Bacteriology exam prep: Spirochaetia, Brachyspira, Borrelia, Leptospira, Mycoplasma

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Questions and Answers

What is the primary site of disease caused by Brachyspira hyodysenteriae?

Large intestine (correct)

Stomach

Esophagus

Small intestine

How do Brachyspira hyodysenteriae bacteria penetrate the intestinal mucosal cells?

Using their flagella (correct)

Through the action of neutrophils

By binding to specific receptors

Through the release of toxins

What is the characteristic shape of Borrelia bacteria?

Circular

Rod-shaped

Filamentous

Spiral-shaped (correct)

Which of the following is NOT a species of Borrelia that causes Lyme disease?

Borrelia hyodysenteriae Signup and view all the answers

What is the common mode of transmission of Borrelia?

Through the bite of infected ticks Signup and view all the answers

Which of the following animals is NOT commonly affected by Borrelia?

Fish Signup and view all the answers

What is the name of the disease caused by Borrelia burgdorferi?

Lyme disease Signup and view all the answers

What is the consequence of Brachyspira hyodysenteriae infection in the large intestine?

All of the above Signup and view all the answers

What is the role of flagella in Brachyspira hyodysenteriae bacteria?

To penetrate the intestinal mucosal cells Signup and view all the answers

What is the name of the ticks that transmit Borrelia?

Ixodes species Signup and view all the answers

What is the name of the reservoirs for Borrelia?

All of the above Signup and view all the answers

What is the primary mode of transmission of Borrelia burgdorferi?

Through the bite of an infected tick Signup and view all the answers

What is the primary symptom of Lyme disease in dogs?

Joint swelling and pain Signup and view all the answers

What is the primary host of Leptospira spp.?

Rodents Signup and view all the answers

What is the primary route of entry for Leptospira spp. infection?

Through skin abrasions or mucous membranes Signup and view all the answers

What is the primary target organ of Leptospira spp. infection?

Kidneys Signup and view all the answers

What is the primary mechanism of Leptospira spp. transmission?

Direct contact with infected animal urine or tissue Signup and view all the answers

What is the primary role of reservoir hosts in Leptospira spp. transmission?

To maintain the infection cycle Signup and view all the answers

What is the primary characteristic of pathogenic Leptospira spp.?

Ability to colonize the proximal renal tubules Signup and view all the answers

What is the primary method of Leptospira spp. classification?

DNA sequencing-based classification Signup and view all the answers

What is the primary consequence of Leptospira spp. infection in animals?

Chronic kidney disease Signup and view all the answers

What is the periplasmic space in the cells of the Spirochaetia class?

A space between the inner and outer cell membranes containing varying amounts of periplasmic flagella Signup and view all the answers

What is the primary characteristic of swine dysentery caused by Brachyspira hyodysenteriae in terms of clinical signs?

Mucohemorrhagic watery diarrhea Signup and view all the answers

Which age group of pigs is most commonly affected by swine dysentery?

Weaned pigs around 2-4 months old Signup and view all the answers

Where is the reservoir of Brachyspira hyodysenteriae found?

Pig large intestine Signup and view all the answers

What is the most common mode of transmission for Brachyspira hyodysenteriae?

Fecal-oral Signup and view all the answers

Which class do Brachyspirales, Leptospirales, and Spirochaetales belong to?

Class Spirochaetia Signup and view all the answers

What are the characteristics of the genus Brachyspira?

Gram-negative, curved or spiral-shaped bacilli, associated with intestinal disease or normal commensals Signup and view all the answers

What is one distinguishing characteristic of diarrhea caused by swine dysentery?

Sweet, putrid odor Signup and view all the answers

Which of the following is NOT a clinical sign of swine dysentery?

Weight gain Signup and view all the answers

What is the usual mortality rate range for swine dysentery?

20-40% Signup and view all the answers

What type of lesions does Leptospira NOT produce at the site of entry?

Necrotic lesions Signup and view all the answers

Which clinical phase of leptospirosis involves the production of antibodies and excretion of bacteria?

Immune phase Signup and view all the answers

Which condition is a result of chronic leptospirosis in horses?

Autoimmune-mediated recurrent uveitis Signup and view all the answers

What is NOT a typical finding in the acute phase of leptospirosis?

High platelet count Signup and view all the answers

What pathological condition is associated with chronic leptospirosis in cattle?

Kidney fibrosis Signup and view all the answers

Which of the following symptoms is specific to pups with leptospirosis?

Hemorrhagic gastroenteritis Signup and view all the answers

What reproductive consequence is caused by leptospirosis in cattle, pigs, and horses?

