International Journal of Applied Microbiology and Biotechnology Research
ISSN: 2053-1818
Vol. 5(2), pp. 12-19, February 2017



In vitro biofilm formation ability of staphylococci under different growth conditions

Fernanda Cristina Possamai Rossatto, Jaqueline Becker Pinto, Géssica Aracéli Costa and Ana Paula Guedes Frazzon*

Programa de Pós-Graduação em Microbiologia Agrícola e do Ambiente. Instituto de Ciências Básicas e da Saúde. Universidade Federal do Rio Grande do Sul. Rua Sarmento Leite, 500. 90050-170, Porto Alegre, Brasil.

*To whom correspondence should be addressed. E-mail: ana.frazzon@ufrgs.br.

Received 9 November, 2016; Received in revised form 12 December, 2016; Accepted 14 December, 2016.

Abstract


Keywords:
Biofilm formation, Growth conditions, Temperature, Staphylococci.


The understandings of the various elements that influence the dynamics of biofilms formation are important to contribute to the knowledge of in vitro biofilm formation by staphylococci. The aim of this study was to analyze the effect of different growth conditions on biofilm formation by staphylococci. A total of 102 Staphylococcus strains, including 60 isolates of coagulase-positives (CoPS) obtained from food and clinical samples and 42 isolates of coagulase-negatives (CoNS) isolated from food, were evaluated. The effects of medium composition on biofilm formation were tested in tryptic soy broth (TSB) with varying concentrations of: Glucose [1% (TSB-1G); 5% (TSB-5G); 10% (TSB-10G)], 0.9% sodium chloride (TSB-NaCl), combination of 5% glucose and 0.9% sodium chloride (TSB-5G/NaCl), or 12.5% of rabbit plasma (TSB-RP). The effects of incubation temperatures (25, 35 and 40°C) was also investigated. The addition of glucose (from 1.0 to 10.0%) did not significantly affect the ability of the food-related CoNS and CoPS strains to adhere on the microplates. Interestingly, clinically-related CoPS strains had a higher rate of strong biofilm formed in TSB-RP (52.94%) (p<0.001). The TSB/NaCl and TSB-RP showed negative and positive effect on the biofilm formation in food-related CoNS strains, respectively. Temperatures of 25 and 40°C had positive effects on the biofilm formation of food-related CoPS strains. The study describes models that could provide relevant insights in staphylococcal biofilm formation for food and clinical research. The present findings also highlighted the need for a careful selection of the assay conditions.

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