Long-Term Benefits of Inhaled Tobramycin in Children with Cystic Fibrosis: First Clinical Observations from Poland

Factors related to changes in the quality of life among Polish adolescents and adults with cystic fibrosis over a 1-year period

BACKGROUND

The aim of this study was to determine the effects of clinical factors, physical activity, and sociodemographic variables on 1-year changes in health-related quality of life (HRQoL) in Polish adolescents and adults with cystic fibrosis (CF).

METHOD

The study included 67 subjects with CF (mean age 21.1±5.1 years; range 14-37 years; 34 males and 33 females). The Cystic Fibrosis Quality of Life Questionnaire was used at baseline and after 1 year. Lung function data, body weight, and body height were extracted from medical records. Clinical assessment was performed with the Shwachman-Kulczycki scale.

RESULTS

The highest scores in both HRQoL examinations came from the domains of physical and social functioning, and the lowest from future concerns, body image, and career concerns. No significant changes of Cystic Fibrosis Quality of Life Questionnaire scores were documented over a period of 1 year. Patients with better baseline spirometry results more frequently reported an improvement in the treatment issues (subjects with FEV1 >50% of predicted, P=0.020) and in the career concerns (patients with FVC >50% of predicted, P=0.039). The improvement in the career concerns also depended upon daily physical activity (P=0.024), which was shown to modulate future concerns (P=0.032), along with place of residence and living conditions (P=0.003). Moreover, the time elapsed from the last pulmonary exacerbation was related to the change in social functioning (P=0.026).

CONCLUSION

When planning treatment, attention should be paid to interventions which may improve HRQoL. Systematic chronic therapy improves lung function, related to treatment issues and career concerns. Maintaining good physical condition and activity may positively influence future and career concerns. Special attention must be devoted to patients living in rural areas and enduring difficult living conditions, as they are especially vulnerable to deterioration in future concerns.

Treatment of pseudomonas and Staphylococcus bronchopulmonary infection in patients with cystic fibrosis

The optimal antibiotic regimen is unclear in management of pulmonary infections due to pseudomonas and staphylococcus in cystic fibrosis (CF). We systematically searched all the published literature that has considered the evidence for antimicrobial therapies in CF till June 2013. The key findings were as follows: inhaled antipseudomonal antibiotic improves lung function, and probably the safest/most effective therapy; antistaphylococcal antibiotic prophylaxis increases the risk of acquiring P. aeruginosa; azithromycin significantly improves respiratory function after 6 months of treatment; a 28-day treatment with aztreonam or tobramycin significantly improves respiratory symptoms and pulmonary function; aztreonam lysine might be superior to tobramycin inhaled solution in chronic P. aeruginosa infection; oral ciprofloxacin does not produce additional benefit in those with chronic persistent pseudomonas infection but may have a role in early or first infection. As it is difficult to establish a firm recommendation based on the available evidence, the following factors must be considered for the choice of treatment for each patient: antibiotic related (e.g., safety and efficacy and ease of administration/delivery) and patient related (e.g., age, clinical status, prior use of antibiotics, coinfection by other organisms, and associated comorbidities ones).

Clinical experimentation with aerosol antibiotics: current and future methods of administration

Currently almost all antibiotics are administered by the intravenous route. Since several systems and situations require more efficient methods of administration, investigation and experimentation in drug design has produced local treatment modalities. Administration of antibiotics in aerosol form is one of the treatment methods of increasing interest. As the field of drug nanotechnology grows, new molecules have been produced and combined with aerosol production systems. In the current review, we discuss the efficiency of aerosol antibiotic studies along with aerosol production systems. The different parts of the aerosol antibiotic methodology are presented. Additionally, information regarding the drug molecules used is presented and future applications of this method are discussed.

Outcome measures for clinical trials assessing treatment of cystic fibrosis lung disease

Cystic fibrosis (CF) is a complex genetic disease characterized by death from loss of lung function. Therapies target pathophysiologic changes associated with pulmonary disease progression. Although therapeutic mechanisms differ, efficacy demonstration is limited to a few accepted outcome measures, each with shortcomings that are becoming more pronounced as CF population health improves. Pulmonary function improvement (as forced expiratory volume in 1 s [FEV₁]) and reduction of pulmonary exacerbation risk are commonly used outcomes. Changes in FEV₁ decline rate, quality of life, linear growth and/or weight gain are less utilized outcomes. Validated outcomes tend to work best in subjects with more aggressive or advanced lung disease and less so in healthier subjects. Assays of effects on primary therapeutic targets have yet to be validated as surrogate measures of clinical efficacy. As CF population health improves, it will become increasingly difficult to employ current clinical outcome measures to demonstrate efficacy.

Novel concepts in evaluating antimicrobial therapy for bacterial lung infections in patients with cystic fibrosis

Cystic fibrosis (CF) patients suffer typically from bacterial infections of their airways. Whilst current antibiotic-based treatment of these infections has brought much benefit to patients, it has been difficult to make either direct or indirect assessments of the in vivo efficacy of any specific treatment used. Traditional culture-based assessment has for example been rarely used to determine the direct impact of therapy on the bacteria in the airways. Instead, the "success" of a treatment is most often gauged through measures of respiratory and general health. New culture-independent approaches though are emerging that offer much promise here however in allowing a more comprehensive evaluation of antimicrobial efficacy. These new methods offer an opportunity to examine bacterial outcomes rather than host outcomes alone. Application of these novel techniques in a systematic way will lead to the rationalisation and, likely greater still individualisation, of therapy for CF patients. This review discusses host and microbiological factors that may influence antibiotic efficacy. Moreover, the degree to which the inherent complexity of CF respiratory infections complicates the process of determining treatment impact and the need to identify more robust microbiological outcome measures will also be reviewed.

Interaction between tobramycin and CSA-13 on clinical isolates of Pseudomonas aeruginosa in a model of young and mature biofilms

The bactericidal activity of a cholic acid antimicrobial derivative, CSA-13, was tested against eight strains of Pseudomonas aeruginosa (both reference and clinical strains) and compared with the response to tobramycin. In planktonic cultures, the minimal inhibitory and minimal bactericidal concentrations of CSA-13 and tobramycin were in the 1-25 mg/L range except for one mucoid clinical strain which was much less sensitive to tobramycin (minimal bactericidal concentration, 65-125 mg/L). In young (24 h) biofilms, the sensitivity to CSA-13 was reduced (half-maximal concentration CSA-13 averaged 88 mg/L) and varied among the eight strains. The sensitivity to tobramycin was also very variable among the strains and some were fully resistant to the aminoglycoside. The combination of tobramycin with CSA-13 was synergistic in five strains. Only one strain showed antagonism between the two drugs at low concentrations of CSA-13. One reference and five clinical strains were tested in mature (12 days) biofilms. The effect of CSA-13 was delayed, some strains requiring 9 days exposure to the drug to observe a bactericidal effect. All the strains were tolerant to tobramycin but the addition of CSA-13 with tobramycin was synergistic in three strains. CSA-13 permeabilized the outer membrane of the bacteria (half-maximal concentration, 4.4 mg/L). At concentrations higher than 20 mg/L, it also permeabilized the plasma membrane of human umbilical vein endothelial cells. In conclusion, CSA-13 has bactericidal activity against P. aeruginosa even in mature biofilms and cationic steroid antibiotics can thus be considered as potential candidates for the treatment of chronic pulmonary infections of patients with cystic fibrosis. Considering its interaction with the plasma membrane of eukaryotic cells, less toxic derivatives of CSA-13 should be developed.