The morphology of the bacteria has been used as a phylogenetic tool which suggested that spherical bacteria is the most evolved morphology.
Spherical bacteria are usually spherical, ovoid, or round in shape referred as coccus (pl. -cocci). This article will provide insights regarding some spherical bacteria examples.
The spherical bacteria examples are as follows:
- Aerococcus urinae
- Chlamydia trachomatis
- Enterococcus faecalis
- Moraxella catarrhalis
- Neisseria gonorrhoeae
- Pediococcus acidilactici
- Pediococcus damnosus
- Sarcina ventriculi
- Staphylococcus aureus
- Streptococcus pneumoniae
- Tetragenococcus halophilus
- Neisseria meningitidis
- Sporosarcina ureae
- Staphylococcus epidermidis
- Staphylococcus haemolyticus
- Staphylococcus saprophyticus
- Streptococcus bovis
- Streptococcus pyogenes
- Micrococcus lutues
- Micrococcus lylae
- Micrococcus roseus
What are spherical bacteria?
Bacteria are single celled microorganisms that occur in various shapes. Some appear as round, spherical while others appear as rod shaped. Some of them appear as spiral shaped. Bacteria are classified based on their shapes, i.e., bacillus (rod-shaped), cocci (spherical shaped), and spirochetes (spiral-shaped).
Spherical bacteria have characteristic round or spherical shape as seen under a microscope, can be categorize depending upon the arrangement of cocci cells and also the plane of division.
Some spherical bacteria examples are listed below:
It is a Gram-positive, catalase-negative spherical bacteria that appear in a cluster of cocci. These are responsible for UTI.
This is a Gram-negative coccoid-shaped bacterium. These are obligate intracellular parasites that lack the outer peptidoglycan cell wall. These are responsible for sexually transmitted disoders and infertility.
This is a Gram-positive bacterium with spherical or ovoid morphology. These bacteria generate oxygen-free radicals that cause chronic inflammation and intestinal inflammation.
These Gram-negative bacilli appear as kidney-bean shaped diplococcus. This fastidious bacteria manifests inflammation in the nervous system and joints.
This is another Gram-negative coffee bean-shaped diplococcus. They typically appear in pairs of 0.6-1um diameter usually with flattened ends. These are responsible for various sexually transmitted ailments in humans.
It is a Gram-positive, catalase-negative, non-motile homofermentative bacteria that either appear as coccoidal or ovoid in shape with 1-2.5 mm diameter. They either present in pairs or in tetrads.
This is a Gram-positive, catalase-negative, vancomycin-resistant homofermentative bacterium that appears as short chains of coccus cells. They usually thrive as obligate anaerobes in fermented foods.
These Gram-positive, obligate anaerobes occur frequently in soil with characteristic tetrad or octet cocci morphology. They can thrive at extremely low pH conditions and are associated with gastritis problems.
These Gram-positive, non-spore-forming, facultatively anaerobic, pathogenic bacteria appear in characteristic grape-like cocci morphology with 1-4mm in diameter. They cause pneumonia.
They display a characteristic cocci shape i.e., lancet-shaped (slightly elongated cells). They either occur in pairs or chains. It also causes respiratory contamination.
This is a Gram-positive, halophilic anaerobe, a coccoid-shaped lactic acid bacterium. They can grow in extremely salt conditions and are tolerant to 18% NaCl solution. These are extensively used in fermenting soy sauce.
This is a Gram-negative bacterium occur in pairs. They are present in nasopharynx of humans and cause bacterial meningitis.
This bacterium is anaerobic, endospore-forming Gram-positive that has coccoid cells. They are arranged either in tetrads or cuboids. They are closely related to Bacilli.
This is a facultative anaerobe, Gram-positive bacterium that occurs frequently on human skin. However, it can become opportunistic bacteria once inside the human body.
This bacterium shows non-coagulase activity with coccoid-shaped cells. It remains as an opportunistic bacterium for immunocompromised patients.
These are coagulase-negative, Gram-positive bacteria. It is associated with UTI.
This Gram-positive, catalase-negative, lactic acid bacterium appears as chains of cocci or remains in pairs. Mostly these are associated with UTI, sepsis, and also colorectal cancer. These are also present in the alimentary tract of ruminant animals.
These are Gram-positive, aerotolerant bacteria that appear as a chain of cocci. It causes many human problems starting from skin rashes to fatal contamination and even leading to sepsis.
This is a Gram-positive saprophytic bacterium that appears as a tetrad. It is catalase and urease positive and coagulase-negative. These usually occur in soil, water, and air as obligate aerobe. It is sensitive against Bacitracin.
This aerobic Gram-positive bacterium appears either as tetrad or irregular clusters of coccus cells. Sometimes they remain in octet form. They occur in their natural habitat.
These Gram-positive aerobic bacteria display pink color, slightly convex colonies with tetrad arrangement of coccus cells. It also occurs in its natural habitat.
What kinds of bacteria are spherical?
Coccus is one single cell spherical bacterial cell. Depending upon the arrangement of coccus, it can be of five types.
Diplococcus bacteria (plural – diplococci) is the most common type of spherical bacteria, emerge when cocci divide and remain together as pairs. They are spherical or ovoid morphologically and occur in pairs. This morphology is present in both Gram-positive and Gram-negative bacteria.
Gram-positive diplococcus is represented by Streptococcus and Enterococcus species, while Neisseria and Moraxella are Gram-negative spherical bacteria examples.
This group belongs to the family Streptococcaceae in the phylum Firmicutes. This bacterium is divided across a single plane and thus appears in pairs or long chains of cocci adhered together. The chain length varies with the species. Enterococcus and Lactococcus belong to the group of the lactic acid bacterium. These Gram-positive bacteria appear either in pairs or in chains.
The symmetrical division of cocci in two or three planes reveals a square group of cells called a tetrad, as seen in the Micrococcus genus. Micrococci bacteria are also Gram-positive bacteria that are arranged in an irregular cluster of coccus cells that often appear in tetrads. Planococcus is another genus that occurs in pairs or tetrads. Other examples are Pediococcus and Aerococcus
Another striking pattern appears in this group is an irregular grape-like structure due to the random division of cocci. This bacterium divides sequentially along the perpendicular planes. Such divisions are less common among the bacterial cells. However, short chains are also seen in fluid smear.
Sarcina is Gram-positive cocci in the family Clostridiaceae. The word ‘sarcina’ means “pack of bundle”. These bacteria are arranged characteristic tetrad that resembles a cube-like octet. This arrangement occurs through three perpendicular divisions of the cells resulting in the formation of a cuboid cluster. This morphology is a striking feature of anaerobic bacteria.