1887

Abstract

produces quorum sensing signalling molecules including 2-alkyl-4-quinolones (AQs), which regulate virulence factor production in the cystic fibrosis (CF) airways.

Culture can lead to condition-dependent artefacts which may limit the potential insights and applications of AQs as minimally-invasive biomarkers of bacterial load.

We aimed to use culture-independent methods to explore the correlations between AQ levels and live load in adults with CF.

Seventy-five sputum samples at clinical stability and 48 paired sputum samples obtained at the beginning and end of IV antibiotics for a pulmonary exacerbation in adults with CF were processed using a viable cell separation technique followed by quantitative polymerase chain reaction (qPCR). Live qPCR load was compared with the concentrations of three AQs (HHQ, NHQ and HQNO) detected in sputum, plasma and urine.

At clinical stability and the beginning of IV antibiotics for pulmonary exacerbation, HHQ, NHQ and HQNO measured in sputum, plasma and urine were consistently positively correlated with live qPCR load in sputum, compared to culture. Following systemic antibiotics live qPCR load decreased significantly (<0.001) and was correlated with a reduction in plasma NHQ (plasma: r=0.463, =0.003).

In adults with CF, AQ concentrations correlated more strongly with live bacterial load measured by qPCR compared to traditional culture. Prospective studies are required to assess the potential of systemic AQs as biomarkers of bacterial burden.

Funding
This study was supported by the:
  • biotechnology and biological sciences research council (Award BB/R012415/1)
    • Principle Award Recipient: PaulWilliams
  • biotechnology and biological sciences research council (Award BB/R012415/1)
    • Principle Award Recipient: MiguelCámara
  • medical research council (Award G0801558/1)
    • Principle Award Recipient: NotApplicable
Loading

Article metrics loading...

/content/journal/jmm/10.1099/jmm.0.001420
2021-10-01
2024-03-29
Loading full text...

Full text loading...

