Antimicrobial prophylaxis in acute leukaemia: prospective randomized study comparing two methods of selective decontamination

Antibiotic prophylaxis for bacterial infections in afebrile neutropenic patients following chemotherapy

BACKGROUND

Bacterial infections are a major cause of morbidity and mortality in patients who are neutropenic following chemotherapy for malignancy. Trials have shown the efficacy of antibiotic prophylaxis in reducing the incidence of bacterial infections but not in reducing mortality rates. Our systematic review from 2006 also showed a reduction in mortality.

OBJECTIVES

This updated review aimed to evaluate whether there is still a benefit of reduction in mortality when compared to placebo or no intervention.

SEARCH METHODS

We searched the Cochrane Cancer Network Register of Trials (2011), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2011), MEDLINE (1966 to March 2011), EMBASE (1980 to March 2011), abstracts of conference proceedings and the references of identified studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing different types of antibiotic prophylaxis with placebo or no intervention, or another antibiotic, to prevent bacterial infections in afebrile neutropenic patients.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from the included trials. Analyses were performed using RevMan 5.1 software.

MAIN RESULTS

One-hundred and nine trials (involving 13,579 patients) that were conducted between the years 1973 to 2010 met the inclusion criteria. When compared with placebo or no intervention, antibiotic prophylaxis significantly reduced the risk of death from all causes (46 trials, 5635 participants; risk ratio (RR) 0.66, 95% CI 0.55 to 0.79) and the risk of infection-related death (43 trials, 5777 participants; RR 0.61, 95% CI 0.48 to 0.77). The estimated number needed to treat (NNT) to prevent one death was 34 (all-cause mortality) and 48 (infection-related mortality).Prophylaxis also significantly reduced the occurrence of fever (54 trials, 6658 participants; RR 0.80, 95% CI 0.74 to 0.87), clinically documented infection (48 trials, 5758 participants; RR 0.65, 95% CI 0.56 to 0.76), microbiologically documented infection (53 trials, 6383 participants; RR 0.51, 95% CI 0.42 to 0.62) and other indicators of infection.There were no significant differences between quinolone prophylaxis and TMP-SMZ prophylaxis with regard to death from all causes or infection, however, quinolone prophylaxis was associated with fewer side effects leading to discontinuation (seven trials, 850 participants; RR 0.37, 95% CI 0.16 to 0.87) and less resistance to the drugs thereafter (six trials, 366 participants; RR 0.45, 95% CI 0.27 to 0.74).

AUTHORS' CONCLUSIONS

Antibiotic prophylaxis in afebrile neutropenic patients significantly reduced all-cause mortality. In our review, the most significant reduction in mortality was observed in trials assessing prophylaxis with quinolones. The benefits of antibiotic prophylaxis outweighed the harm such as adverse effects and the development of resistance since all-cause mortality was reduced. As most trials in our review were of patients with haematologic cancer, we strongly recommend antibiotic prophylaxis for these patients, preferably with a quinolone. Prophylaxis may also be considered for patients with solid tumours or lymphoma.

Antibiotic prophylaxis for bacterial infections in afebrile neutropenic patients following chemotherapy

BACKGROUND

Bacterial infections are a major cause of morbidity and mortality in neutropenic patients following chemotherapy for malignancy. Trials have shown the efficacy of antibiotic prophylaxis in decreasing the incidence of bacterial infections, but not in reducing mortality rates.

OBJECTIVES

This review aimed to evaluate whether antibiotic prophylaxis in afebrile neutropenic patients reduced mortality when compared to placebo or no intervention.

SEARCH STRATEGY

Electronic searches on The Cochrane Cancer Network Register of Trials (2004), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2004), MEDLINE (1966 to 2004) and EMBASE (1980 to 2004) and abstracts of conference proceedings; references of identified studies; the first author of each included trial was contacted.

SELECTION CRITERIA

RCTs or quasi-RCTs comparing different types of antibiotic prophylaxis with placebo or no intervention, or another antibiotic to prevent bacterial infections in afebrile neutropenic patients.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from the included trials. Relative risks (RR) or average differences, with their 95% confidence intervals (CI) were estimated.

MAIN RESULTS

One hundred trials (10,274 patients) performed between the years 1973 to 2004 met inclusion criteria. Antibiotic prophylaxis significantly decreased the risk for death when compared with placebo or no intervention (RR, 0.66 [95% CI 0.54 to 0.81]). The authors estimated the number needed to treat (NNT) in order to prevent 1 death from all causes as 60 (95% CI 34 to 268). Prophylaxis resulted in a significant decrease in the risk of infection-related death, RR 0.58 (95% CI 0.45 to 0.74) and in the occurrence of fever, RR 0.78 (95% CI 0.75 to 0.82). A reduction in mortality was also evident when the more recently conducted quinolone trials were analysed separately. Quinolone prophylaxis reduced the risk for all-cause mortality, RR 0.52 (95% CI, 0.37 to 0.84).

