Difference Between Micrococcus and Staphylococcus

The main difference between Micrococcus and Staphylococcus is that Micrococcus rarely causes infections whereas Staphylococcus often involves in clinical infections. Moreover, Micrococcus is an aerobic bacteria that only grows in the presence of oxygen while Staphylococcus is a facultative anaerobe that is capable of using either aerobic or anaerobic fermentation.

Micrococcus and Staphylococcus are Gram-positive cocci that are non-motile, non-sporing, and Catalase positive. Both live as normal flora on the skin and the mucous membranes. Micrococcus arrangements are mostly tetrads or pairs while Staphylococcus arrangements are mainly clusters, sometimes pairs or short chains.

Key Areas Covered

1. What is Micrococcus
     – Definition, Facts, Importance
2. What is Staphylococcus
     – Definition, Facts, Importance
3. What are the Similarities Between Micrococcus and Staphylococcus
     – Outline of Common Features
4. What is the Difference Between Micrococcus and Staphylococcus
     – Comparison of Key Differences

Key Terms: Arrangements, Micrococcus, Habitat, Infections, Normal Flora, Staphylococcus

What is Micrococcus

Micrococcus a gram-positive bacterium that forms unique tetrad arrangement. Generally, Micrococcus occur in a wide range of environments as soil, water, dairy products, etc. It also occurs in the normal flora. So it rarely causes infections. Therefore, Micrococcus can be either a saprotroph or a commensal. 

Figure 1: Micrococcus mucilaginosis

Some Micrococci species such as M. luteus transforms sweat into compounds with an unpleasant odor. Other Micrococci species such as M. luteus and M. roseus form yellow and red color colonies on mannitol slat agar.

What is Staphylococcus

Staphylococcus is a Gram-positive bacterium that produces a bunch of grape-like bacterial clusters. It is a part of natural microbiota of animals and mainly lives on the skin and mucous membranes. Though most of the Staphylococci are Catalase positive, only Staphylococcus aureus is catalase-negative. Generally, Staphylococci are facultative aerobes that can use fermentation for the energy production in the absence of oxygen.

Figure 2: Staphylococcus

Staphylococci may cause infections such as pneumonia, bacteremia (blood infections), osteomyelitis (bone infections), endocarditis (infections of the inner lining of the heart and its valves), abscesses in internal organs or toxic shock syndrome. The most common symptoms of the Staphylococcal infections are fever, red, swollen, tender pimple-like bumps, chills, and low blood pressure.

Similarities Between Micrococcus and Staphylococcus

• Micrococcus and Staphylococcus are two types of Gram-positive bacteria that live in symbiotic relationships on the skin and in the mucous membranes.
• They are non-motile and do not produce spores.
• Both show positive results to the Catalase test.
• Their asexual reproduction occurs through binary fission.

Difference Between Micrococcus and Staphylococcus

Definition

Micrococcus is a spherical bacterium found on dead or decaying organic matter while Staphylococcus is a gram-positive bacterial genus that produces a bunch of grape-like bacterial clusters.

Habitat

Micrococcus lives in a wide range of environments such as water, soil, and the dust whereas, Staphylococcus lives in the animal body. Furthermore, micrococcus is arranged in tetrads or pairs whereas, Staphylococcus is arranged mainly in clusters but sometimes, in pairs and short chains.

Lysostaphin Sensitivity Test

Micrococci are resistant to Lysostaphin and do not lyse with it while Staphylococci are sensitive to lysostaphin and lyse with it.

Furazolidone Sensitivity Test

Micrococci are resistant to Furazolidone and are not susceptible to antibiotic Furazolidone while Staphylococci are sensitive to Furazolidone susceptible to antibiotic Furazolidone.

Bacitracin Sensitivity Test

Micrococcus is sensitive to Bacitracin and is susceptible to 0.04 U of it while Staphylococcus is resistant to Bacitracin and is not susceptible to 0.04 U of it.

Microdase Test

Micrococcus responds positivly for microdase test whereas, Staphylococcus response negatively.

Type of Metabolism

Micrococcus is an obligate aerobe while Staphylococcus is an facultative anaerobe.

Clinical Significance

Micrococcus rarely cause infections while Staphylococcus always cause infections.

Conclusion

Micrococcus is a bacteria that belongs to the normal flora and it rarely causes infections. But, Staphylococcus is an infectious bacteria though it also belongs to the normal flora. Both Micrococcus and Staphylococcus are Gram-positive bacteria that are non-motile and non-spore producing. Both are positive to the Catalase test as well. The main difference between Micrococcus and Staphylococcus is the role of the bacteria in animals.

Reference:

1. Foster, Timothy. “Staphylococcus.” Advances in Pediatrics., U.S. National Library of Medicine, 1 Jan. 1996, Available Here
2. “Micrococcus.” Wikipedia, Wikimedia Foundation, 11 June 2018, Available Here

Image Courtesy:

1. “Micrococcus mucilaginosis” (Public domain) via Commons Wikimedia
2. “under-a-high-magnification-of-10000x-strain-of-staphylococcus-aureus-bacteria” BY Janice Haney Carr, Matthew J. Arduino, DRPH, USCDCP (CC0) via PIXNIO