Bacterial reservoirs in cystic fibrosis

A pilot study investigating the effects of a manuka honey sinus rinse compared to a standard sinus rinse on sino-nasal outcome test scores in cystic fibrosis patients

Background

People with cystic fibrosis (CF) are prone to bacterial respiratory infections; these are often antibiotic resistant, are difficult to treat, and impact on the quality of life and lung function. The upper respiratory tract can act as a reservoir for these pathogens, and as part of clinical care, sinus rinses are used to alleviate symptoms in the upper airway. We have developed a sinus rinse containing manuka honey, to identify whether it can help improve symptoms or reduce the bacterial load.

Methods

We will undertake a randomised controlled trial where 30 adults with CF will be recruited and randomised to either the control or intervention group. Both groups will follow a sinus rinse protocol for 30 days (± 7 days); the control group will use the standard of care rinse, and the intervention group will use a manuka honey rinse. Both groups will provide samples at day 0 and day 30. The primary outcome measure will be a change in the 22-item Sino-Nasal Outcome Test (SNOT-22) score. Secondary outcomes will include changes to quality of life (questionnaire), bacterial load/community composition, and sputum viscosity.

Discussion

This trial will look at the use of a manuka honey-infused sinus rinse solution on patients diagnosed with cystic fibrosis (CF) suffering with sinusitis; it will allow us to determine the efficacy of the manuka honey sinus rinse compared to standard rinse and will allow us to determine if molecular bacterial diversity analysis will provide in-depth information beyond the usual conventional microbiological. It will allow us to determine the feasibility of recruiting participants to this type of trial, allow us to check participant compliance with the protocol, and inform future studies.

Trial registration

Approval was obtained from the Research Ethics Committee Wales REC7 reference 18/WA/0319. Results of this study will be published at international conferences and in peer-reviewed journals; they will also be presented to the relevant stakeholders and research networks.

Trial registration number: ClinicalTrials.gov Identifier NCT04589897 (retrospectively registered)

Citizen-science based study of the oral microbiome in Cystic fibrosis and matched controls reveals major differences in diversity and abundance of bacterial and fungal species

Introduction: Cystic fibrosis (CF) is an autosomal genetic disease, associated with the production of excessively thick mucosa and with life-threatening chronic lung infections. The microbiota of the oral cavity can act as a reservoir or as a barrier for infectious microorganisms that can colonize the lungs. However, the specific composition of the oral microbiome in CF is poorly understood.Methods: In collaboration with CF associations in Spain, we collected oral rinse samples from 31 CF persons (age range 7-47) and matched controls, and then performed 16S rRNA metabarcoding and high-throughput sequencing, combined with culture and proteomics-based identification of fungi to survey the bacterial and fungal oral microbiome.Results: We found that CF is associated with less diverse oral microbiomes, which were characterized by higher prevalence of Candida albicans and differential abundances of a number of bacterial taxa that have implications in both the connection to lung infections in CF, as well as potential oral health concerns, particularly periodontitis and dental caries.Conclusion: Overall, our study provides a first global snapshot of the oral microbiome in CF. Future studies are required to establish the relationships between the composition of the oral and lung microbiomes in CF.

Upper Airway Findings and Markers of Lung Disease Progression in Patients with Cystic Fibrosis

Introduction  Cystic fibrosis (CF) is a genetic disease that limits the quality of life mainly due to respiratory symptoms. The relationship between findings of the upper airways and CF lung disease is not yet completely understood. Objective  The aim of the present study is to describe the most frequent nasal findings and pathogens in patients with CF and investigate the association between the findings of the upper respiratory tract and markers of lung disease progression. Methods  Retrospective study in patients with CF from the Pediatric Pulmonology Department who underwent otorhinolaryngological evaluation between 2015 and 2017. Nasal endoscopy and nasal swab collection were part of the evaluation. The severity markers used were: percentage of predicted forced expiratory volume in the first second (FEV1%), body mass index (BMI) and the Shwachman-Kulczycki (SK) clinical score. Results  A total of 48 patients with CF were included. The mean of the predicted percentage of FEV1% was 83.36 ± 30.04. The average 14 and SK score 89.11 ± 10.50. The bacteriology of the nasal swab was positive in 27 (54.1%) patients. Staphylococcus aureus was positive in 18 patients, Pseudomonas aeruginosa in 5, Pseudomonas cepacea in 3 and Stenotrophomonas maltophila in 1 patient. Nasal polyps were found in nine participants. Nasal polyps were found in nine participants and were associated with lower SK score. Conclusion  The pathogens found in the upper airway were, in order: S. aureus , P. aeruginosa , P. cepacea e S. maltophila . The presence of polyps in the nasal cavity showed statistical significance and appears to have association with the prognostic factor measured by the SK score.