Reproductive failure Signup and view all the answers

What secondary condition can develop in dogs due to leptospiral invasion of the liver?

Jaundice and fatty liver Signup and view all the answers

Which term does NOT describe lesions that can occur in the lungs due to leptospirosis?

Chronic granulomatous hepatitis Signup and view all the answers

Which symptom is seen in chronic infections of leptospirosis in humans and horses?

Recurrent uveitis and cataracts Signup and view all the answers

Which clinical sign is NOT typically associated with leptospirosis in lactating cows?

Hemoglobinuria Signup and view all the answers

Which serovar is NOT typically associated with leptospirosis in small ruminants?

Autumnalis Signup and view all the answers

What is a common outcome of leptospirosis in swine concerning their reproductive health?

Decreased litter size Signup and view all the answers

Which condition is generally NOT observed in dogs with leptospirosis?

Agalactia Signup and view all the answers

Which serovar is associated with leptospirosis infection in horses globally?

Bratislava Signup and view all the answers

What clinical sign is usually noted in equine acute leptospirosis infection?

Depression Signup and view all the answers

Which reproductive issue is associated with typical equine leptospirosis?

Stillbirths Signup and view all the answers

What pathological condition occurs in a subset of equine recurrent uveitis cases caused by leptospirosis?

Organ specific, autoimmune response Signup and view all the answers

What is a common clinical presentation of leptospirosis in small ruminants?

Subclinical infections Signup and view all the answers

Which pathogenic species is primarily responsible for leptospirosis in dogs?

L.interrogans Signup and view all the answers

What is the main reason for the immune response being ineffective at eliminating mycoplasma infection?

Mycoplasma attaches to host cells and colonizes cell surfaces, activating the innate immune system Signup and view all the answers

Which of the following is a characteristic of invasive mycoplasma disease?

The mycoplasma penetrates epithelial barriers and enters the bloodstream Signup and view all the answers

What is the typical outcome of M. mycoides ssp. capri infection in young goats?

Severe septicemia and high mortality Signup and view all the answers

What is the primary mechanism of transmission of mycoplasma?

Aerosol transmission through respiratory secretions Signup and view all the answers

What is the characteristic of M. hyorhinis infection in pigs?

Colonizes the upper respiratory tract and can disseminate Signup and view all the answers

What is the primary outcome of M. bovis infection in cattle?

Polyarthritis and fibrinopurulent lesions Signup and view all the answers

What is the characteristic of M. synoviae infection in chickens and turkeys?

Causes stunted growth and lameness Signup and view all the answers

What is the primary mechanism of pathogenesis of mycoplasma?

Activation of the innate immune system and production of cytokines Signup and view all the answers

What is the primary reservoir of mycoplasma?

Infected animals Signup and view all the answers

What is the characteristic of hemotropic mycoplasma infections?

Are epicellular parasites of red blood cells Signup and view all the answers

Which species is primarily responsible for causing severe mastitis often accompanied by arthritis, pneumonia, keratoconjunctivitis, and septicemia in cattle?

M.bovis Signup and view all the answers

Which Mycoplasma species are known to cause conjunctivitis in goats and sheep?

M.conjunctivae Signup and view all the answers

In which group of animals is M.capricolum ssp. Capripneumoniae the primary cause of pleuropneumonia with up to 80% mortality?

Goats Signup and view all the answers

Which characteristic is common to both Contagious Bovine Pleuropneumonia (CBPP) and Contagious Caprine Pleuropneumonia (CCPP)?

Accumulation of serosanguinous fluid Signup and view all the answers

Which Mycoplasma species is the common cause of sinusitis, tracheitis, and air sacculitis in birds?

M.gallisepticum Signup and view all the answers

Which term describes the lesions that can become sequestered in fibrous capsules, allowing organisms to remain viable for long periods in CBPP and CCPP?

Fibrinonecrotic pneumonia Signup and view all the answers

Which causative agent is linked to pleuritis in horses and also affects cats with primary or secondary conjunctivitis?

M.felis Signup and view all the answers

What type of infection can result in chronic interstitial pneumonia with progression to more severe secondary bacterial infections in pigs?

Mycoplasma respiratory infection Signup and view all the answers

Which Mycoplasma species is most commonly known to cause mastitis with reduced milk yield and fibrin deposits in cattle?

M.bovis Signup and view all the answers

In which species is the clinical feature of localized mastitis commonly observed?

Cattle and sheep Signup and view all the answers

Which factor does not exacerbate the chronic, endemic disease caused by mycoplasmas?

Diet Signup and view all the answers

Which characteristic is unique to prokaryotes like Mycoplasma?

