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Animal models of polymicrobial pneumonia.

Hraiech S, Papazian L, Rolain JM, Bregeon F - Drug Des Devel Ther (2015)

Bottom Line: However, the concept of one pathogen leading to one infection has been challenged, and recent flu epidemics suggest that some pathogens exhibit highly virulent potential.Although "two hits" animal models have been used to study infectious diseases, few of these models have been described in pneumonia.Therefore the aims of this review were to provide an overview of the available literature in this field, to describe well-studied and uncommon pathogen associations, and to summarize the major insights obtained from this information.

View Article: PubMed Central - PubMed

Affiliation: IHU Méditerranée infection, URMITE CNRS IRD INSERM UMR 7278, Marseille, France ; Réanimation - Détresses Respiratoires et infections Sévères, APHM, CHU Nord, Marseille, France.

ABSTRACT
Pneumonia is one of the leading causes of severe and occasionally life-threatening infections. The physiopathology of pneumonia has been extensively studied, providing information for the development of new treatments for this condition. In addition to in vitro research, animal models have been largely used in the field of pneumonia. Several models have been described and have provided a better understanding of pneumonia under different settings and with various pathogens. However, the concept of one pathogen leading to one infection has been challenged, and recent flu epidemics suggest that some pathogens exhibit highly virulent potential. Although "two hits" animal models have been used to study infectious diseases, few of these models have been described in pneumonia. Therefore the aims of this review were to provide an overview of the available literature in this field, to describe well-studied and uncommon pathogen associations, and to summarize the major insights obtained from this information.

No MeSH data available.


Related in: MedlinePlus

Chronic pneumonia model using agar beads: main steps.Notes: (A) Agar beads synthesis (top row of pictures). Broth containing bacteria and agar is added to mineral oil with continuous shaking and heating. The solution obtained is centrifuged to obtain beads whose size is measured and must be about 100 µM. The precise inoculum is assessed by serial dilutions method. (B) Model of rat pneumonia (bottom row of pictures). After inhaled anesthesia, the rat is suspended by the teeth and intubated into the trachea. Agar beads solution is injected into a tracheal catheter. After animal sacrifice, macroscopic aspects of lung lesions can be observed. Then, the lungs are homogenized for bacterial count.
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f3-dddt-9-3279: Chronic pneumonia model using agar beads: main steps.Notes: (A) Agar beads synthesis (top row of pictures). Broth containing bacteria and agar is added to mineral oil with continuous shaking and heating. The solution obtained is centrifuged to obtain beads whose size is measured and must be about 100 µM. The precise inoculum is assessed by serial dilutions method. (B) Model of rat pneumonia (bottom row of pictures). After inhaled anesthesia, the rat is suspended by the teeth and intubated into the trachea. Agar beads solution is injected into a tracheal catheter. After animal sacrifice, macroscopic aspects of lung lesions can be observed. Then, the lungs are homogenized for bacterial count.

Mentions: Acute pneumonia models are preferred in mortality studies. Infection symptoms are rich and appear rapidly (within a few hours). Bacterial burdens in lungs are high during the first day of infection but rapidly decrease as the animal recovers. Conversely, when using chronic models, the animals exhibit less evident signs of sepsis, but the bacterial pulmonary count and histological lesions of bronchopneumonia remain present for a longer period, occasionally lasting for several weeks.24 The use of a vector solution containing the infectious agent is crucial for the kinetics of the spread of the microorganisms in the airways. Buffered suspensions, such as phosphate-buffered saline, or aqueous solutions facilitate rapid spread and favor the development of acute pneumonia. When chronic carriage is targeted, bacteria embedded in agar beads should be preferred (Figures 3 and 4).25 Beads mediate the slow dissemination of bacteria in the lungs and provide relative protection against immune cells; thus, bacteria persist in the respiratory tractus for several days. Alginate beads have also been successfully used with mucoid strains, as these materials favor biofilm development.26


Animal models of polymicrobial pneumonia.

