Are lower airway or throat cultures predictive of sinus bacteriology in cystic fibrosis?

Abstract

The choice of antibiotics for sinusitis in children with cystic fibrosis (CF) is empirical or based on lower airway cultures, because sinus cultures are difficult to obtain. The aim of this study was to identify the main organisms cultured from CF children with chronic sinusitis, and to evaluate the concordance of concomitant sinus, oropharyngeal swab (OP), and bronchoalveolar lavage fluid (BALF) cultures. OP and BALF cultures were done preoperatively, and sinus cultures were obtained during clinically indicated sinus surgery. The genetic identity of the bacteria was compared if the same organisms were present in upper and lower airway cultures. In total, 45 paired sinus-BALF cultures from 31 patients were included. Twenty-four of these had matched OP cultures. The mean age of patients was 9.5 +/- 4.3 years, and 19 patients were DeltaF508 homozygous. Bacterial sinus infection was present in 96%, caused by S. aureus (49%), P. aeruginosa (42%), and H. influenzae (22%). The diagnostic accuracy of BALF or OP cultures was low in predicting sinus infection, particularly at younger ages. Positive and negative predictive values (PPV and NPV) of BALF for P. aeruginosa infection were 65% and 67%, and for S. aureus, 76% and 63%, respectively. Predictive values for OP cultures were similar. Bacterial species were the same in sinus and OP or BALF samples of 12 patients of these bacteria 83% showed genetic identity. We conclude that S. aureus is an important pathogen in pediatric CF sinusitis, and that BALF or oropharyngeal cultures are poor predictors for organisms present in the sinuses.

Evolution and diversification of Pseudomonas aeruginosa in the paranasal sinuses of cystic fibrosis children have implications for chronic lung infection

“…In a large cohort study, almost half of the patients with a history of chronic P. aeruginosa lung infection also had an infection with the same genotype in the upper airways (Mainz et al, 2009). Identical genotypes in the sinus and bronchoalveolar lavage (lung) samples have also been recovered from one study of CF children with chronic sinusitis, and the frequency of identical genotypes increased from 9% of children up to 8 years old to 30% of children more than 8 years old (Muhlebach et al, 2006).…”

“…Our results show that the second-site colonization events in the sinuses, often being more persistent than those in the lungs, may provide extended opportunities for evolution of the bacteria towards phenotypes, with greatly increased potential of creating chronic lung infections as well. Although it has long been known that the microbiotas of the upper and lower airways are similar in chronically infected CF patients, only a small number of studies have investigated the possibility of cross-infections between the paranasal sinuses and the lungs (Dosanjh et al, 2000;Muhlebach et al, 2006;Mainz et al, 2009). In a large cohort study, almost half of the patients with a history of chronic P. aeruginosa lung infection also had an infection with the same genotype in the upper airways (Mainz et al, 2009).…”

“…Re-colonization could be either from a persistent environmental source or from an undetected reservoir in the patient upper airways such as the paranasal sinuses (Jelsbak et al, 2007). Only few reports have addressed the role of the upper airways, and these studies suggest that the paranasal sinuses can be a possible gateway and reservoir for lung infection in CF patients (Taylor et al, 1992;Dosanjh et al, 2000;Muhlebach et al, 2006;Mainz et al, 2009). The mechanism may be aspiration during sleep or when suffering from a viral infection (Huxley et al, 1978).…”

“…The fair majority of CF patients acquire a chronic bacterial sinusitis with varying degrees of symptoms (Coste et al, 1995;Gysin et al, 2000;Robertson et al, 2008). When colonization of the sinuses occurs, the microbiota of the sinuses and lower airways are quite similar, and identical genotypes of P. aeruginosa (and other pathogens) can be isolated from both sites (Dosanjh et al, 2000;Muhlebach et al, 2006;Mainz et al, 2009). Little is known about the dynamics of the interchange of P. aeruginosa between upper and lower airways in the early stages of lung disease, and the role of the sinuses in the development of chronic lung infection needs further elucidation.…”

Cystic Fibrosis Chronic Rhinosinusitis: A Comprehensive Review

“…[49][50][51][52] Muhlebach et al 53 studied lower airway and throat cultures and reported that P. aeruginosa as well S. aureus are the most common bacterial species found in CF patients. There is a higher frequency of Pseudomonas colonization in the lower airways in patients who have CRS with NPs and is more likely to start in the sinuses at a younger age and progress to involve both the upper and the lower airways.…”