Insignifi cant difference seen on biofi lm production among indwelling medical device associated bacterial isolates

Abstract

Aim of study: Biofilm formation is a developmental process with intercellular signals
that regulate growth. Biofilms contaminate catheters, ventilators and medical implants;
they act as a source of disease for humans, animals and plants. In this study we have done
quantitative assessment of biofilm formation in device-associated clinical bacterial isolates
in response to various concentrations of glucose in tryptic soya broth and with different
incubation time. Materials and Methods: The study was carried out on 100 positive
bacteriological cultures of medical devices which were inserted in hospitalized patients.
The bacterial isolates were processed as per microtitre plate method with tryptic soya
broth alone and with varying concentrations of glucose and were observed in response
to time. Results: The majority of catheter cultures were positive. Out of the total 100
bacterial isolates tested, 88 were biofilm formers. Biofilm production was more in
0.25% than in 0.5% glucose concentration in tryptic soya broth. After 16-h incubation
no significant difference was seen in biofilm production. Conclusions: Availability
of nutrition in the form of glucose enhances the biofilm formation by bacteria, but
further increase in glucose concentration could not enhance biofilm production. Biofilm
formation depends on the adherence of bacteria to various surfaces.