You are here: Home Published Research Non-typeable Haemophilus influenzae isolates from invasive disease and otitis media present higher biofilm formation than strains recovered from respiratory infections.

Carmen Puig, Arnau Domenech, Junkal Garmendia, Jeroen D Langereis, Pascal Mayer, Laura Calatayud, Josefina LiƱares, Carmen Ardanuy, and Sara Marti (2014)

Non-typeable Haemophilus influenzae isolates from invasive disease and otitis media present higher biofilm formation than strains recovered from respiratory infections.

Applied and environmental microbiology.

Biofilm formation by non-typeable Haemophilus influenzae (NTHi) remains a controversial topic. Nevertheless, biofilm-like structures have been observed in the middle-ear mucosa of experimental chinchilla models of otitis media (OM). To date, there have been no studies of biofilm formation in large collections of clinical isolates. This study aimed to investigate the initial adhesion to a solid surface and biofilm formation by NTHi by comparing isolates from healthy carriers, those with non-invasive respiratory disease, and those with invasive respiratory disease. We used 352 isolates from patients with non-bacteremic community acquired pneumonia (NB-CAP), chronic obstructive pulmonary disease (COPD), OM, invasive disease, and a group of healthy colonized children. We then determined the speed of initial adhesion to a solid surface by the biofilm ring test methodology, and quantified biofilm formation by crystal violet staining. Isolates from different clinical sources displayed high levels of biofilm formation on a static solid support after growth for 24 hours. We observed clear differences in initial attachment and biofilm formation depending on the pathology associated with NTHi isolation, with significantly increased biofilm formation for NTHi isolates collected from patients with invasive disease and OM compared with NTHi isolates from patients with NB-CAP, COPD or healthy colonization. In all cases, biofilm structures were detached by proteinase K treatment, suggesting an important role for proteins in the initial adhesion and static biofilm formation measured by crystal violet staining.

 
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