AUTHORS' CONCLUSIONS

Our review demonstrated that prophylaxis significantly reduced all-cause mortality. The most significant reduction in mortality was observed in trials assessing prophylaxis with quinolones. The benefit demonstrated in our review outweighs harm, such as adverse effects, and development of resistance, since all-cause mortality is reduced. Since most trials in our review were of patients with haematologic cancer, prophylaxis, preferably with a quinolone, should be considered for these patients.

Infection prevention in severely myelosuppressed patients: a comparison between ciprofloxacin and a regimen of selective antibiotic modulation of the intestinal flora

PURPOSE

To study whether oral ciprofloxacin would be as effective in preventing bacterial infections in severely myelosuppressed patients as selective antibiotic modulation of the gut flora with neomycin/polymyxin B sulfate/nalidixic acid (NPN).

PATIENTS AND METHODS

One hundred and five patients undergoing allogeneic or autologous bone marrow transplant, or induction therapy for acute leukemia in 1988 and 1989 were studied. Patients were stratified according to the type of therapy, and randomized in a ratio of 2:1 to either oral ciprofloxacin 500 mg BID, or a combination of oral neomycin 250 mg QID, polymyxin-B 100 mg QID, and oral nalidixic acid 1,000 mg BID. Treatment began on admission and continued until the absolute granulocyte count was greater than 500/mm3 for 3 consecutive days.

RESULTS

The 96 evaluable patients were evenly distributed over the 3 treatment groups; 63 patients received ciprofloxacin and 33 received NPN. Fever developed in 92% of patients on ciprofloxacin and in 97% of patients on NPN. (P = 0.66), 6.6 +/- 5.8 and 7.2 +/- 5.3 days from the start of prophylaxis, respectively. Twenty-five patients on ciprofloxacin developed 29 microbiologically documented infections, fewer than the 26 infections in the 22 patients on NPN (P = 0.02). Patients on ciprofloxacin had fewer bacteremias (33%) than did the NPN patients (55%) (P = 0.05). Gram-negative bacteremias were very rare (2 cases; no Enterobacteriaceae), but streptococcal bacteremias were frequent in both arms (27 cases). Side effects were not significantly different, but compliance with ciprofloxacin was better.

CONCLUSIONS

Ciprofloxacin is at least as effective as the combination of neomycin/polymyxin/nalidixic acid in the prophylaxis of bacterial infections in myelosuppressed patients, and is better tolerated. Additional agents to prevent streptococcal infections are needed.

Selective decontamination in neutropenic patients

It is well known that severe neutropenia, as usually seen in patients with acute leukaemia, aplastic anaemia or secondary to aggressive chemotherapy, predisposes to infections with Gram-negative enteric bacilli,Pseudomonas aeruginosa, Staphylococcus aureus, and to fungal infections. Infection with anaerobes, in contrast, is rare in patients with haematologic malignancy [1]. The spectrum of bacterial pathogens in this patient population has recently broadened, and now includes coagulase-negative staphylococci, viridans group streptococci, and, occasionally, coryneforms and other rather unusual opportunistic organisms. All these microorganisms originate either from the patient's own microflora, especially from the digestive tract, or from the hospital environment after having colonized the patient during the hospital stay [2]. Studies have shown that the incidence of fever during periods of severe neutropenia approaches 100%, and most of these fever episodes actually represent bacterial infection. For more than 20 years, methods for the prevention of bacterial and fungal infections have been under investigation in patients with profound neutropenia. These included decontamination trails, oral or systemic antimicrobial prophylaxis, strict reverse isolation and maintenance of germ-free conditions [3–8], prophylactic granulocyte transfusions [9], and, more recently, the application of haemopoietic growth factors [10, 11]. The method which remains the most widely used is oral antimicrobial prophylaxis, especially with agents for so-called selective decontamination of the intestinal tract.

Protecting neutropenic patients from bowel-derived organisms

Prevention of infection from bowel-derived organisms in neutropenic patients requires both the appropriate use of chemoprophylaxis and close attention to the prevention of cross-colonization or cross-infection with resistant Enterobacteriaceae and pseudomonads. Control of common-source infection and control of Gram-positive infection are also important. The objectives of chemoprophylaxis should be considered and their efficacy regularly assessed. Non-absorbable antibiotics may have an important place in minimizing selection of resistant strains, but absorbed agents such as cotrimoxazole (trimethoprim/sulphamethoxazole) and 4-quinolones offer advantages over these and nalidixic acid as prophylactic agents. Ciprofloxacin prophylaxis is probably more effective at reducing Gram-negative bacteraemia than co-trimoxazole but overall mortality may be higher. Further confirmation and investigation of the reasons for this are needed. Protocols of rational antibiotic prophylaxis and treatment involving these agents can be modified to cover only the Gram-negative superinfections that are likely.

