Search

Severe sepsis remains a poorly understood systemic inflammatory condition with high mortality rates and limited therapeutic options in addition to organ support measures. Here we show that the clinically approved group of anthracyclines acts therapeutically at a low dose regimen to confer robust protection against severe sepsis in mice. This salutary effect is strictly dependent on the activation of DNA damage response and autophagy pathways in the lung, as demonstrated by deletion of the ataxia telangiectasia mutated (Atm) or the autophagy-related protein 7 (Atg7) specifically in this organ. The protective effect of anthracyclines occurs irrespectively of pathogen burden, conferring disease tolerance to severe sepsis. These findings demonstrate that DNA damage responses, including the ATM and Fanconi Anemia pathways, are important modulators of immune responses and might be exploited to confer protection to inflammation-driven conditions, including severe sepsis., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background: The prognostic value of Pseudomonas aeruginosa serology for antibiotic therapy in cystic fibrosis patients is not well understood., Methods: Using five antigens from two ELISAs, we assessed whether positive serology in CF patients participating in the multi-center Early Pseudomonas Infection in Children (EPIC) trial would predict treatment failure, time to pulmonary exacerbation and risk for recurrent P. aeruginosa isolation post eradication., Results: Baseline positive P. aeruginosa serology was not significantly associated with failure of initial P. aeruginosa eradication measured at week 10 (adjusted for baseline culture) but seropositivity to the antigens alkaline protease and exotoxin A was significantly associated with increased risk for recurrent P. aeruginosa isolation during the 60 week post eradication follow-up period (p=0.003 and p=0.001 respectively). There was no association between baseline seropositivity and time to pulmonary exacerbation., Conclusion: P. aeruginosa serology may complement culture results in clinicians' efforts to successfully monitor recurrence of early P. aeruginosa in CF patients., (Copyright © 2012 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

In patients with cystic fibrosis (CF) lung damage secondary to chronic infection is the main cause of death. Treatment of lung disease to reduce the impact of infection, inflammation and subsequent lung injury is therefore of major importance. Here we discuss the present status of antibiotic therapy for the major pathogens in CF airways, including prophylaxis against infection, eradication of early infection, suppression of chronic infection, and the treatment of infective exacerbations. We outline measures to optimize maintenance treatment for infection in the light of novel antibiotic drug formulations. We discuss new developments in culture-independent microbiological diagnostic techniques and the use of tools for monitoring the success of antibiotic treatment courses. Finally, cost-effectiveness analyses for antibiotic treatment in CF patients are discussed., (Copyright © 2012 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

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., (Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Background: Antibiotic combination therapy might be more efficient than single antibiotics to combat Pseudomonas aeruginosa biofilms in the airways of patients with cystic fibrosis. We tested the ability of colistin sulphate-tobramycin combinations and single antibiotics to kill P. aeruginosa biofilms., Methods: P. aeruginosa biofilms were generated in vitro and in rat lungs. In a pilot study, 5 patients with cystic fibrosis inhaled colistin and then tobramycin for 4 weeks. The changes in P. aeruginosa counts and lung function were assessed before and after therapy., Results: Antibiotic combination therapy significantly reduced the number of P. aeruginosa cells in P. aeruginosa biofilm models in vitro. When rats were challenged with 1 x 10(7) cfu of P. aeruginosa, which was embedded in alginate beads, mortality rates, lung pathologic findings, and bacterial colony-forming unit counts were significantly lower after 7 days in animals receiving antibiotic combination than in animals receiving single antibiotics. In patients with cystic fibrosis, inhaled colistin-tobramycin was well tolerated and resulted in a mean decrease of 2.52 + /- 2.5 log(10) cfu of P. aeruginosa per milliliter of sputum (P = .027). Measurements of forced expiratory volume in 1 s, obtained both before and after the study, did not differ significantly., Conclusion: Colistin-tobramycin combinations are more efficient than respective single antibiotics for killing P. aeruginosa in biofilms in vitro, and they significantly reduced P. aeruginosa cell counts in a rat lung infection model and in patients with cystic fibrosis.

Dermcidin (DCD) is an antimicrobial peptide constitutively expressed in eccrine sweat glands in human skin. By post-secretory proteolytic processing in sweat, the DCD protein gives rise to anionic and cationic DCD peptides that are able to kill several Gram-positive and Gram-negative bacteria but are only weakly active against Pseudomonas aeruginosa. Here, we questioned whether bacterial resistance to DCD peptides is mediated by proteolytic degradation. It was shown that DCD-derived peptides are degraded by purified bacterial proteases and by extracellular proteases secreted by P. aeruginosa in a concentration-dependent manner. However, protease-deficient mutants of P. aeruginosa PAO1 lacking either lasA, lasB (elastase) or both showed a similar sensitivity towards DCD-derived peptides as the wild-type strain. Finally, inhibition of total protease activity indicated that proteases secreted by P. aeruginosa are not responsible for the poor activity of DCD-derived peptides against P. aeruginosa. These data suggest that the decreased sensitivity of P. aeruginosa to DCD-derived peptides is not mediated by proteolytic degradation under physiological conditions.

