A biphasic response from bladder epithelial cells induced by catheter material and bacteria: an in vitro study of the pathophysiology of catheter related urinary tract infection.
OBJECTIVE
Catheter associated urinary tract infection is the most common type of hospital acquired infection. An understanding of catheter associated urinary tract infection pathogenesis is needed to improve the control and treatment of these infections. We investigated the relationship among catheter material, bacteria and bladder epithelial cell reaction.


METHODS
Urinary catheter sections and a clinical isolate of Escherichia coli were added to human bladder carcinoma epithelial cells in vitro in combination or independently. The catheters were rotated for 30 seconds over the cells, followed by incubation. The cytokines interleukin-6 and 8 were measured by enzyme-linked immunosorbent assay as indicators of inflammation and cell membrane disruption was assessed using a lactate dehydrogenase assay.


RESULTS
The levels of lactate dehydrogenase release and cytokine production depended on the number of bacteria added. Bacteria grown for 3 days caused greater secretion of cytokines than bacteria grown overnight. Silicone catheter material alone caused immediate damage to cells with increased lactate dehydrogenase in the supernatant but little interleukin-6 or 8 production. Silicone catheters caused significantly less cytokine secretion from bladder cells than latex catheters. Conversely bacteria caused little immediate damage to cells but stimulated cytokine production after 12 hours.


CONCLUSIONS
Disruption of bladder epithelial cell membranes in vitro occurred immediately as a result of physical abrasion caused by catheters but delayed inflammation occurred in response to bacterial infection.
Barford
Jessica M T
JM
Department of Medical Microbiology, Cellular and Molecular Medicine, St. George's, University of London, United Kingdom.
Hu
Yanmin
Y
Anson
Ken
K
Coates
Anthony R M
AR
D001422:Bacterial Adhesion; D002404:Catheterization / Q000009:adverse effects*; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000382:microbiology / Q000502:physiology*; D004926:Escherichia coli; D006801:Humans; D066298:In Vitro Techniques; D015850:Interleukin-6 / Q000032:analysis; D016209:Interleukin-8 / Q000032:analysis; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D007840:Latex / Q000009:adverse effects / Q000737:chemistry; D012680:Sensitivity and Specificity; D012828:Silicones / Q000009:adverse effects / Q000737:chemistry; D001743:Urinary Bladder / Q000166:cytology; D014552:Urinary Tract Infections / Q000209:etiology* / Q000503:physiopathology*; D019459:Urothelium / Q000166:cytology / Q000382:microbiology
D015850:Interleukin-6; D016209:Interleukin-8; D007840:Latex; D012828:Silicones; D007770:L-Lactate Dehydrogenase