Effects of selective oral antimicrobial prophylaxis and systemic antibiotics on the fecal flora and fecal beta-aspartylglycine concentration in patients with acute leukemia

The influence of selective oral antimicrobial prophylaxis (SOAP) and systemic antibiotic treatment (SAT) on the intestinal flora of fourteen granulocytopenic patients was investigated. For SOAP, patients received Cotrimoxazole, Polymyxin and Nystatin; Gentamicin, Ticarcillin and Cefuroxime were administered for SAT. Under SOAP, a complete elimination of Enterobacteriaceae and a marked reduction of yeasts and staphylococci was found. A reduction in the number of anaerobic species was also observed; however, the concentration of anaerobic bacteria remained constant. In contrast, additional systemic antibiotic treatment caused a significant reduction of aerobic as well as anaerobic bacteria, except for microorganisms pathogenic to neutropenic patients (i.e. Staphylococcus epidermidis and Candida sp.). The fecal concentration of beta-aspartylglycine was inversely correlated with the presence of anaerobic bacteria.

Ofloxacin for prevention of bacterial infections in granulocytopenic patients

We studied the potential value of oral ofloxacin (200 mg twice daily) for selective decontamination and infection prevention in 40 granulocytopenic patients with acute leukemia, blast crisis of chronic myelogenous leukemia, hairy cell leukemia or severe aplastic anemia. The quality of selective decontamination was acceptable with rapid elimination of Enterobacteriaceae from the alimentary tract, only a slight decrease in concentrations of anaerobes in faeces, and a small number of newly acquired transient (twelve isolates in seven patients) or colonizing (six strains with 28 isolates in four patients) aerobic gram-negative rods and Staphylococcus aureus (one isolate) recovered from 672 surveillance cultures from faeces, oral washings and urine. Two of three patients colonized with ofloxacin-resistant Pseudomonas aeruginosa strains developed Pseudomonas infections. A total of twelve acquired infections was observed. Six were microbiologically documented infections, all caused by ofloxacin-resistant bacteria (two P. aeruginosa, two Staphylococcus epidermidis, one Aerococcus viridans, one Micrococcus sp.). Tolerance was acceptable with no serious side effects observed. Mean drug concentrations in serum and saliva were comparable to those determined in healthy volunteers and were found to be higher in saliva than in serum. We conclude that ofloxacin may be studied as an effective alternative to trimethoprim-sulfamethoxazole for selective decontamination and infection prevention in severely granulocytopenic patients. Careful monitoring of colonizing Pseudomonas spp. with decreased ofloxacin sensitivity, however, seems necessary.

Hematological side effects of co-trimoxazole

Decrease of blood cells may be induced by either components of co-trimoxazole. Side effects of the trimethoprim component are much more frequent, particularly in risk groups. They are dose dependent, usually not severe, only rarely of clinical significance and easily treated or prevented by folate supplementation. In contrast, side effects of the sulfamethoxazole component seem to be extremely rare. They are similar to the hematological side effects of other sulfonamide drugs. They are idiosyncratic, nonpredictable and mostly mediated by the immune-system. They may be of life-threatening severity and no therapy is known except termination of exposure and supportive measures such as substitution of blood cells and antiinfectious therapy by non-related antibiotics.

Antimicrobial prophylaxis in immunocompromised patients

The results of a randomised, prospective trial to investigate the efficacy of prophylactic treatment with ofloxacin during granulocytopenia after cytostatic treatment are presented. 42 patients with metastasised testicular germ-cell tumours entered the study. Cytostatic treatment consisted of at least 4 courses, 2 of which were succeeded by prophylactic treatment with ofloxacin. Three patients undergoing prophylactic treatment developed fever. Fever occurred in 16 patients during control phases (no ofloxacin prophylaxis) of cytostatic treatment. Seven of the 19 infections could be documented microbiologically. No side effects that related to ofloxacin were noted. In conclusion, ofloxacin was highly effective in the prevention of infection and, therefore, should be given prophylactically to patients with granulocytopenia.

