Comparison of the antibacterial effect of uroepithelial cells from healthy donors and children with asymptomatic bacteriuria

Abstract

Bacterial attachment to uroepithelial cells (UEC) and the effect of UEC on bacterial growth was investigated in 15 healthy persons and 12 patients suffering from asymptomatic bacteriuria (ABU) with recurrent urinary tract infections (UTI). Desquamated UEC and mannose-resistant Escherichia coli were co-cultivated for up to 90 min. While no difference in bacterial adherence was observed between healthy controls and patients, 33.4% of the bacteria attached to normal UEC were found to be dead under microscopic evaluation (acridine orange staining), whereas no killing effect could be observed in patients' UEC 5 min after the onset of incubation. This phenomenon was confirmed by investigating the E. coli growth rate in the presence of UEC, measured by counting bacterial colony forming units (CFU) on agar plates. While E. coli showed exponential growth in RPMI medium, the addition of normal UEC suppressed bacterial growth (P less than 0.01). UEC from patients with ABU, however, did not show this effect. It has been concluded that bacterial adhesion may initiate an epithelial defence function, present in healthy controls and lacking in ABU patients.

Long-Term Follow-Up of Children with Surgically Treated Yesicorenal Reflux: Postoperative Incidence of Urinary Tract Infections, Renal Scars and Arterial Hypertension

“…The latter is rather influenced by other host factors such as bladder dysfunction, increased periurethral bac terial colonization and probably a defect in the antibac- terial function of the UEC [26]. In previous experiments we were able to confirm a suppression of bacterial growth by cocultivating E. coli with UEC from healthy donors [15]. This antibacterial effect was missing in girls with asymptomatic bacteriuria (ABU) without urological abnormalities.…”

“…The laboratory methods used have been described in greater detail elsewhere [15]; briefly, 105 UEC obtained from fresh morning urine were cocultivated with 108 bacteria of an uropathogenic Escherichia coli strain (01, Kl, H7). After 15, 30 and 45 min, aliquots ( 100 pi) of the bacteria-cell suspension were diluted 1:105 in RPMI, mixed with liquid Mueller-Hinton agar and transferred to tissue culture plates with a grid.…”

Virulence factors in Escherichia coli urinary tract infection

“…Isolates taken during UTI episodes in patients with recurrent UTI (RUTI) adhere no better to control vaginal epithelial cells than do other strains (134), but vaginal (or buccal, uroepithelial, or periurethral) cells from such patients have a greater adherence capacity for standard E. coli strains than do comparable cells from control patients (50,133,252,256,425,440,475,476,512,525). Uroepithelial cells from UTI-free patients may even possess an antibacterial property that is diminished in cells from patients with RUTI (485). Uroepithelial cells collected near the middle of the menstrual cycle may have an increased bacterial adherence capacity (438,474,527), although this is not a consistent finding (133,463,475,527).…”

“…4 adherence, removing unattached bacteria by repeated washings (512) or filtration (64,425,474), and determining the number of adherent bacteria remaining by using microscopy (64,485,512) or radiometric techniques (425,474,475). A number of technical considerations influence the reliability of such assays (64,463), including the growth conditions used to prepare bacteria (224,517), the origin of the epithelial cell (62,224,524), the cell type (i.e., squamous or transitional) (263,438,512,517,527), and, possibly, the viability of the cell (64,252,438,463,512).…”

Expression of the K54 and O4 specific antigen has opposite effects on the bactericidal activity of squalamine against an extraintestinal isolate of Escherichia coli

“…Whether squalamine or related compounds are present outside of this species is not known. However in the human urinary tract, incompletely de¢ned molecules have been identi¢ed that possess bactericidal activity [13,14]. More recently, a cationic, polyamine-like component of urine (molecular mass of 500^1000) has been isolated that possesses antibacterial activity [15].…”