***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES . To evaluate the role of primary vesicoureteral reflux ( VUR ) in increasing the frequency and severity of urinary tract infections ( UTIs ) and renal parenchymal damage among patients with acute pyelonephritis and to determine whether urinary antibiotic prophylaxis reduces the frequency and /or severity of UTIs and /or prevents renal parenchymal damage among patients with mild/moderate VUR . METHODS . Patients 3 months to 18 years of age with acute pyelonephritis , with or without VUR , were assigned r and omly to receive urinary antibiotic prophylaxis or not . Patients were monitored every 3 months for 1 year . Dimercaptosuccinic acid renal scans were repeated at 6 months or if there was a recurrence of febrile UTI . Urinalysis and urine culture were performed at each clinic visit . Renal ultrasound scans and voiding cystourethrograms were repeated at the end of 1 year of follow-up monitoring . RESULTS . Of the 236 patients enrolled in the study , 218 completed the 1-year follow-up monitoring . Groups were similar with respect to age , gender , and reflux grade distribution for those with VUR . No statistically significant differences were found among the groups with respect to rate of recurrent UTI , type of recurrence , rate of subsequent pyelonephritis , and development of renal parenchymal scars . CONCLUSIONS . After 1 year of follow-up monitoring , mild/moderate VUR does not increase the incidence of UTI , pyelonephritis , or renal scarring after acute pyelonephritis . Moreover , a role for urinary antibiotic prophylaxis in preventing the recurrence of infection and the development of renal scars is not supported by this study The aim of the present study was to obtain data on the outcome of children with persistent vesicoureteral reflux ( VUR ) after cessation of antibiotic prophylaxis . Children with VUR who had been on antibiotic prophylaxis for at least 2 y and were free of urinary tract infections ( UTI ) , had normal voiding patterns , and no hydronephrosis or new kidney scarring , had  antibiotic prophylaxis discontinued , were followed up prospect ively with  urine cultures , voiding cystourethrography , and technecium-99 m dimercaptosuccinate renal scintigraphy .  The findings were compared with those of the same patients while they were on antibiotic prophylaxis . In 54 children ( 39 girls and 15 boys ) , antibiotic prophylaxis was discontinued . The mean follow-up time on and off antibiotic prophylaxis was 4.4±2.1 and 4.4±2.2 y , respectively . Nine UTI episodes occurred during the on- and 8 during the off-prophylaxis period . In 80 of 96 and in 68 of 74 ureters the reflux resolved or down grade d during the on- and off-prophylaxis periods , respectively . No new scar lesions were detected in any of the children . In conclusion , in children with persistent VUR and certain characteristics , antibiotic prophylaxis can be safely discontinued PURPOSE Accepted management of vesicoureteral reflux includes surgical correction or prophylactic antibiotics with the hope for resolution as the child grows . The physician must consider surgery when reflux does not resolve despite uneventful years on prophylactic antibiotics . An alternative is cessation of the antibiotics . We report on the outcome of children taken off antibiotics  with persistent reflux . MATERIAL S AND METHODS During a 14-year period 51 children with documented reflux were taken off antibiotic prophylaxis . Selection criteria included children who were old enough to verbalize the symptoms of a urinary tract infection , and had normal voiding patterns , a minor history of infections and minimal or no renal scarring . Routine followup included nuclear cystography and renal sonography . RESULTS A total of 40 girls and 11 boys maintained on antibiotics for a mean of 4.8 years were taken off prophylaxis and followed for an average of 3.7 years . Mean patient age when prophylactic antibiotics were stopped was 8.6 years . Reflux resolved in 10 children ( 19.6 % ) . A urinary tract infection developed in 5 girls and 1 boy ( 11.8 % ) ( mean age 11 ) an average of 2.3 years ( range 4 months to 9.4 years ) after antibiotic discontinuation . One child had symptoms consistent with cystitis and 5 had febrile urinary tract infections . All were treated with oral antibiotics and 5 had subsequent operations . No new renal scars developed . CONCLUSIONS The majority of children did well following cessation of antibiotic prophylaxis despite persistent vesicoureteral reflux . Cessation of antibiotic prophylaxis is a reasonable option in a highly select patient population with reflux Eighteen girls between the ages of 3 and 13 years -- with a history of at least three culture-documented episodes of bacteriuria in the previous year , but without radiologic evidence of major urinary tract abnormality -- were placed on a double-blind , crossover study comparing the effectiveness of nitrofurantoin macrocrystals against a placebo in preventing the recurrence of bacteriuria . Each child was placed on a daily low dose of nitrofurantoin ( 1.2 to 2.4 mg/kg/day ) or an identical-appearing placebo for six months . Each child was then placed on the opposite capsule for a similar period . There were 35 episodes of bacteriuria ( 4.2 episodes/patient/yr ) in the patients taking the placebo , which compared with a rate of 3.8 episodes/patient/yr during the year prior to the study . Only two episodes ( 0.2 episodes/patient/yr ) occurred in the patients taking the drug . The difference in the rate of recurrent bacteriuria between the girls on placebo and on medication is significant at the 0.01 level using the Wilcoxin matched-pairs test . There were no adverse reactions to the drug . Nitrofurantoin macrocrystals in a single daily low dose appear to be a safe , effective method of preventing recurrent bacteriuria in girls at high risk Abstract In a r and omised controlled trial 45 children ( 47 episodes of urinary-tract infection ) with radiologically normal urinary tracts were given either low-dose prophylactic co-trimoxazole or nitrofurantoin or no prophylaxis after each had been treated with a short course of co-trimoxazole . During prophylaxis none of the 25 children had a further infection whereas half of the 22 who received no prophylaxis had a further infection within a similar period . 8 ( 32 % ) of those children who received prophylaxis had a further infection within 1 yr of completing the course of prophylactic treatment compared with 13 ( 59 % ) of the no-prophylaxis group in the year following the initial course of co-trimoxazole .  24 children had had a previous urinary-tract infection . All 6 of these who did not receive prophylaxis had a further infection whereas only 8 of the 18 ( 44 % ) who had received prophylaxis had a further infection after the course of prophylactic treatment . 24 mos after the start of the study , 68 % of the prophylactic group and 36 % of those who received no prophylaxis were recurrence-free . Differences in symptomatology and timing of reinfections and possible contributory factors are discussed 
    Output:
    
Furthermore , a few recent r and omized controlled trials suggest that antibiotic prophylaxis offers no advantage over intermittent antibiotic therapy of UTIs in terms of prevention of recurrent UTIs or new renal damage