The Spirochetes (4)

Family 2: TREPONEMATACEAE

Genus 1: Borrelia

The genus was named after the French biologist Amédée Borrel (1867 – 15 September 1936), a French biologist.* The study of Borrelia has become increasingly important as more of its pathology is understood. As the causative agent of Lyme disease, understanding its structure and function is now a major focus of modern medicine. One recent study took a strange turn when it concluded that in Dublin, Ireland small rodents were relatively unimportant as reservoir hosts of Borrelia burgdorferi s.l., and suggested that songbirds (Passeriformes) were the most significant hosts.

In Mosby's Medical Dictionary (8th edition. © 2009, Elsevier) its defined as: a genus of coarse, unevenly coiled helical spirochetes, several species of which cause tickborne and louseborne relapsing fever. The organism is spread to offspring from generation to generation. This does not occur in lice. Many animals serve as reservoirs and hosts for Borrelia. The spirochete may be identified by microscopic examination of a smear of blood stained with Wright's stain; it is also easily inoculated onto culture media for bacterial culture and identification.

* See: http://www.pasteur.fr/infosci/archives/bor0.html

Borrelia burgdorferi .Under a magnification of 201X,  this scanning electron micrographic (SEM) image depicted a dorsal view of an unidentified engorged female tick, which had been extracted from the skin of a pet cat while in the process of obtaining its blood meal.

Habitat: Parasites of wild rodents and small mammals, and also arthropods associated with these animals

Oxygen Relationships: Microaerophilic

Major Characteristics: Pathogenic , causing louseborne or tickerborne relapsing fever in humans

Pathology: Lyme disease (named for the town in which it was first identified) can be caused by any number of different species in the genus Borrelia, such as: B. andersonii, B. japonica, B. valaisiana, B. lusitanie, B. turdae. B. tunakii, B. bissettii, and B. lonestari.

Borrelia inhabits the lumen of a tick's digestive tract. The disease is transmitted to humans from a tick bite when the bacteria migrates up to the ticks salivary glands, and through the opening created by the tick. Ticks increase salivation during gorging, prompting the migration of the saliva from the digestive tract. Because migration from the gut takes a few days, transmission of the disease usually does not happen until after the first 24 hours of attachment.

Classic bulls-eye rash (Erythema Migrans) caused by Borrelia

Tick-borne relapsing fever is found primarily in Africa, Spain, Saudi Arabia, Asia in and certain areas of Canada and the western United States.

Other relapsing infections are acquired from other Borrelia species, which can be spread from rodents, and serve as a reservoir for the infection, via a tick vector.

• Borrelia hermsii
• Borrelia parkeri
• Borrelia duttoni, transmitted by the soft-bodied African tick Ornithodoros moubata, is responsible for the relapsing fever found in central, eastern and southern Africa.
• Borrelia miyamotoi

Borrelia hermsii and Borrelia recurrentis cause very similar diseases. However, one or two relapses are common with the disease associated with Borrelia hermsii which is also the most common cause of relapsing disease in the United States. (Three or four relapses are common with the disease caused by B. recurrentis. B. recurrentis has longer febrile and afebrile intervals and a longer incubation period thanBorrelia hermsii.)

Scanning electron micrograph image of Borrelia burgdorferi.

Treatment of Relapsing Fever:  Tetracycline-class antibiotics are most effective. These can, however, induce a Jarisch-Herxheimer reaction in over half those treated, producing anxiety, diaphoresis, fever, tachycardia and tachypnea with an initial pressor response followed rapidly by hypotension. Recent studies have shown that tumor necrosis factor-alpha (TNF-alpha) may be partly responsible for this reaction. 
Species: 

