in addition to sexual transmission. Extravaginal infections with G. vaginalis are increasingly recognized, especially when the toxic anticoagulant polyanetholesulfonate is omitted from blood cultures and when urine cultures are incubated anaerobically for 48 h. The finding that mares harbor G. vaginalis suggests that an equine model can be developed for studies of Gardnerella pathogenesis.

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“…Recent studies have shown that G. vaginalis organisms are resistant in vitro to the bactericidal activity of human serum (Boustouller & Johnson, 1986), which may explain how organisms are able to survive in the bloodstream during bacteraemic episodes. The fact that bacteraemia with G. vaginalis does not appear to persist for prolonged periods may be due to the clearance of the organisms from the bloodstream by phagocytic leucocytes (Easmon et al 1985). Clearly, there is little evidence to suggest that G. vaginalis is invasive under normal conditions, and it would appear that extra-vaginal infections reflect underlying predisposing host conditions.…”

Section: Discussionmentioning

confidence: 99%