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Year : 2007  |  Volume : 25  |  Issue : 3  |  Page : 305--306

Study of biofilm production in Escherichia coli causing urinary tract infection

E Suman1, J Jose1, S Varghese1, MS Kotian2,  
1 Department of Microbiology, Kasturba Medical College, Mangalore - 575 001, Karnataka, India
2 Department of Community Medicine, Kasturba Medical College, Mangalore - 575 001, Karnataka, India

Correspondence Address:
E Suman
Department of Microbiology, Kasturba Medical College, Mangalore - 575 001, Karnataka
India

How to cite this article:
Suman E, Jose J, Varghese S, Kotian M S. Study of biofilm production in Escherichia coli causing urinary tract infection.Indian J Med Microbiol 2007;25:305-306

How to cite this URL:
Suman E, Jose J, Varghese S, Kotian M S. Study of biofilm production in Escherichia coli causing urinary tract infection. Indian J Med Microbiol [serial online] 2007 [cited 2020 Aug 12 ];25:305-306
Available from: http://www.ijmm.org/text.asp?2007/25/3/305/34788

Full Text

Dear Editor,

Urinary tract infections pose a serious health threat with respect to antibiotic resistance and high recurrence rates. Escherichia coli is the predominant organism causing urinary tract infections. Uropathogenic E. coli forms intracellular bacterial communities with many biofilm-like properties within the bladder epithelium. [1] These intracellular biofilm-like pods allow bacteria to outlast a strong host immune response to establish a dormant reservoir of pathogens inside the bladder cells. Re-emergence of bacteria from this reservoir might be source of recurrent infections. [2]

The present study was aimed at in vitro qualitative estimation of biofilm production in E. coli and correlates it with antibiotic resistance and surface hydrophobicity.

A total 50 strains of E. coli showing significant count (>10 5 cfu /mL) were isolated from cases of urinary tract infections. The organisms were identified by standard biochemical reactions. Antibiotic sensitivity test was performed by Kirby-Bauer disk diffusion method. [3] The results are shown in [Table 1]. Surface hydrophobicity was performed by salt aggregation test (SAT) of Lindahl et al . [4]

E. coli ATCC 25922 was used as control. Biofilm production was tested by microtitre plate method and quantitated spectrophotometrically using an ELISA Reader. [5] Biofilm production was correlated with antibiotic resistance as well as surface hydrophobicity. Statistical analysis was performed by Kruskal-Wallis test and Mann Whitney U test.

Forty-six out of 50 strains of E. coli (92%) showed significant production of biofilm. Twenty-one out of 50 (54%) strains were sensitive to gentamicin followed by tobramycin (50%) and cotrimoxazole (44%) and ciprofloxacin (44%)

Multi-drug resistance pattern of the biofilm producing isolates is shown in [Table 2].

Out of the total 50 strains of E. coli isolated, there was significant correlation between biofilm production and resistance to multiple antibiotics such as ampicillin (A), co-trimoxazole (Co), nalidixic acid (Na) and norfloxacin (Nx). 11 out of 50 strains of E. coli showed significant SAT values (> 1.4). These strains were found to show increased biofilm production.

Bacterial biofilms are often associated with long-term persistence of organisms in various environments. Bacteria in biofilm display dramatically increased resistance to antibiotics. [2] The present study also showed significant correlation between biofilm production and multi-drug resistance.

Biofilm production in E. coli may promote colonization and lead to increased rate of urinary tract infections. Such infections may be difficult to treat as they exhibit multi-drug resistance. A greater understanding of the nature of intracellular bacterial communities in chronic or recurrent urinary tract infections will aid in the development of new and more effective treatments for these problematic diseases.

References

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2Anderson GG, Palermo JJ, Schilling JD, Roth R, Heuser J, Hultgren SJ. Intracellular bacterial Biofilm-like pods in urinary tract infections. Science 2003;301 :105-7.
3National Committee for Clinical Laboratory Standards. Performance standards for antimicrobial disc susceptibility testing. 3 rd ed. Approved Standard M2-A3. National Committee for Clinical Laboratory Standards. Vellanova, PA: USA; 1984.
4Lindahl M, Faris A, Wadstrom T, Hjerten S. A new test based on salting out to measure relative surface hydrophobicity of bacterial cells . Biochim Boiphys Acta 1981;677:471-6.
5O'Toole GA, Kolter R. Initiation of biofilm formation in Pseudomonas fluorescens WCS 365 proceeds via multiple, convergent signaling pathways: A genetic analysis. Mol Microbiol 1998;28:449-61.