Hraiech S, Papazian L, Rolain JM, Bregeon F - Drug Des Devel Ther (2015)

Chronic pneumonia model using agar beads: main steps.Notes: (A) Agar beads synthesis (top row of pictures). Broth containing bacteria and agar is added to mineral oil with continuous shaking and heating. The solution obtained is centrifuged to obtain beads whose size is measured and must be about 100 µM. The precise inoculum is assessed by serial dilutions method. (B) Model of rat pneumonia (bottom row of pictures). After inhaled anesthesia, the rat is suspended by the teeth and intubated into the trachea. Agar beads solution is injected into a tracheal catheter. After animal sacrifice, macroscopic aspects of lung lesions can be observed. Then, the lungs are homogenized for bacterial count.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492661&req=5

f3-dddt-9-3279: Chronic pneumonia model using agar beads: main steps.Notes: (A) Agar beads synthesis (top row of pictures). Broth containing bacteria and agar is added to mineral oil with continuous shaking and heating. The solution obtained is centrifuged to obtain beads whose size is measured and must be about 100 µM. The precise inoculum is assessed by serial dilutions method. (B) Model of rat pneumonia (bottom row of pictures). After inhaled anesthesia, the rat is suspended by the teeth and intubated into the trachea. Agar beads solution is injected into a tracheal catheter. After animal sacrifice, macroscopic aspects of lung lesions can be observed. Then, the lungs are homogenized for bacterial count.
Mentions: Acute pneumonia models are preferred in mortality studies. Infection symptoms are rich and appear rapidly (within a few hours). Bacterial burdens in lungs are high during the first day of infection but rapidly decrease as the animal recovers. Conversely, when using chronic models, the animals exhibit less evident signs of sepsis, but the bacterial pulmonary count and histological lesions of bronchopneumonia remain present for a longer period, occasionally lasting for several weeks.24 The use of a vector solution containing the infectious agent is crucial for the kinetics of the spread of the microorganisms in the airways. Buffered suspensions, such as phosphate-buffered saline, or aqueous solutions facilitate rapid spread and favor the development of acute pneumonia. When chronic carriage is targeted, bacteria embedded in agar beads should be preferred (Figures 3 and 4).25 Beads mediate the slow dissemination of bacteria in the lungs and provide relative protection against immune cells; thus, bacteria persist in the respiratory tractus for several days. Alginate beads have also been successfully used with mucoid strains, as these materials favor biofilm development.26

Bottom Line: However, the concept of one pathogen leading to one infection has been challenged, and recent flu epidemics suggest that some pathogens exhibit highly virulent potential.Although "two hits" animal models have been used to study infectious diseases, few of these models have been described in pneumonia.Therefore the aims of this review were to provide an overview of the available literature in this field, to describe well-studied and uncommon pathogen associations, and to summarize the major insights obtained from this information.

View Article: PubMed Central - PubMed

Affiliation: IHU Méditerranée infection, URMITE CNRS IRD INSERM UMR 7278, Marseille, France ; Réanimation - Détresses Respiratoires et infections Sévères, APHM, CHU Nord, Marseille, France.

ABSTRACT
Pneumonia is one of the leading causes of severe and occasionally life-threatening infections. The physiopathology of pneumonia has been extensively studied, providing information for the development of new treatments for this condition. In addition to in vitro research, animal models have been largely used in the field of pneumonia. Several models have been described and have provided a better understanding of pneumonia under different settings and with various pathogens. However, the concept of one pathogen leading to one infection has been challenged, and recent flu epidemics suggest that some pathogens exhibit highly virulent potential. Although "two hits" animal models have been used to study infectious diseases, few of these models have been described in pneumonia. Therefore the aims of this review were to provide an overview of the available literature in this field, to describe well-studied and uncommon pathogen associations, and to summarize the major insights obtained from this information.

No MeSH data available.


Related in: MedlinePlus