Infections of the Genital Systems
Keith Struthers in Clinical Microbiology, 2017
Gardnerella vaginalis is a gram-variable facultative organism associated with bacterial vaginosis. Other organisms include Mycoplasma hominis and the anaerobe Mobiluncus. They have the ability to overwhelm the lactobacillus population of the vagina, with the resulting inflammatory response producing the discharge. Gardnerella can be detected on gram-stained preparations adherent in large numbers to vaginal epithelial cells, termed ‘clue’ cells.
Factors Affecting the Microflora of the Lower Genital Tract of Healthy Women
Michael J. Hill, Philip D. Marsh in Human Microbial Ecology, 2020
There is considerable variation and controversy between the reports of Gardnerella vaginalis (formerly known as Haemophilus vaginalis or Corynebacterium vaginale) in normal women. The original report of the isolation of G. vaginalis by Gardner and Dukes in 195530 found this organism was absent in normal women but present in the majority of women with nonspecific vaginitis (now known as bacterial vaginosis). Improved cultural techniques, mainly the use of human blood bilayer medium,31,32 have since allowed the isolation of small numbers of G. vaginalis.31,33 Subsequently, there have been reports of normal women colonized by G. vaginalis but always with low numbers. However, the literature should be read and interpreted with caution. The criteria for the diagnosis of bacterial vaginosis have been inconsistent throughout the last 30 years and have affected the reported prevalence of G. vaginalis in normal women. In most early studies the presence of symptoms, i.e., increased vaginal discharge in the absence of a pathogen such as Trichomonas vaginalis, Neisseria gonorrhoeae, or Candida spp., was used. The isolation of G. vaginalis from asymptomatic “normal” women in such studies was between 0 and 70.5%.12,30,34–41 An individual patient’s ability to tolerate an increased vaginal discharge has been shown to vary42,43 and this single factor probably accounts for the differences found. Clinical assessment of the amount of discharge was also found to be difficult43,44 and led to the suggestion that well-defined criteria were necessary for the diagnosis of bacterial vaginosis.45,46 The use of specific criteria that reflect the change in normal vaginal ecology seen in bacterial vaginosis was described by Spiegel et al.47 in 1980 and was recommended for the diagnosis of bacterial vaginosis in 1983.48 The criteria used are, first, the absence of a recognized pathogen and, second, the presence of three or more of the following: (1) homogeneous vaginal secretion, (2) pH of the vaginal discharge greater than 4.5, (3) presence of clue cells, and (4) the production of a fishy smell on the addition of 10% potassium hydroxide to the discharge.45 Amsel et al.49 used these criteria to diagnose bacterial vaginosis in unselected university students attending a health center gynecology clinic. They confirmed that symptoms were not a reliable means of diagnosis; in their population, 50% of patients with bacterial vaginosis were asymptomatic and 12% were aware of symptoms but were not complaining. When “normal” women have been defined as having less than three of the above criteria, approximately 40% were found to be colonized with G. vaginalis,49,50 although in lower numbers than women with bacterial vaginosis.50
Alteration of vaginal microbiota in patients with recurrent miscarriage
Published in Journal of Obstetrics and Gynaecology, 2022
Xuejuan Jiao, Lanling Zhang, Danli Du, Lingling Wang, Qianqian Song, Shuyu Liu
As previously reported, human vaginal microbiota play a crucial role in guarding various urogenital diseases, such as bacterial vaginosis, sexually transmitted infections and urinary tract infections (Ravel et al. 2011). Nevertheless, there are finite studies demonstrating a direct association between RM and vaginal microbiota. Vaginal microbiota species has less diversity compared with the intestinal microbiota, there were about 40 species of bacteria and facultative anaerobic in women of childbearing including Bacteroides, Gardneria, Lactobacillus, Coccidioides, Corynebacterium, Escherichia coli and Velveti (Raphael et al. 2011). Bacterial vaginosis is characterised by a complete loss of lactobacilli and a concomitant increase in Gram-variable and Gram-negative rods, primary among them Gardnerella vaginalis, as well as Bacteroides, Prevotella and Mobiluncus species. The presence of an abnormal vaginal microbiota in early pregnancy is a recognised risk factor for preterm delivery and low birth weight (Petricevic et al. 2015).
Biofilm-related disease
Published in Expert Review of Anti-infective Therapy, 2018
There are considerably fewer reports of the clinical impact of biofilms formed by anaerobic organisms, perhaps owing to the difficulties and technical expertise required to cultivate anaerobic organisms. An exception is the important field of dental anaerobic biofilms. In addition to the oral cavity, anaerobic organisms are abundant in the human gastrointestinal tract. Biliary stents can become colonized with gastrointestinal bacteria since they are placed in passages that communicate openly with the gastrointestinal lumen. Anaerobes also predominate in the human female genitourinary tract. Microcolonies of commensal anaerobic flora adhering to vaginal epithelial cells has been suggested as typical of normal human biology. In contrast, a dense adherent overgrowth (i.e. a biofilm) of Gardnerella vaginalis is observed in the clinical syndrome of bacterial vaginosis [60], which persists after moxifloxacin therapy, with a 40% recurrence rate 10–12 weeks after therapy. More proximally in the genitourinary tract, anaerobes have been recovered from long-term intrauterine devices after culture, with scanning electron microscopy observation of biofilms [61]. Several studies have observed anaerobic biofilm growth on respiratory tract prostheses, including voice prostheses, commonly placed to enable phonation after a laryngectomy due to cancer.
Use of copper intrauterine device is not associated with higher bacterial vaginosis prevalence in Thai HIV-positive women*
Published in AIDS Care, 2018
Nadia Kancheva Landolt, Surasith Chaithongwongwatthana, Sumanee Nilgate, Nipat Teeratakulpisarn, Sasiwimol Ubolyam, Tanakorn Apornpong, Jintanat Ananworanich, Nittaya Phanuphak
The question of what creates a healthy cervicovaginal microbiome is complex and still under research (Ravel et al., 2011). To better understand BV, and its clinical significance, there is a need to improve diagnostic methods in the clinical practice, as we found threefold difference in BV prevalence assessed by Nugent score and Amsel criteria. Our finding corraborates other reports of Amsel criteria being inferior to Nugent score in BV diagnosis (Sha et al., 2005). Quantitative bacterial PCR of certain bacteria associated with BV could improve the sensitivity and specificity of the diagnosis (Menard et al., 2010; Sha et al., 2005). It is important to apply thresholds, for improving the accuracy of the molecular methods (Datcu, 2014). Gardnerella vaginalis, for instance, can also have commensal isolates with reduced cytotoxicity, that are nearly identical to the pathogenic strain at the molecular level (Harwich et al., 2010).
Related Knowledge Centers
- Bacteria
- Colistin
- Vagina
- Bacterial Vaginosis
- Species
- Gram Stain
- Facultative Anaerobic Organism
- Coccobacillus
- Oxolinic Acid
- Flora