Sinus bacteriology in patients with cystic fibrosis or primary ciliary dyskinesia: A systematic review

BACKGROUND

A correlation exists between the microbial flora of the upper and lower airways in patients with cystic fibrosis (CF) or with primary ciliary dyskinesia (PCD). The sinuses can function as a bacterial reservoir where gram-negative bacteria adapt to the airways and repeatedly are aspirated to and colonize the lungs according to the theory of the united (unified) airways. Whereas the pattern of bacterial flora in the lower airways has been extensively studied, the upper airways have drawn limited attention.

OBJECTIVE

Our aim was to review the literature that reported bacterial flora in the sinuses and nasal cavities of patients with CF or PCD.

METHODS

A number of medical literature data bases were systematically searched between January 1960 and July 2016. We applied the following inclusion criteria: a minimum of one case of PCD (or Kartagener syndrome) or CF, and microbiology analyses from the nose or paranasal sinuses.

RESULTS

We included 46 studies (1823 patients) from 16 countries. Staphylococcus aureus was found in 30% of the noses and sinuses of patients with CF. Other common bacteria found included Pseudomonas aeruginosa, coagulase negative staphylococci, and Haemophilus influenzae. In PCD, H. influenzae was the most common bacteria (28%), followed by Streptococcus pneumoniae and P. aeruginosa. If studies that included nonsurgical swab and blowing samples were excluded, then P. aeruginosa was the most common bacterium in patients with CF (34%) and in patients with PCD (50%), followed by S. aureus and H. influenza.

CONCLUSION

S. aureus, P. aeruginosa, coagulase negative staphylococci, and H. influenzae dominated in the upper airways of patients with CF. In patients with PCD, H. influenzae, S. pneumoniae, and P. aeruginosa dominated. When studies that included swab and blowing samples were excluded, P. aeruginosa was the most common bacterium in both groups. Direct comparisons among the studies were restricted due to very heterogeneous methods, and a better standardization of procedures and outcomes is needed.

Clinical implications of Pseudomonas aeruginosa location in the lungs of patients with cystic fibrosis

WHAT IS KNOWN AND OBJECTIVE

Pseudomonas aeruginosa is the leading cause of lung infection in patients with cystic fibrosis (CF) and is associated with significant morbidity and mortality. Antibiotics are regarded as the foundational pharmacological treatment for the suppressive management of chronic P. aeruginosa infections and to eradicate the first infection by P. aeruginosa. Inhalation remains a preferred route for drug administration, providing direct access to the site of infection while minimizing systemic side effects. Effective suppressive management of P. aeruginosa infections, however, requires an understanding of the location of the bacteria in the lungs and consideration of the factors that could limit access of the inhaled antibiotic to the infected area. This review provides a systematic assessment of the scientific literature to gain insight into the location of P. aeruginosa in the lungs of patients with CF and its clinical implications. The characteristics of antibiotic inhalation systems are also discussed in this context.

METHODS

We reviewed evidence-based literature from both human and animal studies in which P. aeruginosa lung location was reported. Relevant publications were identified through a screening strategy and summarized by reported P. aeruginosa location.

RESULTS AND DISCUSSION

Most areas of the conductive and respiratory zones of the lungs are susceptible to P. aeruginosa colonization. Deposition of an inhaled antibiotic is dependent on the device and formulation characteristics, as well as the ability of the patient to generate sufficient inhaled volume. As patients with CF often experience a decline in lung function, the challenge is to ensure that the inhaled antibiotic can be delivered throughout the bronchial tree.

WHAT IS NEW AND CONCLUSION

An effective drug delivery system that can target P. aeruginosa in both the respiratory and conductive zones is required. The chosen inhalation device should also offer a drug formulation that can be quickly and effectively delivered to specific lung locations, with minimal inspiratory effort from the patient.

