What is the Difference Between Staphylococcus Aureus and Staphylococcus Saprophyticus

The key difference between Staphylococcus Aureus and Staphylococcus Saprophyticus is that Staphylococcus aureus is a pathogenic bacterial species that mainly causes soft tissue infections, bloodstream infections, pneumonia, bone and joint infections, while Staphylococcus saprophyticus is a pathogenic bacterial species that mainly causes urinary tract infections.

Staphylococcus is a genus of Gram-positive bacteria that cause a wide range of clinical diseases in humans. The infections caused by the pathogens of this genus are both hospital-acquired and community-acquired. Staphylococcus species are facultative anaerobic organisms and form grape-like clusters. In fact, it is one of the leading infections in hospitals, and there are at least 43 species under this genus. Staphylococcus aureus and Staphylococcus saprophyticus are two pathogenic bacterial species of this genus.

CONTENTS

1. Overview and Key Difference
2. What is Staphylococcus Aureus 
3. What is Staphylococcus Saprophyticus
4. Similarities – Staphylococcus Aureus and Staphylococcus Saprophyticus
5. Staphylococcus Aureus vs. Staphylococcus Saprophyticus in Tabular Form
6. Summary – Staphylococcus Aureus vs. Staphylococcus Saprophyticus

What is Staphylococcus Aureus?

Staphylococcus aureus is a gram-positive spherical-shaped bacterium in the microbiota of the human body. It is mainly found in the upper respiratory tract and on the skin. S. aureus is a facultative anaerobe and is often positive for catalase and nitrate reduction tests. Even though it is a commensal, it can be an opportunistic pathogen. As an opportunistic pathogen, it commonly causes abscesses, respiratory infections like sinusitis, and food poisoning. It can also cause bloodstream infections and bone and joint infections. The pathogenic strains of this species promote their infection through virulent factors such as potent protein toxins and the expression of cell surface protein (that binds and inactivates antibodies).

S. aureus is one of the leading causes of death associated with antimicrobial resistance. Numerous antibiotic-resistant strains, such as methicillin-resistant S. aureus (MRSA), have occurred throughout the world, which is a major problem for clinical medicine. Despite all efforts, no vaccine has yet been approved for S. aureus. Furthermore, in the United States, around 500,000 hospital patients contract staphylococcal infection each year. In addition, approximately 50,000 deaths are reported each year in the United States that are linked to staphylococcal infection.

What is Staphylococcus Saprophyticus?

Staphylococcus saprophyticus is a gram-positive coccus bacterium belonging to the genus Staphylococcus. It mainly causes community-acquired urinary tract infections. Moreover, in humans, S. saprophyticus can be found in the normal flora of the female genital tract and perineum.  S. saprophyticus usually results in 10–20% of urinary tract infections (UTIs). S. saprophyticus is positive for catalase and urease tests and negative for motility, coagulase, nitrate reduction, and oxidase tests.

The virulent factors of this bacterial species are adherence to urothelial cells through a surface-associated protein, lipoteichoic acid, hemolysin, and the production of extracellular slime. Furthermore, urinary tract infections of S. Saprophyticus can be treated through trimethoprim-sulfamethoxazole or with a quinolone (norfloxacin) and ampicillin & ceftriaxone.

What are the Similarities Between Staphylococcus Aureus and Staphylococcus Saprophyticus?

• Staphylococcus aureus and Staphylococcus saprophyticus are two pathogenic bacterial species under the genus Staphylococcus.
• Both are normally commensal in humans.
• They become opportunistic pathogens in humans.
• Both are round or spherical in shape and gram-positive in nature.
• They are resistant to some antibiotics.

What is the Difference Between Staphylococcus Aureus and Staphylococcus Saprophyticus?

Staphylococcus aureus is a pathogenic bacterial species mainly causing soft tissue infections, bloodstream infections, pneumonia, and bone and joint infections, while Staphylococcus saprophyticus is a pathogenic bacterial species mainly causing urinary tract infections. Thus, this is the key difference between Staphylococcus Aureus and Staphylococcus Saprophyticus. Furthermore, Staphylococcus aureus is mainly found in the upper respiratory tract and on the skin of humans. On the other hand, Staphylococcus saprophyticus is mainly found in the normal flora of the female genital tract and perineum.

The infographic below presents the differences between Staphylococcus Aureus and Staphylococcus Saprophyticus in tabular form for side-by-side comparison.

Summary – Staphylococcus Aureus vs. Staphylococcus Saprophyticus

Staphylococcus aureus and Staphylococcus saprophyticus are two pathogenic bacterial species under the genus Staphylococcus. They are normally commensals and can be opportunistic pathogens in humans. Staphylococcus aureus is a more common pathogenic bacterial species mainly causing soft tissue infections, bloodstream infections, pneumonia, and bone and joint infections in humans, while Staphylococcus saprophyticus is a less common pathogenic bacterial species mainly causing urinary tract infections. So, this summarizes the difference between Staphylococcus Aureus and Staphylococcus Saprophyticus.

Reference:

1. “Staphylococcus Aureus in Healthcare Settings.” Centers for Disease Control and Prevention.
2. “Staphylococcus Saprophyticus Infection.” Statpearls – NCBI Bookshelf.

Image Courtesy:

1. “Staphylococcus aureus appearance on agar plates” By HansN. – Own work (CC BY 3.0) via Commons Wikimedia
2. “Staphylococcus saprophyticus” By Riraq25 – Own work (CC BY-SA 3.0) via Commons Wikimedia