***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 
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    ***EXAMPLES*** 
    Input: We conducted a r and omized , double-blind , placebo-controlled study to determine the efficacy of postcoital antibiotic prophylaxis in healthy young women prone to recurrent urinary tract infections . Sixteen patients were r and omized to receive postcoital administration of a combination product of trimethoprim and sulfamethoxazole , while 11 received postcoital placebo .  The treatment groups were similar with respect to age , parity , diaphragm use , history of lifetime urinary tract infections , frequency of intercourse , and number of lifetime sexual partners . In over 6 months of observation , postcoital administration of trimethoprim-sulfamethoxazole was highly effective in preventing recurrent urinary tract infections . Nine of 11 patients who took the placebo developed urinary tract infections ( infection rate , 3.6 per patient-year ) , compared with only two of 16 patients who received postcoital trimethoprim-sulfamethoxazole ( infection rate , 0.3 per patient-year ) . Postcoital administration of trimethoprim-sulfamethoxazole was effective in patients with both low ( two or fewer times per week ) and high ( three or more times per week ) intercourse frequencies . Side effects were few and compliance was excellent . We conclude that postcoital trimethoprim-sulfamethoxazole is a safe , effective , and inexpensive approach to management of recurrent urinary tract infections in young women A total of 102 women with recurrent urinary tract infections were included in this open r and omized study ; 55 received 200 mg of norfloxacin daily and 47 received 50 mg of nitrofurantoin daily over 6 months . Fifty-three and 41 women from the norfloxacin- and nitrofurantoin-treated  groups , respectively , completed the 6-month follow-up period . Forty-four ( 81 % ) of the norfloxacin-treated patients and 27 ( 65 % ) of the nitrofurantoin-treated patients remained free of symptoms ( P = 0.05 ) , and urine sample s from 49 ( 92.4 % ) and 29 ( 70.7 % ) of the patients , respectively , were sterile ( P less than 0.005 ) . Side effects occurred with similar frequencies in both groups ( 15 and 17 % ) but were more severe in the women who received nitrofurantoin . Despite the better results obtained with norfloxacin , the difference in the costs of the two agents must be considered PURPOSE We evaluated and compared the efficacy of post-intercourse and daily oral ciprofloxacin prophylaxis against  recurrent lower urinary tract infections in 135 sexually active premenopausal women . MATERIAL S AND METHODS Post-intercourse ( group 1 , 70 patients ) and daily ( group 2 , 65 patients )  prophylactic regimens of 125 mg . ciprofloxacin were started following a curative , conventional treatment of the initial acute urinary tract infection . Prophylaxis was maintained for 12 months and during this period patients were followed clinical ly and bacteriologically with urine and introital sample s. Patients were subsequently followed for an additional year after the end of preventive treatment . RESULTS While 3.67 urinary tract infections per patient in group 1 and 3.74 in group 2 occurred during an identical mean time of 12.2 months before start of the corresponding prophylactic regimen , only 0.043 infection per patient in group 1 and 0.031 in group 2 developed during prophylaxis ( p < 0.0001 ) . Before prophylaxis 86 % of the vaginal vestibule cultures yielded gram-negative Enterobacteriaceae , equally distributed between both treatment arms , compared to 5.6 % and 2.5 % during postcoital and daily prophylaxis , respectively . The overall improvement in the incidence of the urinary infections per patient and the rate of introital colonization with enteric gram-negative bacteria was maintained after the end of prophylaxis , with a mean incidence of infections of 0.44 per patient ( occurring in 34 % of the total patient population ) , while 36 % of all women had abnormal introital colonization . CONCLUSIONS Long-term post-intercourse prophylaxis with ciprofloxacin proved to be equally effective as daily prophylaxis , and the major advantage of the former therapy was use of only a third of the amount of drug consumed in daily prophylaxis Summary One hundred and twenty women , aged