Amitriptyline, a blocker of acid sphingomyelinase and acid ceramidase, significantly reduces Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) mice with concurrent increase of survival. Our aim was to establish whether amitriptyline is safe and effective in the treatment of CF patients. In a randomised, double-blinded, placebo-controlled, cross-over pilot study, 4 adult CF patients received 37.5 mg of amitriptyline or placebo twice daily for 14 days. Subsequently in a phase II study 19 adult CF patients were randomly allocated to three treatment groups receiving amitriptyline once daily for 28 days at doses of 25 mg (n=7), 50 mg (n=8), or 75 mg (n=8) or placebo (n=13). The primary outcome was the difference of forced expiratory volume in 1 sec (FEV(1)) at day 14 between amitriptyline and placebo. Primary endpoint measures improved significantly in three of four patients in the pilot study after amitriptyline treatment vs placebo (relative FEV(1): 14.7+/-5%; p = 0.006) and in the 25 mg treatment group of the phase II study (relative FEV(1): 4.0+/-7%; p = 0.048). Amitriptyline was well tolerated in both studies and 96% of the patients completed the studies. Amitriptyline as a novel therapeutic option in patients with CF is safe and seems to be efficacious., (2009 S. Karger AG, Basel.)

Background: Temocillin is currently used in the treatment of acute pulmonary exacerbations caused by Burkholderia cepacia complex and multi-resistant Pseudomonas aeruginosa in cystic fibrosis (CF) patients despite little published clinical data. This study assessed if intravenous (IV) antibiotic therapy including temocillin was equivalent to standard combination therapy for an acute exacerbation., Methods: A retrospective, pilot cross-over study. Adult patients attending two CF centres between 1997 and 2006 who had received a course of IV antibiotics including temocillin (TIV) and a further IV course (within +/-1 year) which did not include temocillin (NTIV) were included. Outcome measures at the start and end of each IV course were recorded (FEV(1)%, FVC%)., Results: Twenty six patients had received temocillin. Baseline values of FEV(1)% predicted were comparable for both groups (TIV: 37(18%), NTIV: 39(20%)). FEV(1)% increased by 7.12(11.67)% after TIV (p<0.01) and 6.65(7.62)% after NTIV (p<0.01). There was no significant difference between the IV courses in mean %change in lung function TIV versus NTIV (FEV(1) 0.46% [95%CI: -4.55 to 5.48%])., Conclusion: These data suggest equivalence in the lung function outcome of IV antibiotic therapy includingtemocillin versus standard IV antibiotic therapy.

Background: Data on the effects of long-term treatment with azithromycin (AZM) on inflammatory markers in cystic fibrosis patients chronically infected with Pseudomonas aeruginosa are scarce. So far there is no pharmacokinetic and clinical data on once-weekly dosage of AZM in CF patients., Methods: In a randomised double-blind, placebo-controlled trial, patients received AZM or placebo 1 per week for 8 weeks (AZM dosage--20-29 kg: 500 mg, 30-39 kg: 750 mg, 40-49 kg: 1000 mg and > or = 50 kg: 1250 mg) after a course of intravenous antipseudomonal antibiotics. Pulmonary function tests, the serum markers LPS-binding protein (LBP), interleukin-8 (IL-8), CRP, P. aeruginosa alginate in sputum samples and quality of life scores were evaluated., Results: Thirty-eight patients (21 AZM/17 placebo) (mean age: 23.7 years; mean FEV(1): 62% of predicted) were recruited. After treatment (mean dose of 21.2 mg/kg body weight once a week) pulmonary function declined in both groups compared to baseline (i.e. after cessation of i.v. antibiotics). The AZM group was significantly better for mean changes in serum CRP (AZM: +0.9 mg/l, placebo: +21.6 mg/l, p=0.019), lipopolysaccharide binding protein in serum, LBP (AZM: +0.9 microg/ml, placebo: +7.0 microg/ml, p=0.015), serum interleukin-8 (AZM: -3.1 pg/ml, placebo: +2.9 pg/ml, p=0.001) and alginate in sputum (AZM: +85 microg/ml, placebo: +353 microg/ml, p=0.048). Quality of life was significantly better after AZM and there was no increase in treatment-related adverse events., Conclusion: Once-weekly azithromycin ameliorated inflammatory reactions and improved quality of life. A decline of pulmonary function after cessation of i.v. antibiotics could not be prevented.

