title: Increased biofilm formation by nontypeable Haemophilus influenzae isolates from patients with invasive disease or otitis media versus strains recovered from cases of respiratory infections.
abstract: Biofilm formation by nontypeable (NT) Haemophilus influenzae 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 NT H. influenzae by comparing isolates from healthy carriers, those with noninvasive respiratory disease, and those with invasive respiratory disease. We used 352 isolates from patients with nonbacteremic community-acquired pneumonia (NB-CAP), chronic obstructive pulmonary disease (COPD), OM, and 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 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 h. We observed clear differences in initial attachment and biofilm formation depending on the pathology associated with NT H. influenzae isolation, with significantly increased biofilm formation for NT H. influenzae isolates collected from patients with invasive disease and OM compared with NT H. influenzae isolates from patients with NB-CAP or COPD and healthy colonized subjects. 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.
authors.affiliation: Microbiology Department, Hospital Universitari Bellvitge, IDIBELL-Universitat de Barcelona, Barcelona, Spain Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Puig
authors.affiliation: Microbiology Department, Hospital Universitari Bellvitge, IDIBELL-Universitat de Barcelona, Barcelona, Spain Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.
authors.forename: Arnau
authors.initials: A
authors.lastname: Domenech
authors.affiliation: Institute for Agrobiotechnology, CSIC-Public University of Navarra-Gobierno de Navarra, Mutilva, Spain Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.
authors.forename: Junkal
authors.initials: J
authors.lastname: Garmendia
authors.affiliation: Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud University Medical Centre, Nijmegen, The Netherlands Laboratory of Medical Immunology, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Jeroen D
authors.initials: JD
authors.lastname: Langereis
authors.affiliation: Biofilm Control, Saint-Beauzire, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Mayer
authors.affiliation: Microbiology Department, Hospital Universitari Bellvitge, IDIBELL-Universitat de Barcelona, Barcelona, Spain Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Calatayud
authors.affiliation: Microbiology Department, Hospital Universitari Bellvitge, IDIBELL-Universitat de Barcelona, Barcelona, Spain Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain.
authors.forename: Josefina
authors.initials: J
authors.lastname: Liñares
authors.affiliation: Microbiology Department, Hospital Universitari Bellvitge, IDIBELL-Universitat de Barcelona, Barcelona, Spain Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain c.ardanuy@bellvitgehospital.cat smartinm@bellvitgehospital.cat.
authors.forename: Carmen
authors.initials: C
authors.lastname: Ardanuy
authors.affiliation: Microbiology Department, Hospital Universitari Bellvitge, IDIBELL-Universitat de Barcelona, Barcelona, Spain Research Network for Respiratory Diseases (CIBERES), ISCIII, Madrid, Spain c.ardanuy@bellvitgehospital.cat smartinm@bellvitgehospital.cat.
authors.forename: Sara
authors.initials: S
authors.lastname: Marti
mesh_terms: D001422:Bacterial Adhesion; D015373:Bacterial Typing Techniques; D018441:Biofilms; D006192:Haemophilus Infections / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology*; D006801:Humans; D010033:Otitis Media / Q000382:microbiology*; D012141:Respiratory Tract Infections / Q000382:microbiology*