between 18 and 90 years , with a history of at least four episodes of symptomatic urinary tract infection in the preceding 12 months , were r and omized in an open , prospect i ve study to prophylactic treatment with cefaclor 250 mg at bedtime or macrocrystalline nitrofurantoin 50 mg at bedtime for 12 months . Ninety-seven ( 49 taking cefaclor , 48 taking macrocrystalline nitrofurantoin ) were assessed for efficacy ; 80 % of these were symptomatically improved and remained abacteriuric during the period of prophylaxis . Symptomatic attacks while patients were taking prophylaxis occurred at least five times less often than before prophylaxis had started . Seventy percent of the patients continued in an improved condition after having stopped prophylaxis . All 120 patients were assessed for adverse events ;  these were twice as frequent in patients taking macrocrystalline nitrofurantoin ( 20 % vs. 10 % ) , but only 11 patients ( three taking cefaclor , eight taking macrocrystalline nitrofurantoin ) withdrew from the study . Due to the small numbers of patients experiencing adverse events , these differences are not statistically significant . No significant changes in haematological or biochemical parameters were found during or after the end of the 12-month course . The 22 patients assessable for efficacy who had a non-obstructive radiological abnormality  responded as well to prophylaxis as those with no detectable abnormality . Long-term , low-dose prophylaxis with a suitable antimicrobial agent is highly effective management for patients with recurrent urinary tract infections , and can appropriately be provided by the family doctor . Prophylaxis given for 1 year gives better results than when given for 6 months . Zusammenfassung120 Frauen mit mindestens vier Episoden einer symptomatischen Harnwegsinfektion in den vergangenen 12 Monaten wurden in einer offenen , prospektiven Studie für eine 12-monatige Prophylaxe mit 250 mg Cefaclornocte oder 50 mg makrokristallinem Nitrofurantoinnocte r and omisiert . Für die Auswertung st and en 97 Frauen ( 49 nahmen Cefaclor und 48 makrokristallines Nitrofurantoin ) zur Verfügung . 80 % waren symptomatisch gebessert oder blieben für die Zeit der Prophylaxe ohne Rezidive . Symptomatische Schübe traten während der Prophylaxe mindestens 5mal seltener auf als vor Beginn der Prophylaxe . 70 % der Patientinnen waren nach Absetzen der Prophylaxe noch in gebessertem Zust and . Alle 120 Frauen wurden hinsichtlich Nebenwirkungen beurteilt . Bei Frauen , die makrokristallines Nitrofurantoin einnahmen , waren Nebenwirkungen zweimal so häufig ( 20 % gegenüber 10 % ) ; aus der Studie schieden aber nur 11 Frauen aus , 3 unter Cefaclor und 8 unter makrokristallinem Nitrofurantoin . Diese Unterschiede sind wegen der kleinen Zahlen von Frauen mit Nebenwirkungen nicht statistisch signifikant . In den hämatologischen oder biochemischen Parametern f and en sich während oder nach dem Ende der 12-monatigen Prophylaxephase keine Veränderungen . Die 22 Frauen , die nicht-obstruktive röntgenologische Veränderungen aufwiesen und für Wirksamkeit auswertbar waren , hatten auf die Prophylaxe ebenso gut angesprochen wie Frauen ohne erkennbare anatomische Abweichung . Eine Langzeitprophylaxe mit einem geeigneten Antibiotikum in niedriger Dosierung ist eine hochwirksame Maßnahme für Patienten mit rezidivierenden Harnwegsinfektionen und kann durch den Hausarzt adäquat verordnet werden The effects of antibiotics used for prophylaxis in women with recurrent urinary tract infections ( UTIs ) on the aerobic intestinal flora were investigated . Twenty-one patients with recurrent UTIs were r and omly divided into three groups . The patients of each group received monotherapy with oral norfloxacin , trimethoprim-sulfamethoxazole or nitrofurantoin for one month . Urine and stool quantitative aerobic cultures were performed before prophylaxis , 2 and 4 weeks after the initiation of therapy , and 2 weeks after antibiotics were discontinued . The gram-negative aerobic flora was strongly suppressed during the administration of norfloxacin and trimethoprim-sulfamethoxazole , while Enterococcus spp . were not affected . Resistant strains of Escherichia coli were detected in two patients , one in the norfloxacin and one in the trimethoprim-sulfamethoxazole group . The aerobic intestinal flora was not affected by