Acquisition and adaptation of the airway microbiota in the early life of cystic fibrosis patients

Cystic fibrosis (CF) is a genetic disease in which bacterial infections of the airways play a major role in the long-term clinical outcome. In recent years, a number of next-generation sequencing (NGS)-based studies aimed at deciphering the structure and composition of the airways’ microbiota. It was shown that the nasal cavity of CF patients displays dysbiosis early in life indicating a failure in the first establishment of a healthy microbiota. In contrast, within the conducting and lower airways, the establishment occurs normally first, but is sensitive to future dysbiosis including chronic infections with classical pathogens in later life. The objective of this mini-review is to give an update on the current knowledge about the development of the microbiota in the early life of CF patients. Microbial acquisition in the human airways can be described by the island model: Microbes found in the lower airways of CF patients represent “islands” that are at first populated from the upper airways reflecting the “mainland.” Colonization can be modeled following the neutral theory in which the most abundant bacteria in the mainland are also frequently found in the lower airways initially. At later times, however, the colonization process of the lower airways segregates by active selection of specific microbes. Future research should focus on those processes of microbial and host interactions to understand how microbial communities are shaped on short- and long-term scales. We point out what therapeutic consequences arise from the microbiome data obtained within ecological framework models.

Bronchiectasis in Children: Current Concepts in Immunology and Microbiology

Bronchiectasis is a complex chronic respiratory condition traditionally characterized by chronic infection, airway inflammation, and progressive decline in lung function. Early diagnosis and intensive treatment protocols can stabilize or even improve the clinical prognosis of children with bronchiectasis. However, understanding the host immunologic mechanisms that contribute to recurrent infection and prolonged inflammation has been identified as an important area of research that would contribute substantially to effective prevention strategies for children at risk of bronchiectasis. This review will focus on the current understanding of the role of the host immune response and important pathogens in the pathogenesis of bronchiectasis (not associated with cystic fibrosis) in children.

Infection Transmission by Saliva and the Paradoxical Protective Role of Saliva

Saliva is produced by both major (parotid and submandibular and sublingual) and minor (located in the mouth) glands, with different constituents and properties between the two groups. In the mouth saliva is a colorless, odorless, tasteless, watery liquid containing 99% water and 1% organic and inorganic substances and dissolved gases, mainly oxygen and carbon dioxide. Salivary constituents can be grouped into proteins (e.g., amylase and lysozyme), organic molecules (e.g., urea, lipids, and glucose mainly), and electrolytes (e.g., sodium, calcium, chlorine, and phosphates). Cellular elements such as epithelial cells, leukocytes and various hormones, and vitamins have also been detected. The composition of saliva is modified, depending on factors such as secreted amount, circadian rhythm, duration and nature of stimuli, diet, and medication intake, among others.

A case of failed eradication of cystic fibrosis-related sinus colonisation by Pseudomonas aeruginosa

BACKGROUND

Pseudomonas aeruginosa is a pathogen associated with cystic fibrosis that has potential to decrease lung function and cause respiratory failure. Paranasal sinuses are increasingly recognised as potential reservoirs for intermittent colonisation by P. aeruginosa. This case documents investigation and outcome of P. aeruginosa recurrence in a male paediatric patient over an eight year period.

CASE PRESENTATION

A 12 year old Irish male paediatric cystic fibrosis patient experienced intermittent culturing of P. aeruginosa from the oropharyngeal region, indicating chronic infection of the sinuses despite absence of symptoms, retaining good lung function, and normal bronchoscopy and bronchoalveolar lavage. However, P. aeruginosa was isolated from a sinus wash-out and was identified as a unique strain of P. aeruginosa that was also cultured from cough swabs. Despite treatment, successful eradication from the paranasal sinuses was not achieved.

CONCLUSIONS

Few reports have addressed the paranasal sinuses as a reservoir for lung infection in cystic fibrosis patients despite increased recognition of the need to investigate this niche. In this case, attempts at eradication of P. aeruginosa present in paranasal sinuses including oral and nebulised antimicrobials proved unsuccessful. However, detection of P. aeruginosa in the paranasal sinuses instigated antimicrobial treatment which may have contributed to prevention of migration to the lower airways. Our outcome provides additional insight and may indicate utility of nasal lavage or nasal endoscopy in paediatric cystic fibrosis patients' annual review clinic visits.

