ABSTRACT

A total of 65 isolates of Staphylococcus aureus (25) and Escherichia coil (30) were isolated from different clinical samples. Bioflim formation was determined in trypticase soy broth and brain heart infusion broth using three different methods (Tissue culture plate method, Tube method and Congo red agar method). The result shows that biofilm production was detected by all the methods. Positive cases were more frequently observed in tissue culture plate method (high; 30.8%) than in tube method (high; 24.6%) and congo red agar method (high; 15 4%). The influence of incubation temperature on bioflim formation was investigated at 22°C, 3Ø0 C and 37°C. The mean quantities of bioflim formed at 30°C (0.42±0.0 1) were higher than those formed at both 37°C (0.35±0.03) and 22°C (0.28±0.01). The biofilm formation was high under aerobic conditions and low under anaerobic conditions. The amount of biofilm formed by all the isolates decreased with decrease in pH. The amount of biofllm produced in pH 3 (0.01±0.01) and pH 5 (0.05±0.01) were very low compared to formation at pH 9 and 12. Biofilm formed on glass and catheter surfaces and the amount formed was directly proportional to the duration of cultivation. The amount increased significantly with increase in time. Supplementation of the culture medium with sugars yielded an increase in bioflim production. All S. aureus isolates tested were resistant to penicillin, ceftazidime, chloramphenicol, cotrimoxazole, clinafloxacin. All S. aureus isolates were susceptible to gentamicin ofloxacin and augmentin, while 60% were susceptible to rifampin and ceftriaxone. All E. coil isolates were resistant to ceftriaxone, chloramphenicol and ciprofloxacin and were susceptible to gentamicin and nalixidic acid, while 60% were susceptible to ofloxacin and levofloxacin. Biofilm formation is best studied with the tissue culture plate method under aerobic conditions at 30°C or 37°C in neutral or alkaline pH. It is enhanced by sugar supplementation. Gentamicin, augmentin and ofloxacin are effective against S. aureus and E. coii.