biology

Pasteurella canis

Pasteurella canis is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Pasteurella canis rather than just read about it. In short: Pasteurella canis is a Gram-negative, nonmotile, penicillin-sensitive coccobacillus from the family Pasteurellaceae. Bacteria from this family cause zoonotic infections in humans, which manifest themselves as skin or soft-tissue infections after an animal bite.

Key takeaways

Pasteurella canis belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Pasteurella canis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Pasteurella canis from memory before moving on to harder problems.

Reference excerpt

Pasteurella canis is a Gram-negative, nonmotile, penicillin-sensitive coccobacillus from the family Pasteurellaceae. Bacteria from this family cause zoonotic infections in humans, which manifest themselves as skin or soft-tissue infections after an animal bite. This species has been known to cause serious disease in immunocompromised patients. Pasteurella was first described around 1880 and thought to be associated with chicken cholera and hemorrhagic septicemia in animals. The genus was first cultured in 1885. In 1920, strains of Pasteurella were isolated and observed in human infections.

Nomenclature Pasteurella canis sp. nov. was previously classified as P. multocida biotype 6 or “dog-type” strains. In 1985, Pasteurella underwent taxonomic reclassification based on DNA hybridization, resulting in several subspecies of P. multocida and new Pasteurella species, including P. canis. Pasteurella canis includes two biotypes: biovar 1 originated from canines, whereas biovar 2 originated from bovines. The two biotypes are distinguishable from an indole test: biovar 1 is indole positive whereas biovar 2 is indole negative.

Microbiology Pasteurella canis is a Gram-negative coccobacillus that shows bipolar staining. P. canis forms small, grey-colored, round, and smooth colonies. Colonies are non-haemolytic. P. canis is non-motile. Pasteurella canis is reported as aerobic and facultative anaerobic in different sources. It metabolizes both glucose and sucrose. In addition to morphological typing, biochemical tests are commonly used to identify the species. P. canis is positive for catalase, oxidase, and ornithine decarboxylase, but negative for lysine decarboxylase, V-factor (nicotinamide adenine dinucleotide), D-mannitol, dulcitol, D-sorbitol, urease, maltose, and L-arabinose. P. canis can also be indole positive or negative depending on the biotype.

Molecular typing Molecular analysis of the genome has become the popular method to identify bacteria. The genome of P. canis has yet to be fully sequenced, but several genes and their sequences were already identified. Among them, 16S rRNA, 23S rRNA, RNA polymerase subunit B (rpoB), and manganese-dependent superoxide dismutase (sodA) are used to study Pasteurella phylogeny. However, molecular and biochemical analyses often show conflicting results. For example, research has suggested some P. canis strains were in fact members of P. multocida based on DNA analysis. Phylogenetic analysis of P. canis and P. dagmatis also showed conflicting results, based on their 16s rRNA sequences and biochemical tests done on the strains.

Disease Pasteurella canis is an opportunistic pathogen that can infect both animals and humans.

Animal infections Pasteurella canis can be found in healthy domesticated, farm-raised, and wild animals, such as dogs, cats, rabbits, horses, sheep, cattle, ferrets, deer, and even California sea lions. The bacteria are normally isolated from the oral cavities and respiratory tracts of these animals. P. canis biotype 1 was shown to secrete a toxin analogous to P. multocida toxin, but its identity is unknown. P. canis is responsible for a number of canine infections, including systemic infection, external otitis, bacterial rhinitis, vertebral osteomyelitis, meningomyelitis (a type of myelitis), bronchopneumonia, tracheitis, paranasal sinus inflammation, and toxicosis. Horses infected with the bacteria may develop arthritis. The bacteria also cause pneumonia in cattle and various infections in sheep, cats, rabbits, and deer.

Human infections Pasteurella canis usually does not affect humans but may be transmitted from animals to humans through animal bites, scratches, or licking over wounds. However, some patients developed infections without any scratches and puncture wounds. In one case, a patient exposed to rabbit secretions was infected with P. canis. Those with rheumatoid arthritis, cirrhosis, and diabetes mellitus are more susceptible to the bacteria. Patients who are immunocompromised also have higher risk of infections. Pasteurella canis often causes soft-tissue infections and wound infections, as well as systemic bacteremia in humans. These infections include peritonitis, conjunctivitis, osteomyelitis, and arthritis. Joint prosthetics can also be infected by the bacteria. Less commonly, this bacterium may result in respiratory infections, septic arthritis, endocarditis, and meningitis. Most patients with pulmonary infections caused by this species are elderly with pre-existing chronic lung diseases such as COPD.

Antibiotics treatment and resistance Many common antibiotics can successfully treat P. canis infections in both humans and animals. P. canis has shown sensitivity to ampicillin (penicillin), cefuroxime (second-generation cephalosporin), most third-generation cephalosporins (cefixime, cefotaxime, ceftriaxone, and cefoperazone), ciprofloxacin (quinolones), trimethoprim/sulfamethoxazole (sulfonamides), chloramphenicol, most aminoglycosides, and tetracycline. However, the bacterium is also resistant to numerous drugs, such as dicloxacillin (penicillin), some aminoglycosides (spectinomycin and neomycin), vancomycin (glycopeptides), cephalexin and cefadoxil (first-generation cephalosporin), erythromycin (macrolides), and imipenem (carbapenem).

References

External links Animal bite infections (healthAtoZ.com) Bacterio entry Type strain of Pasteurella canis at BacDive - the Bacterial Diversity Metadatabase

Worked examples

Example 1 — a first encounter with Pasteurella canis

Start with the simplest possible case. Write down what Pasteurella canis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Pasteurella canis before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Pasteurella canis ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Pasteurella canis

In research: Pasteurella canis appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Pasteurella canis in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Pasteurella canis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bacteria described in 1985, Bacterial diseases, Gram-negative bacteria, so understanding it makes those chapters shorter.
In everyday life: Look for Pasteurella canis outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Pasteurella canis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Pasteurella canis means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Pasteurella canis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Pasteurella canis in simple terms?

Why does Pasteurella canis matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Pasteurella canis?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Pasteurella canis.