Pseudomonas aeruginosa and Periodontal Pathogens in the Oral Cavity and Lungs of Cystic Fibrosis Patients: a Case-Control Study

Cystic fibrosis (CF) is the most frequent lethal genetic disease in the Caucasian population. Lung destruction is the principal cause of death by chronic Pseudomonas aeruginosa colonization. There is a high prevalence of oropharyngeal anaerobic bacteria in sputum of CF patients. This study was carried out due to the lack of results comparing subgingival periodontal pathogenic bacteria between the oral cavity and lungs in patients with CF in relation with P. aeruginosa presence. Our first goal was to detect P. aeruginosa in oral and sputum samples by culture and molecular methods and to determine clonality of isolates. In addition, subgingival periodontal anaerobic bacteria were searched for in sputum. A cross-sectional pilot case-control study was conducted in the CF Reference Center in Roscoff, France. Ten CF patients with a ΔF508 homozygous mutation (5 chronically colonized [CC] and 5 not colonized [NC]) were enrolled. P. aeruginosa was detected in saliva, sputum, and subgingival plaque samples by real-time quantitative PCR (qPCR). Subsequently, periodontal bacteria were also detected and quantified in subgingival plaque and sputum samples by qPCR. In CC patients, P. aeruginosa was recovered in saliva and subgingival plaque samples. Sixteen P. aeruginosa strains were isolated in saliva and sputum from this group and compared by pulsed-field gel electrophoresis (PFGE). Subgingival periodontal anaerobic bacteria were found in sputum samples. A lower diversity of these species was recovered in the CC patients than in the NC patients. The presence of the same P. aeruginosa clonal types in saliva and sputum samples underlines that the oral cavity is a possible reservoir for lung infection.

Upper aero-digestive contamination by Pseudomonas aeruginosa and implications in Cystic Fibrosis

BACKGROUND

Cystic Fibrosis (CF) is a severe genetic disorder that is common among the Caucasian population. Bacterial respiratory infections are the main cause of morbidity and mortality in CF patients. Pseudomonas aeruginosa is the main pathogen of lower airways (LAW) decline.

METHOD

To understand chronic broncho-pulmonary colonization, a systematic review is conducted. The aim of our article is to identify the pathways of contamination in the upper aero-digestive tract.

RESULTS

A large number of articles report that P. aeruginosa is established first at nasopharyngeal sites. The vast majority of authors agree that the upper aero-digestive tract is the first location of colonization by P. aeruginosa and its presence appears to be predictive of subsequent broncho-pulmonary colonization.

CONCLUSION

This review supports the possible involvement of the nasal and paranasal sinuses and oral cavity as means of contamination.

Staphylococcus aureus in early cystic fibrosis lung disease

Staphylococcus aureus: is a common bacterial organism infecting children with cystic fibrosis (CF). Emerging evidence suggests early lower airway infection with this organism in young children with CF results in the deterioration of lung function, poorer nutrition parameters and heightens the airway inflammatory response. Despite contributing significantly to the burden of early lung disease among this group, there are ongoing controversies in the management of S. aureus infection, and gaps in our understanding of exactly how this organism causes lung disease. To reduce the morbidity and mortality of early infection ongoing research is needed to: (i) understand the early host immune response that enables this pathogen to reside within the CF lung; (ii) determine if there are organism specific factors that are associated with CF lung disease; and (iii) clarify the utility of anti-staphylococcal antibiotic prophylaxis and/or eradication in the treatment of this patient population.

New insights into the pathogenesis of cystic fibrosis sinusitis

BACKGROUND

People with cystic fibrosis (CF) sinus disease have developmental sinus abnormalities with airway bacterial infection, inflammation, impaired mucociliary clearance and thick obstructive mucus. The pathophysiology of airway disease in CF is not completely understood, and current treatments in CF sinus disease ameliorate symptoms but do not provide a cure.

METHODS

This manuscript reviews the history of CF, its manifestations in sinus disease, and the potential impact and relationship of CF on the upper and lower airway.

RESULTS

There is increasing evidence that CF sinus disease may affect CF lung disease, the most common cause of mortality in CF. We have been limited in treating the symptoms of advanced CF sinus disease with our current therapies.

CONCLUSIONS

Recent discoveries in the pathophysiology of CF using the CF porcine animal model and exciting treatments that address the primary gene defect that may translate into improved outcomes in CF and non-CF sinusitis in humans.