Osmotic stability maintained by cholesterol Signup and view all the answers

What is the name of the disease caused by Mycoplasma mycoides ssp. Mycoides?

Contagious Bovine Pleuropneumonia (CBPP) Signup and view all the answers

Which characteristic allows mycoplasmas to maintain osmotic stability despite the absence of a cell wall?

Integration of cholesterol in the membrane Signup and view all the answers

What makes the pathogenic role of Mycoplasma difficult to assess?

Isolation from mucosal surfaces does not always indicate etiological significance Signup and view all the answers

Which feature of Mycoplasma contributes to its susceptibility to environmental conditions?

Lack of a cell wall Signup and view all the answers

How do mycoplasmas compensate for their lack of biosynthetic capability?

Importing nutrients from the host Signup and view all the answers

Which statement accurately describes the membrane structure of Mycoplasma?

It is bound by a laminar membrane with proteins, glycoproteins, lipoproteins, phospholipids, and sterols. Signup and view all the answers

How do mycoplasmas manage to survive despite being susceptible to environmental conditions?

By forming biofilms Signup and view all the answers

Which of the following statements about animal mycoplasmas is true?

They are referred to as extracellular parasites. Signup and view all the answers

Study Notes

Genus Spirochaetia

Slender, helically coiled, motile, flexuous, and unicellular
Three important veterinary medicine related orders:
- Brachyspirales (Brachyspiraceae, Brachyspira)
- Leptospirales (Leptospiraceae, Leptospira)
- Spirochaetales (Borreliaceae, Borrelia)

Class Spirochaetia

Cells consist of a protoplasmic cylinder bound by loosely connected inner and outer cell membranes
Periplasmic space between inner and outer cell membranes containing varying amounts of periplasmic flagella/endoflagella/axial filaments

Genus Brachyspira

Gram-negative, curved or spiral-shaped bacilli
Associated with intestinal disease or normal commensals in several species of wild and domestic animals and birds
Brachyspira hyodysenteriae causes swine dysentery
- Affects weaned pigs (2-4 months old) with morbidity of 90% and mortality of 20-40%
- Clinical signs: mucohemorrhagic watery diarrhea, fever, hyporexia, weight loss, and dehydration
- Transmission: fecal-oral, reservoir in pig large intestine

Genus Borrelia

Long, slender, spiral-shaped bacteria
Borreliosis (Lyme disease) caused by Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii
- Affects humans, dogs, cats, cattle, and horses
- Transmitted by Ixodes species ticks
- Reservoirs: rodents (white-footed mouse) and non-human vertebrates
- Clinical signs in dogs: acute or subacute arthritis, joint swelling, shifting lameness, fever, and neurological problems

Genus Leptospira

Leptospirosis is a widespread, global, zoonotic disease
Causes disease in primarily domestic and wild animals
Classified into two ways:
- Serology (serovariants) based on LPS carbohydrate composition
- DNA sequencing (species) using phylogenetics
≥65 species, including pathogenic species Leptospira interrogans, Leptospira borgpetersenii, and Leptospira kirschneri
Transmission: direct or indirect contact with urine or tissues of infected animals, contaminated environment, or oral, conjunctival, respiratory, or genital routes
Pathogenesis: colonization of proximal renal tubules, transcutaneous migration, localized replication in adipose tissue, and rapid hematogenous spread to target organs (kidneys, liver, lungs)

Leptospirosis

Leptospira does not produce lesions at the site of entry, unlike other Spirochaeta.
During hematogenous dissemination, symptoms include:
- Fever
- High WBC count (leukocytosis)
- Low platelet count (thrombocytopenia)
- Hemorrhagic lesions in target organs

Pathological Changes

Leptospiral invasion of the liver:
- Dogs: Chronic granulomatous hepatitis, apoptosis of hepatocytes, jaundice, and fatty liver
- Cattle: Hemoglobinuria, kidney fibrosis
Other lesions:
- Splenic necrosis
- Catarrhal enteritis
- Severe congestion (brain)
- Metritis and placentitis secondary to vasculitis (resulting in abortion)
- Uveitis and cataracts (seen in chronic infections in horses and humans)

Clinical Presentation and Signs

Clinical disease can present biphasically:
- Acute or Septicemic phase (1 week duration)
- Immune phase (production of antibodies and excretion of bacteria)
Significant variability in manifestation of clinical signs due to large host range and range of symptoms

