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Streptococcus Canis: Biochemical Test & Identification

I’ve always found myself intrigued by the world of microscopic organisms. It’s amazing how such tiny entities can wield substantial impact, especially in the field of health and disease. Among these minute creatures, there’s one that I have spent considerable time studying – a bacterium known as Streptococcus Canis.

This bacteria might be small in size, but their effects are anything but insignificant. While commonly associated with animals, particularly dogs and cats, Streptococcus canis has increasingly been recognized as contributing to human illness as well. From skin infections to sepsis, this sneaky pathogen knows its way around a host body.

Understanding it better is our key to combating the diseases it causes effectively. Hence, the importance of biochemical tests in identifying Streptococcus canis cannot be overstated.

Streptococcus Canis Metabolic Tests

Biochemical testing is like detective work in the world of microbiology. It involves identifying unknown bacteria based on their specific metabolic reactions when exposed to certain chemicals or conditions. Cool? Yes, I think so too! However, it requires meticulous research and solid understanding because microbes can behave strangely under different scenarios.

Marking these metabolic tests down in a table provides easier ways to visualize them:

Basic CharacteristicsProperties (Streptococcus canis)
CAMPNegative (-ve)
CatalaseNegative (-ve)
Alkaline PhosphatasePositive (+ve)
Arginine DehydrolasePositive (+ve)
Esculin HydrolysisPositive (+ve)
Gram StainingPositive (+ve)
OF (Oxidative-Fermentative)Facultative anaerobes
UreaseNegative (-ve)
VP (Voges Proskauer)Negative (-ve)
Fermentation of AdonitolNegative (-ve)
ArabinoseNegative (-ve)
ArabitolNegative (-ve)
ArbutinPositive (+ve)
DulcitolNegative (-ve)
ErythritolNegative (-ve)
FructosePositive (+ve)
GalactosePositive (+ve)
GlucosePositive (+ve)
GlycogenNegative (-ve)
HippurateNegative (-ve)
InositolNegative (-ve)
InulinNegative (-ve)
LactosePositive (+ve)
MaltosePositive (+ve)
MannitolNegative (-ve)
MannosePositive (+ve)
MelibioseNegative (-ve)
RaffinoseNegative (-ve)
RhamnoseNegative (-ve)
RibosePositive (+ve)
SalicinPositive (+ve)
SorbitolNegative (-ve)
StarchPositive (+ve)
SucrosePositive (+ve)
XyloseNegative (-ve)

Defining Streptococcus Canis

Streptococcus canis is a Gram-positive, facultatively anaerobic bacteria belonging to the genus Streptococcus. Known for its round or oval shape when observed under a microscope, they usually stick together, forming chains that resemble a string of beads.

Defining Streptococcus Canis
Streptococcus Canis

This bacterium is prevalent in various animal species but is particularly associated with dogs and cats, where the disease manifestation is most evident.

Possessing β-hemolytic properties (an ability to break down red blood cells), Streptococcus canis plays a role in many diseases affecting our companions from furry friends, primarily dogs and cats.

Cases of skin infections, otitis externa (inflammation of the outer ear), and wound infections are typical instances where you will encounter this microorganism; it’s even linked with severe systemic conditions like sepsis.

Although commonly found in pets mentioned above, S. canis also has zoonotic potential, meaning it could transfer from animals to humans – however rare it may be! In humans, though, S.canis infection may result in sporadic cases of bacteremia and endocarditis among people having close contact with infected domestic animals.

Also Read: Exploring Differences: Gram Positive vs Gram Negative Bacteria

Nature of Streptococcus Canis

Streptococcus canis is inherently opportunistic, meaning it tends to attack when the host’s immune defenses are compromised. They are commensals in nature, regularly found in the mucus membranes and skin of the pets they inhabit, co-existing without causing any disease most of the time.

However, they can transform into vicious pathogens when circumstances favor them – for instance, a weakened immune system due to another illness or stress.

In terms of habitat, S. canis prefers environments that are rich in nutrients and oxygen but is capable of surviving under low-oxygen conditions as well due to its facultative anaerobic nature.

They’re widespread across domesticated animals worldwide; however, prevalence varies among populations and species based on elements like geographic climate and hygiene practices.

The significance of S.canis lies in its potential to cause serious illnesses ranging from skin infections to systemic ones like meningitis or streptococcal toxic shock syndrome, both in animals and humans.

