***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    Input: INTRODUCTION The use of fluoroquinolones as prophylaxis for bacterial infections in patients with chemotherapy induced neutropenia is debatable . The present study was conducted to assess the prophylactic efficacy of fluoroquinolones in adult neutropenic patients with hematologic malignancies . MATERIAL S AND METHODS For the period 1994 through 2000 a prospect i ve , r and omized trial was conducted at the University Clinic of Hematology ( Medical University , Plovdiv ) . Two groups of patients were included -- experimental group , consisting of 36 patients with 41 granulocytopenic episodes and a control group of 34 patients with 41 granulocytopenic episodes . Non parametrical and psi methods were used for statistical analysis . Kaplan-Meier test was employed to determine patients ' survival rate . Comparison of survival rates between the two groups was performed using the log-rank test . RESULTS A statistically significant difference between the two groups was found in the number of infection-free neutropenic episodes ( P < 0.001 ) , in infection-related mortality rate ( p = 0.001 ) and mortality rate within 1 month of the onset of infection ( p < 0.001 ) . Difference in long term survival rates was not statistically significant ( p > 0.05 ) . CONCLUSIONS Prophylaxis with fluoroquinolones reduced the occurrence of infection in adult neutropenic patients without affecting the long-term survival . Moreover , it is especially beneficial for patients with severe neutropenia and during the active phase of the disease We compared ciprofloxacin alone with ciprofloxacin plus rifampin ( C + R ) as a prophylactic antibacterial regimen for 40 patients with solid tumors treated with high-dose chemotherapy and autologous stem cell transplantation support . No differences were found between groups in the time elapsed to the onset of fever , incidence of febrile episodes , amphotericin B use , and length of hospital stay . However , C + R combination prophylaxis significantly reduced the incidence of gram-positive bacteremia ( five versus zero episodes ) but was associated with a higher incidence of drug-related side effects In neutropenic patients , quinolone-based oral antibacterial chemoprophylaxis has reduced morbidity and mortality attributable to aerobic gram-negative bacteria [ 1 - 3 ] . Gram-positive organisms , predominantly viridans streptococci and coagulase-negative staphylococci , have emerged as the most common pathogens isolated in association with infection among neutropenic persons receiving quinolone [ 4 - 7 ] . St and ard empiric antibacterial regimens that target aerobic gram-negative pathogens have required the addition of broader-spectrum gram-positive coverage to achieve a response [ 8 , 9 ] . Newer quinolone agents with broader in vitro gram-positive activity have recently emerged as possible c and i date s for antibacterial chemoprophylaxis regimens . Ofloxacin is a synthetic carboxyquinolone agent with in vitro activity against aerobic gram-negative bacilli similar to that of norfloxacin but with greater activity against gram-positive organisms , such as staphylococci and streptococci [ 10 ] . Early studies [ 11 - 15 ] suggested a promising role for this agent for antibacterial prophylaxis in neutropenic patients ; however , gram-positive infections have remained a problem . Strategies to reduce gram-positive infection by combining prophylactic trimethoprim-sulfamethoxazole or quinolones with other gram-positive agents , such as erythromycin [ 16 - 18 ] , roxithromycin [ 19 ] , or the penicillins [ 15 , 20 , 21 ] , have had variable success . Studies of prophylaxis with ofloxacin in neutropenic rats at the University of Manitoba [ 22 ] showed that adding rifampin to ofloxacin reduced both viridans streptococcal and staphylococcal bacteremia . Accordingly , the National Cancer Institute of Canada Clinical Trials Group design ed an open , r and omized , controlled phase III clinical trial to test the hypothesis that an increase in the gram-positive activity of an oral quinolone-based antibacterial prophylaxis regimen would have a clinical ly significant effect on the incidence of gram-positive infection in neutropenic patients with cancer receiving cytotoxic therapy . Methods Patients Patients between 18 and 70 years of age were eligible for inclusion in this trial if they 1 ) had acute myeloid leukemia