Antibiotic penetration through Pseudomonas aeruginosa colony biofilms

Content Provider	Semantic Scholar
Author	Walters, Marshall Charles
Copyright Year	2001
Abstract	Paeruginosa has been implicated in infections pertaining to nearly every organ system. Despite numerous treatment methods total eradication of infections has proved to be impossible in most cases. Heightened resistance to intensive chemotherapy has lead to the hypothesis that P. aeruginosa infections involve a biofilm state of growth. The exact mechanism(s) providing this resistance within biofilms is unknown. The failure of antibiotics to fully penetrate through the biofilm is one hypothesis which was experimentally investigated in this work. The penetration of tobramycin and ciprofloxacin through biofilms formed by a. mucoid clinical isolate o ff. aeruginosa was measured. Colony biofilms of strain FRD-I were formed by inoculation of microporous membranes resting on trypic soy agar plates. Such colony biofilms formed a primitive model of the biofilm that may form in the airways of people with cystic fibrosis. Bacteria in biofilms were profoundly resistant to killing by tobramycin. When biofilms were challenged with 10 pg/mL of tobramycin for up to 100 h there was no decrease in the number of viable cells. Treatment with this concentration of tobramycin for 4 h was sufficient to kill (greater then 4 log reduction) planktonic cells or bacteria resuspended from colony biofilms. Tobramycin failed to penetrate colony biofilms at detectable levels in 12 h exposure. When challenged with I pg/mL ciprofloxacin, biofilms again exhibited resistance while planktonic cells or resuspended bacteria were extremely sensitive. In contrast, ciprofloxacin fully penetrated colony biofilms within a few hours. These results show that there is not a generic barrier to antibiotic transport through such biofilms, but that some mechanism, does hinder the delivery of tobramycin through P. aeruginosa biofilm.
Starting Page	1
Ending Page	63
Page Count	63
File Format	PDF HTM / HTML
Alternate Webpage(s)	https://scholarworks.montana.edu/xmlui/bitstream/handle/1/8055/31762103446736.pdf?isAllowed=y&sequence=1
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article