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Modeling Mucosal Candidiasis in Larval Zebrafish by Swimbladder Injection
Published on: November 27, 2014
Zebrafish and Galleria mellonella: Models to Identify the Subsequent Infection and Evaluate the Immunological
Xiucai Zhang1, Yajie Zhao2, Qing Wu1
1Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
Abstract:
The intestine is the main reservoir of bacterial pathogens in most organisms. Klebsiella pneumoniae is an important opportunistic pathogen associated with nosocomial bacterial infections. Intestinal colonization with K. pneumoniae has been shown to be associated with an increased risk of subsequent infections. However, not all K. pneumoniae strains in the intestine cause further infection, and the distinction of the difference among strains that cause infection after colonization and the ones causing only asymptomatic colonization is unclear. In this study, we report a case of a hospitalized patient from the ICU. We screened out two intestine colonization strains (FK4111, FK4758) to analyze the subsequent infection conditions. We set up infection models of zebrafish and Galleria mellonella to establish the differences in the potential for causing subsequent infection and the immunological specificities after K. pneumoniae intestine colonization. Sudan Black B and neutral red staining results indicated that FK4758 was more responsive to neutrophil recruitment and phagocytosis of macrophages than FK4111. The results of the assessment of the organ bacterial load revealed that FK4111 and FK4758 both had the highest bacterial loads in the zebrafish intestine compared to those in other organs. However, in the zebrafish spleen, liver, and heart, the FK4758 load was significantly higher than that of FK4111. The ST37 strain FK4111, which does not produce carbapenemase, did not cause infection after colonization, whereas the ST11 strain FK4758, which produces carbapenemase, caused infection after intestinal colonization. Our finding demonstrated that not all intestinal colonization of K. pneumoniae subsequently caused infections, and the infections of K. pneumoniae after colonization are different. Therefore, the infection models we established provided possibility for the estimation of host-microbial interactions.
Insights
Not all intestinal Klebsiella pneumoniae colonization leads to infection. Strain characteristics, like carbapenemase production, determine if colonization progresses to disease, impacting host-microbial interactions.
Area of Science:
- Microbiology
- Infectious Diseases
- Host-Pathogen Interactions
Background:
- Intestinal colonization by Klebsiella pneumoniae increases infection risk.
- The factors differentiating asymptomatic colonization from subsequent infection are unclear.
- Klebsiella pneumoniae is a significant opportunistic pathogen in healthcare settings.
Purpose of the Study:
- To investigate the differences between Klebsiella pneumoniae strains causing asymptomatic intestinal colonization versus those leading to subsequent infections.
- To analyze the immunological specificities and infection potential of distinct Klebsiella pneumoniae strains after intestinal colonization.
- To establish and utilize infection models for differentiating Klebsiella pneumoniae pathogenicity.
Main Methods:
- Screening of intestinal colonization strains (FK4111, FK4758) from a hospitalized patient.
- Infection modeling using zebrafish and Galleria mellonella.
- Assessment of neutrophil recruitment and macrophage phagocytosis using Sudan Black B and neutral red staining.
- Quantification of organ bacterial load in zebrafish models.
Main Results:
- The ST37 strain FK4111 (non-carbapenemase-producing) did not cause infection post-colonization.
- The ST11 strain FK4758 (carbapenemase-producing) caused infection after intestinal colonization.
- FK4758 showed higher responsiveness to neutrophil recruitment and macrophage phagocytosis compared to FK4111.
- FK4758 exhibited significantly higher bacterial loads in zebrafish spleen, liver, and heart than FK4111.
Conclusions:
- Intestinal colonization by Klebsiella pneumoniae does not uniformly result in infection.
- Carbapenemase production and specific sequence types (STs) influence Klebsiella pneumoniae's ability to cause infection after colonization.
- Established infection models offer a platform for evaluating host-microbial interactions and predicting infection potential.
