Renal Allograft Injury Is Associated with Urinary Tract Infection Caused by Escherichia coli Bearing Adherence Factors

Abstract

Urinary tract infections are the most common infection in renal transplant patients and Escherichia coli (E. coli) is the most common clinical isolate. Although acute allograft injury (AAI) secondary to urinary tract infection (UTI) has been reported, the incidence of AAI associated with UTI, the virulence factors express by uropathic E. coli and whether virulence factors are associated with renal allograft outcome have not been described. We collected E. coli from our renal transplant patients with UTI, determined O:H serotypes, P and Dr fimbriae expression and the clinical presentation and allograft function during the UTI and post-UTI period. Pyelonephritis occurred in 40% of our patients, 82% of which had AAI (>20% increase in SCr). Sixtytwo percent of E. coli isolates that expressed P fimbriae were associated with AAI, whereas only 29% that did not express P fimbriae had AAI (p = 0.03). The pattern of P fimbriae and O serotypes differed from reported isolates, as the P fimbriae PapG class II and the O25 serotype were the most common. Dr adhesin was expressed on 7 isolates, including 2 of 3 with urosepsis. We propose a unique pattern of uropathogenic serotypes and adherence factors contribute to acute allograft injury in renal transplant patients with UTI.

The Role of Host Factors and Bacterial Virulence Genes in the Development of Pyelonephritis Caused by Escherichia coli in Renal Transplant Recipients

“…Our prevalence of 27% of papGII in PN is not high if compared with other studies that reported rates of 54% to 93% in the non-Tx population (5,11,12,15). In Tx patients, Rice et al (21) found significant differences regarding the papGII prevalence between PN and lower UTIs-47% versus 18%. Nevertheless, in experimental models, Mobley et al (42) have shown that adherence mediated by the P-fimbrial adhesin played only a subtle role in the development of PN.…”

“…Thus, the lack of papGIII in E. coli strains was an independent factor associated with PN in all patients (OR ϭ 4.88) and Tx patients (OR ϭ 5.07). On the other hand, some studies did not find any association between papGIII and PN in non-Tx (5,11,13,15) or Tx patients (21), with the prevalence ranging from 4% to 35%.…”

“…Although there are several studies assessing E. coli virulence genes in upper UTI (5,(11)(12)(13), only one of them has been conducted in renal Tx recipients (21). We aimed to evaluate host and bacterial virulence factors mostly associated with PN by E. coli in Tx patients.…”

“…Acute PN was defined by the presence of fever (Ͼ38°C axillary) plus flank pain, with or without dysuria or urinary frequency. In renal Tx patients, PN was defined by the presence of fever and/or an increase of serum creatinine Ն20% over baseline values (21) on the occasion of the positive urine culture. Other accompanying symptoms or signs of PN included renal allograft tenderness, bacteremia, or a renal allograft biopsy specimen confirming bacterial PN.…”

The Impact of Infection on Chronic Allograft Dysfunction and Allograft Survival After Solid Organ Transplantation

“…Acute pyelonephritis can also contribute to chronic allograft dysfunction by direct kidney injury, as shown in a study in which multiple focal scarring defects were observed by technetium Tc 99m dimercaptosuccinic acid single photon emission computed tomography, or 99m Tc-DMSA SPECT, in kidney transplant recipients with recurrent late UTI. Acute allograft injury was observed only in patients with infection with uropathogenic E coli that expressed virulence factors such as P fimbriae but not with infection by other strains (174).…”