T. Pressler

Early aggressive eradication therapy for intermittent Pseudomonas aeruginosa airway colonization in cystic fibrosis patients: 15 years experience.

BACKGROUND Since 1989, CF-patients intermittently colonized with Pseudomonas aeruginosa have been treated with inhaled colistin and oral ciprofloxacin in the Copenhagen CF-centre. The study evaluates 15 years results of this treatment. METHODS All isolates of P. aeruginosa from CF-patients intermittently colonized with P. aeruginosa from 1989 to 2003 were identified All anti-P. aeruginosa treatments were evaluated for antibiotics used, treatment duration, pseudomonas-free interval and development of chronic infection. All P. aeruginosa isolates were assessed for resistance and for non-mucoid or mucoid phenotype. RESULTS 146 CF-patients were included in the study (1106 patient-years). 99 patients had first ever isolate during the study period. Median observation time 7 years (0.1-14.9). 12 patients developed chronic infection. A Kaplan Meyer plot showed protection from chronic infection in up to 80% of patients for up to 15 years. 613 colistin/ciprofloxacin treatments were given. There was no difference in pseudomonas-free interval comparing 3 weeks (5 months) and 3 months (10.4 months) of colistin and ciprofloxacin, but a significant difference compared to no treatment (1.9 months). Patients developing chronic infection had significantly shorter pseudomonas-free interval after treatment of first ever isolate compared to patients remaining intermittently colonized (p<0.003). Treatment failure (P. aeruginosa-positive culture immediately after ended treatment of first ever isolate) was a strong risk factor for development of chronic infection after 3-4 years, OR 5.8. 1093 pseudomonas-isolates were evaluated (86.6% non-mucoid). No colistin-resistance was found. Ciprofloxacin-resistance was found in 4% of isolates. CONCLUSION Treatment of intermittent P. aeruginosa colonization in CF-patients using colistin and ciprofloxacin can protect up to 80% of patients from development of chronic infection for up to 15 years. A positive culture immediately after treatment of first ever isolate is a strong risk factor for development of chronic infection. We found no colistin-resistance and minimal ciprofloxacin-resistance.

Inflammation in Achromobacter xylosoxidans infected cystic fibrosis patients

BACKGROUND Achromobacter xylosoxidans infection may cause conspicuous chronic pulmonary inflammation in cystic fibrosis (CF) patients similar to Pseudomonas aeruginosa and the Burkholderia cepacia complex (Bcc). Evolution in lung function was compared in chronically infected patients. Cytokine concentrations in CF patients with and without chronic infection were compared to healthy controls. METHODS Cytokines in serum and sputum were measured using multiplex bead based immunoassay. RESULTS Sixty CF patients, 11 with A. xylosoxidans, 11 with Bcc, 21 with P. aeruginosa and 17 non-infected CF patients were compared to 11 healthy controls. A. xylosoxidans patients were younger, but had a FEV(1) decline similar to P. aeruginosa patients. Bcc patients had the steepest decline in FEV(1). Serum levels of G-CSF, IL-6 and TNF-alpha were significantly higher in CF patients compared to healthy controls. Chronically infected CF patients had significantly higher serum levels of IFN-gamma and IL-6 compared to non-infected CF patients. Bcc patients had significantly lower serum G-CSF and A. xylosoxidans patients had significantly higher sputum TNF-alpha compared to the other groups of chronically infected patients. CONCLUSION A. xylosoxidans can cause a level of inflammation similar to P. aeruginosa in chronically infected CF patients. A. xylosoxidans is a clinically important pathogen in CF and should be treated accordingly.

Chronic Pseudomonas aeruginosa infection definition: EuroCareCF Working Group report

Chronic pulmonary infection with P. aeruginosa develops in most patients with cystic fibrosis (CF); by adulthood 80% of patients are infected and chronic P. aeruginosa infection is the primary cause of increased morbidity and mortality in CF. Chronic infection is preceded by an intermittent stage of infection. The initial stage is characteristically followed by the gradual emergence of mucoid variants of the colonizing strains and a rise in anti-Pseudomonas antibodies. In addition to optimizing existing therapeutic strategies, effective new agents need to be identified. Studies in patients with CF are particularly challenging: the progressive nature of the disease and the wide variation in severity influence considerably the outcome of drug testing. A validated, universally accepted, and clinically useful classification of patients infected with P. aeruginosa, particularly those chronically infected, is needed that can be used as both a criterion for patient selection for clinical trials and as a study endpoint.