1. Borrelia afzelii
2. Borrelia americana
3. Borrelia anserina]
4. Borrelia baltazardii
5. Borrelia brasiliensis
6. Borrelia burgdorferi
7. Borrelia carolinensis
8. Borrelia caucasica
9. Borrelia coriaceae
10. Borrelia crocidurae
11. Borrelia dugesii
12. Borrelia duttonii
13. Borrelia garinii
14. Borrelia graingeri
15. Borrelia harveyi
16. Borrelia hermsii
17. Borrelia hispanica
18. Borrelia japonica
19. Borrelia latyschewii
20. Borrelia lusitaniae
21. Borrelia mazzottii
22. Borrelia miyamotoi
23. Borrelia parkeri
24. Borrelia persica
25. Borrelia recurrentis
26. Borrelia sinica
27. Borrelia spielmanii
28. Borrelia tanukii
29. Borrelia theileri
30. Borrelia tillae
31. Borrelia turcica
32. Borrelia turdi
33. Borrelia turicatae 
34. Borrelia valaisiana Wang et al. 1997, sp. nov.
35. Borrelia venezuelensis

(For more information: http://www.bacterio.cict.fr/b/borrelia.html)

The Spirochetes (4)

Syphilis

Tertiary Stage of Syphilis

It is a multistage infection caused by spirochete Treponema pallidum. It is a sexually transmitted disease (STD). The primary route of transmission is through sexual contact; it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis.

The signs and symptoms of syphilis vary depending in which of the four stages it presents (primary, secondary, latent, and tertiary). The primary stage classically presents with a single chancre (a firm, painless, non-itchy skin ulceration), secondary syphilis with a diffuse rash which frequently involves the palms of the hands and soles of the feet, latent syphilis with little to no symptoms, and tertiary syphilis with gummas, neurological, or cardiac symptoms. It has, however, been known as "the great imitator" due to its frequent atypical presentations. Diagnosis is usually via blood tests; however, the bacteria can also be visualized under a microscope.

A patient with syphilis

Symptoms

Primary Stage: One or more painless ulcers (know as chancres) appear at the place where the syphilis bacteria entered the body. On average, this will be 21 days after sexual contact with an infected person. Chancres may be difficult to notice and are highly infectious. The usual locations for chancres are:

1. On the vulva (outside the vagina) or on the cervix (neck of the womb) in women
2. On the penis in men



Primary Stage

3. Around the anus and mouth (both sexes)

Secondary Stage: If the infection has not been treated, the secondary stage of syphilis will usually occur from 3 to 6 weeks after the appearance of chancres. The symptoms often include:

1. A flu-like illness, a feeling of tiredness and loss of appetite, accompanied by swollen glands (this can last for weeks or months).
2. A non-itchy rash covering the whole body or appearing in patches.
3. Flat, warty-looking growths on the vulva in women and around the anus in both sexes.
4. White patches on the tongue or roof of the mouth.
5. Patchy hair loss.

Secondary Stage

Tertiary and Latent Stage: If a person infected with syphilis has not received treatment during the first two stages of the disease then it will progress to the latent stage. The person will no longer experience any symptoms of the earlier stages, but their infection can still be diagnosed with a blood test.

If left untreated, the infection may develop into symptomatic late syphilis, also known as the tertiary stage. This usually develops after more than 10 years and is often very serious. It is at this stage that syphilis can affect the heart and possibly the nervous system.

If treatment for syphilis is given during the latent stage the infection can be cured. However, any heart or nervous-system damage that occurred before the start of treatment may be irreversible.

See: http://www.avert.org/syphilis.htm, http://www.nhs.uk/Conditions/Syphilis/Pages/Symptomspg.aspx, http://en.wikipedia.org/wiki/Syphilis

Causes

1. Syphilis is caused by bacteria called Treponema pallidum. The bacteria can enter your body if you have close contact with an infected sore, normally during intercourse.
2. It may also be possible to catch syphilis if you are an injecting drug user and you share a needle with somebody who is infected.
3. Pregnant women can pass the condition on to their unborn babies, which can cause stillbirth or death of the baby shortly after labor.
4. It is extremely rare for syphilis to be spread through blood transfusions as all blood transfusions in the UK are routinely tested for syphilis.

