What is the Difference Between Neisseria and Moraxella

The key difference between Neisseria and Moraxella is that Neisseria is a genus that belongs to the class of beta proteobacteria while Moraxella is a genus that belongs to the class of gamma proteobacteria.

Proteobacteria is a major phylum comprised of gram-negative bacteria. This phylum consists of a wide variety of pathogenic genera such as Escherichia, Salmonella, Vibrio, Helicobacter, Neisseria, Yersinia, Legionella, etc. Others in this phylum are free-living non-parasitic bacteria. Many of the bacteria in this phylum can also fix atmospheric N₂. Carl Woese established this group in 1987. There are nine classes of proteobacteria based on the ribosomal RNA (rRNA) sequences: alpha, beta, gamma, delta, epsilon, zeta, etc. Neisseria and Moraxella are two types of proteobacteria that belong to the phylum proteobacteria.

CONTENTS

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

What is Neisseria?

Neisseria is a large genus that belongs to beta proteobacteria. Generally, Neisseria colonizes in the mucosal surfaces of many animals. Out of the 11 species that colonize in humans, only two are pathogenic bacteria: N. meningitidis and N. gonorrhoeae. However, most gonococcal infections are asymptomatic and self-resolving. Neisseria species are gram-negative bacteria. They are also diplococci that resemble coffee bean shapes when viewing under the microscope. Moreover, Neisseria species are catalase and oxidative positive in biochemical testing.

Neisseria species normally grow in pairs but occasionally can be tetrads. They thrive best at 98.6 ⁰F in the animal body or serum culture. N. meningitidis causes meningitidis and septicaemia, while N. gonorrhoeae causes gonorrhoea. These two species have the ability to breach the important barriers in the human body. Furthermore, these species avoid most of the defence mechanisms, such as neutrophils, phagocytosis, and the complement system. Neisseria species also show antigenic variation by altering their antigens. In addition, they have type IV pili which have various functions such as attachment, twitching motility, microcolony formation, antigenic variation, etc. This genus also has some commensal or non-pathogenic species: N. bacilliformis, N. cinerea, N. elongata, N. flavescens, etc.

What is Moraxella?

Moraxella is a genus that belongs to the class of gammaproteobacteria. They are gram-negative bacteria. They belong to the family of Moraxellaceae. This bacterium is named after Swiss ophthalmologist Victor Morax. Moraxella species can be short rods, coccobacilli or diplococci. These species are normally asaccharolytic, oxidase-positive and catalase-positive. M. catarrhalis is the most clinically important species under this genus. Moraxella is a commensal of mucosal surfaces. But sometimes, these species give rise to opportunistic infections.

M. catarrhalis usually resides in the upper respiratory tract. But it can gain access to the lower respiratory tract in patients with chronic chest disease. Hence, this causes pneumonia. Moreover, M. lacunata causes blepharoconjunctivitis in humans and M. bovis causes infectious bovine keratoconjunctivitis in cattle.

What are the Similarities Between Neisseria and Moraxella?

• Neisseria and Moraxella are two genera of proteobacteria.
• Both are gram negative.
• They are diplococci.
• Both are strict aerobes.
• They are catalase positive and oxidative positive.
• Both genera have pathogenic and non-pathogenic species.

What is the Difference Between Neisseria and Moraxella?

Neisseria is a genus that belongs to the class of beta proteobacteria while, Moraxella is a genus that belongs to the class of gamma proteobacteria. So, this is the key difference between neisseria and moraxella. Furthermore, Neisseria is a monophyletic genus, while Moraxella is a paraphyletic genus.

The below infographic lists the differences between neisseria and moraxella in tabular form for side by side comparison.

Summary – Neisseria vs Moraxella

Proteobacteria is a major phylum of gram negative bacteria. Neisseria and Moraxella are two genera of proteobacteria. Neisseria is a genus that belongs to the class of beta proteobacteria. Moraxella is a genus that belongs to the class of gamma proteobacteria. Thus, this is the key difference between neisseria and moraxella.

Reference:

1. “Neisseria.” An Overview | ScienceDirect Topics.
2. “Moraxella.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Neisseria gonorrhoeae with pus cells” By Dr Graham Beards – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Moraxella Catarrhalis” By CDC/Dr. W.A. Clark – (CC0) via Commons Wikimedia