title: The relationship between biofilm formations and capsule in Haemophilus influenzae.
abstract: To evaluate the biofilm formation of non-typeable Haemophilus influenzae (NTHi) and H. influenzae type b (Hib) clinical isolates, we conducted the following study. Serotyping and polymerase chain reaction were performed to identify β-lactamase-negative ampicillin (ABPC)-susceptible (BLNAS), β-lactamase-negative ABPC-resistant (BLNAR), TEM-1 type β-lactamase-producing ABPC-resistant (BLPAR)-NTHi, and Hib. Biofilm formation was investigated by microtiter biofilm assay, as well as visually observation with a scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) in a continuous-flow chamber. As a result, totally 99 strains were investigated, and were classified into 4 groups which were 26 gBLNAS, 22 gBLNAR, 28 gBLPAR-NTHi and 23 Hib strains. The mean OD600 in the microtiter biofilm assay of gBLNAS, gBLNAR, gBLPAR-NTHi, and Hib strains were 0.57, 0.50, 0.34, and 0.08, respectively. NTHi strains were similar in terms of biofilm formations, which were observed by SEM and CLSM. Five Hib strains with the alternated type b cap loci showed significantly increased biofilm production than the other Hib strains. In conclusion, gBLNAS, gBLNAR, and gBLPAR-NTHi strains were more capable to produce biofilms compared to Hib strains. Our data suggested that resistant status may not be a key factor but capsule seemed to play an important role in H. influenzae biofilm formation.
authors.affiliation: Division of Infectious Diseases, Department of Infectious Medicine, Kurume University School of Medicine, Fukuoka, Japan. Electronic address: shin_ryou@med.kurume-u.ac.jp.
authors.forename: Liang
authors.initials: L
authors.lastname: Qin
authors.affiliation: Division of Microbiology, Department of Infectious Medicine, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kida
authors.affiliation: Department of Pediatrics, Chiba University Graduate School of Medicine, Chiba, Japan.
authors.forename: Naruhiko
authors.initials: N
authors.lastname: Ishiwada
authors.affiliation: Department of Microbiology, Regeneration and Advanced Medical Science, Gifu University Graduate School of Medicine, Gifu, Japan.
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Ohkusu
authors.affiliation: Department of Internal Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Chiharu
authors.initials: C
authors.lastname: Kaji
authors.affiliation: Division of Infectious Diseases, Department of Infectious Medicine, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Sakai
authors.affiliation: Department of Internal Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Kiwao
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Department of Internal Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Akitsugu
authors.initials: A
authors.lastname: Furumoto
authors.affiliation: Electron Microscopy Shop Central Laboratory, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Akitoyo
authors.initials: A
authors.lastname: Ichinose
authors.affiliation: Division of Infectious Diseases, Department of Infectious Medicine, Kurume University School of Medicine, Fukuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016667:Bacterial Capsules / Q000737:chemistry*; D018441:Biofilms; D006192:Haemophilus Infections / Q000382:microbiology; D006193:Haemophilus influenzae / Q000737:chemistry* / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009305:Nasopharynx / Q000382:microbiology; D013183:Sputum / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents
keywords: Biofilm; H. influenzae type b; Haemophilus influenzae; Non-typeable H. influenzae