Swimming Motility in a Longitudinal Collection of Clinical Isolates of Burkholderia cepacia Complex Bacteria from People with Cystic Fibrosis

Abstract

Chronic bacterial lung infections in cystic fibrosis (CF) are the leading cause of morbidity and mortality. While a range of bacteria are known to be capable of establishing residence in the CF lung, only a small number have a clearly established link to deteriorating clinical status. The two bacteria with the clearest roles in CF lung disease are Pseudomonas aeruginosa and bacteria belonging to the Burkholderia cepacia complex (BCC). A number of common adaptations by P. aeruginosa strains to chronic lung infection in CF have been well described. Typically, initial isolates of P. aeruginosa are nonmucoid and display a range of putative virulence determinants. Upon establishment of chronic infection, subsequent isolates ultimately show a reduction in putative virulence determinants, including swimming motility, along with an acquisition of the mucoid phenotype and increased levels of antimicrobial resistance. Infections by BCC are marked by an unpredictable, but typically worse, clinical outcome. However, in contrast to P. aeruginosa infections in CF, studies describing adaptive changes in BCC bacterial phenotype during chronic lung infections are far more limited. To further enhance our understanding of chronic lung infections by BCC bacteria in CF, we assessed the swimming motility phenotype in 551 isolates of BCC bacteria from cystic fibrosis (CF) lung infections between 1981 and 2007. These data suggest that swimming motility is not typically lost by BCC during chronic infection, unlike as seen in P. aeruginosa infections. Furthermore, while we observed a statistically significant link between mucoidy and motility, we did not detect any link between motility phenotype and clinical outcome. These studies highlight the need for further work to understand the adaptive changes of BCC bacteria during chronic infection in the CF lung.

Phenotypic diversity and genotypic flexibility of Burkholderia cenocepacia during long-term chronic infection of cystic fibrosis lungs

“…For instance, a random sampling of 44 P. aeruginosa colonies from a single sputum sample of a clinically stable CF patient showed a wide range of phenotypes, from variations in protease and exotoxin productions to antibiotic susceptibility (Darch et al 2015). Consistent with this, we observed broad phenotypic and genotypic variation for B. cenocepacia isolates obtained from the same patient at the same time point (Zlosnik et al 2014;Clark et al 2015). We thus emphasize the value of bacterial isolate collections that not only sample longitudinally but also sample populations at single time points, irrespective of observed variation of colony morphology.…”

An Oxygen-Sensing Two-Component System in the Burkholderia cepacia Complex Regulates Biofilm, Intracellular Invasion, and Pathogenicity

“…dolosa to swim was measured in low density LB agar using published methods [57]. Briefly, 10 μL of overnight B .…”

Gene Expression Profiling of Burkholderia cenocepacia at the Time of Cepacia Syndrome: Loss of Motility as a Marker of Poor Prognosis?

“…Nonetheless, it is noteworthy that such data need to be considered strictly strain specific. A recent study on a large collection of various B. cenocepacia CF strains did not find any correlation between motility and clinical outcomes, despite the fact that 38% of the tested isolates were nonmotile (24).…”