We determined the protective effect of moxifloxacin, azithromycin, and amoxicillin against Streptococcus pneumoniae infection of respiratory cells. Moxifloxacin and azithromycin effectively killed intracellular S. pneumoniae strains and protected respiratory epithelial cells significantly even when given 6 h after S. pneumoniae challenge. Amoxicillin was less effective.

The fluoroquinolones moxifloxacin and ciprofloxacin display excellent in vitro activities against many respiratory tract pathogens. Here we show that moxifloxacin and ciprofloxacin accumulate approximately 7- to 10-fold in primary human respiratory epithelial cells, derived from nasal polyps and grown in 3-dimensional vesicles. Furthermore, using these vesicles, we assessed the bactericidal effect of moxifloxacin on Staphylococcus aureus and Streptococcus pneumoniae and that of ciprofloxacin on Pseudomonas aeruginosa and Haemophilus influenzae. Finally, we determined the protective effect of the fluoroquinolones on vesicles infected with these pathogens. All four bacterial strains were highly toxic for vesicles. S. aureus and S. pneumoniae were readily killed by moxifloxacin regardless whether the antibiotics were present intra/extracellularly or only intracellularly in vesicles. Similar results were obtained for the killing of H. influenzae and P. aeruginosa. Exclusively intracellularly located fluoroquinolones rescued 42% to 76% of the cells after bacterial challenge compared to the rescue of 48% to 94% cells when the fluoroquinolones were present intra/ extracellularly. Without addition of fluoroquinolones cell survival in vesicles was 0% to 38%. The results suggest that intracellular accumulation of moxifloxacin and ciprofloxacin is important for the protection of respiratory epithelial cells from the cytotoxic effects of major respiratory tract pathogens.

In cystic fibrosis (CF) patients early antibiotic treatment of lung infection has been shown to lead to Pseudomonas aeruginosa eradication. The present study determined: 1) the time period from eradication to new P. aeruginosa acquisition; 2) P. aeruginosa re-growth and new acquisition; and 3) the impact of eradication therapy on lung function, antimicrobial resistance, emergence of other pathogens and treatment costs. Ciprofloxacin and colistin were used to eradicate P. aeruginosa in 47 CF patients. Bacterial pathogens, lung function decline, P. aeruginosa antimicrobial resistance and anti-pseudomonal serum antibodies were assessed quarterly and compared with an age-matched CF control group. Additionally, costs of antibiotic therapy in both groups were assessed. Early antibiotic therapy leads to a P. aeruginosa free-period of a median (range) of 18 (4-80) months. New acquisition with different P. aeruginosa genotypes occurs in 73% of episodes. It also delays the decline of lung function compared with chronically infected patients, prevents the occurrence of antibiotic resistant P. aeruginosa strains, does not lead to emergence of other pathogens, and significantly reduces treatment costs. The treatment substantially lowers P. aeruginosa prevalence in CF. In conclusion, early antibiotic therapy exerts beneficial effects on the patient's clinical status and is cost-effective compared with conventional antibiotic therapy for chronically infected cystic fibrosis patients.

PCR has proved superior to conventional blood culture for diagnosing bacteraemia in the presence of antibiotics. Nevertheless, even PCR might yield false-negative results if the template DNA were to be cleaved by serum DNAases after antibiotics had induced bacterial death. To evaluate the cleavage of bacterial template DNA by human serum DNAase I, serum samples inoculated with purified Escherichia coli DNA were incubated with increasing amounts of recombinant human DNAase (rhDNAase) and then examined by a PCR specific for E. coli. As a prerequisite of potential DNAase attack, the release of E. coli DNA after antibiotic-induced bacterial death was quantified by fluorescence microscopy and flow cytometry. Finally, the influence of rhDNAase on the PCR-based detection of antibiotic-killed E. coli in serum was assessed. The results indicated that purified E. coli DNA is remarkably stable in human serum; positive PCR results did not decrease significantly until the ratio of recombinant human DNAase I:E. coli rose to 106:1. As only 14.8-28.4% of the total E. coli DNA was released after antibiotic killing, the PCR-based detection of E. coli fell by only 10% when cefotaxime-killed E. coli were incubated with rhDNAase. It was concluded that human serum DNAases and antibiotic killing do not compromise the reliability of PCR examinations for bacteraemia.

