Bacteriology of the paranasal sinuses in pediatric cystic fibrosis patients

OBJECTIVES

To review the characteristic microbiology of the paranasal sinuses in patients with cystic fibrosis who undergo endoscopic sinus surgery. To examine the subtypes of organisms cultured from the maxillary sinuses and determine their sensitivity to antibiotic therapy.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary care children's hospital.

METHODS

Sinus cultures were obtained from 51 patients with cystic fibrosis during endoscopic sinus procedures between 2000 and 2004 at a tertiary care children's hospital. A retrospective chart review was undertaken to obtain culture and sensitivity data of the sinus contents.

RESULTS

The most common bacteria isolated was Staphylococcus aureus (71%), followed by Pseudomonas aeruginosa (PSA) (27%), Haemophilus influenzae (21%), Staphylococcus non-aureus (16%) and Streptococcus viridans (12%). Streptococcus pneumoniae and Moraxella catarrhalis were rarely isolated (2% and 0% respectively). Twenty-nine percent of the patients with cultures positive for PSA were of the mucoid variant. Only one patient had culture positive Escherichia coli. Antibiotic resistance among the more common organisms cultured from the sinus samples is also listed.

CONCLUSION

Staph. aureus is the most common isolate in the sinuses of this pediatric CF population followed by P. aeruginosa and H. influenzae. Although many isolates are pansensitive, some isolates are panresistant.

Colonisation and infection of the paranasal sinuses in cystic fibrosis patients is accompanied by a reduced PMN response

BACKGROUND

We studied whether the sinuses might be foci for Pseudomonas aeruginosa lung infection.

METHODS

Endoscopic Sinus Surgery was performed in 78 CF patients; PFGE was used for bacterial genotyping. Material from sinuses and lungs were Gram-stained to detect biofilms. Immunoglobulins were measured in serum and saliva.

RESULTS

When P. aeruginosa was cultured simultaneously from the sinuses and the lungs they were genetically identical in 38 of the 40 patients (95%). In the sinuses, P. aeruginosa formed biofilms with minimal cellular inflammation, probably because of a significantly higher local production of secretory IgA compared with IgG (p<0.001).

CONCLUSIONS

We have shown that P. aeruginosa form biofilm in the sinuses, which constitute an important bacterial reservoir for subsequent lung infection. The high amount of IgA in the upper airways probably protects P. aeruginosa from the inflammatory immune system, and they can proceed unnoticed into a permanent infectious focus that cannot be eradicated with antibiotics.

Posttransplant sinus surgery in lung transplant recipients with cystic fibrosis: a single institutional experience

Chronic rhinosinusitis is hypothesised to play a major role in lung transplant recipients with cystic fibrosis. Paranasal sinuses are considered to accumulate a significant bacterial load, potentially leading to lung allograft infection with ensuing complications such as bronchiolitis obliterans syndrome, i.e. allograft rejection. We therefore would like to present our combined medical and surgical treatment plan, which consists of an endoscopic fronto-spheno-ethmoidectomy as well as a meticulous daily nasal care program. The microbiological results show that our combined concept is effective, whereas especially daily nasal care with isotonic saline solution is the cornerstone in preventing significant colonisation of the sinuses and spreading bacteria to the lower respiratory tract causing lung allograft infection. Regarding the surgical part of our treatment, it should be emphasised that all sinuses and ethmoidal air cells should be widely opened. Edges such as bony overhangs should be smoothened to avoid mucus retention and consecutive bacterial recolonisation requiring subsequent revision surgery.

Defective fluid secretion from submucosal glands of nasal turbinates from CFTR-/- and CFTR (ΔF508/ΔF508) pigs

Background

Cystic fibrosis (CF), caused by reduced CFTR function, includes severe sinonasal disease which may predispose to lung disease. Newly developed CF pigs provide models to study the onset of CF pathophysiology. We asked if glands from pig nasal turbinates have secretory responses similar to those of tracheal glands and if CF nasal glands show reduced fluid secretion.

Methodology/Principal Findings

Unexpectedly, we found that nasal glands differed from tracheal glands in five ways, being smaller, more numerous (density per airway surface area), more sensitive to carbachol, more sensitive to forskolin, and nonresponsive to Substance P (a potent agonist for pig tracheal glands). Nasal gland fluid secretion from newborn piglets (12 CF and 12 controls) in response to agonists was measured using digital imaging of mucus bubbles formed under oil. Secretion rates were significantly reduced in all conditions tested. Fluid secretory rates (Controls vs. CF, in pl/min/gland) were as follows: 3 µM forskolin: 9.2±2.2 vs. 0.6±0.3; 1 µM carbachol: 143.5±35.5 vs. 52.2±10.3; 3 µM forskolin + 0.1 µM carbachol: 25.8±5.8 vs. CF 4.5±0.9. We also compared CF^{ΔF508/ΔF508} with CFTR^-/- piglets and found significantly greater forskolin-stimulated secretion rates in the ΔF508 vs. the null piglets (1.4±0.8, n = 4 vs. 0.2±0.1, n = 7). An unexpected age effect was also discovered: the ratio of secretion to 3 µM forskolin vs. 1 µM carbachol was ∼4 times greater in adult than in neonatal nasal glands.

Conclusions/Significance

These findings reveal differences between nasal and tracheal glands, show defective fluid secretion in nasal glands of CF pigs, reveal some spared function in the ΔF508 vs. null piglets, and show unexpected age-dependent differences. Reduced nasal gland fluid secretion may predispose to sinonasal and lung infections.

Marked increase in incidence of Achromobacter xylosoxidans infections caused by sporadic acquisition from the environment

BACKGROUND

An increased incidence of Achromobacter xylosoxidans infections has been observed at the Cystic Fibrosis Centre at Aarhus University Hospital, as the proportion of patients colonised with A. xylosoxidans increased from 6 to 10% from 2005 to 2009.

METHODS

Pulsed field gel electrophoresis (PFGE) was used to type isolates of A. xylosoxidans.

RESULTS

Four patients infected for 2-7 years were part of a larger epidemic spread involving both Danish CF centres, while 11 patients carried strains with unique genotypes. Longitudinal analysis of isolates from ten patients with multiple preserved isolates showed that each patient persistently carried isolates of a single genotype. Following lung transplantation, two patients showed re-colonisation of the lung grafts with the pre-transplant A. xylosoxidans strain.

CONCLUSIONS

A. xylosoxidans has been transmitted between patients from our clinic, but the recent increase in incidence is not caused by cross infections.