Leptospirosis in Different Species

Dogs

Clinical signs:
- Icteric, uremic, hemorrhagic, reproductive
- Leptospiral pulmonary hemorrhagic syndrome
- Hemorrhagic gastroenteritis (pups)
- Abortion
- Premature and weak pups
Pathogenic species: L. interrogans, L. kirschneri
Associated serovars: Icterohaemorrhagiae, Grippotyphosa, Canicola, Bratislava, Pomona

Cattle

Significant implications economically in the agriculture industry
Clinical signs:
- Reproductive failure
- Stillbirths
- Weak newborns
- Pyrexia
- Hemoglobinuria
- Icterus
- Haemolytic anemia
- Meningitis
- Death
Incidental infections in lactating cows:
- Blood-tinged milk
- Drop in milk yield
- Agalactia

Leptospirosis in Small Ruminants and Swine

Small Ruminants

Generally unnoticed with subclinical infections
Acute infection more often in goats
Clinical signs similar to those in cattle
Serovars: Grippotyphosa, Australis, Hardjo, Sejroe, Hebdomadis

Swine

Clinical signs:
- Reproductive disorders
- Increased stillbirths
- Decreased litter size
- Decrease of weaning piglets
- Increased weaning to estrus interval

Leptospirosis in Horses

Can be affected by a wide range of serovars
Europe: Grippotyphosa and Pomona
Globally: Bratislava
Clinical signs:
- Subclinical with low-grade fever, depression, and anorexia
- Acute infection symptoms:
  - Jaundice
  - Depression
  - Conjunctival effusion
  - Hemoglobinuria
  - Renal disease
- Typical equine leptospirosis is associated with reproductive diseases:
  - Abortion
  - Stillbirths
  - Weak, sickly foals
- Uveitis can occur 2-8 months after infection
- Subset of infectious, recurrent uveitis cases caused by Leptospira

Genus Mycoplasma

Belongs to class Mollicutes
Many commensals, but a few species cause acute mortality
Cannot survive in the environment for a long time, but can form biofilms for some protection
Each major domestic animal species is a host to several different pathogenic mycoplasmas, causing chronic, endemic disease
Generally cause mild to moderate disease, exacerbated by cofactors such as age, genetics, environment, stress, and concurrent infections

Characteristics

Lack genetic capacity to form a cell wall
Bound by a single, true laminar membrane composed of proteins, glyco- & lipo-proteins, phospholipids, and sterols
Susceptible to desiccation and disinfecting substances
Smallest cell size and smallest genome of all free-living organisms
Highly pleomorphic, with cytoskeleton controlling shape
Rely on import systems to get nutrients from the host to survive
Lack biosynthetic capability to make their own nutrients
Osmotic stability maintained by integration of cholesterol in the membrane
Cholesterol obtained exogenously, a unique characteristic of prokaryotes

Transmission and Pathogenesis

Reservoirs of pathogenic species are infected hosts, which can be subclinically infected and carry organisms on mucosal surfaces
Transmission occurs horizontally through aerosols, milk, reproductive tract secretions, and vertically through eggs
Mycoplasma attaches to host cells, colonizing cell surfaces, and activating the innate immune system
Production of cytokines leads to inflammation, and cells adjacent to inflammation become damaged
Damaged cells release nutrients for mycoplasma growth, and metabolic products further damage cells
Immune-complexes develop, causing more damage, and can lead to coagulopathy and vascular thrombosis

Disease Patterns and Pathology

Two types of mycoplasma disease: invasive and localized
Invasive mycoplasma disease can cause polyserositis, arthritis, or tenosynovitis
Septicemia diseases are acute and associated with fever and sometimes death
Generalized infection of acute septicemia may occur
Species-specific disease patterns:
- M. mycoides ssp. mycoides: Contagious Bovine Pleuropneumonia (CBPP)
- M. capricolum ssp. capricolum: septicemia in young goats, fibrinopurulent polyarthritis, and thromboembolic lesions
- M. hyorhinis: colonization of upper respiratory tracts in young and weanling age pigs, causing serofibrinous pleuritis, pericarditis, peritonitis, and polyarthritis
- M. hyosynoviae: similar to M. hyorhinis infections but milder joint lesions
- M. synoviae: causes synovitis in chickens and turkeys
- M. bovis: causes arthritis and polyarthritis in cattle
- M. agalactiae: causes mastitis in sheep and goats, accompanied by arthritis, pneumonia, keratoconjunctivitis, and septicemia
- M. haemofelis: causes hemolytic anemia in cats
- M. ovis: causes hemolytic anemia in lambs
- M. suis: causes hemolytic anemia in pigs

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Description

Learn about the characteristics of the genus Spirochaetia, such as motility and unicellularity, and explore the three important veterinary medicine related orders: Brachyspirales, Leptospirales, and Spirochaetales.