Pseudomonas fluorescens is not generally considered a bacterial pathogen in humans; however, multiple culture-based and culture-independent studies have identified it at low levels in the indigenous ...microbiota of various body sites. With recent advances in comparative genomics, many isolates originally identified as the "species" P. fluorescens are now being reclassified as novel Pseudomonas species within the P. fluorescens "species complex." Although most widely studied for its role in the soil and the rhizosphere, P. fluorescens possesses a number of functional traits that provide it with the capability to grow and thrive in mammalian hosts. While significantly less virulent than P. aeruginosa, P. fluorescens can cause bacteremia in humans, with most reported cases being attributable either to transfusion of contaminated blood products or to use of contaminated equipment associated with intravenous infusions. Although not suspected of being an etiologic agent of pulmonary disease, there are a number of reports identifying it in respiratory samples. There is also an intriguing association between P. fluorescens and human disease, in that approximately 50% of Crohn's disease patients develop serum antibodies to P. fluorescens. Altogether, these reports are beginning to highlight a far more common, intriguing, and potentially complex association between humans and P. fluorescens during health and disease.
The Microbiome in Cystic Fibrosis Huang, Yvonne J; LiPuma, John J
Clinics in chest medicine,
03/2016, Volume:
37, Issue:
1
Journal Article
Peer reviewed
Open access
Observations from studies during the last decade have changed the conventional view of cystic fibrosis (CF) microbiology, which has traditionally focused on a limited suite of opportunistic bacterial ...pathogens. It is now appreciated that CF airways typically harbor complex microbial communities, and that changes in the structure and activity of these communities have a bearing on patient clinical condition and lung disease progression. Recent studies of gut microbiota also suggest that disordered bacterial ecology of the CF gastrointestinal tract is associated with pulmonary outcomes. These new insights may alter future clinical management of CF.
Bacteria that infect the airways of persons with cystic fibrosis (CF) include a group of well-described opportunistic pathogens as well as numerous, mainly obligate or facultative anaerobic species ...typically not reported by standard sputum culture. We sequenced the V3-V5 hypervariable region of the bacterial 16S rRNA gene in DNA derived from 631 sputum specimens collected from 111 CF patients over 10 years. We describe fluctuations in the relative abundances of typical CF pathogens, as well as anaerobic species, in relation to changes in patients' clinical state and lung disease stage. Both bacterial community diversity and the relative abundance of anaerobes increased during exacerbation of symptoms (prior to antibiotic treatment), although this trend was not observed uniformly across disease stages. Community diversity and the relative abundance of anaerobic species decreased during antibiotic treatment. These results support current hypotheses regarding the role of anaerobes in CF pulmonary exacerbations and lung disease progression.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background Monitoring potential changes in the epidemiology of cystic fibrosis (CF) pathogens furthers our understanding of the potential impact of interventions. Methods We performed a retrospective ...analysis using data reported to the Cystic Fibrosis Foundation Patient Registry (CFFPR) from 2006 to 2012 to determine the annual percent changes in the prevalence and incidence of selected CF pathogens. Pathogens included Pseudomonas aeruginosa , methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S aureus (MRSA), Haemophilus influenzae , Burkholderia cepacia complex, Stenotrophomonas maltophilia , and Achromobacter xylosoxidans . Changes in nontuberculous mycobacteria (NTM) prevalence were assessed from 2010 to 2012, when the CFFPR collected NTM species. Results In 2012, the pathogens of highest prevalence and incidence were MSSA and P aeruginosa , followed by MRSA. The prevalence of A xylosoxidans and B cepacia complex were relatively low. From 2006 to 2012, the annual percent change in overall (as well as in most age strata) prevalence and incidence significantly decreased for P aeruginosa and B cepacia complex, but significantly increased for MRSA. From 2010 to 2012, the annual percent change in overall prevalence of NTM and Mycobaterium avium complex increased. Conclusions The epidemiology of CF pathogens continues to change. The causes of these observations are most likely multifactorial and include improvements in clinical care and infection prevention and control. Data from this study will be useful to evaluate the impact of new therapies on CF microbiology.
The structure and dynamics of bacterial communities in the airways of persons with cystic fibrosis (CF) remain largely unknown. We characterized the bacterial communities in 126 sputum samples ...representing serial collections spanning 8–9 y from six age-matched male CF patients. Sputum DNA was analyzed by bar-coded pyrosequencing of the V3–V5 hypervariable region of the 16S rRNA gene, defining 662 operational taxonomic units (OTUs) from >633,000 sequences. Bacterial community diversity decreased significantly over time in patients with typically progressive lung disease but remained relatively stable in patients with a mild lung disease phenotype. Antibiotic use, rather than patient age or lung function, was the primary driver of decreasing diversity. Interpatient variability in community structure exceeded intrapatient variability in serial samples. Antibiotic treatment was associated with pronounced shifts in community structure, but communities showed both short- and long-term resilience after antibiotic perturbation. There was a positive correlation between OTU occurrence and relative abundance, with a small number of persistent OTUs accounting for the greatest abundance. Significant changes in community structure, diversity, or total bacterial density at the time of pulmonary exacerbation were not observed. Despite decreasing community diversity in patients with progressive disease, total bacterial density remained relatively stable over time. These findings show the critical relationship between airway bacterial community structure, disease stage, and clinical state at the time of sample collection. These features are the key parameters with which to assess the complex ecology of the CF airway.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Abstract Background We recently described a multilocus sequence typing scheme for Achromobacter that identified several novel species in this genus. Methods We assessed the ability of nrdA sequence ...analysis to differentiate Achromobacter species, including the seven previously named species and 14 recently described genogroups. Confirmation of distinctness between groups was confirmed using the k parameter. Using this single locus sequence to differentiate species, we analyzed Achromobacter isolates obtained from 341 CF patients in the U.S. Results We found that Achromobacter xylosoxidans accounts for 42% of Achromobacter infections, while Achromobacter ruhlandii accounted for 23.5% of infections. Isolates from 17% of patients were members of the novel genogroup 14. The remaining 17.5% of strains belonged to 11 other species/genogroups. Conclusion The use of nrdA sequence analysis allows differentiation of the several Achromobacter species that can infect persons with CF. Achromobacter species other than A. xylosoxidans account for the majority of Achromobacter infection in CF patients in the U.S.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Antimicrobial susceptibility testing (AST) has been used to guide therapy of airway infection in persons with cystic fibrosis (CF) for decades. However, evidence that AST adds benefit to ...treatment outcomes in CF is lacking. In fact, the routine use of AST has potential to exacerbate inappropriate antibiotic use. Several features of airway infection in CF contribute to the limitations of AST in predicting treatment outcomes, providing rationale for abandoning this practice altogether. Other features of CF infection suggest, however, that select use of AST can provide worthwhile guidance to antibiotic selection.
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