Sneathia vaginalis (formerly Sneathia amnii)

Sneathia vaginalis is cytotoxic to vaginal cells, and forms pores in and kills eukaryotic cells (like mitochondria) in culture. Contributes to preterm birth.

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S. amnii has very complicated growth requirements. It is able to metabolize few carbohydrates, including glucose, maltose, glycogen and glucosamine. This species, however, lacks the ability to ferment starch, mucin, fructose, sucrose or mannose (Eisenberg et al., 2018). S. amnii’s fermentative style of metabolism leaves lactic acid, formic acid, a small amount of acetic acid and sometimes succinic acids as the waste products after metabolizing glucose. Since the epithelium of the vagina produces a lot of glucose, especially when a woman is at reproductive age, S. amnii is able to use this carbohydrate source despite its reduced metabolic capabilities with other carbohydrates.

 More information about fermentative metabolism of glucose: o https://umaine.edu/carbohydrates/carbohydrate-digestion/fermentation/ (University of Maine, n.d.)

 Sneathia strains tend to be susceptible to and best treated with antimicrobials, such as metronidazole, but can be resistant to erythromycin, kanamycin, vancomycin, aminoglycosides, and fluoroquinolone. We know that S. amnii is one of the anaerobic microbes that plays a role in the development of bacterial vaginosis. The overuse of metronidazole in treatment may have caused the recent relative resistance to it (Eschenbach, 2007). This conclusion comes from a study that showed increase failure rate of a treatment course using metronidazole spanning over two weeks of time.

Individual cells of S. amnii lack flagellar proteins and pilin when observed under a microscope. S. amnii doesn’t have genes that code for those proteins nor were they indicated with varying forms of electron microscopy. Sneathia amnii’s cells can have different shapes. There can be a mixture of rods longer than 10 micrometers that can be chains of short rods attached end to end, shorter rods and cocci (Eisenberg et al., 2018). Older cultures of Sneathia amnii are shown to be more likely to have the short rods, which are representative of variants of S. amnii that don’t have a cell wall (Eisenberg et al., 2018). Its cells are also fusiform or shaped in a spindle (Holm et al., 2020).

 Colonies of S. amnii can show pleomorphism, meaning that the cells can change their form and function. The change in structure and function is triggered by varying conditions of the environment such as changes in pH or presence of an antibiotic. Sneathia amnii is Gram-stain-negative, so for this form of test for cell differentiation it does not keep the violet color from the stain. Instead of purple, it is red (Harwich et al., 2012). This would mean that the cell would be made up of a single thin layer of peptidoglycan. The peptidoglycan provides strength to the cell wall, especially when antibiotics are attacking, and it is involved in cell reproduction. Sneathia amnii grows best when no oxygen is present. Although anaerobic conditions are most ideal, there can still be a small amount of growth in aerobic conditions. Optimal temperature would be similar to that of the body, which would be close to 37° Celsius (Harwich et al., 2012). Conditions where there is no UV present and a low, or acidic, pH are ideal. On a chocolate agar the colonies were gray in color, flat, crystalline and its diameter was approximately 1 millimeter (Eisenberg et al., 2018). When observed on a Brain Heart Infusion agar that had fresh human blood, colonies of S. amnii had a diameter or about 2 millimeters and were mucoid, raised and amorphous (Eisenberg et al., 2018).

 S. amnii is non-motile meaning that it lacks the ability to move and remains in place (Eisenberg et al., 2018). This may explain the lack of flagellar proteins. The antibiotic resistance profile of S. amnii showed that it is highly resistant to nafcillin, which is not uncommon for bacteria that are Gram negative. Nafcillin has little to no effect on Gram-negative bacteria because of the outer membrane that is very impermeable. S. amnii is more sensitive to metronidazole, a common antibiotic for bacterial vaginosis, than other Gram-negative bacteria (Eisenberg et al., 2018). Gram-negative bacteria, like S. amnii, are assumed to be resistant to vancomycin for the most part. Vancomycin is too big to be able to easily bypass the membrane. Interestingly enough, Sneathia amnii shows sensitivity to vancomycin despite being Gram negative which may go to show that its membrane may have a different makeup than other Gram-negative microbes (Eisenberg et al., 2018). Since most Gram-negative bacteria are resistant to vancomycin, sensitivity to vancomycin could be used as a secondary test to actually using the Gram stain. S. amnii is highly resistant to tetracycline and ciprofloxacin, in dosages over 50 and 25 micrograms per milliliters, respectively (Eisenberg et al., 2018).

Impact on foetus

Snethia amnii’s ability to damage fetuses comes from its production of cyotpathegonic toxin component A, or CptA (Gentille et al., 2020). CptA acts in a virulent way by lysing human red blood cells, leading to the damage of the fetal membrane’s cells. This is interesting because there is not much detail known about the virulence factor and mechanism of disease of S. amnii. It seems that the gene is cotranscribed along with a second gene that encodes a protein, similar to two-partner system transporters. Gram negative bacteria often use the two-partner secretion system to export hemolysins and other virulence factors. CptA contains 1,881 amino acids and weighs about 200 kDa. Cyotpathegonic toxin component A shows very little amino acid sequence homology to other known toxins. It performs its toxic actions by binding to the membranes of red blood cell and forming pores 2.0 to 3.0 nm long, resulting in cell lysis (Gentille et al., 2020).

References^​1,2​

Microbial information

What are the symptoms of Sneathia vaginalis (formerly Sneathia amnii)?

• Yet to be determined

What causes Sneathia vaginalis (formerly Sneathia amnii)?

• No causes found for Sneathia vaginalis (formerly Sneathia amnii), yet.

What are the risk factors associated with Sneathia vaginalis (formerly Sneathia amnii)?

• No risk factors for Sneathia vaginalis (formerly Sneathia amnii), yet.

How do you diagnose Sneathia vaginalis (formerly Sneathia amnii)?

• No diagnoses found for Sneathia vaginalis (formerly Sneathia amnii), yet.

How do you treat Sneathia vaginalis (formerly Sneathia amnii)?

Treatments for Sneathia vaginalis (formerly Sneathia amnii) are only for practitioners and people who purchased the book Killing BV and Killing BV for men.

Which treatments are likely to be ineffective for Sneathia vaginalis (formerly Sneathia amnii)?

• Gentian Violet - Probably

What complications are associated with Sneathia vaginalis (formerly Sneathia amnii)?

• No complications found for Sneathia vaginalis (formerly Sneathia amnii), yet.

References

http://jcm.asm.org/content/45/7/2344.fullhttps://www.ncbi.nlm.nih.gov/pubmed/23281612