The incidence of anaerobes in the sputum of patients with cystic fibrosis

Jewes, Linda; Spencer, R. C.

doi:10.1099/00222615-31-4-271

Cited by 32 publications

(19 citation statements)

References 13 publications

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“…In the study by Worlitzsch et al, lung function was not associated with the presence or absence of anaerobic bacteria (662). Although additional studies are required to determine the clinical relevance of anaerobes in CF patients, it is noteworthy that they are present in concentrations similar to those of P. aeruginosa (292,610,611) and persist up to 11 months in the CF airways (662).…”

Section: Other Microbesmentioning

confidence: 95%

“…Oxygen tension is low in CF airway secretions (663), suggesting a niche suitable for the growth of anaerobic bacteria, and several reports have indicated that anaerobic bacteria do indeed reside in CF airways. Frequently identified anaerobes include Prevotella, Bacteroides, Veillonella, Propionibacterium, Peptostreptococcus, and Actinomyces species as well as Staphylococcus saccharolyticus (193,292,610,662). Newer molecular approaches are dramatically expanding this list (231,241,495).…”

Section: Other Microbesmentioning

confidence: 99%

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Clinical Significance of Microbial Infection and Adaptation in Cystic Fibrosis

et al. 2011

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SUMMARY A select group of microorganisms inhabit the airways of individuals with cystic fibrosis. Once established within the pulmonary environment in these patients, many of these microbes adapt by altering aspects of their structure and physiology. Some of these microbes and adaptations are associated with more rapid deterioration in lung function and overall clinical status, whereas others appear to have little effect. Here we review current evidence supporting or refuting a role for the different microbes and their adaptations in contributing to poor clinical outcomes in cystic fibrosis.

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Section: Other Microbesmentioning

confidence: 95%

Section: Other Microbesmentioning

confidence: 99%

Clinical Significance of Microbial Infection and Adaptation in Cystic Fibrosis

et al. 2011

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“…[11,12] A few studies have demonstrated that high numbers of anaerobes are found during pulmonary exacerbations associated with P. aeruginosa. [13,14] The main anaerobes identified in these studies were prevotella and veilonella species. The clinical significance of anaerobes is unclear, but they may well contribute to the pathophysiology of infection in the CF airway.…”

mentioning

confidence: 99%

New Antimicrobial Strategies in Cystic Fibrosis

Westreenen

Tiddens

2010

Pediatric Drugs

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With more antibiotic resistance and emerging pathogens in cystic fibrosis (CF) patients, the need for new strategies in the lifelong treatment of pulmonary infection has increased. Most of the focus is on chronic infection with Pseudomonas aeruginosa, which is still thought to be the main pathogen leading to advanced CF lung disease. Other bacterial species are also recognized in the pathogenesis of CF lung disease, even though their definitive role is not well established yet. Clearly, expansion of treatment options is urgently needed. This article focuses on recent developments in the field of new antimicrobial strategies for CF. It is clear that studies on new classes of antibiotics or antimicrobial-like drugs are scarce, and that most studies involve new (inhalation) formulations, new routes of delivery, or analogs of existing classes of antibiotics. Studies of new antibiotic-like drugs are, in most cases, in preclinical phases of development and only a few of these agents may reach the market. Importantly, new inhaled antibiotics, e.g. aztreonam, levofloxacin, and fosfomycin, and new, more efficient delivery systems such as dry powder inhalation and liposomes for current antibiotics are in the clinical phase of development. These developments will be of great importance in improving effective treatment and reducing the treatment burden for CF patients in the near future.

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“…aeruginosa CF lung infections are frequently modeled under aerobic laboratory conditions; however, direct oxygen measurements within CF lung sputum in situ indicate that sputum contains hypoxic, and potentially anaerobic, regions (38). In addition, strict anaerobic bacteria have been detected in sputum samples from multiple CF patients (21,29), suggesting that environments capable of sustaining these species are present in vivo. There are several factors that could potentially reduce oxygen levels within CF sputum: cultured CF lung epithelial cells consume oxygen at a higher rate than non-CF lung epithelial cells, oxygen diffusion through sputum is restricted, and oxygen is consumed by resident sputum microorganisms, including P. aeruginosa (38).…”

mentioning

confidence: 99%

Membrane-Bound Nitrate Reductase Is Required for Anaerobic Growth in Cystic Fibrosis Sputum

2007

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The autosomal recessive disorder cystic fibrosis (CF) affects approximately 70,000 people worldwide and is characterized by chronic bacterial lung infections with the opportunistic pathogen Pseudomonas aeruginosa. To form a chronic CF lung infection, P. aeruginosa must grow and proliferate within the CF lung, and the highly viscous sputum within the CF lung provides a likely growth substrate. Recent evidence indicates that anaerobic microenvironments may be present in the CF lung sputum layer. Since anaerobic growth significantly enhances P. aeruginosa biofilm formation and antibiotic resistance, it is important to examine P. aeruginosa physiology and metabolism in anaerobic environments. Measurement of nitrate levels revealed that CF sputum contains sufficient nitrate to support significant P. aeruginosa growth anaerobically, and mutational analysis revealed that the membrane-bound nitrate reductase is essential for P. aeruginosa anaerobic growth in an in vitro CF sputum medium. In addition, expression of genes coding for the membrane-bound nitrate reductase complex is responsive to CF sputum nitrate levels. These findings suggest that the membrane-bound nitrate reductase is critical for P. aeruginosa anaerobic growth with nitrate in the CF lung.Cystic fibrosis (CF) is a heritable disease characterized by accumulation of large volumes of mucus (sputum) within the lungs and persistent colonization with opportunistic pathogens. While numerous bacterial species transiently colonize CF sputum or persist at low cell densities, the opportunistic pathogen Pseudomonas aeruginosa establishes a chronic infection and can attain densities of Ͼ10 9 cells/ml of sputum (19). Chronic P. aeruginosa infection is the leading cause of morbidity and mortality in CF patients (20). Once established, P. aeruginosa CF lung infections are highly refractory to antibiotic treatments, and even aggressive therapies fail to fully eradicate the bacterium from the lung (20). Several aspects of P. aeruginosa physiology are believed to contribute to its high antibiotic resistance in vivo, including biofilm formation and overproduction of the viscous exopolysaccharide alginate (23).P. aeruginosa CF lung infections are frequently modeled under aerobic laboratory conditions; however, direct oxygen measurements within CF lung sputum in situ indicate that sputum contains hypoxic, and potentially anaerobic, regions (38). In addition, strict anaerobic bacteria have been detected in sputum samples from multiple CF patients (21, 29), suggesting that environments capable of sustaining these species are present in vivo. There are several factors that could potentially reduce oxygen levels within CF sputum: cultured CF lung epithelial cells consume oxygen at a higher rate than non-CF lung epithelial cells, oxygen diffusion through sputum is restricted, and oxygen is consumed by resident sputum microorganisms, including P. aeruginosa (38). Collectively these factors may effectively reduce oxygen to levels insufficient for aerobic respiration. Interestingly, ...

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The incidence of anaerobes in the sputum of patients with cystic fibrosis

Cited by 32 publications

References 13 publications

Clinical Significance of Microbial Infection and Adaptation in Cystic Fibrosis

Clinical Significance of Microbial Infection and Adaptation in Cystic Fibrosis

New Antimicrobial Strategies in Cystic Fibrosis

Membrane-Bound Nitrate Reductase Is Required for Anaerobic Growth in Cystic Fibrosis Sputum

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