Actinobacillus pleuropneumoniae It is a gram negative bacterium, mainly responsible for porcine pleuropneumonia. Although it was isolated for the first time in 1957, it was not until many decades later (1983) that it was located in the genus Actinobacillus, since DNA tests showed certain similarities with bacteria of the same genus.
It is a bacterium that has wreaked havoc on pig farms, causing an infection that can be life threatening, as well as being highly contagious and difficult to eradicate.
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The taxonomic classification of Actinobacillus pleuropneumoniae is the next:
The Actinobacillus pleuropneumoniae it is a gram negative bacteria. When subjected to the gram stain procedure, instead of turning purple, they are colored fuchsia. This occurs because its cell wall does not have the required structure to retain the dye particles..
For its culture, 5% blood agar is used and conditions that cover a temperature of 35 ° C - 37 ° C are needed. The time it takes for colonies to develop is 48-72 hours. In the cultures, a small hemolytic halo is observed around the colonies. Therefore Actinobacillus pleuropneumoniae is a beta hemolytic bacteria.
When it is desired to differentially identify this bacterium, it is subjected to numerous biochemical tests, in which the following results are obtained:
Likewise, this bacterium is considered a facultative anaerobic organism, that is, it can develop both in the presence and in the absence of oxygen.. Actinobacillus pleuropneumoniae also carries out the fermentation process of some carbohydrates such as ribose and glucose to obtain organic compounds.
The latter, on occasions, has been a determining element when making a differential diagnosis of this bacterium..
Actinobacillus pleruopneumoniae It is a bacterium that belongs to the group of coccobacilli. The form of this type of bacteria is intermediate between cocci and bacilli. Taking this into account, this bacterium is shaped like very short bars. Sometimes they can be mistaken for coconuts. Each cell measures approximately 0.3-0.5 microns wide by 0.6-1.4 microns long.
Bacterial cells are generally found singly or in pairs. On very rare occasions it is possible to find them forming chains. Likewise, Actinobacillus pleruopneumoniae does not form spores.
Colonies of this bacterium, when on chocolate agar medium, exhibit a grayish-white color and have an approximate diameter of 3 millimeters. On the contrary, if the culture is on blood agar, a thin halo of hemolysis is evidenced.
Actinobacillus pleuropneumoniae is a bacterium that can be pathogenic for some mammals, especially pigs.
Diseases that are caused by Actinobacillus pleuropneumoniae They are caused by a cycle of infection that occurs from the moment in which the mother's immunity is reduced.
Because of this, it is much easier for piglets to become infected. This in turn brings about a kind of chain reaction that includes the following events: replication of the bacteria, shedding of the bacteria and reinfection of young piglets. If this continues, it is possible that even sows could be re-infected.
There are pigs in which the bacteria are confined to the tonsillar crypts. They do not show any clinical symptoms, but they are carriers of the bacteria and can transmit it to other pigs.
This is a bacterium that affects almost exclusively pigs, specifically at the level of the nasal cavity and the tonsils. However, there are various strains that can colonize the lower airways, even reaching the lungs..
It is a highly contagious disease that is caused by the uncontrolled proliferation of bacteria Actinobacillus pleuropneumoniae. This type of bacteria has strains that are capable of synthesizing toxins, which are generally called RTX.
Likewise, these toxins represent a virulence factor for the induction of certain pathologies. The mechanism of action of RTX toxins is that they act at the level of the cell membrane of the cells they attack, causing the formation of pores in them. Through this mechanism, it contributes to enhance the cytotoxic activities of the cell.
Generally the onset of the disease is abrupt. Cases have even been reported in which pigs die without apparent cause and the bacteria appear at autopsy Actinobacillus pleuropneumoniae.
In the case of symptomatic patients, they manifest the following signs and symptoms:
In this sense, if the infection is not treated in time, a chronic form develops that is characterized by a persistent cough and growth retardation..
Likewise, in the lung tissue there are certain lesions, which are characterized by being dark red and firm, like infarcted areas. It can be unilateral or bilateral, together with fibrinous pleurisy.
The treatment for this pathology focuses on the eradication of the bacteria through the use of antibiotics. The most used are:
Taking into account that several strains of this bacterium have developed resistance to some antibiotics such as tetracyclines, it is important to perform a sensitivity test for the treatment to be really effective..
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