Digital stereology to quantify the filling rate of bacterial aggregates of Pseudomonas aeruginosa

Bentzmann, S Girod de; Laudinat, O.Bajolet; Plotkowski, C.; Bonnet, N.

doi:10.1016/0167-7012(93)90046-k

Cited by 7 publications

(5 citation statements)

References 5 publications

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“…Quantification of bacterial adherence to HAEC. Quantification of staphylococcal adherence to HAEC was performed using a computer-assisted scanning electron microscope, as previously described (11). The software has been adapted for S. aureus quantification.…”

Section: Methodsmentioning

confidence: 99%

Fibronectin-Binding Proteins of Staphylococcus aureus Are Involved in Adherence to Human Airway Epithelium

et al. 2002

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This study was designed to investigate the molecular mechanisms of Staphylococcus aureus adherence to human airway epithelium. Using a humanized bronchial xenograft model in the nude mouse and primary cultures of human airway epithelial cells (HAEC), we showed that S. aureus adhered mainly to undifferentiated HAEC whereas weak adherence (11- to 20-fold lower) to differentiated HAEC was observed (P < 0.01). A fibronectin (FN)-binding protein (FnBP)-deficient strain of S. aureus had a fivefold-lower adherence level to undifferentiated HAEC than did the parental strain (P < 0.005), suggesting that S. aureus FN-binding capacity is involved in the adherence to HAEC. We also showed that 97% of 32 S. aureus clinical strains, isolated from the airway secretions of cystic fibrosis patients (n = 18) and patients with nosocomial pneumonia (n = 14), possessed the two fnb genes. The strains from pneumonia patients had a significantly (P < 0.05) higher FN-binding capacity than did the strains from CF patients. This result was confirmed by the expression of FnBPs, investigated by Western ligand affinity blotting. Our results suggest a major role of FnBPs in the colonization of the airways by S. aureus and point to the importance of the adhesin regulatory pathways in the staphylococcal infectious process.

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Section: Methodsmentioning

confidence: 99%

Fibronectin-Binding Proteins of Staphylococcus aureus Are Involved in Adherence to Human Airway Epithelium

et al. 2002

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“…At the extreme periphery of the outgrowth, 35 nonconsecutive fields of 1,530 m 2 each at a constant magnification of ϫ2,700 were analyzed for each cell culture. The aggregates of bacteria were counted with the help of software that we developed (9). It was based on the results of a two-dimensional stereological study performed with more than 30 different transmission electron microscopy sections of P. aeruginosa aggregates, which allowed us to determine the filling rate of these aggregates (9).…”

Section: Methodsmentioning

confidence: 99%

Asialo GM1 is a receptor for Pseudomonas aeruginosa adherence to regenerating respiratory epithelial cells

Bentzmann¹,

Roger²,

Dupuit³

et al. 1996

Infect Immun

155

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We investigated the implication of asialo GM1 as an epithelial receptor in the increased Pseudomonas aeruginosa affinity for regenerating respiratory epithelial cells from cystic fibrosis (CF) and non-CF patients. Human respiratory epithelial cells were obtained from nasal polyps of non-CF subjects and of CF patients homozygous for the ⌬F 508 transmembrane conductance regulator protein (CFTR) mutation and cultured according to the explant-outgrowth model. At the periphery of the outgrowth, regenerating respiratory epithelial cells spreading over the collagen I matrix with lamellipodia were observed, characteristic of respiratory epithelial wound repair after injury. P. aeruginosa adherence to regenerating respiratory epithelial cells was found to be significantly greater in the ⌬F 508 homozygous CF group than in the non-CF group (P < 0.001). In vitro competitive binding inhibition assays performed with rabbit polyclonal antibody against asialo GM1 demonstrated that blocking asialo GM1 reduces P. aeruginosa adherence to regenerating respiratory epithelial cells in ⌬F 508 homozygous CF cultures (P < 0.001) as well as in non-CF cultures (P < 0.001). Blocking of asialo GM1 was significantly more efficient in CF patients than in non-CF subjects (P < 0.05). Distribution of asialo GM1 as determined by preembedding labelling and immunoelectron microscopy clearly demonstrated the specific apical membrane expression of asialo GM1 by regenerating respiratory epithelial cells, whereas other cell phenotypes did not apically express asialo GM1. These results demonstrate that (i) asialo GM1 is an apical membrane receptor for P. aeruginosa expressed at the surface of CF and non-CF regenerating respiratory epithelial cells and (ii) asialo GM1 is specifically recovered in regenerating respiratory epithelium. These results suggest that in CF, epithelial repair represents the major event which exposes asialo GM1 for P. aeruginosa adherence.

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“…Studies of P. aeruginosa adherence were executed by adding a constant inoculum of P. aeruginosa of 10 8 colony-forming units (CFU)·mL -1 after making the wound, at 2, 24 and 48 h, 72 h (wound closure), and 84 h (12 h after the wound closure had occurred). After incubation for 1 h to allow adherence, the different wound tissues were prepared for quantification of adherence by computer-assisted scanning electron microscopy [43,44].…”

Section: P Aeruginosa Adherence To Respiratory Epithelium Undergoingmentioning

confidence: 99%

Pseudomonas aeruginosa adherence to remodelling respiratory epithelium

Bentzmann¹,

Roger²,

Puchelle³

1996

Eur Respir J

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P Ps se eu ud do om mo on na as s a ae er ru ug gi in no os sa a a ad dh he er re en nc ce e t to o r re em mo od de el ll li in ng g r re es sp pi ir ra at to or ry y e ep pi it th he el li iu um m Normal respiratory epithelium is protected against bacteria via mucus and mucociliary clearance. Alteration of mucociliary clearance and of glycosylation of mucins in CF facilitates the access of bacteria to the underlying airway epithelial cells. Intact respiratory epithelium does not bind P. aeruginosa, whereas injured respiratory epithelium is highly susceptible to P. aeruginosa adherence. We found that the high affinity of respiratory epithelium, from CF and non-CF sources, for P. aeruginosa, during the wound repair process is related to the apical expression of asialo ganglioside M1 (aG M1 ). The affinity of repairing respiratory epithelium for P. aeruginosa is time-dependent, and is related to transient apical expression of aG M1 at the surface of repairing respiratory epithelial cells. CF respiratory epithelial cells apically express more aG M1 residues with relation to an increased affinity for P. aeruginosa than non-CF cells.High epithelial damage followed by repair represents a major cause of P. aeruginosa adherence to airway epithelium in cystic fibrosis. However, P. aerurignosa adherence and colonization are not restricted to cystic fibrosis disease and P. aeruginosa pneumonia may also occur in severely immunocompromised patients, suggesting that epithelial injury and decreased host-response favour the colonization of the airways by P. aeruginosa.

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Digital stereology to quantify the filling rate of bacterial aggregates of Pseudomonas aeruginosa

Cited by 7 publications

References 5 publications

Fibronectin-Binding Proteins of Staphylococcus aureus Are Involved in Adherence to Human Airway Epithelium

Fibronectin-Binding Proteins of Staphylococcus aureus Are Involved in Adherence to Human Airway Epithelium

Asialo GM1 is a receptor for Pseudomonas aeruginosa adherence to regenerating respiratory epithelial cells

Pseudomonas aeruginosa adherence to remodelling respiratory epithelium

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