The key difference between actinomyces and nocardia is that Actinomyces is a genus of actinobacteria comprised only of facultative anaerobic bacteria, while Nocardia is a genus of actinobacteria comprised only of strict aerobic bacteria.
Actinomyces and Nocardia are two clinically important genera of actinobacteria. Actinobacteria is a gram-positive bacterial group with high G+C DNA content. It is one of the largest bacterial classes. Bacteria in this class are ubiquitously distributed in both aquatic and terrestrial ecosystems. Actinobacteria play diverse roles in their associations with higher organisms. These bacteria are of major importance for biotechnology, medicine, and agriculture since they produce two-third of naturally derived antibiotics. They also produce anticancer, anthelminthic, and antifungal products as well.
CONTENTS
1. Overview and Key Difference
2. What is Actinomyces
3. What is Nocardia
4. Similarities – Actinomyces and Nocardia
5. Actinomyces vs Nocardia in Tabular Form
6. Summary
What is Actinomyces?
Actinomyces is a genus of actinobacteria that only comprises facultative anaerobic bacteria. The bacteria in this genus are gram-positive and rod-shaped. They often produce endospores. They may also form colonies that have fungus-like branched networks of hyphae. Hence, previously this led to the incorrect assumption that these bacteria were fungi. Actinomyces species are usually ubiquitous. They occur in the soil as well as in the microbiota of animals and humans. The bacteria in this genus are also known for their important role in soil ecology. These bacteria produce a number of enzymes that help to degrade organic plant material, lignin and chitin. Therefore, the presence of these bacteria in the soil is highly important for compost formation.
Figure 01: Actinomyces
Moreover, certain species are commensal in the skin flora, oral flora, gut flora, and virginal flora of humans and other livestock. Sometimes, Actinomyces species cause diseases in humans and livestock. In rare cases, opportunistic infections of these bacteria can cause actinomycosis, which is a disease characterized by the formation of abscesses in the mouth, lungs, or gastrointestinal tract. The common treatment for actinomycosis is antibiotics such as penicillin or amoxicillin for 5 to 12 months.
What is Nocardia?
Nocardia is a genus of actinobacteria that contains only strict aerobic bacteria. These bacteria are also gram-positive and rod-shaped. Nocardia species are normally catalase-positive and form partially acid-fast beaded branching filaments. This genus contains a total of 85 different species. Some species are non-pathogenic, while others cause nocardiosis.
Figure 02: Nocardia
Nocardia species are found commonly in soil rich in organic matter. In addition, they are also found in the microflora in healthy gingiva and periodontal pockets. Usually, most Nocardia species cause an acquired infection through traumatic introduction or by inhalation of the bacteria. The most common form of human nocardial species disease is pneumonia. Moreover, nocardial species are also involved in the process of encephalitis, which causes brain abscesses. The treatment of choice is typically antibiotics such as trimethoprim-sulfamethoxazole.
What are the Similarities Between Actinomyces and Nocardia?
- Actinomyces and Nocardia are two clinically important genera of actinobacteria.
- They all are gram-positive and rod-shaped bacteria.
- These bacterial species cause opportunistic infections.
- Both groups contain bacteria that live in the soil and microbiota of humans.
- These groups comprise bacteria that are fastidious.
What is the Difference Between Actinomyces and Nocardia?
Actinomyces is a genus of actinobacteria that comprises only facultative anaerobic bacteria, while Nocardia is a genus of actinobacteria that comprise only strict aerobic bacteria. So, this is the key difference between actinomyces and nocardia. Furthermore, Actinomyces causes actinomycosis in humans, while Nocardia causes nocardiosis in humans.
The below infographic lists the differences between actinomyces and nocardia in tabular form for side by side comparison.
Summary – Actinomyces vs Nocardia
Actinobacteria is a highly diverse gram-positive bacterial class with high G+C DNA content in their genome. Actinomyces and Nocardia are two clinically important genera of actinobacteria. Actinomyces is a genus that comprises only facultative anaerobic bacteria, while Nocardia is a genus that comprises only strict aerobic bacteria. Thus, this is the key difference between actinomyces and nocardia.
Reference:
1.“Actinomycete.” An Overview | ScienceDirect Topics.
2. “Nocardia.” An Overview | ScienceDirect Topics.
Image Courtesy:
1. “Actinomyces – high mag” By Nephron – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Nocardia” By Del45 – Own work (CC BY-SA 4.0) via Commons Wikimedia