Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Sep 8:12:196.
doi: 10.1186/1471-2180-12-196.

Macrolides decrease the minimal inhibitory concentration of anti-pseudomonal agents against Pseudomonas aeruginosa from cystic fibrosis patients in biofilm

Larissa Lutz  1 , Dariane Castro Pereira, Rodrigo Minuto Paiva, Alexandre Prehn Zavascki, Afonso Luis Barth
Affiliations

Macrolides decrease the minimal inhibitory concentration of anti-pseudomonal agents against Pseudomonas aeruginosa from cystic fibrosis patients in biofilm

Larissa Lutz et al. BMC Microbiol. .

Abstract

Background: Biofilm production is an important mechanism for bacterial survival and its association with antimicrobial resistance represents a challenge for the patient treatment. In this study we evaluated the in vitro action of macrolides in combination with anti-pseudomonal agents on biofilm-grown Pseudomonas aeruginosa recovered from cystic fibrosis (CF) patients.

Results: A total of 64 isolates were analysed. The biofilm inhibitory concentration (BIC) results were consistently higher than those obtained by the conventional method, minimal inhibitory concentration, (MIC) for most anti-pseudomonal agents tested (ceftazidime: P = 0.001, tobramycin: P = 0.001, imipenem: P < 0.001, meropenem: P = 0.005). When macrolides were associated with the anti-pseudomonal agents, the BIC values were reduced significantly for ceftazidime (P < 0.001) and tobramycin (P < 0.001), regardless the concentration of macrolides. Strong inhibitory quotient was observed when azithromycin at 8 mg/L was associated with all anti-pseudomonal agents tested in biofilm conditions.

Conclusions: P. aeruginosa from CF patients within biofilms are highly resistant to antibiotics but macrolides proved to augment the in vitro activity of anti-pseudomonal agents.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Azithromycin and clarithromycin action on biofilm inhibitory concentration (BIC) of non-susceptible P. aeruginosa isolates combined with anti-pseudomonal agents. Detailed legend: CAZ - ceftazidime, CIP - ciprofloxacin, TOB - tobramycin, IPM - imipenem, MEM - meropenem, CLR - clarithromycin, AZM – azithromycin. Results are expressed as median of BIC. Solid lines represent association with AZM; dashed lines represent association with CLR.
Figure 2
Figure 2
Inhibitory Quotient (IQ) of combinations of macrolide antibiotics to anti-pseudomonal agents against P. aeruginosa isolates. Detailed legend: CAZ 2AZM – ceftazidime with 2 mg/L of azithromycin, CAZ 8AZM - ceftazidime with 8 mg/L of azithromycin, CAZ 2CLR - ceftazidime with 2 mg/L of clarithromycin, CAZ 8CLR - ceftazidime with 8 mg/L of clarithromycin, CIP 2AZM – ciprofloxacin with 2 mg/L of azithromycin, CIP 8AZM - ciprofloxacin with 8 mg/L of azithromycin, CIP 2CLR - ciprofloxacin with 2 mg/L of clarithromycin, CIP 8CLR - ciprofloxacin with 8 mg/L of clarithromycin, TOB 2AZM – tobramycin with 2 mg/L of azithromycin, TOB 8AZM - tobramycin with 8 mg/L of azithromycin, TOB 2CLR - tobramycin with 2 mg/L of clarithromycin, TOB 8CLR - with 8 mg/L of clarithromycin, IPM 2AZM – imipenem with 2 mg/L of azithromycin, IPM 8AZM - imipenem with 8 mg/L of azithromycin, IPM 2CLR - imipenem with 2 mg/L of clarithromycin, IPM 8CLR - imipenem with 8 mg/L of clarithromycin, MEM 2AZM – meropenem with 2 mg/L of azithromycin, MEM 8AZM – meropenem with 8 mg/L of azithromycin, MEM 2CLR – meropenem with 2 mg/L of clarithromycin, MEM 8CLR – meropenem with 8 mg/L of clarithromycin. STRONG IQ (Black bar) means that there was a reduction in biofilm inhibitory concentration (BIC) when macrolides combination was tested and the isolates changed its profile from “Resistant” to “Susceptible”; WEAK IQ (Grey bar) means that there was a reduction in BIC value when the isolate profile changed from “Resistant” to “Intermediate”.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Staab D. Cystic fibrosis - therapeutic challenge in cystic fibrosis children. Eur J Endocrinol. 2004;151(Suppl 1):S77–S80. - PubMed
    1. Baltimore RS, Christie CD, Smith GJ. Immunohistopathologic localization of Pseudomonas aeruginosa in lungs from patients with cystic fibrosis. Implications for the pathogenesis of progressive lung deterioration. Am Rev Respir Dis. 1989;140:1650–1661. doi: 10.1164/ajrccm/140.6.1650. - DOI - PubMed
    1. Costerton JW, Cheng KJ, Geesey GG, Ladd TI, Nickel JC, Dasgupta M, Marrie TJ. Bacterial biofilms in nature and disease. Annu Rev Microbiol. 1987;41:435–464. doi: 10.1146/annurev.mi.41.100187.002251. - DOI - PubMed
    1. Drenkard E, Ausubel FM. Pseudomonas biofilm formation and antibiotic resistance are linked to phenotypic variation. Nature. 2002;416:740–743. doi: 10.1038/416740a. - DOI - PubMed
    1. Singh PK, Schaefer AL, Parsek MR, Moninger TO, Welsh MJ, Greenberg EP. Quorum-sensing signals indicate that cystic fibrosis lungs are infected with bacterial biofilms. Nature. 2000;407:762–764. doi: 10.1038/35037627. - DOI - PubMed

Publication types