In vitro biofilm activity of non-Candida albicans Candida species.
Candidosis has been attributed to C. albicans; however, infections caused by non-Candida albicans Candida (NCAC) species are increasingly being recognised. The ability of Candida to grow as a biofilm is an important feature that promotes both infection and persistence in the host. The biofilms' activity is significant since high activity might be associated with enhanced expression of putative virulence factors, whilst in contrast low activity has previously been suggested as a mechanism for resistance of biofilm cells to antimicrobials. The aim of this study was to determine the metabolic activity of in vitro biofilms formed by different clinical isolates of NCAC species. The in situ total metabolic activity of C. parapsilosis, C. tropicalis and C. glabrata biofilms was determined using 2,3-(2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay, and the number of cultivable cells was also established by CFU (colony forming unit) counts. The biofilm structure was assessed by scanning electron microscopy (SEM). Results showed that total biofilm metabolic activity was species and strain dependent. C. glabrata exhibited the lowest biofilm metabolic activity despite having the highest number of biofilm cultivable cells. Similarly, the metabolic activity of resuspended C. glabrata biofilm and planktonic cells was lower than that of the other species. This study demonstrates the existence of intrinsic activity differences amongst NCAC species, which could have important implications in terms of species relative virulence. Furthermore, the absence of an obvious correlation, between cultivable cells number and total biofilm activity, raises the question about which parameter is the most appropriate for the in vitro assessment of biofilms and their potential clinical significance.
Silva
Sónia
S
Institute for Biotechnology and Bioengineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
Henriques
Mariana
M
Oliveira
Rosário
R
Williams
David
D
Azeredo
Joana
J
D018441:Biofilms / Q000254:growth & development*; D002175:Candida / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D015169:Colony Count, Microbial; D006801:Humans; D008855:Microscopy, Electron, Scanning; D013778:Tetrazolium Salts / Q000378:metabolism
D013778:Tetrazolium Salts; C059087:2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide
Eur J Clin Microbiol Infect Dis. 2003 Aug;22(8):470-4
12884068
Surg Infect (Larchmt). 2003 Fall;4(3):263-71
14588161
J Am Acad Dermatol. 1994 Sep;31(3 Pt 2):S2-5
8077502
Clin Microbiol Rev. 1999 Jan;12(1):80-96
9880475
Microbes Infect. 2009 Jul-Aug;11(8-9):753-61
19409507
J Clin Microbiol. 2003 Jan;41(1):506-8
12517908
Am J Clin Pathol. 1980 Apr;73(4):518-21
7369176
Arch Oral Biol. 2007 Aug;52(8):761-7
17321487
J Med Microbiol. 1999 Jul;48(7):671-679
10403418
BMC Infect Dis. 2006 Feb 10;6:21
16472387
J Clin Microbiol. 2003 Jul;41(7):2961-7
12843027
Oral Dis. 2002;8 Suppl 2:151-60
12164650
J Clin Microbiol. 1995 Sep;33(9):2476-9
7494052
J Med Microbiol. 2006 Aug;55(Pt 8):999-1008
16849719
Br J Biomed Sci. 2006;63(1):5-11
16613134
Trends Microbiol. 2003 Jan;11(1):30-6
12526852
Infect Immun. 2003 Aug;71(8):4333-40
12874310
Trends Microbiol. 2001 Jan;9(1):34-9
11166241
Annu Rev Microbiol. 1995;49:711-45
8561477
Infect Immun. 2002 Feb;70(2):878-88
11796623
J Bacteriol. 2001 Sep;183(18):5385-94
11514524
J Med Vet Mycol. 1996 Mar-Apr;34(2):149-52
8732362
Eukaryot Cell. 2005 Apr;4(4):633-8
15821123
J Med Microbiol. 1998 Mar;47(3):253-6
9511830
Infect Immun. 1994 Mar;62(3):915-21
8112864
J Antimicrob Chemother. 2000 Sep;46(3):397-403
10980166
J Clin Microbiol. 2002 Apr;40(4):1244-8
11923339