The microorganisms known as "normal floras" are those that dwell unharmed on a healthy person's skin or mucous membrane. Bacteria and fungi that colonise the skin or mucous membrane for a little time or for the rest of their lives do not affect the host are considered to be part of the normal flora.
.webp "Normal Flora of the Eye and Ear Microbiota (Microbiome)")
Because the conjunctiva, the outside layer of the eye, is immediately exposed to the outside world, it has a variety of bacterial flora. However, the natural flora in the eyes is relatively scarce because to the continuous cleansing activity of tears and the suppressive effect of lysozyme. Similar to this, the ear canal and outer ear both contain several species of the typical microbial flora. The inner surfaces of the eyes and ears are typically devoid of any microbial flora.
Table of Contents
- List of Normal Flora of the Ear
- List of Norma Flora of the Eye
- Gram +ve and Gram -ve Bacteria of Eye and Ear
- Staphylococcus spp.
- Streptococcus spp.
- Corynebacterium spp.
- Microbacterium spp.
- Bacillus spp.
- Arthrobacter spp.
- Turicella otitidis
- Micrococcus spp.
- Pseudomonas spp.
- Moraxella spp.
- Haemophilus spp.
- Neisseria spp.
- Fungal Microbiota of Eye and Ear
- Aspergillus spp.
- Candida spp.
- Penicillium spp.
List of Normal Flora of the Ear
|
Gram-Positive Bacteria |
Gram-Negative Bacteria |
Fungi |
|
Staphylococcus spp. |
Pseudomonas spp. |
Aspergillus spp. |
List of Norma Flora of the Eye
|
Gram-Positive Bacteria |
Gram-Negative Bacteria |
Gram-Positive
Bacteria |
|
Staphylococcus spp. |
Haemophilus spp. |
Staphylococcus spp. |
Gram +ve and Gram -ve Bacteria of Eye and Ear
Staphylococcus spp.
- Gram-positive
- Catalase-positive
- Coagulase positive and coagulase-negative
- Aerobic
- Cocci bacteria
- Family – Staphylococcaceae
- Known for producing grape-like clusters under a microscope
The outer ear canal naturally contains Staphylococcus species as resident bacteria. The most frequent species found in the ear canal are S. epidermidis and S. auricularis. Other prevalent Staphylococci in the ear canal include S. aureus, S. capitis, S. caprae, S. haemolyticus, S. hominis, S. pasteuri, and S. warneri.
The conjunctiva contains S. aureus, S. albus, S. epidermidis, and a few additional coagulase-negative Staphylococci.
Streptococcus spp.
- Gram-positive
- Anaerobic and facultative anaerobic
- Catalase-negative
- Cocci bacteria arranged in the chain under a microscope
- Family – Streptococcaceae
Non-hemolytic streptococci are present in the conjunctiva.
Corynebacterium spp.
- Gram-positive
- Rod-shaped (club-shaped),
- Aerobic bacteria
- Family – Corynebacteriaceae
- The characteristic features of high mesodiaminopimelic acid and highly repeated arabinogalactan.
C. amycolatum, C. auris, C. falsenii, C. mucifaciens, C. tuberculostearicum, and other Corynebacterium spp. are found in the external auditory canal of humans.
Corynebacterium spp. are also found in the conjunctiva. C. xerosis is dominant Corynebacteria in healthy human conjunctiva.
Microbacterium spp.
- Gram-positive
- Rod-shaped
- Non-sporing
- Family – Microbacteriaceae
M. harmaniae subsp. B and subsp. C and other Microbacterium spp. are found in the outer ear canal.
Bacillus spp.
- Gram-positive
- Rod-shaped
- Motile
- Obligate aerobic and some facultative anaerobic
- Spore forming
- Family – Bacillaceae
Bacillus species that are part of the typical microbiota in the outer ear canal include B. cereus, B. circulans, B. fusiformis, B. megaterium, B. simplex, B. pumilus, and B. choshinensis.
Arthrobacter spp.
- Gram-positive
- Rod as well as cocci (pleomorphic)
- Strictly aerobic
- Family – Micrococcaceae
- A characteristic feature of snapping type cell division
Some people's ear canals are said to naturally harbour a few species of Arthrobacter.
Turicella otitidis
- Gram-positive
- Pleomorphic
- Non-sporing
- Non-fermentative
- Catalase-positive
- Family – Corynebacteriaceae
A typical commensal Corynebacterium found in human ear canals is T. otitidis.
Micrococcus spp.
- Gram-positive
- Mostly non-motile (few species are motile)
- Strictly aerobic
- Cocci in clusters
- Family – Micrococcaceae
In eyes, Micrococcus species are present as a passing flora. They are among the Gram-positive bacteria that predominate in human eyes.
In the ear canal, Micrococcus spp. are also present. The predominant species is M. luteus.
Pseudomonas spp.
- Gram-negative
- Rod-shaped
- Aerobic
- Gammaproteobacteria
- Family – Pseudomonadaceae
P. aeruginosa and P. stutzeri are reported in the ear canal of few people.
Moraxella spp.
- Gram-negative
- Rod-shaped or coccobacilli (M. catarrhalis are diplococci)
- Oxidase and catalase positive
- Aerobic
- Gammaproteobacteria
- Family – Moraxellaceae
M. catarrhalis, M. osloensis subspecies are found in ear canals. Moraxella spp. are also normal flora of human conjunctiva.
Haemophilus spp.
- Gram-negative
- Coccobacilli (pleomorphic)
- Aerobic or facultative anaerobic
- Gammaproteobacteria
- Family – Pasteurellaceae
In many people, Haemophilus spp. form part of the natural flora. In the human eye, they are the most common Gram-negative bacteria.
Neisseria spp.
- Gram-negative
- Aerobic or facultative anaerobic
- Cocci (and diplococci)
- Betaproteobacteria
- Family – Neisseriaceae
N. catarrhalis and N. sicca are reported as normal flora of the human conjunctiva.
Fungal Microbiota of Eye and Ear
Aspergillus spp.
A genus of filamentous fungus belonging to the Ascomycota order is called Aspergillus. Some persons have A. flavus, A. fumigatus, A. niger, and other species in their outer ear canals.
Candida spp.
A genus of yeast in the Saccharomycetaceae family is called Candida. The most often reported species are Candida albicans and Candida parapsilosis.
Penicillium spp.
A genus of filamentous fungus belonging to the Ascomycota class is called Penicillium. The natural microflora of the human ear canal also includes Penicillium species such as P. chrysogenum, P. glabrum, P. viridicatum, and others.
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