The control of urinary tract infections in kidney-transplant recipients (UTI) through various protocols aims to avoid related complications in order to not compromise the prognosis of renal transplantation (TX).
The objective of this study is to know the prophylaxis protocols against recurrent urinary tract infections in renal transplant recipients in the usual clinical practice and the results of these strategies.

A retrospective study of 1845 renal transplant recipients in 4 general hospitals in Spain was conducted. The following study groups were considered: 
* Group A: patients with post-tx urinary tract infection. 
* Group B: patients without urinary tract infection after receiving a kidney transplant.
The following subgroups according to urinary tract infections' management were distinguished:
•	Subgroup A1 (n = 324): patients who received on-demand antibiotics; Subgroup A2 (n = 45): patients who received on-demand antibiotic, plus prophylactic oral supplement (D-mannose + proanthocyanidins + ursolic acid);
•	Subgroup A3 (n = 18): patients who received on-demand antibiotics, plus conventional antibiotic prophylaxis, in a continuous low-dose nocturnal dose of 160 mg of trimethoprim plus 800 mg of sulfamethoxazole;
•	Subgroup A4 (n = 63): patients who received conventional nocturnal low-dose antibiotic prophylaxis;
•	Subgroup A5 (n = 81): patients who received sublingual polybacterial vaccine (Uromune®);
•	Subgroup A6 (n = 864): patients who received different treatment or prophylaxis than the other Group A subgroups.
•	Subgroup B1 (n = 224): patients who received on-demand antibiotics due to suspicious uinary tract infection that is not confirmed neither analytically nor microbiologically;
•	Subgroup B2 (n = 18): patients who received conventional nocturnal low-dose antibiotic prophylaxis.
•	Subgroup B3 (n = 207): patients who received neither treatment nor prophylaxis against urinary tract infections.
Age, gender, body mass index, personal history, functional result of the transplant, urine cultures, episodes classified as urinary tract infection were analysed. Descriptive statistics, ANOVA analysis, Student's t test, Fisher's exact test were performed; p <0.05 was considered significant.

On-demand antibiotic treatment plus continuous antibiotic prophylaxis was mostly indicated in younger transplant recipients compared to the elderly. The patients in whom on-demand antibiotic plus continuous antibiotic prophylaxis was indicated were all men. Women received more frequently (66%) polyvalent bacterial vaccine against on-demand antibiotic (44%). 
In Group A there was a high prevalence of hypertension, with differences between the different management groups of the UTIs: polybacterial vaccine (A5; 98.76%), on-demand antibiotics (A1; 80.24%), continuous prophylactic antibiotic (A4; 69.84%), diverse (A6; 66.66%), on-demand antibiotic plus continuous antibiotic prophylaxis (A3; 44.44%) and finally, lower in the group that received on-demand antibiotic plus prophylactic oral supplement with D-mannose (A2; 17.77%). 
In the patients who presented urinary tract infections after transplantation, pre-transplant urinary tract infections were more frequent (Group A; 14.26%) compared to those who did not present urinary tract infections after transplantation (Group B; 2.22%). 
The polyvalent bacterial vaccine was indicated in patients in whom a higher risk of infection or complicated infection was suspected (higher percentage of pretransplant urinary tract infections).

Urinary tract infection is the most common infection occurring in renal transplant recipients. Risk factors that promote urinary infection in these patients may predate transplant, be associated with the transplant procedure itself, or follow transplantation (1). In the latter group, immunosuppressive therapy or persistent urologic abnormalities, such as strictures, stone formation, or hydronephrosis, increase the frequency of infection. This study shows the efficacy and benefit of the use of the polybacterial vaccine (Uromune ®) in this specific population. This vaccine favours immunoactive prophylaxis using a suspension of inactivated complete cells of differents strains of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Enterococcus faecalis. Furthermore, the avoidance of continuous antimicrobial treatment may prevent the appearance of antibiotic-resistant strains.

There is no established protocol for recurrent urinary tract infections' prophylaxis in kidney transplant recipients. In our sample, 14.83% of patients with UTI after transplantation received a similar prophylaxis to that used in recurrent urinary tract infections in non-transplant patients, while 23.22% of them were managed with sporadic urinary tract infections criteria. In usual clinical practice, there are several effective prophylaxis protocols without differences in the results.

Nicolle LE. Urinary tract infections in special populations: diabetes, renal transplant, HIV infection, and spinal cord injury. Infect Dis Clin North Am. 2014 Mar;28(1):91-104. doi: 10.1016/j.idc.2013.09.006.