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Pilus-mediated co-aggregation with Lactobacillus crispatus increases meningococcal susceptibility to antimicrobial
Kenny Lidberg1, Sarah Pilheden1, Samuddi Nawarathne1
1Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, SE-10691, Sweden.
Background:
Neisseria meningitidis asymptomatically colonizes the nasopharyngeal mucosa, but occasionally, the bacteria disseminate to cause sepsis and meningitis. In the epithelial cell layer, the pathogen co-colonizes with other resident inhabitants, such as Lactobacillus species that are part of the nasopharyngeal-oral microbiota. In this study, we investigated the interaction between lactobacilli and meningococci.
Results:
We demonstrated that Lactobacillus crispatus strain MV24 can co-aggregate with meningococci, whereas all other Lactobacillus strains tested did not co-aggregate. The binding ability of L. crispatus was not strain- or serogroup-specific but was dependent on the ability of meningococci to form microcolonies. The finding that N. meningitidis lacking pili did not co-aggregate with L. crispatus, but that hyperpiliated N. meningitidis exhibited strong co-aggregation, led us to examine the interaction between purified meningococcal pili and lactobacilli. Our results showed that L. crispatus MV24 can bind to purified meningococcal Class I and II pili, explaining the aggregative clusters observed under the microscope. Co-aggregation with L. crispatus disrupted microcolony formation, and increased the killing of meningococci by LL-37, hBD2 and cephalexin. Further, co-aggregation had the added effect of impeding motility.
Conclusion:
N. meningitidis pili bind to L. crispatus, which interferes with the meningococcal microcolonies and increases sensitivity to antimicrobial agents. Taken together, our findings suggest that L. crispatus MV24 may have a beneficial effect on the host through co-aggregating with meningococci.
Insights
Lactobacillus crispatus binds to Neisseria meningitidis pili, disrupting bacterial microcolonies and increasing susceptibility to antimicrobials. This interaction suggests a beneficial role for L. crispatus in host defense against meningococcal infections.
Area of Science:
- Microbiology
- Immunology
- Host-pathogen interactions
Background:
- Neisseria meningitidis asymptomatically colonizes the nasopharynx but can cause severe invasive diseases like meningitis and sepsis.
- The nasopharyngeal mucosa harbors commensal bacteria, including Lactobacillus species, which may interact with pathogens.
- Understanding these interactions is crucial for developing novel therapeutic strategies.
Purpose of the Study:
- To investigate the interaction between Lactobacillus species and Neisseria meningitidis.
- To determine the role of bacterial pili in this interaction.
- To assess the impact of this interaction on meningococcal virulence and host defense.
Main Methods:
- Co-aggregation assays between various Lactobacillus strains and N. meningitidis.
- Analysis of N. meningitidis pili (Class I and II) interaction with L. crispatus.
- Assessment of microcolony formation, bacterial killing by antimicrobial agents (LL-37, hBD2, cephalexin), and bacterial motility.
Main Results:
- Lactobacillus crispatus strain MV24 specifically co-aggregated with N. meningitidis.
- This co-aggregation was mediated by the binding of L. crispatus to N. meningitidis pili.
- Co-aggregation disrupted meningococcal microcolony formation, enhanced killing by antimicrobials, and impeded bacterial motility.
Conclusions:
- N. meningitidis pili interact with L. crispatus, leading to significant interference with meningococcal colonization and virulence.
- L. crispatus MV24 demonstrates a potential beneficial role in host defense by modulating N. meningitidis behavior.
- These findings highlight the therapeutic potential of leveraging commensal bacteria for controlling invasive meningococcal disease.
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