Illnesses Associated with Streptococcus Canis

Streptococcus canis, although it lives in harmony with the bodies of our domesticated feline and canine friends without causing any trouble most of the time, can become quite an adversary when opportunistically infecting a weakened host or breaking through protective barriers due to injury.

For dogs and cats, some of the significant diseases associated with S. canis are often related to skin and soft tissue infections. For example, dogs may suffer from pyoderma (a bacterial skin infection), typically characterized by pus-filled blisters on their skins.

Playing a starring role in otitis externa (outer ear infections) is yet another common scenario for dogs infected by S.canis; this usually results in inflamed ears coupled with severe discomfort or pain.

Similarly, our feline companions may also succumb to wound infection if they’re unlucky enough to get a scrape or cut contaminated by this bacterium.

Systemic illnesses related to S.canis are also worth mentioning. In severe cases, sepsis may occur due to an immune response towards infection, leading to worse multi-organ dysfunction – an undeniably serious condition requiring immediate medical attention.

Biochemical Test for Streptococcus Canis

In the microbial world, correct identification is key, and this holds true for Streptococcus canis. It aids in effective disease management – be it an infection in our canine pals or a rare occurrence in humans.

Biochemical Test for Streptococcus Canis
Biochemical Test for Streptococcus Canis

That’s where biochemical tests come into play. They are fundamental tools used by microbiologists to identify bacterial species based on their specific biochemical activities.

Biochemical tests for Streptococcus canis may include standard protocols like catalase testing, hemolysis on blood agar plates, and fermentation patterns of various under-investigation carbohydrates.

These tests consider how our bacterium of interest reacts to different environments or substrates, providing unique combinations that help with definitive identification.

For instance, S.canis is catalase-negative (does not produce bubbles when mixed with hydrogen peroxide) and makes β-hemolysis on blood agar — these real-time behaviors allow it to “stand out” among potential contaminants during identification attempts.

Thus, biochemical testing serves as an efficient platform for identifying not just S.canis but unruly bacterial patrons we might encounter in microbiology.

Also Read: Unmasking Streptococcus Mutans: Role and Identification of the Bacterium

Common Methods for Testing

Accurate identification of Streptococcus Canis is paramount to initiate effective treatment strategies. Biochemical testing remains an indispensable aspect of this process; it involves several steps and methods as follows:

  • Catalase Test: The basic starting point, the Catalase test helps distinguish between Staphylococci (Catalase-positive) and Streptococci (Catalase-negative). But, if the culture bubbles up when hydrogen peroxide is added – it’s not StreptoCoccus can is.
  • Hemolysis Examination: To perform this, we streak the bacteria onto a sheep or horse blood agar plate. This test will reveal if the bacterium has α(Alpha), β(Beta), or γ(Gamma) hemolysis characteristics – indicators of their pathogenic capabilities. S.Canis typically exhibits Beta-hemolysis characterized by clear zones around colonies.
  • BSA Hydrolysis Test: Utilizing Bovine Serum Albumin agar plates for this test can show whether S.Canis can hydrolyze albumin proteins — only some strains are capable of doing so!
  • Lancefield Grouping: A serological method that identifies carbohydrate antigens found in bacterial cell walls to differentiate between various streptococcus species. StreptoCanisOpenicus belongs to Lancefield group G, but it’s critical to remember that not all members cause disease!

These are some common tests run during cultivation and identification efforts for S.canis, each providing valuable insights into their biochemical properties and ultimately helping diagnose infections they cause more precisely.

Procedures Used for the Identification of Streptococcus Canis

Identifying Streptococcus canis involves the following procedures:

Specimen Collection

The first step in identifying the presence of S. canis is to collect a specimen from the suspected infected area. This could be a wound swab, blood sample, tissue sample or any other suitable biological material, depending on where the infection is feared to exist.

Culturing Sample

The acquired specimen then gets cultured in an appropriate nutritive medium such as blood agar plates – an ideal medium for growing streptococcus species, given their hemolytic nature.

Observing Hemolysis

During the incubation period at optimum temperature, we look for β-hemolysis (clear zones around colonies), which gives us an indicative sign of possible S.canis presence, given its beta-hemolytic activity.

Gram Staining

Concurrently, a gram staining test is conducted on a smear prepared from a suspected colony where a Gram-positive result reinforces the suspicion further, as S.canis is a gram-positive bacterium.

Catalase Test

The catalase test follows next, which differentiates between staphylococci and streptococci based on enzyme catalase production capability (Streptococci, including S.canis, are catalase negative).

