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Short report
Comparative evaluation of the effect of different growth media on in vitro sensitivity to azithromycin in multi-drug resistant Pseudomonas aeruginosa isolated from cystic fibrosis patients
Alexander H. Dalpke
Technische Universitat Dresden Medizinische Fakultat Carl Gustav Carus
Corresponding Author
ORCiD: https://orcid.org/0000-0003-1648-6618
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View the published version at Antimicrobial Resistance and Infection Control.
Long-term treatment with azithromycin is a therapeutic option in Cystic Fibrosis (CF) patients chronically infected with P. aeruginosa. It was recently shown that azithromycin has direct antimicrobial activity when P. aeruginosa isolates are tested in Roswell Park Memorial Institute medium supplemented with fetal calf serum (RPMI 1640/FCS) by broth microdilution. We now investigated whether (i) azithromycin might also be active against multidrug resistant (MDR) P. aeruginosa isolated from CF patients and (ii) how in vitro sensitivity assays perform in synthetic cystic fibrosis sputum medium (SCFM), a medium that mimics the particular CF airway environment. In 17 (59%) out of 29 MDR P. aeruginosa CF isolates MICs for azithromycin ranged between 0.25 and 8 µg/ml and 12 isolates (41%) showed a MIC ≥512 µg/ml when measured in RPMI/FCS. In contrast, MICs were ≥256 µg/ml for all P. aeruginosa MDR isolates when tested in either SCFM or in conventional cation-adjusted Mueller Hinton Broth. High MIC values observed in CF adapted medium SCFM for both PAO1 and MDR P. aeruginosa CF isolates, as opposed to findings in RPMI, argue against routine azithromycin MIC testing of CF isolates.
Keywords
cystic fibrosis, Pseudomonas aeruginosa, multidrug resistance, broth microdilution, azithromycin, SCFM
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Editorial decision: Major revision
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Reviewer #2 agreed
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On 04 Aug, 2020
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Editor invited
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This preprint is under consideration at Antimicrobial Resistance and Infection Control. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Short report
Comparative evaluation of the effect of different growth media on in vitro sensitivity to azithromycin in multi-drug resistant Pseudomonas aeruginosa isolated from cystic fibrosis patients
Alexander H. Dalpke
Technische Universitat Dresden Medizinische Fakultat Carl Gustav Carus
Corresponding Author
ORCiD: https://orcid.org/0000-0003-1648-6618
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Published
Published
On 09 Dec, 2020
No community comments so far
Editorial decision: Accept
On 18 Nov, 2020
Editor assigned
On 17 Nov, 2020
Submission checks complete
On 17 Nov, 2020
Editor invited
On 17 Nov, 2020
Version 2
Posted 03 Nov, 2020
No comments provided
Review #2 received
Received 03 Nov, 2020
Reviewer #2 agreed
On 02 Nov, 2020
Editor assigned
On 29 Oct, 2020
Reviewers invited
Invitations sent on 28 Oct, 2020
Reviewer #1 agreed
On 28 Oct, 2020
Submission checks complete
On 28 Oct, 2020
Editor invited
On 28 Oct, 2020
No comments provided
Editorial decision: Major revision
On 28 Aug, 2020
Review #2 received
Received 27 Aug, 2020
Review #1 received
Received 23 Aug, 2020
Reviewer #2 agreed
On 13 Aug, 2020
Reviewer #1 agreed
On 04 Aug, 2020
Reviewers invited
Invitations sent on 28 Jul, 2020
Editor assigned
On 27 Jul, 2020
Editor invited
On 26 Jul, 2020
Submission checks complete
On 22 Jul, 2020
First submitted
On 21 Jul, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published version at Antimicrobial Resistance and Infection Control.
Long-term treatment with azithromycin is a therapeutic option in Cystic Fibrosis (CF) patients chronically infected with P. aeruginosa. It was recently shown that azithromycin has direct antimicrobial activity when P. aeruginosa isolates are tested in Roswell Park Memorial Institute medium supplemented with fetal calf serum (RPMI 1640/FCS) by broth microdilution. We now investigated whether (i) azithromycin might also be active against multidrug resistant (MDR) P. aeruginosa isolated from CF patients and (ii) how in vitro sensitivity assays perform in synthetic cystic fibrosis sputum medium (SCFM), a medium that mimics the particular CF airway environment. In 17 (59%) out of 29 MDR P. aeruginosa CF isolates MICs for azithromycin ranged between 0.25 and 8 µg/ml and 12 isolates (41%) showed a MIC ≥512 µg/ml when measured in RPMI/FCS. In contrast, MICs were ≥256 µg/ml for all P. aeruginosa MDR isolates when tested in either SCFM or in conventional cation-adjusted Mueller Hinton Broth. High MIC values observed in CF adapted medium SCFM for both PAO1 and MDR P. aeruginosa CF isolates, as opposed to findings in RPMI, argue against routine azithromycin MIC testing of CF isolates.
Figure 1