or acute lymphocytic leukemia or had received an autologous bone marrow transplant ; 2 ) were receiving cytotoxic therapy for primary remission-induction , reinduction for first relapse , postremission consolidation , or conditioning for bone marrow autografting ; 3 ) had an absolute neutrophil count ( segmented plus b and neutrophils ) of 0.5 109/L or greater at study entry , with an expectation that severe neutropenia [ neutrophil count less than 0.5 109/L ] would occur at 14 days or thereafter ; 4 ) had a negative pregnancy test result [ a criterion applicable to women of child-bearing age ] ; and 5 ) provided informed written consent . Patients were excluded if they were febrile ( oral temperature more than 38 C ) ; had gastrointestinal conditions that might interfere with drug absorption ; were hypersensitive to any of the study agents ; had major renal ( serum creatinine level more than 180 mol/L ) , hepatic ( liver function test results more than twice normal ) , or cardiovascular ( uncontrolled hypertension or congestive failure ) disorders ; had received systemic antimicrobial therapy for more than 48 hours within 7 days before study entry ; or had previously been entered in this trial . Design The study was an open , r and omized , controlled phase III clinical trial . Before r and omization , patients were stratified according to diagnosis and intent of cytotoxic therapy ( primary remission-induction , reinduction , consolidation , or bone marrow autograft ) to ensure an even distribution of patients among the study groups . The r and omization list was generated by a computerized r and om-number generator . After patient eligibility was confirmed by telephone , assignments were allocated sequentially within the diagnostic grouping from the central office of the National Cancer Institute of Canada Clinical Trials Group . Equal numbers of patients were r and omly allocated to receive norfloxacin , 400 mg orally every 12 hours ; ofloxacin , 400 mg orally every 12 hours ; or ofloxacin , 400 mg orally every 12 hours , plus rifampin , 300 mg orally every 12 hours . Antibacterial prophylaxis was begun on the first day of the cytotoxic regimen and was continued until antimicrobial agents were administered parenterally for suspected infection , the neutrophil count increased to 0.5 109/L or greater , or the patient withdrew from the study for any reason . During the neutropenic period , infection was suspected if the patient 's oral temperature increased to more than 38 C on at least three occasions during a 12-hour period , if the patient 's oral temperature increased to more than 39 C on one occasion and was associated with chills or rigors , or if focal clinical signs of infection were present with a temperature greater than 38 C on one occasion . When an infection was suspected , a history was obtained , a physical examination was done , blood sample s were collected for culture , and , when appropriate , cultures were done on specimens obtained from sites of the suspected infection . Empiric antibacterial therapy with piperacillin and tobramycin was administered according to established guidelines [ 23 ] . Colonization Profiles Serial surveillance cultures of the nasopharynx , oropharynx , and rectum were taken twice weekly during the study at one participating center ( Winnipeg ) , as described elsewhere [ 24 ] , to examine the effect of allocation on clearance and acquisition of aerobic gram-negative bacilli and on acquisition and colonization by opportunistic fungi . Acquisition was defined by the isolation of a microorganism not present in baseline surveillance cultures . Colonization was defined by isolation of the same species of microorganism from at least two sequential surveillance cultures at a given site , as described elsewhere [ 24 ] . Cytotoxic Therapy Cytotoxic regimens were classified according to a cytotoxicity scale on the basis of cytarabine dosing : group 1 ,  cytarabine-containing regimens  with a total cytarabine dose greater than 2 g/m2 body surface area ( n = 24 ; 21.6 % ) ; group 2 ,  cytarabine-containing regimens  with a total cytarabine dose between 2 and 8 g/m2 ( n = 29 ; 26.1 % ) ; group 3 ,  cytarabine-containing regimens with total doses greater than 8 g/m2 [ n = 23 ; 20.7 % ] ; group 4 ,  regimens for acute myeloid leukemia not based on cytarabine consisting of 1 ) etoposide at total doses of 0.5 g/m2 or less plus idarubicin , mitoxantrone , or amacrine , 2 ) other high-dose etoposide-based regimens [ more than 0.5 g/m2 ] plus carboplatin or melphalan , or 3 ) a high-dose cyclophosphamide regimen ( 50 to 60 mg/kg of body weight per day ) ( n = 15 ; 13.5 % ) ; and group 5 , all other regimens ( n = 20 ; 18 % ) . Outcome Measures The primary end points were the incidence of suspected or documented infection and the spectrum of pathogens isolated . Infections were classified according to recommended guidelines [ 25 ] as microbiologically documented infections ( bacteremic or nonbacteremic ) , clinical infections , or unexplained fevers . The secondary end points included adverse events related to study drugs , infections correlated by cytotoxic regimen , the time from allocation to suspected infection , the time to response to empiric antibacterial therapy , the time to infection according to cytotoxic regimen , and the colonization profiles . Statistical Analysis Categorical variables were analyzed using the Pearson chi-square statistic or the Fisher exact test when the expected cell sizes were small . For patients who had an infection , the time from the start of prophylaxis until the beginning of parenteral therapy was used as an end point representing time to infection . For patients without an infection , the time was censored at the last date of prophylaxis . Time-to-event analyses were done using the Kaplan-Meier product-limit method [ 26 ] and were compared using the log rank test . The prognostic relation of cytotoxic therapy to bacteremic infection was examined using a Cox regression procedure [ 27 ] . A P value less than 0.05 was considered statistically significant . All tests were two sided . Results Eligibility and Evaluability One hundred twenty-seven patients were enrolled from 14 centers between 1 July 1989 and 30 June 1992 . The data set was frozen for analysis on 1 July 1994 . Seven patients were ineligible because their neutrophil counts were less than 0.5 109/L at r and omization ( n = 2 ) , they previously received systemic antibiotic therapy ( n = 3 ) , their chemotherapy was insufficiently myelosuppressive ( n = 1 ) , or the underlying diagnosis was unacceptable according to the protocol ( n = 1 ) . Of the remaining 120 patients , 9 were inevaluable because they never received the study agents ( n = 4 ) or because febrile events requiring parenteral antibiotics occurred within the first 24 hours after allocation ( n = 5 ) . Of the remaining 111 patients , 38 received norfloxacin , 38 received ofloxacin , and 35 received ofloxacin plus rifampin .  All included patients had similar demographic characteristics ( Table 1 ) . Table 1 . Demographic Characteristics of Study Patients * Adverse Events Adverse events were grade d as none , mild , moderate , and severe , and the relations of these events to the study regimens were design ated as not related , possibly related , probably related , or definitely related . Gastrointestinal disturbance occurred in 28 % of norfloxacin recipients , 51 % of ofloxacin recipients , and 51 % of ofloxacin plus rifampin recipients ( p equals 0.07 ) . The incidence of gastrointestinal disturbances that were considered probably or definitely related to the study agents was very low ( 2.8 % ) and was independent of treatment allocation . No other clinical ly important side effects were seen . Compliance , measured by dose intensity , was similar in all three groups ( Table 1 ) . Five patients died during this trial . Three ( 2.7 % ) died of their presenting infections , one from each treatment group . Two others died The prophylactic efficacy of ofloxacin ( OFLX ) therapy was evaluated in 51 granulocytopenic episodes in 22 patients with hematological malignancies during post-remission chemotherapy in a prospect i ve , r and omized , controlled trial . Oral administration of OFLX plus amphotericin-B ( AMPH ) and polymyxin-B ( PL ) reduced episodes of fever and infection more than did the control regimen with PL and AMPH alone ( p less than 
    Output:
    
Patients treated with quinolones have a non-significant increase in colonization by quinolone-resistant bacteria .
There is no difference in the number of infections caused by pathogens resistant to quinolones .
As quinolone prophylaxis reduces the risk of death in neutropenic patients , the risk associated with colonization and infections caused by quinolone-resistant organisms does not outweigh the gain .