References

  1. Emerson J, Rosenfeld M, McNamara S, Ramsey B, Gibson RL. Pseudomonas aeruginosa and other predictors of mortality and morbidity in young children with cystic fibrosis. Pediatr Pulmonol 2002; 34:91–100 [View Article] [PubMed]
    [Google Scholar]
  2. Silva Filho LVRF da, Ferreira F de A, Reis FJC, Britto MCA de, Levy CE et al. Pseudomonas aeruginosa infection in patients with cystic fibrosis: Scientific evidence regarding clinical impact, diagnosis, and treatment. J Bras Pneumol 2013; 39:495–512 [View Article] [PubMed]
    [Google Scholar]
  3. Passos da Silva D, Schofield MC, Parsek MR, Tseng BS. An update on the sociomicrobiology of quorum sensing in gram-negative biofilm development. Pathogens 2017; 6: [View Article]
    [Google Scholar]
  4. Diggle SP, Cornelis P, Williams P, Cámara M. 4-Quinolone signalling in Pseudomonas aeruginosa: Old molecules, new perspectives. Int J Med Microbiol 2006; 296:83–91 [View Article] [PubMed]
    [Google Scholar]
  5. Rampioni G, Falcone M, Heeb S, Frangipani E, Fletcher MP et al. Unravelling the genome-wide contributions of specific 2-Alkyl-4-Quinolones and PqsE to Quorum Sensing in Pseudomonas aeruginosa. PLoS Pathog 2016; 12:e1006029 [View Article]
    [Google Scholar]
  6. Smyth AR, Cifelli PM, Ortori CA, Righetti K, Lewis S et al. Garlic as an inhibitor of Pseudomonas aeruginosa quorum sensing in cystic fibrosis--a pilot randomized controlled trial. Pediatr Pulmonol 2010; 45:356–362 [View Article] [PubMed]
    [Google Scholar]
  7. Lepine F, Milot S, Deziel E, He J, Rahme LG. Electrospray/mass spectrometric identification and analysis of 4-hydroxy-2-alkylquinolines (HAQs) produced by Pseudomonas aeruginosa. J Am Soc Mass Spectrom 2004; 15:862–869 [View Article] [PubMed]
    [Google Scholar]
  8. Coulon PML, Groleau M-C, Déziel E. Potential of the Burkholderia cepacia complex to produce 4-hydroxy-3-methyl-2-alkyquinolines. Front Cell Infect Microbiol 2019; 9:33 [View Article]
    [Google Scholar]
  9. Barr HL, Halliday N, Cámara M, Barrett DA, Williams P et al. Pseudomonas aeruginosa quorum sensing molecules correlate with clinical status in cystic fibrosis. European Respiratory Journal 2015; 46:1046–1054
    [Google Scholar]
  10. Barr HL, Halliday N, Barrett DA, Williams P, Forrester DL et al. Diagnostic and prognostic significance of systemic alkyl quinolones for P. aeruginosa in cystic fibrosis: A longitudinal study. J Cyst Fibros 2017; 16:230–238 [View Article] [PubMed]
    [Google Scholar]
  11. Nocker A, Sossa-Fernandez P, Burr MD, Camper AK. Use of propidium monoazide for live/dead distinction in microbial ecology. Appl Environ Microbiol 2007; 73:5111–5117 [View Article] [PubMed]
    [Google Scholar]
  12. Rosenfeld M, Emerson J, Williams-Warren J, Pepe M, Smith A et al. Defining a pulmonary exacerbation in cystic fibrosis. J Pediatr 2001; 139:359–365 [View Article] [PubMed]
    [Google Scholar]
  13. Rogers GB, Marsh P, Stressmann AF, Allen CE, Daniels TV et al. The exclusion of dead bacterial cells is essential for accurate molecular analysis of clinical samples. Clin Microbiol Infect 2010; 16:1656–1658 [View Article] [PubMed]
    [Google Scholar]
  14. Rogers GB, Zain NMM, Bruce KD, Burr LD, Chen AC et al. A novel microbiota stratification system predicts future exacerbations in bronchiectasis. Ann Am Thorac Soc 2014; 11:496–503 [View Article] [PubMed]
    [Google Scholar]
  15. Ortori CA, Dubern JF, Chhabra SR, Camara M, Hardie K et al. Simultaneous quantitative profiling of N-acyl-L-homoserine lactone and 2-alkyl-4(1H)-quinolone families of quorum-sensing signaling molecules using LC-MS/MS. Anal Bioanal Chem 2011; 399:839–850 [View Article] [PubMed]
    [Google Scholar]
  16. Lenhard W, Lenhard A. Hypothesis tests for comparing correlations. Bibergau (Germany): Psychometrica; 2014 https://www.psychometrica.de/correlation.html
  17. Deschaght P, Van daele S, De Baets F, Vaneechoutte M. PCR and the detection of Pseudomonas aeruginosa in respiratory samples of CF patients. A literature review. J Cyst Fibros 2011; 10:293–297 [View Article] [PubMed]
    [Google Scholar]
  18. Deschaght P, Schelstraete P, Van Simaey L, Vanderkercken M, Raman A et al. Is the improvement of CF patients, hospitalized for pulmonary exacerbation, correlated to a decrease in bacterial load?. PLoS One 2013; 8:e79010 [View Article]
    [Google Scholar]
  19. Pye A, Stockley RA, Hill SL. Simple method for quantifying viable bacterial numbers in sputum. J Clin Pathol 1995; 48:719 [View Article] [PubMed]
    [Google Scholar]
  20. Mowat E, Paterson S, Fothergill JL, Wright EA, Ledson MJ et al. Pseudomonas aeruginosa population diversity and turnover in cystic fibrosis chronic infections. Am J Respir Crit Care Med 2011; 183:1674–1679 [View Article] [PubMed]
    [Google Scholar]
  21. Lam JC, Somayaji R, Surette MG, Rabin HR, Parkins MD. Reduction in Pseudomonas aeruginosa sputum density during a cystic fibrosis pulmonary exacerbation does not predict clinical response. BMC Infect Dis 2015; 15:145 [View Article] [PubMed]
    [Google Scholar]
  22. McLaughlin FJ, Matthews WJ Jr, Strieder DJ, Sullivan B, Taneja A et al. Clinical and bacteriological responses to three antibiotic regimens for acute exacerbations of cystic fibrosis: ticarcillin-tobramycin, azlocillin-tobramycin, and azlocillin-placebo. J Infect Dis 1983; 147:559–567 [View Article] [PubMed]
    [Google Scholar]
  23. Regelmann WE, Elliott GR, Warwick WJ, Clawson CC. Reduction of sputum Pseudomonas aeruginosa density by antibiotics improves lung function in cystic fibrosis more than do bronchodilators and chest physiotherapy alone. Am Rev Respir Dis 1990; 141:914–921 [View Article]
    [Google Scholar]
  24. Palmer KL, Mashburn LM, Singh PK, Whiteley M. Cystic fibrosis sputum supports growth and cues key aspects of Pseudomonas aeruginosa physiology. J Bacteriol 2005; 187:5267–5277 [View Article]
    [Google Scholar]
  25. Clancy JP, Cotton CU, Donaldson SH, Solomon GM, VanDevanter DR et al. CFTR modulator theratyping: Current status, gaps and future directions. J Cyst Fibros 2019; 18:22–34 [View Article] [PubMed]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/jmm/10.1099/jmm.0.001420
Loading
/content/journal/jmm/10.1099/jmm.0.001420
Loading

Data & Media loading...

Supplements

Supplementary material 1

PDF
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error