Does alkalinised urine reduce the rate of encrustation in patients with ureteric stents? A randomised controlled study.

PURPOSE: Stent encrustation is not uncommonly encountered with a high number of ureteric stents. The exact pathophysiology is not well understood. Therefore, we investigated the relationship between the use of sodium citrate and likelihood of stent encrustation. METHODS: This prospective, randomised, intervention study was conducted between October 2018 and October 2019 in a tertiary hospital. Overall, 115 patients with ureteral stents that were inserted after lithotripsy surgeries were recruited. The study subjects were randomised into two groups: one group was administered sodium citrate (Utix sachets) three times per day until stent removal (intervention group), and the second group was not administered Utix sachets (control group). Stents were removed after 1 month and inspected under macroscopic visualisation from the proximal to distal end for any crystallisation; a second inspection was done with a 60 × magnification lens. Any crystallisation observed was considered to be encrustation. RESULTS: Patients who had Utix sachets post-insertion of a ureteric stent constituted 50.4% of the study cohort. The rate of encrustation in the control group was 52.6%. In the intervention group, the rate of encrustation was 46.6%. The difference was not statistically significant with the chi-squared test (p value, 0.514). CONCLUSION: Alkaline citrate medications had no significant effect on stent encrustation rate. More studies are needed to elucidate different agents and their roles in reducing stent encrustation as it incurs high morbidity.

Identification of strains of RotaTeq rotavirus vaccine in infants with gastroenteritis following routine vaccination.

BACKGROUND: RotaTeq vaccine was introduced into the Australian National Immunisation Program in 2007. This study identified and characterised rotavirus strains excreted by infants who presented with symptoms of gastroenteritis following recent RotaTeq vaccination. METHODS: Fecal samples (N = 61) from children who developed gastroenteritis following recent RotaTeq vaccination were forwarded to the Australian Rotavirus Surveillance Program (ARSP). RotaTeq-positive samples were genotyped and regions of the VP3, VP4, VP6, and VP7 genes were sequenced. Also, 460 rotavirus-positive ARSP routine surveillance samples were analyzed by dot-blot Northern hybridization to detect RotaTeq vaccine-derived strains circulating in the community. RESULTS: Thirteen of the 61 samples collected from infants developing gastroenteritis after RotaTeq vaccination contained vaccine-derived (vd) rotavirus strains. Of these, 4 contained a vdG1P[8] strain derived by reassortment between the G1P[5] and G6P[8] parental vaccine strains. Northern hybridization analysis of 460 surveillance samples identified 3 samples that contained RotaTeq vaccine-derived strains, including 2 vdG1P[8] reassortant vaccine strains. CONCLUSIONS: During replication and excretion of RotaTeq vaccine, reassortment of parental strains can occur. Shedding of RotaTeq vaccine strains in 7 of 13 infants was associated with underlying medical conditions that may have altered their immune function. The benefits of vaccination outweigh any small risk of vaccine-associated gastroenteritis.