Diagnosis

The doctor or nurse will examine your genitals. For men, this involves looking at the penis, foreskin and urethra (the hole at the end of the penis where urine comes out). For women, it involves an internal examination of the vagina. Both men and women may also have their anus examined.

Treatment

The spirochetes are extremely sensitive to penicillin, plasma concentration as low as 0.03 unit per ml being spirocheticidal.

Syphilis can be effectively treated with the preferred intramuscular penicillin G (given intravenously for neurosyphilis), as or else ceftriaxone, and in those who have a severe pencillin allergy, oral doxycycline or azithromycin.

Complications

It is estimated that people with syphilis are three to five times more likely to catch HIV. This is because the genital sores caused by syphilis can bleed easily, making it easier for the HIV virus to enter the blood during sexual activity.

Treponema pallidum, the causative microorganism of syphilis 

The Spirochetes (3)

Family 1: SPIROCHAETACEAE

Genus 3: Cristispira

Cristispira sp.

Cristispira is a genus of large spirochetes, with unclear divisions into different species.  The organism was first found by Cretes when he found the organism inhabiting the digestive tract of oysters.  It wasn’t until 1910; however that Gross proposed the establishment of the genus Cristispira. They are generally found in the digestive tracts, specifically the crystalline styles, of both freshwater and marine mollusks. This is a commensal relationship, where the microbe gets nutrients and shelter, and the mollusk is neither harmed or benifited.  However, not all mollusks in a population will contain Cristispira, and when an organism is host to the microbe there are generally no other bacteria found. They are currently distinguished from other spirochetes only by their physical structure, as they have not yet been cultured in the lab.  Individual cells have a diameter between .4 and 10 μm and can grow up to 150 μm in length. They are also characterized by the presence of a “crista”, a crest like structure.The crista can be seen under the microscope and appears as a bundle of filaments bound to the outer sheath. Cristispira is a facultative anaerobe, and has an optimum temperature of 15˚ C. Currently, there is no biochemical or genetic data for Cristispira but scientists are trying to find the link between the microbe and the crystalline style in order to cultivate them in the lab.

A study was done in 1981 to study the unique relationship between Cristispira and its host using a scanning electron microscope (SEM). Scanning electron microscopy was employed to observe the physical interactions between Cristispira spp. and the crystalline style of the Chesapeake Bay oyster (Crassostrea virginica Gmelin 1791). Cristispira organisms were found associated with both the inner and outer layers of the posterior two-thirds of the style. The spirochetes possessed blunt-tipped ends, a cell diameter range of 0.6 to 0.8 ,um, and distended spirochetal envelopes which followed the contour of the cells. Transmission electron microscopy showed that the distension of the envelope was probably due to the containment of numerous axial filaments. In addition, they were found to possess two distinct spiral shapes which were dependent on whether their location was inside or on the surface of the style. (http://aem.asm.org/content/42/2/336.full.pdf)

Cristispira pectinis

Habitat: Harmless parasites of freshwater and marine molluscs and some gastropods.

Oxygen Relationships: Unknown

Major character: Have never been isolated; have unusually large number of periplasmic flagella

Species: Main species are, C. balbianii, C. anodontae, C. pinnae, C. pectinis.

The Spirochetes (2)

Family 1: SPIROCHAETACEAE

Genus 2: Saprospira

The saprospiras are wonderful, versatile microbes. They are not rare, but, perhaps because they apparently include no pathogens, they are still all too little studied. They glide, moving on solid surfaces where they can hope to find potentially nutrient substrates or prey bacteria, but how they move is still under investigation.

The first marine lytic bacteriophage was found in a saprospira, but not all saprospiras succumb to it. All known saprospiras are coloured, due to different kinds of carotenoids.