Nitrous oxide production in sputum from cystic fibrosis patients with chronic Pseudomonas aeruginosa lung infection

Chronic lung infection by Pseudomonas aeruginosa is the major severe complication in cystic fibrosis (CF) patients, where P. aeruginosa persists and grows in biofilms in the endobronchial mucus under hypoxic conditions. Numerous polymorphonuclear leukocytes (PMNs) surround the biofilms and create local anoxia by consuming the majority of O2 for production of reactive oxygen species (ROS). We hypothesized that P. aeruginosa acquires energy for growth in anaerobic endobronchial mucus by denitrification, which can be demonstrated by production of nitrous oxide (N2O), an intermediate in the denitrification pathway. We measured N2O and O2 with electrochemical microsensors in 8 freshly expectorated sputum samples from 7 CF patients with chronic P. aeruginosa infection. The concentrations of NO3 − and NO2 − in sputum were estimated by the Griess reagent. We found a maximum median concentration of 41.8 µM N2O (range 1.4–157.9 µM N2O). The concentration of N2O in the sputum was higher below the oxygenated layers. In 4 samples the N2O concentration increased during the initial 6 h of measurements before decreasing for approximately 6 h. Concomitantly, the concentration of NO3 − decreased in sputum during 24 hours of incubation. We demonstrate for the first time production of N2O in clinical material from infected human airways indicating pathogenic metabolism based on denitrification. Therefore, P. aeruginosa may acquire energy for growth by denitrification in anoxic endobronchial mucus in CF patients. Such ability for anaerobic growth may be a hitherto ignored key aspect of chronic P. aeruginosa infections that can inform new strategies for treatment and prevention.

Long-term, low-dose azithromycin treatment reduces the incidence but increases macrolide resistance in Staphylococcus aureus in Danish CF patients

BACKGROUND Since 2001, long-term, low-dose azithromycin treatment has been used for CF patients chronically infected with Pseudomonas aeruginosa in the Copenhagen CF centre. Our study investigates changes in incidence of colonization with Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis and changes in macrolide sensitivity in these microorganisms during azithromycin treatment. METHODS CF patients treated continuously with azithromycin for at least 3 months were included. Results of microbiological examination, including phage typing results of S. aureus, obtained during treatment were compared to results obtained 2 years before treatment. RESULTS 70 patients (median age 29.1 years) treated for a median of 4 years (range 0.7-5.1) were included. Before treatment, 44 patients had at least one culture positive for S. aureus compared to 25 patients during treatment (p<0.01). Mean percentage of sputum samples with growth of S. aureus decreased from 12.1% (range 0-82.6%) before treatment to 6.1% (range 0-93.2) during treatment (p<0.0006). Prevalences of H. influenzae and S. pneumoniae also decreased significantly. Fifteen of 214 isolates (7%) of S. aureus were macrolide resistant before treatment, increasing to 95 of 181 isolates (52.5%) during treatment (p<0.001). Macrolide resistant strains were found in 3 of 44 S. aureus colonized patients before treatment and in 11 of 25 patients at some time during treatment (p<0.03), all belonging to different phage types. First resistant S. aureus isolate was isolated after a median treatment duration of 1.5 years (range 0.3-2.9). No MRSA were isolated. Only 1 macrolide resistant isolate of M. catarrhalis was found during treatment. No macrolide resistance was found in H. influenzae or S. pneumoniae. CONCLUSION Long-term, low-dose treatment with azithromycin in CF patients leads to reduced prevalence of S. aureus, S. pneumoniae, and H. influenzae, but increased macrolide resistance in S. aureus. Reduction in the prevalence of S. aureus will make increasing macrolide resistance clinically insignificant in these patients.

IgG subclass antibodies to Pseudomonas aeruginosa in sera from patients with chronic Ps. aeruginosa infection investigated by ELISA

ELISAs using subclass‐specific monoclonal antibodies were developed for the quantification of human IgGl, IgG2, IgG3 and IgG4 antibodies to Ps. aeruginosa. We investigated the pattern of IgG subclass antibodies against Ps. aeruginosa in serum from patients with cystic fibrosis (CF). other patients with chronic Ps. aeruginosa infection, and healthy controls. Healthy controls and patients with CF but without Ps. aeruginosa infection showed no or very low litres of antibodies against Ps. aeruginosa. In the early stage of chronic Ps. aeruginosa infection, antibody litres in all four subclasses were significantly higher than either normals or CF patients without infection. Other patients with Ps. aeruginosa infection showed the same increased level of IgG subclass antibodies as CF patients in an early stage of infection. Sixteen patients (eight in good and eight in poor clinical condition) have been followed for an average of 13 years with multiple serum samples covering the pre‐infection, early and late stages of chronic infection. Patients in a poor clinical condition showed significantly higher levels of IgG3 antibodies in the first year of infection and 2 years later also had significantly higher IgG2 antibody levels. We conclude that elevated levels of IgG2 and lgG3 antibodies to Ps. aeruginosa are a sign of poor prognosis in CF.