Alpha-AP-2 directs myosin VI-dependent endocytosis of cystic fibrosis transmembrane conductance regulator chloride channels in the intestine

The actin motor myosin VI regulates endocytosis of cystic fibrosis transmembrane conductance regulator (CFTR) in the intestine, but the endocytic adaptor linking CFTR to myosin VI is unknown. Dab2 (Disabled 2) is the binding partner for myosin VI, clathrin, and alpha-AP-2 and directs endocytosis of low density lipoprotein receptor family members by recognizing a phosphotyrosine-binding domain. However, CFTR does not possess a phosphotyrosine-binding domain. We examined whether alpha-AP-2 and/or Dab2 were binding partners for CFTR and the role of myosin VI in localizing endocytic adaptors in the intestine. CFTR co-localized with alpha-AP-2, Dab2, and myosin VI and was identified in a complex with all three endocytic proteins in the intestine. Apical CFTR was increased in the intestines of Dab-2 KO mice, suggesting its involvement in regulating surface CFTR. Glutathione S-transferase pulldown assays revealed binding of CFTR to alpha-AP-2 (but not Dab2) in the intestine, whereas Dab-2 interacted with alpha-AP-2. siRNA silencing of alpha-AP-2 in cells significantly reduced CFTR endocytosis, further supporting alpha-AP-2 as the direct binding partner for CFTR. alpha-AP-2 and Dab2 localized to the terminal web regions of enterocytes, but Dab2 accumulated in this location in Snell's Waltzer myosin VI((sv/sv)) intestine. Ultrastructural examination revealed that the accumulation of Dab2 correlated with prominent involution and the loss of normal positioning of the intermicrovillar membranes that resulted in expansion of the terminal web region in myosin VI((sv/sv)) enterocytes. The findings support alpha-AP-2 in directing myosin VI-dependent endocytosis of CFTR and a requirement for myosin VI in membrane invagination and coated pit formation in enterocytes.

Upper and lower airway cultures in children with cystic fibrosis: do not neglect the upper airways

BACKGROUND

Airways of cystic fibrosis (CF) patients are colonised with bacteria early in life. We aimed to analyse differences between results of simultaneously taken upper airway (UAW) and lower airway (LAW) cultures, to describe clinical characteristics of patients with positive versus negative cultures and to follow up the patients with P. aeruginosa positive UAW cultures.

METHODS

Bacteriological and clinical data from 157 children were collected during annual check up. The number of positive UAW and LAW cultures and correspondence between these results and clinical characteristics were analysed.

RESULTS

Positive LAW and UAW cultures were found in 79.6% and 43.9% of patients respectively (p<0.001). Patients with positive LAW cultures were significantly older (11.9 vs. 9.8years, p<0.05) and had more LAW symptoms (73.6% vs. 46.7%, p<0.05), especially when P. aeruginosa was found. Patients with positive UAW cultures (especially S. aureus) had more nasal discharge (50.7% vs. 25.0%, p<0.001). In 65% of patients with positive UAW and negative LAW culture for P. aeruginosa the next LAW became P. aeruginosa positive.

CONCLUSION

UAW cultures and LAW cultures differ in children with CF and there are differences in clinical characteristics between patients with positive versus negative culture results. P. aeruginosa positive UAW cultures appeared to precede positive LAW cultures in a substantial part of patients, suggesting some kind of cross-infection between the UAW and LAW.

Reducing the risk: the use of placebo respiratory equipment in clinical practice

Placebo respiratory devices, such as inhalers, large volume spacers and peak flow meters provide reli able methods of teaching patients effective drug able methods of teaching patients effective drug delivery techniques and monitoring compliance and treatment progress. Concern has been raised that using such demonstration devices on more than one person may expose patients to the risk of cross-infection with pathogenic organisms. The lack of regulation and guidance on the use and decontamination of placebo devices prompted us to complete a risk assessment, examining the likelihood and consequence of acquisition of pathogens and resultant illness in our respiratory patient group.

Disease surveillance using bronchoalveolar lavage

The role of pulmonary infection and inflammation in the pathogenesis of destructive lung disease in cystic fibrosis (CF) is undisputed. The use of bronchoscopy and bronchoalveolar lavage (BAL) has demonstrated that these processes may begin early in life and be present in the absence of overt clinical symptoms. Some children diagnosed following newborn screening can be infected with Pseudomonas aeruginosa in infancy. Studies using BAL have demonstrated a relationship between lower airway inflammation and bacterial load in the lungs; however, inflammation may occur in the absence of obvious current infection. BAL has the potential to provide a greater understanding of the pathogenesis of CF lung disease and microbiological surveillance provides the opportunity for early detection and eradication of P. aeruginosa. Lack of standardization inhibits the ability to compare data from different centres and to optimize treatment strategies. This review discusses the recommendations from a workshop held in early 2007 aimed at achieving a standardized approach to BAL in infants and young children with CF.

