RESUMO
Medical devices-associated infections continue to be a significant source of morbidity and mortality, and lead to increased medical expenses by prolonging hospitalization. These infections are most commonly caused by biofilm producing organisms. Study microbial biofilm in different medical devices, their association with infections and their antimicrobial resistance. Hundred and three egyptian patients with different indwelling medical devices were studied to isolate and to identify the organisms present on the device surfaces. Biofilm production was tested qualitatively using tube and plate adherence methods and semi-quantitatively by measuring optical density of adherence by spectrophotometer. Antimicrobial resistance was detected using Calgary's device. The presence of biofilm, on some of the devices, was confirmed using scanning electron microscopy. Different species were isolated from 65.1% of the studied devices. Associated infections, detected by blood and urine cultures, were 48% and 61%, respectively. Biofilm production by the isolates showed that 11.9% were weak, 17.9% were strong and 70.2% were non producers. Staphylococcus spp. represented 40% of biofilm producing organisms. Antimicrobial resistance showed statistically significant difference between planktonic and biofilm cells as measured by Minimum Inhibitory Concentration [MIC] and Minimum Biofilm Eradication Concentration [MBEC]. There were a significant percentage of organisms able to grow within biofilm on indwelling medical device surfaces and considered as a source of infection. Both plate adherence and spectrophotometric methods are reliable tests, any of them can be used to diagnose biofilm formation. Spectrophotometric method is the most reliable test to differentiate between weak and strong biofilm producers. Biofilm producing isolates were highly resistant to antimicrobials in comparison to their planktonic counterparts