***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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    Input: BACKGROUND Little is known about the role of asymptomatic bacteriuria ( AB ) treatment in young women affected by recurrent urinary tract infection ( UTI ) . We aim ed to evaluate the impact of AB treatment on the recurrence rate among young women affected by recurrent UTI . METHODS A total of 673 consecutive asymptomatic young women with demonstrated bacteriuria from January 2005 to December 2009 were prospect ively enrolled . Patients were split into 2 groups : not treated ( group A , n = 312 ) and treated ( group B , n = 361 ) .  Microbiological and clinical evaluations  were performed at 3 , 6 , and 12 months . Quality of life was also measured . Recurrence-free rate at the end of the entire study period was the main outcome measure . RESULTS At baseline , the 2 most commonly isolated pathogens were Escherichia coli ( group A , 38.4 % ; group B , 39.3 % ) and Enterococcus faecalis ( group A , 32.7 % ; group B , 33.2 % ) . At the first follow-up visit , there was no difference between the 2 groups ( relative risk [ RR ] , 1.05 ; 95 % confidence interval [ CI ] , 1.01 - 1.10 ) , whereas after 6 months , 23 ( 7.6 % ) in group A and 98 ( 29.7 % ) in group B showed recurrence with a statistically significant difference ( RR , 1.31 ; 95 % CI , 1.21 - 1.42 ; P < .0001 ) . At the last follow-up , 41 ( 13.1 % ) in group A and 169 ( 46.8 % ) in group B showed recurrence ( RR , 3.17 ; 95 % CI , 2.55 - 3.90 ; P < .0001 ) . One patient in group A and 2 patients in group B were found to have pyelonephritis . CONCLUSIONS This study shows that AB should not be treated in young women affected by UTI , suggesting it may play a protective role in preventing symptomatic recurrence BACKGROUND Persistent Escherichia coli asymptomatic bacteriuria ( ASB ) is common among persons with diabetes mellitus , but the duration of colonization and the rates of recolonization are unknown . We estimated the duration of colonization and the rate of recolonization among successively isolated E. coli from diabetic women with ASB and compared the virulence profiles with uropathogenic and commensal E. coli . METHODS A total of 105 women with diabetes were enrolled in a r and omized , controlled clinical trial for treatment of ASB in Manitoba , Canada , and were observed at least every 3 months for up to 3 years . We analyzed 517 isolates from 70 women with repeated E. coli ASB for genetic similarity using enterobacterial repetitive intergenic consensus polymerase chain reaction  . Unique strains were screened for uropathogenic virulence characteristics using dot blot hybridization and compared with different collection s of E. coli isolates . RESULTS On average , differences were found among women assigned to treatment for ASB , those treated only for symptomatic infections , and untreated women in ( 1 ) follow-up time with bacteriuria ( 29 % , 31 % , and 66 % , respectively ; P<.001 ) , ( 2 ) duration of bacteriuria ( 2.2 , 2.5 , and 3.7 months , respectively ; P=.04 ) , and ( 3 ) carriage of unique isolates ( 2.4 , 2.8 , and 4 months , respectively ; P=.03 ) . Women assigned to antibiotic treatment usually had recurrent infection ( 76 % ) , 64 % of the time with a genetically new E. coli strain . Virulence characteristics of these isolates were comparable to those of fecal isolates from healthy women . CONCLUSIONS Treatment may reduce the overall proportion of time infected in the long term and carriage of a unique strain , but most treatment regimens were followed by subsequent recolonization . Infecting strains did not have virulence factors characteristic of uropathogenic E. coli This prospect i ve r and omized study was undertaken to determine the efficacy of antimicrobial therapy compared with no therapy for bacteriuria in elderly ambulatory nonhospitalized women . Sixty-one women ( mean age , 85.8 years ) with bacteriuria were in the no therapy control group and 63 women ( mean age , 85.8 years ) with bacteriuria were in the therapy group ; none had symptoms of urinary tract infection . One short course of antimicrobial therapy achieved a cure rate of 68.3 % ( 43 of 63 women cured ) two weeks after treatment . During the six-month follow-up period , ten ( 16.4 % ) of 61 women in the no therapy group and five ( 7.9 % ) of 63 women in the therapy group developed symptomatic urinary tract infection . At the time of six-month follow-up , 19 ( 34.5 % ) of 55 women in the no therapy group and 35 ( 63.6 % ) of 55 women in the therapy group did not have bacteriuria . We conclude that for asymptomatic bacteriuria in elderly ambulatory nonhospitalized women , short-course antimicrobial therapy is effective at two-week follow-up and that antimicrobial therapy can eliminate bacteriuria in most of these women for at least a six-month period OBJECTIVE To determine whether treatment of symptomatic bacteriuria in older ambulatory women affects the subsequent development of symptoms of urinary tract infection . DESIGN A controlled clinical trial . PARTICIPANTS Older women not having urinary catheters . MEASUREMENTS Urine cultures every 6 months ( the same organism at 10(5 ) colony-forming units or more per mL on two midstream urine specimens defined asymptomatic bacteriuria ) and question naire surveys for the new development of symptoms of urinary tract infection ( dysuria , frequency , urgency , low back pain with fever ) 1 , 3 , and 6 months after the initial survey . RESULTS Of the 23 initially culture-positive participants receiving antibiotic treatment for symptomatic bacteriuria , nine were culture positive at 6 months , which contrasts with 18 of 27 who received no treatment or placebo , P = .05 . However , symptoms of urinary tract infection were more common in the antibiotic-treated group . CONCLUSION Antibiotic therapy effectively reduced the subsequent occurrence of positive urine cultures , but symptoms were not reduced . Based on this study of morbidity , previous studies failing to show any relation to mortality , and the cost and complications of antibiotic therapy in the older population , treatment of asymptomatic bacteriuria in older women is contraindicated Fifty elderly ( mean age , 83.4 + /- 8.8 years ) institutionalized women with asymptomatic bacteriuria were r and omly assigned either to receive therapy for treatment of all episodes of bacteriuria identified on monthly culture or to receive no therapy unless symptoms developed . Subjects were followed for one year . The therapy group had a mean monthly prevalence of bacteriuria 31 + /- 15 percent lower than those in the no-therapy group , but periods free of bacteriuria lasting six months or longer were documented for only five ( 24 percent ) subjects . For residents receiving no therapy , 71 percent showed persistent infection with the same organism(s ) . Antimicrobial therapy was associated with an increased incidence of reinfection ( 1.67 versus 0.87 per patient-year ) and adverse antimicrobial drug effects ( 0.51 versus 0.046 per patient-year ) as well as isolation of increasingly resistant organisms in recurrent infection when compared with no therapy . No differences in genitourinary morbidity or mortality were observed between the groups . Thus , despite a lowered prevalence of bacteriuria , no short-term benefits were identified and some harmful effects were observed with treatment of asymptomatic bacteriuria . These data support current recommendations of no therapy for asymptomatic bacteriuria in this population Abstract . Background : The objective of this study was to examine the expression of Escherichia coli virulence-associated factors among the strains isolated from a group of women with a history of recurrent urinary tract infections ( UTIs ) , in whom asymptomatic bacteriuria ( ABU ) was detected at follow-up , and from a group of children without a history of previous UTI , in whom ABU was detected during the screening . Possible differences between the virulence potential of these strains were investigated . Material s and Methods : Hemolysin production , the ability to adhere to Buffalo green monkey cell line and hemagglutination ( HA ) ability of the ABU-associated E. coli strains were tested . E. coli strains isolated from patients with acute recurrent UTIs served as a comparison . Results : The well-known low virulence of strains isolated from patients with ABU was demonstrated . In contrast to strains isolated from recurrent uncomplicated UTIs , the ABU-associated strains were mostly nonhemolytic ( 75 % ) , nonadherent ( 70 % ) and lacked HA ability ( 61 % ) . HA ability was significantly more common among the strains isolated from children without a history of UTI than among the strains isolated from women with recurrent UTIs ( χ2 = 9.97 , p < 0.01 ) , whereas the adherence and hemolytic abilities did not differ between the two ABU groups . Conclusion : A further prospect i ve study is needed to determine whether the HA ability is the predictor of subsequent symptomatic UTI In a prospect i ve longitudinal study , ambulatory elderly men were followed from 1 to 4.5 years to gain insight into the prevalence rates , clinical characteristics , and patterns of clinical ly inapparent ( asymptomatic ) bacteriuria ( CIB ) . The prevalence of CIB was 12 % ( 29/238 ) and increases with age . Unlike the gram-negative organisms that cause overt urinary tract infection in this age group , gram-positive organisms dominated the CIB group . Both the CIB and abacteriuric patients have multiple chronic medical conditions and are indistinguishable on that basis . Twenty-nine elderly men with bacteriuria and 105 abacteriuric subjects were followed with serial urine cultures . During the study period the bacteriuric subjects exhibited spontaneous temporary or permanent resolution ( 76 % , 22/29 ) , intermittency ( 21 % , 6/29 ) , and probable bacterial persistence ( 38 % , 11/29 ) . No consistent pattern of bacteriuria was evident . Therefore , antimicrobial therapy is not warranted in the treatment of asymptomatic or clinical ly inapparent bacteriuria in ambulatory elderly men Asymptomatic bacteriuria , a common problem of the elderly , has been associated with increased mortality in the elderly [ 1 - 4 ] , although not all studies have confirmed this finding [ 5 - 9 ] . To reconcile these conflicting results , we did a longitudinal study of urinary tract infection in ambulatory elderly women to evaluate the putative relation between asymptomatic bacteriuria and mortality . We considered resolution of this issue to be important because of the implication s for clinical practice . If asymptomatic bacteriuria were shown to be an independent risk factor for mortality and if it could also be shown that eradication of the infection by antimicrobial therapy decreased the risk for death , then screening and antimicrobial treatment of elderly ambulatory women with asymptomatic bacteriuria might be warranted and the cost of identifying and treating such infections might be justified . Conversely , failure to confirm a relation would support the view that programs to screen for bacteriuria would not be justified if their goal was to enhance survival . This report summarizes the findings of our 9-year study to determine whether asymptomatic bacteriuria in elderly ambulatory women is a marker of increased mortality and , if so , whether it is because of an association with other determinants of mortality or because asymptomatic bacteriuria is itself an independent cause , the removal of which might improve longevity . The components of the study were a longitudinal study in elderly ambulatory women to compare mortality in those with and without asymptomatic bacteriuria and a double-blind , controlled clinical trial in which antimicrobial therapy was administered for asymptomatic bacteriuria to assess whether treatment decreases mortality . Methods Participant enrollment and the participating institutions have been described previously [ 10 , 11 ] . Elderly ambulatory residents of the Philadelphia Geriatric Center and of 21 continuing care retirement communities in the greater Philadelphia metropolitan area who gave informed consent were enrolled in this long-term study of urinary tract infection in the elderly . Enrollment continued throughout the course of the study . Philadelphia Geriatric Center houses about 1000 residents who primarily are Jewish ; incomes are higher than the maximum Social Security payment ; and congregate living is provided either in an apartment house or in a nursing home . In contrast , the continuing care retirement communities are smaller ( bed size range , 108 to 675 ) ; incomes are higher ; residents are primarily not Jewish ; and a higher proportion of residents are fully independent . All female residents were eligible to participate except those with indwelling catheters or those incapable of providing midstream clean-catch urine specimens for culture . Specimens were obtained on enrollment and every 6 months thereafter . The protocol was approved by the appropriate institutional review boards , and informed consent was obtained from the participants or their surrogates . Table 1 shows the study periods and chronology of important study events . Throughout the study , urine cultures were obtained at about 6-month intervals . An observational study to compare mort 
    Output:
    
No differences were observed between antibiotics versus no treatment of asymptomatic bacteriuria for the development of symptomatic UTI , complications or death .
Antibiotics were superior to no treatment for the bacteriological cure but with significantly more adverse events .
There was no clinical benefit from treating asymptomatic bacteriuria in the studies included in this review