<abstract xmlns="http://www.w3.org/1999/xhtml"><p><italic>Acinetobacter baumannii</italic> is the main causative pathogen of nosocomial infections that causes severe infections in the lungs. In this study, we analyzed the histopathological characteristics of lung infection with two strains of <italic>A. baumannii</italic> (ATCC 19606 and the clinical isolate TK1090) and <italic>Pseudomonas aeruginosa</italic> PAO-1 in C3H/HeN mice to evaluate the virulence of <italic>A. baumannii</italic>. Survival was evaluated over 14 days. At 1, 2, 5, or 14 days postinfection, mice of C3H/HeN were sacrificed, and histopathological analysis of lung specimens was also performed. Histopathological changes and accumulation of neutrophils and macrophages in the lungs after infection with <italic>A. baumannii</italic> and <italic>P. aeruginosa</italic> were analyzed. Following intratracheal inoculation, the lethality of ATCC 19606- and TK1090-infected mice was lower than that of PAO-1-infected mice. However, when mice were inoculated with a sub-lethal dose of <italic>A. baumannii</italic>, the lung bacterial burden remained in the mice until 14 days post-infection. Additionally, histopathological analysis revealed that macrophages infiltrated the lung foci of ATCC 19606-, TK1090-, and PAO-1-infected mice. Although neutrophils infiltrated the lung foci of ATCC 19606- and TK1090-infected mice, they poorly infiltrated the lung foci of PAO-1-infected mice. Accumulation of these cells in the lung foci of ATCC 19606- and TK1090-infected mice, but not PAO-1-infected mice, was observed for 14 days post-infection. These results suggest that <italic>A. baumannii</italic> is not completely eliminated despite the infiltration of immune cells in the lungs and that inflammation lasts for prolonged periods in the lungs. Further studies are required to understand the mechanism of <italic>A. baumannii</italic> infection, and novel drugs and vaccines should be developed to prevent <italic>A. baumannii</italic> infection.</p></abstract>

Acinetobacter baumannii is the main causative pathogen of nosocomial infections that causes severe infections in the lungs. In this study, we analyzed the histopathological characteristics of lung infection with two strains of A. baumannii (ATCC 19606 and the clinical isolate TK1090) and Pseudomonas aeruginosa PAO-1 in C3H/HeN mice to evaluate the virulence of A. baumannii. Survival was evaluated over 14 days. At 1, 2, 5, or 14 days postinfection, mice of C3H/HeN were sacrificed, and histopathological analysis of lung specimens was also performed. Histopathological changes and accumulation of neutrophils and macrophages in the lungs after infection with A. baumannii and P. aeruginosa were analyzed. Following intratracheal inoculation, the lethality of ATCC 19606- and TK1090-infected mice was lower than that of PAO-1-infected mice. However, when mice were inoculated with a sub-lethal dose of A. baumannii, the lung bacterial burden remained in the mice until 14 days post-infection. Additionally, histopathological analysis revealed that macrophages infiltrated the lung foci of ATCC 19606-, TK1090-, and PAO-1-infected mice. Although neutrophils infiltrated the lung foci of ATCC 19606- and TK1090-infected mice, they poorly infiltrated the lung foci of PAO-1-infected mice. Accumulation of these cells in the lung foci of ATCC 19606- and TK1090-infected mice, but not PAO-1-infected mice, was observed for 14 days post-infection. These results suggest that A. baumannii is not completely eliminated despite the infiltration of immune cells in the lungs and that inflammation lasts for prolonged periods in the lungs. Further studies are required to understand the mechanism of A. baumannii infection, and novel drugs and vaccines should be developed to prevent A. baumannii infection.

Histopathological Analysis of <italic>Acinetobacter baumannii</italic> Lung Infection in a Mouse Model

Polish Journal of Microbiology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Histopathological Analysis of  Lung Infection in a Mouse Model

Acinetobacter baumannii is the main causative pathogen of nosocomial infections that causes severe infections in the lungs. In this study, we analyzed the...

Histopathological Analysis of Acinetobacter baumannii Lung Infection in a Mouse Model

Article Category: original-paper

Publié en ligne: 20 déc. 2021

Pages: 469 - 477

Reçu: 25 août 2021

Accepté: 31 oct. 2021

DOI: https://doi.org/10.33073/pjm-2021-044

Mots clés
neutrophils, macrophages, a mouse lung infection model

© 2021 Shigeru Tansho-Nagakawa et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Histopathological Analysis of Acinetobacter baumannii Lung Infection in a Mouse Model

Article Category: original-paper

Publié en ligne: 20 déc. 2021

Pages: 469 - 477

Reçu: 25 août 2021

Accepté: 31 oct. 2021

DOI: https://doi.org/10.33073/pjm-2021-044

Mots clésneutrophils, macrophages, a mouse lung infection model

© 2021 Shigeru Tansho-Nagakawa et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Mots clés
neutrophils, macrophages, a mouse lung infection model