How is Actinomyces different from Nocardia?

Actinomyces are part of the normal flora of the mouth and gastrointestinal tract and are generally low virulence. In contrast, Nocardia are saprophytic organisms with a worldwide distribution in soil. Human infections result from direct inoculation of the skin or soft tissue or by inhalation of contaminated soil.

What are Actinomyces and Nocardia?

Actinomyces and Nocardia are gram-positive rods characterized by filamentous, tree-like branching growth, which has caused them to be confused with fungi in the past. They are opportunists that can sometimes produce indolent, slowly progressive diseases.

What makes actinomycetes different from other bacteria?

Actinomyces species are facultatively anaerobic (except A. meyeri and A. israelii are obligate anaerobes), and they grow best under anaerobic conditions. Actinomyces species may form endospores, and while individual bacteria are rod-shaped, Actinomyces colonies form fungus-like branched networks of hyphae.

What is the difference between Actinomyces and actinomycetes?

Actinomyces is a genus of actinomycetes, which are gram-positive non-acid-fast bacteria, while actinomycetes are a group of gram-positive bacteria that produce filament like colonies on solid substrates. So, this is the key difference between actinomyces and actinomycetes.

How do I identify Nocardia?

Identification of Nocardia species

White colonies on culture plates, branching Gram-positive bacilli, positive acid-fast staining, and positive partial acid-fast staining were identified as Nocardia species.

Actinomycetes Vs Nocardia: Points you need to know

How can you tell the difference between Mycobacterium and Nocardia?

The laboratory diagnosis is based on microscopy and culture isolation, but Nocardia can be mistaken for Mycobacterium, as they not only grow in specific media for mycobacteria, but also form partially acid-fast beaded branching filaments, similar to those formed by rapidly growing mycobacteria¹⁸.

What does Actinomyces cause?

Actinomycosis is a rare, infectious disease in which bacteria spread from one part of the body to another through body tissues. Over time, it can result in linked abscesses, pain, and inflammation. It can affect the skin or deeper areas within the body and sometimes the blood.

Is Nocardia gram-positive or negative?

The genus Nocardia is an aerobic actinomycete, catalase-positive, gram-positive bacillus, with a branching filamentous form first described in 1888 by Edmond Nocard.

What is so special about actinomycetes?

Actinomycetes, one of the most diverse groups of filamentous bacteria, are well recognized for their metabolic versatility. The bioactive potential of these bacteria facilitates their survival even in distress and unfavourable ecological conditions.

What is the difference between actinomycetes and Actinobacteria?

The main difference between actinomycetes and bacteria is that the actinomycetes are a type of bacteria considered as the transitional state of fungi from bacteria whereas the bacteria is a single-celled organism with a simple cellular structure.

How do actinomycetes and bacteria colonies differ in appearance?

The main difference between bacterial and fungal colonies is that bacterial colonies are small, smooth or rough colonies with defined margins while fungal colonies are large colonies with a fuzzy appearance. Furthermore, bacterial colonies look wet and shiny while fungal colonies are powder-like.

Is Actinomyces aerobic or anaerobic?

Actinomyces species are facultative, anaerobic, non–spore-forming, filamentous, gram-positive rods that commonly inhabit the oropharynx. Although individual bacteria are filamentous, colonies form fungus-like branched networks of hyphae.

Why actinomycetes are fascinating group of microorganisms?

Apart from being widely distributed, Actinomycetes are also nutritionally versatile and capable of producing different kinds of spores. These characteristics have allowed the group to successfully compete with other organisms in their surroundings.

Is Actinomyces gram-positive or negative?

Actinomyces spp. are filamentous Gram-positive bacilli, mainly belonging to the human commensal flora of the oropharynx, gastrointestinal tract, and urogenital tract.

Is Nocardia a fungus?

Nocardia is a genus of weakly staining Gram-positive, catalase-positive, rod-shaped bacteria. It forms partially acid-fast beaded branching filaments (acting as fungi, but being truly bacteria). It contains a total of 85 species.

Is Actinomyces acid-fast positive?

Abstract. Open-lung biopsy in a child with chronic pneumonia revealed branched gram-positive acid-fast organisms, later identified as Actinomyces israelii. Like Nocardia asteroides, A israelii can be acid fast by the commonly used Putt stain. The pneumonia was cured with 12 weeks of penicillin treatment.

Which bacteria are considered as actinomycetes?

Actinomycetes are Gram-positive mycelial bacteria, known to produce a wide variety of industrially and medically relevant compounds (antibiotics, chemotherapeutics, fungicides, herbicides and immunosuppressants).

Why do actinomycetes produce antibiotics?

In particular, an appreciable number of Actinobacteria produce antibiotics, which they use to compete with fungi and other bacteria for resources (and because they are totally badass).

Which genus of actinomycetes is most commonly used in antibiotic production?

Today, 80% of the antibiotics are sourced from the genus Streptomyces, actinomycetes being the most important. This can be seen in Fig. 1. The molecular basis of this action is well understood and the main targets are well known.

What type of bacteria is Nocardia?

Nocardiosis is a disease caused by a type of bacteria that is found in the environment, typically in standing water, decaying plants, and soil. These bacterial species belong to the genus Nocardia giving the disease its name. Nocardia and other related bacteria are considered to be opportunistic pathogens.

Is Nocardia anaerobic or aerobic?

Another useful clue is that Nocardia grow under aerobic conditions, whereas Actinomyces grow under anaerobic conditions.

Is Nocardia a bacilli?

Nocardia are obligate aerobic, partially acid-fast, beaded, branching, gram-positive bacilli. The genus Nocardia has many species and an increasing number are recognized as causes of human disease. N. asteroides usually causes pulmonary and disseminated infection.

What does nocardia cause?

Nocardiosis is a disease caused by bacteria found in soil and water. It can affect the lungs, brain, and skin. It is most common in people with weakened immune systems who have difficulty fighting off infections (for example, people with cancer or those taking certain medications such as steroids).

Which group of antibiotics do Actinomyces bacteria produce?

Actinomycosis is treated with antibiotics and surgical drainage of lesions. In all Actinomyces infections penicillin is the drug of choice.

How is Actinomyces diagnosed?

Actinomycosis is suspected clinically and confirmed by identification of A. israelii or other Actinomyces species using microscopy and culture of sputum (ideally obtained endoscopically), pus, or a biopsy specimen. Imaging tests (eg, chest x-ray, abdominal or thoracic CT) are often done depending on findings.