In Staphylococcus aureus infection hemolysis caused by the extracellular protein alpha-toxin encoded by hla is thought to contribute significantly to its multifactorial virulence. In vitro, subinhibitory concentrations of beta-lactam antibiotics and fluoroquinolones increase the levels of hla and alpha-toxin expression, whereas aminoglycosides decrease the levels of hla and alpha-toxin expression. In the present study we investigated the effects of subinhibitory concentrations of amoxicillin, gentamicin, and moxifloxacin on hla and alpha-toxin expression and total hemolysis of S. aureus strain 8325-4, a high-level alpha-toxin producer, and its alpha-toxin-negative mutant, DU 1090, in vitro and in a rat model of chronic S. aureus infection. The levels of expression of hla and alpha-toxin and total hemolysis did not differ significantly when amoxicillin, gentamicin, or moxifloxacin was added to cultures of S. aureus strain 8325-4. In vivo, strain 8325-4 induced a significantly increased level of hemolysis in infected pouches compared to that in uninfected control pouches, but the hemolysis was reduced to control levels by treatment with doses of amoxicillin, gentamicin, or moxifloxacin that reduced bacterial numbers by 2 orders of magnitude. Additionally, the effects of subinhibitory concentrations of the three antibiotics on total hemolysis of four methicillin-resistant S. aureus and three methicillin-sensitive S. aureus (MSSA) clinical isolates were assessed in vitro. A significant increase in total hemolysis was observed for only one MSSA strain when it was treated with amoxicillin but not when it was treated with moxifloxacin or gentamicin. When purified alpha-toxin was incubated with purified human neutrophil elastase, alpha-toxin was cleaved nearly completely. The results suggest that the penicillin-induced increases in S. aureus alpha-toxin expression are strain dependent, that reduction of bacterial numbers in vivo counteracts this phenomenon effectively, and finally, that in localized S. aureus infections alpha-toxin activity is controlled by neutrophil elastase.

Cystic fibrosis (CF) is the most common lethal hereditary disorder with autosomal recessive heredity in caucasians. The majority of CF patients suffer from chronic respiratory infection with the opportunistic bacterial pathogen Pseudomonas aeruginosa. No consensus among clinicians has been reached so far concerning antibiotic treatment against P. aeruginosa in CF patients. Consensus answers to 24 important questions in this context, based on current evidence, are presented, given by a panel of 34 European experts. Questions addressed and answered are: The diagnosis of P. aeruginosa lung colonization in CF; The impact of P. aeruginosa on the clinical state of CF patients; The assessment of P. aeruginosa susceptibility against antibiotics and the importance of these results for the clinician; The use of monotherapy versus combination therapy; The development of microbial resistance; The achievement of optimal airway concentrations; The effects of subinhibitory concentrations of antibiotics on P. aeruginosa; Statements on the pharmacokinetics of antibiotics in CF patients; Recommendations for doses and dosing intervals and length of treatment regimens; and Toxic side effects due to repeated antibiotic therapy was addressed. The expert panel answered further questions on the use of fluoroquinolones in children with CF, on the administration of nebulized antibiotics and whether prevention of P. aeruginosa lung colonization is possible in CF using antibiotic therapy. Problems of antibiotic therapy at home and in the hospital were addressed, a consensus statement on regular maintenance treatment, or treatment on demand, was given and different routes of administration of antibiotics were recommended for different clinical situations. Finally, the factors which determine the choice of the antibiotic, the dosage, and the duration of the treatment in cystic fibrosis patients were addressed and the design of future antibiotic studies in the context of Pseudomonas aeruginosa lung infection in cystic fibrosis patients were recommended.

In chronic Pseudomonas aeruginosa pulmonary infection of patients with cystic fibrosis (CF), antibiotic therapy generally fails to eradicate the bacterial pathogen. The mucoid bacterial phenotype, high sputum production by the host, and low airway levels of antibiotics seem to be responsible for the observed decrease in antibiotic efficacy. We hypothesized that early antibiotic treatment by inhalation in CF patients may be able to prevent or at least delay airway infection. In a prospective placebo-controlled, double-blind, randomized multicenter study, 22 CF patients received either 80 mg b.i.d. of aerosolized tobramycin or placebo for a period of 12 months shortly after the onset of P. aeruginosa pulmonary colonization. Two patients in the tobramycin and six patients in the placebo group stopped inhalation before the 12 month treatment period. Using life table analysis, the time to conversion from a P. aeruginosa-positive to a P. aeruginosa-negative respiratory culture was significantly shorter in the tobramycin-treated group than in the placebo group (P < 0.05, log rank test). Lung function parameters and markers of inflammation did not change in either group during treatment. The results of this study suggest that early tobramycin inhalation may prevent and/or delay P. aeruginosa pulmonary infection in CF patients.