Electron Microscopic Observation of <i>Branhamella catarrhalis</i>

Ahmed, Kawsar; Rikitomi, Naoto; Nagatake, Tsuyoshi; Matsumoto, Keizō

doi:10.1111/j.1348-0421.1990.tb01518.x

Cited by 18 publications

(11 citation statements)

References 14 publications

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“…The morphology of B. catarrhalis and the peritrichously arranged fimbriae were similar to the previous in vitro observation (1). The previous observations (1, 3) convinced us that fimbriae are important in the pathogenesis of B. catarrhalis infections.…”

Section: Discussionsupporting

confidence: 75%

Expression of Fimbriae and Host Response in Branhamella catarrhalis Respiratory Infections

Ahmed

Masaki

Dai

et al. 1994

Microbiology and Immunology

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Sputum during the acute exacerbation of chronic respiratory diseases were observed under the electron microscope, to determine the in vivo expression of surface structures of Branhamella catarrhalis (B. catarrhalis), the polymorphonuclear neutrophil (PMN) response to B. catarrhalis infections, and the composition of sputum. It was found that during infection fimbriae are expressed in B. catarrhalis. However, there were sparsely to densely fimbriated bacteria in each sputum sample. The length of the fimbriae were from 50 to 76 nm. In the sparsely fimbriated B. catarrhalis, external to the cell wall, a thin, granular, electron-dense layer was observed. Due to the presence of fimbriae, this layer was not seen in densely fimbriated B. catarrhalis. Blebs were also found in B. catarrhalis. PMNs were found to phagocytose both B. catarrhalis and debris. Evidence was found that debris were formed mainly by the destruction of PMNs. Bacteria as well as debris were phagocytosed by PMNs.

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Section: Discussionsupporting

confidence: 75%

Expression of Fimbriae and Host Response in Branhamella catarrhalis Respiratory Infections

Ahmed

Masaki

Dai

et al. 1994

Microbiology and Immunology

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“…No correlation is observed between the presence of pili, adherence to human oropharyngeal epithelial cells, and hemagglutination (6,145). No other putative adhesins have been identified in B. catarrhalis.…”

Section: Pili (Fimbriae)mentioning

confidence: 89%

“…Most strains of B. catarrhalis have pili, as shown by electron microscopy (2,3,5,6,114,145). Expression of pili decreases with in vitro passage (5).…”

Section: Pili (Fimbriae)mentioning

confidence: 99%

Lower respiratory tract infection

Sharland¹

2016

OSH Manual of Childhood Infections

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“…For example, Ahmed et al . () identified one pili‐negative strain of M. catarrhalis (F strain) by electron microscopy. This group also reported that the pili of M. catarrhalis are associated with bacterial adherence to oropharyngeal epithelial cells (Ahmed et al ., ).…”

Section: Introductionmentioning

confidence: 94%

“…Many strains of M. catarrhalis have pili, which were revealed by electron microscopy to be 50-to 70-nm fibrils on the surface of the bacteria (Marrs & Weir, 1990;Ahmed et al, 1994). For example, Ahmed et al (1990) identified one pili-negative strain of M. catarrhalis (F strain) by electron microscopy. This group also reported that the pili of M. catarrhalis are associated with bacterial adherence to oropharyngeal epithelial cells (Ahmed et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Pili play an important role in enhancing the bacterial clearance from the middle ear in a mouse model of acute otitis media withMoraxella catarrhalis

et al. 2013

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Moraxella catarrhalis is a Gram-negative aerobic diplococcus that is currently the third most frequent cause of bacterial acute otitis media (AOM) in children. In this study, we developed an experimental murine AOM model by inoculating M. catarrhalis in the middle ear bulla and studied the local response to this inoculation, and modulation of its course by the pili of M. catarrhalis. The pili-positive and pili-negative M. catarrhalis showed differences in bacterial clearance and infiltration of inflammatory cells in the middle ear. Pili-negative M. catarrhalis induced a more delayed and prolonged immune response in the middle ear than that of pili-positive M. catarrhalis. TLR2, -4, -5 and -9 mRNA expression was upregulated in neutrophils that infiltrated the middle ear cavity during AOM caused by both pili-positive and pili-negative bacteria. TLR5 mRNA expression and TLR5 protein in the neutrophils were induced more robustly by pili-positive M. catarrhalis. This immune response is likely to be related to neutrophil function such as toll-like 5-dependent phagocytosis. Our results show that mice may provide a useful AOM model for studying the role of M. catarrhalis. Furthermore, we show that pili play an important role in enhancing M. catarrhalis clearance from the middle ear that is probably mediated through neutrophil-dependent TLR5 signaling.

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Electron Microscopic Observation of Branhamella catarrhalis

Cited by 18 publications

References 14 publications

Expression of Fimbriae and Host Response in Branhamella catarrhalis Respiratory Infections

Expression of Fimbriae and Host Response in Branhamella catarrhalis Respiratory Infections

Lower respiratory tract infection

Pili play an important role in enhancing the bacterial clearance from the middle ear in a mouse model of acute otitis media withMoraxella catarrhalis

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