BACTERIAL MYCOPLASMA

 BACTERIAL MYCOPLASMA

MYCOPLASAMA:

    Mycoplasmas are the smallest self-replicating organisms.Common in nature, they are a group of simple bacteria characterized by a lack of a cell wall and a small genome.The cell varies from a spherical or pear shape.There are more than 200 known species in the class of Mollicutes (cell wall–free bacteria) lack a cell wall around their cell membranes. Peptidoglycan is absent.Fried-egg-shaped colonies are seen on agar. Mycoplasmas have no flagella, produce no spores, and are gram negative.This characteristic makes them naturally resistant to antibiotics that target cell wall synthesis.

 

Examples of mycoplasma Bacteria:

ü M. amphoriforme

ü M. buccale

ü M. faucium

ü M. fermentans

ü M. genitalium

ü M. hominis

ü M. incognitus

ü M. lipophilum

ü M. orale

ü M. penetrans

ü M. pirum

ü M. pneumoniae

ü M. primatum

ü M. salivarium

ü M. spermatophilum

 

MYCOPLASAMA LAYER COMPOSITION:

    The cell is devoid of cell wall which makes them readily deformable showing irregular and variable shapes. They may be ring-like, granular, coccoid, pear-shaped, filamentous, etc.. The filaments are of two types unbranched or branched. The cells are very small and measure 0.3-0.9 µm in diameter.The cells are covered by cytoplasmic (lipoprotein) membrane. Cell membrane covers the cytoplasm which contains nucleoplasm like structure and ribosomes. The genetic material is composed of DNA and RNA. It is about less than 50%, the amount present in other prokaryotic organisms. The amount of RNA (8%) is more than DNA (4%).They are usually non-motile, but some forms show gliding movements. They reproduce by vegetative means i.e., by binary fission and budding. 

 

 

 

                         

 

 

MYCOPLASAMA VIRULENCE FACTORS:

 

The main virulence factor in the pathogenesis of the species of Mycoplasma is the ability of these organisms to adhere to the host’s epithelial mucus membrane and colonize the affected tissue . Many mycoplasmas rely on the concentration of adhesins and adhesin-related accessory proteins at the cytadherence tip organelle for attachment and motility . None of the genes encoding the adhesins and adhesin-related accessory proteins have homologs across the various species and are not part of the core genome of these organisms. The virulence genes are in fact specific for each species of Mycoplasma, forming their own category within the Mycoplasma genome. It has, therefore, been speculated that the cytadherence tip organelle might indeed be a homoplasy resulting from evolutionary convergence .This would explain the diversity in protein composition and structural arrangement in the tip organelle in different Mycoplasma species.Most mycoplasmas that infect humans and other animals are surface parasites, adhering to the epithelial linings of the respiratory and urogenital tracts. Adherence is firm enough to prevent the elimination of the parasites by mucous secretions or urine. The intimate association between the adhering mycoplasmas and their host cells provides an environment in which local concentrations of toxic metabolites excreted by the parasite build up and cause tissue damage.

Attachment of M pneumoniae and M genitalium is affected by pretreatment of the host cells with neuraminidase, sialoglycoproteins and/or sialoglycolipids of the host cell membrane appear to be receptor sites for these mycoplasmas. There is evidence that several M pneumoniae membrane proteins act as adhesins and that they have high affinity for the specific receptors for M pneumoniae on host cells. Monoclonal antibodies to one of these proteins, protein P1, inhibit attachment of the parasite. Ferritin labeling of the antibodies has shown that P1 concentrates on the tip structure of the mycoplasma, a finding that further supports the notion that the tip serves as an attachment organelle.

The nature of the toxic factors that damage the mucosal surfaces infected by mycoplasmas is still unclear. Toxins are rarely found in mycoplasmas. Consequently, researchers considered whether the end products of mycoplasma metabolism were responsible for tissue damage.

 

Humans and Animals infection:

   Humans:

Ex: Mycoplasma pneumoniae are bacteria that can cause illness by damaging the lining of the respiratory system throat, lungs, windpipe. People can have the bacteria in their nose or throat at one time or another without being ill.

Spreads:

When someone infected with M. pneumoniae coughs or sneezes, they create small respiratory droplets that contain the bacteria. Other people can get infected if they breathe in those droplets

Animals:

Mycoplasma bovis (M. bovis) is a cause of mastitis, arthritis and bovine respiratory disease (BRD). Respiratory disease caused by M. bovis targets beef and dairy calves and can be chronic, leading to irreversible lung damage, mortality and high costs.

Spreads:

Suckling beef calves, prevalence of M. bovis is generally low. However, stressful events, including transportation, commingling, entry into feedlot, and cold or heat stress, are associated with increased infection and transmission.

	Humans	Animals
Prevention	ü Cover your mouth and nose with a tissue when you cough or sneeze. ü Put your used tissue in a waste basket. ü If you don’t have a tissue, cough or sneeze into your upper sleeve or elbow, not your hands. ü Wash your hands often with soap and water for at least 20 seconds. ü If soap and water are not available, use an alcohol-based hand rub.	ü Evaluate biosecurity protocols. ü ventilation and avoid overcrowding ü create a separate hospital area for infected animals. ü Maintain proper sanitation ü Utilize effective colostrum management on dairy operations. ü adequate nutrition with fresh feed and clean water. ü Use low-stress cattle handling techniques.
Antibiotic therapy	Most people will recover from an infection caused by M. pneumoniae without antibiotics. Doctor or pharmacist about over-the-counter medicines that can help you feel better while you are recovering.	Tulathromycin, Gamithromycin, Enrofloxacin.