nitrofurantoin . These findings help in the selection of the most appropriate antimicrobial agent for prophylaxis in recurrent UTIs , so as to reduce the possibility of emergence of resistant bacterial strains To study once-daily antimicrobial prophylaxis of urinary tract infections , we gave trimethoprim-sulfamethoxazole ( 40 mg/200 mg ) , trimethoprim ( 100 mg ) , nitrofurantoin macrocrystals ( 100 mg ) , or placebo to 60 women for 6 months . During prophylaxis , infections per patient year were comparable in the groups receiving trimethoprim ( 0.0 ) , nitrofurantoin ( 0.14 ) , or trimethoprim-sulfamethoxazole ( 0.15 ) and occurred less frequently than in patients receiving placebo ( 2.8 ; P less than 0.001 , placebo versus each drug regimen ) . The effectiveness of prophylaxis was limited to the 6 months that antimicrobials were given , and infections were more likely to develop after prophylaxis in women who had three or more infections in the year before prophylaxis ( P less than 0.005 ) . Further , women whose preprophylaxis infection was positive for antibody-coated bacteria were more likely to have same-strain relapse when infections recurred ( P = 0.001 ) . Emergence of trimethoprim-resistant Escherichia coli was rare , but non-E. coli infections occurred more often after prophylaxis ( P less than 0.05 ) . Prophylaxis with these drugs is effective , well tolerated , and did not produce emergence of resistant E. coli but may predispose to non-E. coli urinary tract infections after its discontinuation In a prospect i ve r and omized study 38 patients with recurrent urinary tract infections ( rUTI ) were included to take either 50 mg Nitrofurantoin ( n=19 ) or 50 mg Trimethoprim ( n=19 ) as low-dose long-term prophylaxis for half a year . Compliance was checked weekly byBacillus subtilis spore test strips sent in by mail . The infection rate was reduced from more than three per patient year to 0.01 . There were no significant differences between the two groups concerning the recurrence rate ( Nitrofurantoin : one rUTI ; Trimethoprim : three rUTI ) or side effects . Under Nitrofurantoin treatment 3 symptomatic fungal infections occurred . Trimethoprim and Nitrofurantoin are equally suitable for low-dose long-term prophylaxis in rUTI . Surveillance of compliance gives important hints for failure of prophylaxis This prospect i ve , multicentre , r and omized , double-blind and placebo controlled study was performed to describe the natural course of uncomplicated lower urinary tract infection ( UTI ) . A total of 1143 women 18 y and above , consulting at 18 primary health care centres in northern Sweden for symptoms suggestive of UTI were included . The symptoms urgency , dysuria , suprapubic pain and loin pain were registered , and urine cultures performed at inclusion and follow-up visits 8–10 d and 5–7 weeks later . Associations between all symptoms and bacteriuria or bacterial counts were unpredictable . Eradication of symptoms and bacteriuria and combinations of them were studied in 288 patients placebo treated for 7 d , of whom 39 % dropped out after the first follow-up visit . The spontaneous cure rate of symptoms was 28 % after the first week , and 37 % had neither symptoms nor bacteriuria after 5–7 weeks . Considering the high dropout rate after the first follow-up visit , the spontaneous cure rate of symptoms and bacteriuria was calculated to 24 % at the end of study . We conclude that patient near-laboratory tests are required to establish the diagnosis of lower UTI , and the guidelines for diagnosis of UTI need to be revised To evaluate factors associated with recurrent urinary tract infection ( UTI ) in postmenopausal women , we conducted a case-control study comparing 149 postmenopausal women referred to an infectious diseases outpatient clinic who had a history of recurrent UTI ( case patients ) with 53 age-matched women without a history of 
    Output:
    
Weekly pefloxacin was more effective than monthly .
REVIEW ERS ' CONCLUSIONS Continuous antibiotic prophylaxis for 6 - 12 months reduced the rate of UTI during prophylaxis when compared to placebo .
One RCT compared postcoital versus continuous daily ciprofloxacin and found no significant difference in rates of UTIs , suggesting that postcoital treatment could be offered to woman who have UTI associated with sexual intercourse