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  Table of Contents  
Year : 2015  |  Volume : 33  |  Issue : 2  |  Page : 319-320

Biofilm formation by bacterial isolates from patients on indwelling medical devices

1 Department of Microbiology, Gauhati Medical College Hospital, Guwahati, Assam, India
2 Department of Microbiology, Assam Medical College Hospital, Dibrugarh, Assam, India

Date of Submission07-Mar-2014
Date of Acceptance23-Sep-2014
Date of Web Publication10-Apr-2015

Correspondence Address:
M Gogoi
Department of Microbiology, Gauhati Medical College Hospital, Guwahati, Assam
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0255-0857.154896

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How to cite this article:
Gogoi M, Sharma A, Hazarika N K. Biofilm formation by bacterial isolates from patients on indwelling medical devices. Indian J Med Microbiol 2015;33:319-20

How to cite this URL:
Gogoi M, Sharma A, Hazarika N K. Biofilm formation by bacterial isolates from patients on indwelling medical devices. Indian J Med Microbiol [serial online] 2015 [cited 2019 Dec 11];33:319-20. Available from:

Dear Editor,

Biofilms are being recognized as an important source of bacterial pathogens especially in those with indwelling medical devices. They also contribute significantly to emergence and dissemination of antibiotic resistance traits in nosocomial setting. [1] The present study was therefore undertaken to compare the three methods used for detection of biofilm formation i.e. tissue culture plate method (TCP), tube method (TM) and Congo red agar method (CRA) and to study antibiotic susceptibility pattern of the biofilm producers and the non-biofilm producers.

Clinical specimens i.e. blood, urine from urinary catheter, endotracheal tubes, tracheal aspirates, central line tips, drainage catheter specimens were collected from patients with clinical diagnosis of device-associated infections from different ICUs. The 115 bacterial isolates were identified by standard microbiological procedures. The antimicrobial susceptibility testing was done by Kirby-Bauer disc diffusion method. Detection of biofilm formation was done by TCP, TM and CRA method. [2],[3],[4] Biofilm-producing Pseudomonas aeruginosa (ATCC 27853) and non-biofilm forming Staphylococcus aureus (ATCC 25923) and  Escherichia More Details coli (ATCC 25922) were used as controls. [5]

The TCP, TM and CRA detected 61.7%, 41.7% and 18.2% of biofilm producers, respectively [Table 1]. Maximum biofilm producers were isolated from tracheal aspirate and endotracheal tubes (52.1%) followed by blood (17%) and urine (12.6%), respectively. 92.3% of biofilm producing non-lactose fermenters were MDR whereas only 50% non-producers were MDR. Similarly, 72% of biofilm producing enterobacteriaceae isolates were MDR whereas only 57.1% non-biofilm producers were MDR. Fifty percent of biofilm producing  S.aureus Scientific Name Search  isolates were MRSA whereas only 33% non-producers were MRSA. A significant association was found between the biofilm producers and multidrug resistance (P value: 0.0125 by Fisher exact test). To conclude, TCP was the most sensitive method. Also, MDR among biofilm producers was significantly higher than non-producers thus, limiting the treatment options. Therefore, emphasis has to be laid on effective biofilm-control strategies.
Table 1: Showing the quantitative analysis of biofilm production by bacterial isolates as detected by tissue culture plate method

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 ~ References Top

The direct medical costs of healthcare-associated infections in U.S. hospitals and the benefits of Prevention. CS200891-A, March; 2009.  Back to cited text no. 1
Christensen GD, Simpson WA, Yonger JJ, Baddour LM, Barrett FF, Melton DM, et al. Adherence of Coagulase-negative staphylococci to plastic tissue cultures: A quantitative model for the adherence of staphylococci to medical device. J Clin Microbiol 1985;22:996-1006.  Back to cited text no. 2
Christensen GD, Simpson WA, Bisno AL, Beachey EH. Adherence of slime - producing strains of Staphylococcus epidermidis to smooth surfaces. Infect Immun 1982;37:318-26.  Back to cited text no. 3
Freeman DJ, Falkiner FR, Keane CT. New method for detecting slime production by Coagulase negative staphylococci. J Clin Pathol 1989;42:872-4.  Back to cited text no. 4
Rao RS, Karthika RU, Singh SP, Shashikala P, Kanungo R, Jayachandran S, et al. Correlation between biofilm production and multiple drug resistance in imipenem resistant clinical isolates of Acinetobacter baumannii. Indian J Med Microbiol 2008;26:333-7.  Back to cited text no. 5
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