Detection of biofilm formation by Escherichia coli with its antibiogram profile

Gaurab Risal, Aayush Shrestha, Saroj Kunwar, Gajal Paudel, Rameshwor Dhital, Man Bahadur Budha, Rupa Nepal


Background: In urinary tract infections, an important role is played by bacterial biofilms which are responsible for persistence infections together with the antimicrobial resistance. Higher resistance can be seen in biofilm forming uropathogens in comparison with free-floating bacteria. So, the present study was performed with a goal to find the prevalence of biofilm formation and also the antimicrobial resistant pattern of uropathogens.

Methods: A descriptive method was conducted at Modern Technical College, Sanepa, Lalitpur in samples isolated from UTI suspected patients. The overall duration of this study was approximately 3 months. Total of 50 isolated E. coli was tested for biofilm formation and antimicrobial susceptibility testing was done by Kirby-Bauer disc diffusion method on Mueller Hinton agar as per CLSI guidelines.

Results: From the 50 isolates of E. coli, 32 were biofilm producers (3 strong and 29 moderate) and 18 were weak/non-biofilm producers. Among the biofilm producers, cefotaxime was more resistant in 20 of the isolates followed by ceftriaxone in 16 and amoxyclav in 13, whereas amikacin was least resistant in 2 of the isolates.

Conclusions: Among the isolated E. coli, biofilm-forming isolates showed higher antimicrobial resistance as compared to the non-biofilm producer. Thus, uropathogen should be routinely screened for biofilm formation.



Uropathogen, UTI, Biofilm formation, Antimicrobial resistance pattern

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Hall-Stoodley L, Costerton JW, Stoodley P. Bacterial biofilms: From the Natural environment to infectious diseases. Nature Rev Microbiol. 2004;2(2):95-108.

Lear G, Lewis GD, eds. Microbial Biofilms: Current Research and Applications. Caister Academic Press; 2012.

Briandet R, Herry J, Bellon-Fontaine M. Determination of the van der Waals, electron donor and electron acceptor surface tension components of static Gram-positive microbial biofilms. Colloids and Surfaces B: Biointerfaces. 2012;21(4):299-310.

Takahashi H, Suda T, Tanaka Y, Kimura B. Cellular hydrophobicity of Listeria monocytogenes involves initial attachment and biofilm formation on the surface of polyvinyl chloride. Letters Appl Microbiol. 2010;50:618-25.

Lewis K. Riddle of Biofilm Resistance. Antimicrob Agents Chemother. 2001;45(4);999-1007.

Kunin CM. Urinary tract infections in females. Clin Infect Dis. 1994;18:1–12.

Christensen GD, Simpson WA, Younger JJ, Baddour LM., Barrett FF, Melton DM, et al. Adherence of coagulase-negative staphylococci to plastic tissue culture plates: a quantitative model for the adherence of staphylococci to medical devices. J Clin Microbiol. 1985;22(6):996-1006.

Christensen GD, Simpson WA, Bisno AL, Beachey EH. Adherence of Slime-Producing Strains of Staphylococcus Epidermidis to Smooth Surfaces. Infect Immun. 1982;37(1):318-26.

Freeman DJ, Falkiner FR, Keane CT. New method for detecting slime production by coagulase negative staphylococci. J Clin Pathol. 1989;42(8):872–4.

Panda PS, Chaudhary U, Dube SK. Comparison of four different methods for detection of biofilm formation by uropathogens. Indian J Pathol Microbiol. 2016;59(2):177-9.

Mathur T, Singhal S, Khan S, Upadhyay DJ, Fatma T, Rattan A. Detection of biofilm formation among the clinical isolates of staphylococci: an evaluation of three different screening methods. Indian J Med Microbiol. 2006;24(1):25-9.

Römling U, Balsalobre C. Biofilm infections, their resilience to therapy and innovative treatment strategies. J Intern Med. 2012;272(6):541-61.

Stowe SD, Richards JJ, Tucker AT, Thompson, R., Melander C, Cavanagh J. Anti-Biofilm Compounds Derived from Marine Sponges. Mar Drugs. 2011;9(10):2010–35.

O’toole GA. Microtiter Dish Biofilm Formation Assay. J Vis Exp. 2011;(47):2437.

Stepanović S, Vuković D, Hola V, Bonaventura GD, Djukić S, Cirković I, et al. Quantification of biofilm in microtiter plates: Overview of testing conditions and practical recommendations for assessment of biofilm production by staphylococci. Apmis 2007;115(8):891-9.

CLSI. M100-S25 performance standards for antimicrobial susceptibility testing; Twenty-fifth informational supplement; 2015.

Jabalameli F, Mirsalehian A, Khoramian B, Aligholi M, Khoramrooz SS, Asadollahi P, et al. Evaluation of biofilm production and characterization of genes encoding type III secretion system among Pseudomonas aeruginosa isolated from burn patients. Burns. 2012;38(8):1192-7.

Hassan A, Usman J, Kaleem F, Omair M, Khalid A, Iqbal M. Evaluation of different detection methods of biofilm formation in the clinical isolates. Braz J Infect Dis. 2011;15(4):305-11.

Ronald AR, Nicolle LE, Stamm E, Krieger J, Warren J, Schaeffer A. et al. Urinary tract infection in adults: Research priorities and strategies. Int J Antimicrob Agents. 2001;17:343–8.

Gupta K, Hooton TM, Stamm WE. Increasing Antimicrobial Resistance and the Management of Uncomplicated Community-Acquired Urinary Tract Infections. Ann Internal Med. 2001;135(1):41.

Graham JC, Galloway A. ACP Best Practice No 167: The laboratory diagnosis of urinary tract infection. J Clin Pathol. 2001;54(12):911-9.

Tayal RA, Baveja SM, De AS. Analysis of biofilm formation and antibiotic susceptibility pattern of uropathogens in patients admitted in a tertiary care hospital in India. Int J Health Allied Sci. 2015;4:247-52.

Tajbakhsh E, Ahmadi P, Abedpour-Dehkordi E, Arbab-Soleimani N, Khamesipour F. Biofilm formation, antimicrobial susceptibility, serogroups and virulence genes of uropathogenic E. coli isolated from clinical samples in Iran. Antimicrob Resist Infect Control. 2016;5:11.