Nontuberculous Mycobacterial Disease Is Not a Contraindication to Lung Transplantation in Patients With Cystic Fibrosis: A Retrospective Analysis in a Danish Patient Population

Whether nontuberculous mycobacterial (NTM) disease is a contraindication to lung transplantation remains controversial. We conducted a nationwide study to evaluate the clinical importance of NTM infection among lung transplant patients with cystic fibrosis (CF) in Denmark and to determine if NTM infection poses a contraindication to lung transplantation. All CF patients with current or prior NTM who had undergone lung transplantation were identified. Out of 52 lung transplant patients with CF 9 (17%) had NTM disease. Five patients had known infection at the time of transplantation. Two of these died of non-NTM-related causes whereas two developed deep Mycobacterium abscessus wound infections and one was transiently culture negative until M abscessus was reactivated. One patient was subsequently cured; the other two remained on therapy with good performance status. The study supports the contention that CF patients with prior or active NTM can undergo lung transplantation although postoperative complications can be expected.

Does Centralized Treatment of Cystic Fibrosis Increase the Risk of Pseudomonas aeruginosa Infection

ABSTRACT. Two hundred and forty Danish patients with cystic fibrosis (97% of the total CF population in Denmark) participated in a point‐prevalence study of Pseudomonas aeruginosa infection. One hundred and ninety‐two patients were treated at the Danish CF centre and 48 patients were treated in other places. The age distribution was significantly different as no patients older than 19 years were found in the non‐centre group. Pathogenic bacteria were isolated from the sputum of 96% of the patients. P. aeruginosa was more prevalent in patients from the centre, whereas Staphylococcus aureus was more prevalent in the non‐centre group. No difference in serogroup and phage pattern of P. aeruginosa was found. There was a tendency that non‐centre treated patients acquired chronic broncho‐pulmonary P. aeruginosa infection later, but at the age of 16 years 90% of all patients will be chronically infected. Chronic P. aeruginosa infection was significantly more common in the age group 10‐14 years at the centre than outside the centre. It is not possible to prevent chronic P. aeruginosa infection in CF patients treated in small groups and because of the better prognosis of centralized treatment the latter must be recommended.

Increased IgG2 and IgG3 Concentration Is Associated with Advanced Pseudomonas Aeruginosa Infection and Poor Pulmonary Function in Cystic Fibrosis

ABSTRACT. The concentrations of IgG subclass immunoglobulins were determined by radial immunodiffusion in serum from 126 patients with cystic fibrosis (CF). The results were compared to values from age‐matched healthy children and adults and correlated to patients age, duration of chronic Pseudomonas aeruginosa infection and lung function parameters. Fifty‐two percent of the patients had an elevated concentration of at least one of the IgG subclasses; IgG1 28%, IgG2 16%, IgG3 18% and IgG4 48%. There was significant correlation between elevated serum levels of IgG2, and to a lesser extent IgG3, with decreased lung function (for FEV1; p=0.0001, and p=0.001 respectively) and high levels of antipseudomonas precipitins (p=0.008, and p=0.002). A similar correlation was not found for IgG1 and IgG4. IgG subclasses vary in their ability to promote phagocytosis and to activate complement and it is possible that individual differences in the IgG subclass pattern could explain the variable course of this disease.

Early treatment with inhaled antibiotics postpones next occurrence of Achromobacter in cystic fibrosis

OBJECTIVES In this nationwide retrospective study, we analysed species distribution, antimicrobial susceptibility and time to next occurrence of Achromobacter in Danish cystic fibrosis (CF) patients from 2000 to 2011. METHODS Thirty-four primary isolates were identified to species level and subjected to antimicrobial susceptibility testing. Effectiveness of early antimicrobial treatment was assessed by a Kaplan-Meier estimation of time to recurrence. RESULTS Achromobacter xylosoxidans accounted for 13 (38%) of the isolates, and an unnamed species accounted for 11 (32%) of the isolates. Meropenem, piperacillin-tazobactam and trimethoprim-sulfamethoxazole were highly active against chemotherapy-naïve Achromobacter, while ceftazidime, colistin and tobramycin were judged adequate for inhalation therapy. Fifty-five percent of 25 patients treated with inhaled ceftazidime, colistin, or tobramycin remained free of Achromobacter three years after acquisition, in contrast to 17% of 22 patients who did not receive inhaled antibiotics (P<0.01). CONCLUSIONS Early treatment with inhaled antibiotics may prevent or postpone chronic infection with Achromobacter in CF patients.