Microbial interaction between a CTXM-15-producingEscherichia coliand a susceptible Pseudomonas aeruginosaisolated from bronchoalveolar lavage: influence of cefotaxime in the dual-species biofilm formation

Bessa, L. J., Mendes, Â. , Gomes, R., Curvelo, S., Cravo, S., Sousa, E., Vasconcelos, V. and Martins da Costa, P. (2015) Microbial interaction between a CTXM-15-producingEscherichia coliand a susceptible Pseudomonas aeruginosaisolated from bronchoalveolar lavage: influence of cefotaxime in the dual-species biofilm formation. Environmental Microbiology Reports, 7(3), pp. 420-426. (doi: 10.1111/1758-2229.12266) (PMID:25625458)

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Abstract

Two isolates, Escherichia coli ella00 and Pseudomonas aeruginosa ella01, obtained from bronchoalveolar lavage, were found to be closely associated in clusters in agar medium. Escherichia coli ella00 was multidrug resistant and CTXM-15 extended-spectrum β-lactamase producer, while P. aeruginosa ella01 was susceptible to all antimicrobials tested. These observations impelled for further studies aimed to understand their microbial interaction. The P. aeruginosa ella01 biofilm-forming capacity was reduced and not affected when it was co-cultured with E. coli ella00 and E. coli ATCC 25922 respectively. Interestingly, the co-culture of ella isolates in the presence of high concentrations, such as 160 μg ml–1, of cefotaxime allowed the formation of more biofilm than in the absence of the antibiotic. As revealed by fluorescence in situ hybridization, in co-culture, P. aeruginosa ella01 survived and subsequently flourished when exposed to this third-generation cephalosporin at a concentration 10 × higher than its minimum inhibitory concentration (MIC), and this was mostly due to β-lactamases production by E. coli ella00. In fact, it was demonstrated by high-performance liquid chromatography that cefotaxime was absent for the culture medium 4 h after application. In conclusion, we demonstrate that bacterial species can interact differently depending on the surrounding conditions (favourable or stressing), and that those interactions can switch from unprofitable to beneficial.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mendes, Ângelo
Authors: Bessa, L. J., Mendes, Â., Gomes, R., Curvelo, S., Cravo, S., Sousa, E., Vasconcelos, V., and Martins da Costa, P.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Environmental Microbiology Reports
Publisher:Wiley
ISSN:1758-2229
ISSN (Online):1758-2229
Published Online:27 January 2015

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