Prevention of infection in acute leukemia: a prospective randomized study on the efficacy of two different drug regimens for antimicrobial prophylaxis

In a prospective study patients with acute leukemia undergoing remission induction therapy were randomized to receive either a regimen of non-absorbable antimicrobial drugs (colistin and neomycin) or of absorbable and non-absorbable drugs (trimethoprim-sulfamethoxazole [TMP-SMZ] and colistin) for antibacterial prophylaxis. For antifungal prophylaxis patients in both groups were given oral amphotericin B. The proportion of patients without acquired infections and the median of study time to the first acquired infection did not differ significantly between the two treatment groups (p greater than 0.05). Septicemias occurred in nine out of 49 recipients of colistin and neomycin and in one out of 56 patients receiving TMP-SMZ and colistin (p = 0.03). Localized infections and fever episodes without proven infections were equally distributed between the two groups. The incidence of febrile days and of days on parenteral antibiotic therapy was significantly lower in the group given TMP-SMZ and colistin (p less than 0.05). The duration of severe granulocytopenia and thrombocytopenia did not differ significantly between the two groups (p greater than 0.05).

Binding to and antibacterial effect of aztreonam, temocillin, gentamicin and tobramycin on human faeces

Aztreonam, temocillin, gentamicin and tobramycin were studied for their effect on the human faecal flora in vitro and for their usefulness for selective decontamination (SD) of the gastrointestinal tract. The sensitivities of the obligately anaerobic flora and the Gram-negative facultatively anaerobic bacteria were determined and the ratio was expressed as SD factor. The high SD factor of the flora from most subjects for aztreonam and tobramycin indicates that the drugs are useful for SD in contrast to temocillin and gentamicin. Binding to and subsequent release of tobramycin from faeces are presumed to facilitate the maintenance of adequate concentrations in the intestine despite the discontinuous intake.

Therapy for acute myeloid leukemia in 119 adults: a comparison of two treatment protocols

Of 119 patients with acute myeloid leukemia, 69 were treated with Adriamycin, Vincristine and Cytosine Arabinoside (Therapy 1) and 50 with Daunorubicin, Cytosine Arabinoside and 6-Thioguanine (Therapy 2) as well as a consolidation therapy. The maintenance therapy with Cytosine Arabinoside and 6-Thioguanine was the same for both groups. The complete remission rate was 44% for Therapy 1 and 68% for Therapy 2 (p less than 0.05). - The median values for remission duration were 7 and 13 months respectively (p = 0.10); for survival time the median values were 18 and 19 months. These figures show in retrospect that high remission rates can be attained through intensive induction therapy and that longer remission duration is correlated with more aggressive induction therapy. A mild form of maintenance therapy seems to have little effect on the duration of complete remission.

Selective decontamination and the anaerobic faecal flora

Selective decontamination with non-absorbable antibiotics of the gastrointestinal tract of patients with impaired host defense is increasingly applied to prevent infections with gram-negative facultatively anaerobic rods. In vivo experiments on the effect of antibiotics on the human intestinal flora were performed with (ex-germ-free) mice. The experiments have shown that the human obligately anaerobic flora did not change during selective decontamination with polymyxin B, but Enterobacteriaceae were eliminated. The magnitude of differences between the sensitivity to antibiotics of the human obligately anaerobic flora and the Enterobacteriaceae in vitro may be used as an index for the usefulness of the antibiotic for selective decontamination. Binding of the antibiotics to intestinal contents has been found to be important for the estimation of the daily dose. The release of the bound antibiotic could contribute to the maintenance of equable concentrations in the intestine.

[Bone marrow transplantation in panmyelopathy, acute leukemia and chronic myelocytic leukemia: results of the Ulm Transplantation Group]

From 1972-1983 53 patients underwent bone marrow transplantation. The median age was 18 years (3-41). 27 patients suffered from severe aplastic anaemia, 22 patients had acute leukaemia and 4 patients had chronic granulocytic leukaemia in chronic phase. Out of 22 patients with acute leukaemia, 2 had florid leukaemia, 2 had an early relapse and 18 patients were in first or second remission of their disease. 2/53 patients received a syngeneic transplant, 51/53 patients an allogeneic transplant. 47/51 patients had a HLA-A, B, C-identical, MLC-negative sibling donor, 1/51 had a HLA-A, B-C-identical, MLC-positive sibling donor, 2/51 a HLA-phaenotypical identical parental donor and 1/51 a HLA-identical, MLC-negative unrelated donor. The comparison of the results obtained in patients with severe aplastic anaemia transplanted from 1972-1979 with those transplanted from 1980-1983 shows that the bone marrow transplantation has to be performed in an early stage of the disease before the patients become multiple transfused, sensitized and severely infected and that the conditioning regimen for polytransfused patients has to be more intensive than in untransfused patients. From the patient group transplanted 1972-1979, only 1/14 patients is a long-term survivor in contrast to 8/13 patients transplanted from 1980-1983. 11/22 patients with acute leukaemia are alive between more than 5 years and 14 days after bone marrow transplantation. Only 1/4 patients, who were transplanted not in remission, is alive.(ABSTRACT TRUNCATED AT 250 WORDS)