They are not photosynthetic. They require for growth some or all of the so-called essential amino acids that we animals do, and presumably for the same reason. Many are even more like animals, living by predation on other microbes, including diatoms and  dinoflagellates as well as bacteria. In some, the mucilage tracks that they employ for motility have been pre-adapted to be sticky and thereby to catch bacterial prey, notably species of Vibrio, by their flagella. Then an ixotrophic saprospira can kill them by extracelluar toxins and digest them by extracellular enzymes, thereby liberating the amino acids that it needs for growth. But the natures of that sticky mucilage, and of those toxins and enzymes, need to be further studied.

Scanning electron micrograph of S. grandis Sa g1

Habitat: Saprospiras are marine bacterium. Also found in intestinal tract of oysters. S. thermalis are the only species found in fresh water.

Oxygen Relationships: strictly aerobic

Major character: Spiral portoplasm without an axial filament. Motility is active and rotating. Chemoorganotrophs.

Pathology: S. grandis prey on other bacteria and protists. Unsuspecting bacteria swimming nearby become trapped when the tips of their flagella become stuck in the mucilage on the saprospira filament. No chemotaxis seems to be involved, just approaching too closely. Dozens of live bacteria still spinning on their axes become attached to a single filament, eventually to cover its surface. Extracellular enzymes secreted by the saprospira finish them off. Not all motile bacteria qualify as prey. For example, non-marine but flagellated cells such as E. coli aren't prey, and only 7 out of 25 marine members of the Vibrionaceae could be caught and destroyed.

Significance: S. grandis is useful in preventing harmful algal blooms.

Species: Main species are: S. grandis, S. punctum, S. lepta, S. thermalis.

Phase-contrast micrograph of filaments of a freshwater Saprospira sp.

The Spirochetes (1)

Characteristics: Gram negative; flexible; helical; have periplasmic flagella; saprophytes or paracytes.

Family 1: SPIROCHAETACEAE

Genus 1: Spirochaeta

The genus Spirochaeta represents a group of free-living, saccharolytic non-pathogenic, obligate or facultative anaerobic helical shaped bacteria. Isolated strains have been obtained from a variety of freshwaters and marine waters. Extremophilic species include anaerobic, thermophilic isolated form hot springs in New Zealand, the moderately thermophilic Spirochaeta caldaria from cyanobacterial mats of hot springs in Utah and Oregon and the extremely thermophilic Spirochaeta thermophila from marine areas in Shiaskotan Island in Russia. There are also alkaliphilic spirochetes such as S. alkalica, S. africana, S. asiaticaisolated from the alkaline Lake Magadi in Kenya and from sulfide-saturated mud sediments of Lake Khatyn in Siberia (Hoover et al, 2003).

In addition, culture-independent studies revealed the presence of Spirochaeta species in other environments such as anaerobic bioreactors, and the digestive tract of termites (Drone et al, 2003). A number of members of the genus Spirochaeta inhabit extreme environments with respect to temperature, salinity, and pressure . These microorganisms may hence harbor enzymes with potential biotechnological applications (Leschine et al, 2006).

  A cell of Spirochaeta zuelzerae. These morphologically distinct prokaryotes are also phylogenetically distinct

        

Habitat: Harmless inhabitants of water, mud, and sediments of marine and freshwater environments.

Oxygen Relationships: Anaerobic and facultatively anaerobic

Major character: Use carbohydrates but not amino acids as carbon and energy source.

Species: 

1. Spirochaeta africana
2. Spirochaeta alkalica
3. Spirochaeta americana
4. Spirochaeta asiatica
5. Spirochaeta aurantia
6. Spirochaeta bajacaliforniensis
7. Spirochaeta caldaria
8. Spirochaeta coccoides
9. Spirochaeta halophila
10. Spirochaeta isovalerica
11. Spirochaeta litoralis
12. Spirochaeta smaragdinae
13. Spirochaeta stenostrepta
14. Spirochaeta taiwanensis
15. Spirochaeta thermophila
16. Spirochaeta xylanolyticus
17. Spirochaeta zuelzerae

Applications: Harbor enzymes with potential biotechnological applications.

Colony of Spirochaeta (Uruguay, 1999)