Rod-shaped bacteria can be found in several arrangements such as diplo (in pairs), strepto (in chains), cocco (oval), or in palisade arrangement.ĭiplobacilli Bacteria: Diplobacilli are short rod-shaped bacteria that occur in pairs. It is pathogenic and is usually implicated in gastrointestinal disorders such as gastroparesis or gastric ulcers. This arrangement is formed when bacteria divide into three perpendicular planes forming packets of 8 or more cells. Sarcinae Bacteria: These bacteria are usually non-motile, with sizes between 1.8 and 3.0 µm in diameter. Another example of this bacteria is Streptococcus bovis, which causes urinary tract infections. An example of streptococci bacteria is Streptococcus pyogenes, known to cause rheumatic fever, tonsillitis, strep throat, and other respiratory infections. This species causes a variety of conditions in humans. The arrangement of streptococcus resembles cells in chains attached. Streptococci Bacteria: The term streptococcus originates from the words “ strepto” meaning chains and coccus, meaning berry. It is known to be non-pathogenic but can be rendered pathogenic (i.e., harmful) in immunosuppressed individuals. Another example of this species is Staphylococcus epidermis, which is normally found on the skin and is a part of the normal skin flora. It is found in the nose, respiratory tract, and skin. An important example is that of Staphylococcus aureus, which is frequently implicated in food poisoning. These are universally present on mucous membranes and the skin, usually characterized as gram-positive facultative aerobes. The arrangement of staphylococci resembles cells aggregating in a grape-like structure. Staphylococci Bacteria: The term staphylococcus comes from the word Staphylo meaning grape-like clusters and coccus, meaning berry. Aerococcus urinae is an emerging cause of urinary tract infections, which was previously thought to be non-pathogenic (i.e., harmless) and a clinically insignificant urinary contaminant. Examples of tetrad-forming bacteria are Aerococcus, a urinary tract pathogen, Pediococcus, and Tetragenococcus, both of which ferment foods. Tetrad Bacteria: They are formed when the bacterium divides into two planes to form a square of four bacteria called a tetrad. Another example of diplococcus strain is Moraxella catarrhalis that is a gram-negative bacterium that causes infections of the respiratory system. A typically gram-negative bacterium causes a sexually transmitted infection called gonorrhea. One example of a diplococci strain is Neisseria gonorrhea. The name originates from the word diplo, meaning double, and coccus, meaning berry. They can be found in different arrangements, namely, diplococci (in pairs), tetrads (arrangement of groups of four), streptococci (in pairs), and staphylococci (in clusters).ĭiplococci Bacteria: These bacteria are usually found in pairs as two joined cells. These bacteria are round, flattened cells adjacent to each other. In this article, we will explore different shapes of bacteria, examples, and diseases caused by bacteria. They can be found in various shapes and sizes. The average size of a bacterium is about 2 µm (microns or micrometers). The main difference between them is that Gram-positive bacteria contain single-layered cell walls whereas, Gram-negative bacteria contain double-layered cell walls. There are several distinguishing features that Gram’s stain can identify. It also endows the bacterium with flexibility and other added advantages.īacteria are grouped into 2 major groups, Gram +ve or Gram -ve, based on the response to Gram’s stain. The rigidity of its cell wall determines the shape of a bacterium. The prokaryotic kingdom consists of unicellular microscopic microorganisms called bacteria.īacteria or a bacterium (sing.) are simple single-celled organisms that lack organized nucleus and any chlorophyll pigments but they possess a rigid cell wall. Shapes of Bacteria: Bacteriology (study of bacteria) is a major part in Microbiology.
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