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

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.

Complementary role of MR imaging of ethmomaxillary sinus disease depicted at CT in cystic fibrosis

PURPOSE

To assess whether MR imaging can improve characterization of ethmomaxillary opacification diagnosed at CT in patients with cystic fibrosis (CF) in order to select patients that may benefit from functional endoscopic sinus surgery (FESS).

MATERIAL AND METHODS

Sixty-two CF patients (26 females and 36 males) aged 4-50 years (median 20 years) with ethmomaxillary sinus disease at CT underwent MR examination of the paranasal sinuses (coronal T1 and STIR sequences). FESS had been performed in 28 of the patients prior to this study. MR signal intensities were interpreted as mucosal thickening or infectious material, according to a previous study.

RESULTS

Three major maxillary sinus MR patterns could be distinguished: Air-filled, oval-shaped pus-filled, and streaky-shaped pus-filled sinus lumen. For air-filled maxillary sinuses with mucosal thickening, CT and MR imaging were diagnostically equivalent. Where CT showed homogeneous opacification of the maxillary sinuses, MR imaging differentiated between thickened mucosa and pus-filled areas. Patients who had undergone FESS most commonly had air-filled or streaky-shaped pus-filled maxillary sinus lumen. In non-operated patients oval-shaped pus-filled sinus lumen was most common and could occur without ethmoid disease.

CONCLUSION

MR imaging of the paranasal sinuses can differentiate between infectious material and thickened mucosa and should be used to select CF patients with pus-filled areas that can be eradicated with FESS.

Epidemiology of chronic Pseudomonas aeruginosa infections in the airways of lung transplant recipients with cystic fibrosis

BACKGROUND

The source of airway colonisation with Pseudomonas aeruginosa is not well defined in patients with cystic fibrosis after lung transplantation. Using a DNA-based typing system a study was undertaken to investigate whether lung transplant recipients acquired new strains of P aeruginosa or retained those they had before transplantation.

METHODS

Seventy four P aeruginosa isolates taken before and after transplantation were analysed from 11 patients with cystic fibrosis who had undergone lung transplantation in the Medical School of Hannover between 1988 and 1994. The genetic relatedness of the 74 P aeruginosa strains was evaluated from macrorestriction fragment pattern similarity.

RESULTS

Each of the 11 lung transplant recipients harboured one identical P aeruginosa clone before and after transplantation. The airways of four of the 11 patients were preoperatively colonised by two or three different clones, but six months after transplantation only one clone was detectable.

CONCLUSIONS

These results show that there is no change in the P aeruginosa population in the airways of lung transplant recipients before and after transplantation and it is assumed that the chronic drainage of P aeruginosa into the lung allografts is caused by the bacterial reservoir in the paranasal sinuses and the trachea.

Extrapulmonary sites of Pseudomonas aeruginosa in adults with cystic fibrosis

BACKGROUND

Pseudomonas aeruginosa infection is seldom eradicated in patients with cystic fibrosis despite intensive antipseudomonal treatment. Upper airway sites of infection may contribute to perpetuation of lower airways infection. This study was designed to find out which extrapulmonary sites are infected and whether the strains at these sites are identical to those in the lungs.

METHODS

Sputum and upper airway samples from 42 patients were cultured for P aeruginosa and stool samples from 20 patients were also tested. Nineteen isolates from sputum and extrapulmonary sites from four patients were genotyped with the pCM tox probe.

RESULTS

P aeruginosa was isolated from the sputum of 36 patients, 34 of whom had infection in the upper airways. Six of the 20 patients tested were positive for P aeruginosa in the stool. The nasopharynx was colonised in 30 patients, the oropharynx in 29, the middle meatus in 13, the external nares in six, and the inferior turbinate in four. Three of four patients tested had the same strain of P aeruginosa (a different one in each individual) in the sputum and the upper airways, and in two of the three the stool isolate was a different strain.

CONCLUSION

Most adults with cystic fibrosis and P aeruginosa pulmonary infection have upper airway reservoirs of the organism and strains from these sites are identical to those in the lungs.