Biochemical Testing

If it’s still uncertain whether the strep bacteria detected are Streptococcus canis or other species, additional biochemical tests like esculin hydrolysis, sorbitol fermentation, and pyrrolidonyl arylamidase (PYR) would be executed.


In some cases, serology might be added where antigens on bacteria surface assist in establishing bacterial identity more conclusively – this further helps distinguish it from similar family members like Streptooccus agalactiae or Streptooccus dysgalactiae, which otherwise exhibit overlapping features.

Identification procedures can vary slightly depending on available facilities or context, but generally, they hover around similar steps I mentioned above for accurate detection of Streptococcus canis.

Practical Examples and Case Studies

1. Case of Septicemia in a Dog: In one instance, a young Labrador retriever was brought to the local veterinarian hospital, showing signs of general illness and weakness. The animal’s condition worsened despite initial treatments and supportive care, prompting blood culture testing.

The lab reports identified the bacterium as Streptococcus canis, which explained the dog’s serious condition; it was suffering from septicemia (blood poisoning) caused by an S.canis infection. Unfortunately, despite aggressive treatment, including antibiotics targeted against S.canis bacteria, this young Lab could not survive the disease.

2. Skin Infection in a Domestic Cat: Another case involved a domestic cat that developed unusual sores and wounds on its skin. On presenting to a veterinary clinic, samples were taken from the cat’s lesions for analysis.

The test results confirmed an overgrowth of S.canis bacteria causing dermatitis (skin inflammation) due to bacterial invasion; appropriate antibiotics led to the successful resolution of skin conditions in this feline patient.

3. Endocarditis Infection in Humans: A rare human case comes from medical literature where an otherwise healthy elderly woman started displaying symptoms suggestive of heart problems – fatigue, palpitations, and mild fever persisted over weeks, creating concern among her treating doctors.

Upon further investigation through blood cultures and echocardiographic studies, endocarditis was diagnosed – much surprisingly though, due to zoonotic transfer via her pet dog infected with Streptococcus canis! This eye-opening case made headlines, reminding health professionals about zoonotic threats lurking around common household settings.

Impact on Veterinary Practice

The increasing understanding of Streptococcus canis has severely impacted veterinary practice in many invaluable ways. With better knowledge about the infectious nature of this bacterium, steps have been taken to prevent infection transmission among pets and from pets to humans.

Clinical diagnosis and treatment protocols have evolved due to advanced techniques for identifying bacteria like S.canis rapidly and accurately. Furthermore, efforts are being made in therapeutic research aimed at curbing the effect of these infections on our beloved animals.

The continuous studies on S.canis have also generated discussions on zoonosis, which has led to improved hygiene practices within the clinic environment and homes.

Also Read: O Antigen and H Antigen – Unraveling Our Body’s Heroes

Frequently Asked Questions

What biochemical test is used to identify Streptococcus species?

The bacitracin test, along with the Lancefield antigen A test, is used for greater specificity in the identification of S. pyogenes since other β-hemolytic strains of streptococci that may contain the group A antigen are resistant to bacitracin. The bacitracin test is also used to distinguish S.

What are the biochemical characteristics of Streptococcus species?

Streptococci are Gram-positive, nonmotile, nonsporeforming, catalase-negative cocci that occur in pairs or chains. Older cultures may lose their Gram-positive character. Most streptococci are facultative anaerobes, and some are obligate (strict) anaerobes. Most require enriched media (blood agar.)

Is Streptococcus canis Gram-positive or negative?

Streptococcus canis is a Gram-positive beta-hemolytic group G Streptococcus that colonizes the epithelial, respiratory, gastrointestinal, and urogenital surfaces of cats and dogs [1,2,3].

What is the typical appearance of Streptococcus under a microscope?

Streptococci are coccoid bacterial cells microscopically and stain purple (Gram-positive) when Gram staining technique is applied. They are nonmotile and non-spore-forming. These cocci measure between 0.5 and 2 μm in diameter.


In closing, understanding the nature and behavior of Streptococcus canis proves integral to our fight against infections it causes in animals and rare instances in humans.

Biochemical test identification of this bacterium is fundamental in enforcing effective treatment strategies, ultimately aiding us in preserving the health of our beloved pets and maintaining optimal interactions between humans and animals.

As we continue to innovate within veterinary practices, evolving knowledge about S. canis will not only shape how we manage related infections but also offer a secure foundation for studying different bacteria that share similar characteristics. Remember – an inkling may all be needed to predict biochemical behaviors for a healthier society!