Co-trimoxazole versus non-absorbable antibiotics in acute leukaemia

Primary prophylaxis of bacterial infections and Pneumocystis jirovecii pneumonia in patients with hematologic malignancies and solid tumors: 2020 updated guidelines of the Infectious Diseases Working Party of the German Society of Hematology and Medical Oncology (AGIHO/DGHO)

Hematologic and oncologic patients with chemo- or immunotherapy-related immunosuppression are at substantial risk for bacterial infections and Pneumocystis jirovecii pneumonia (PcP). As bacterial resistances are increasing worldwide and new research reshapes our understanding of the interactions between the human host and bacterial commensals, administration of antibacterial prophylaxis has become a matter of discussion. This guideline constitutes an update of the 2013 published guideline of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO). It gives an overview about current strategies for antibacterial prophylaxis in cancer patients while taking into account the impact of antibacterial prophylaxis on the human microbiome and resistance development. Current literature published from January 2012 to August 2020 was searched and evidence-based recommendations were developed by an expert panel. All recommendations were discussed and approved in a consensus conference of the AGIHO prior to publication. As a result, we present a comprehensive update and extension of our guideline for antibacterial and PcP prophylaxis in cancer patients.

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.

Oral ciprofloxacin plus colistin: prophylaxis against bacterial infection in neutropenic patients. A strategy for the prevention of emergence of antimicrobial resistance

Following a 2-year study, the combination of oral ciprofloxacin and colistin has been used continuously for 10 years without the emergence of resistance. During a 2-year period (1987-1989), we compared ciprofloxacin + colistin (CIP + COL) with neomycin + colistin (NEO + COL) in a randomized trial--combinations chosen because of the potential for prophylaxis of Gram-negative infection by ciprofloxacin, with colistin given to reduce the risk of emergence of resistance. Sixty-four patients with similar demographics in each arm were evaluable for efficacy analysis. Patients on CIP + COL had a significantly lower proportion of neutropenic days with fever (P < 0.001) and neutropenic days on intravenous antibiotics (P < 0.001) than patients on NEO + COL. A total of 54 (15 bacteriologically documented) pyrexial episodes occurred in patients on CIP + COL and 77 (41 bacteriologically documented) in patients on NEO + COL. Only two Gram-negative bacterial infections occurred in the CIP + COL arm compared with 16 in the NEO + COL arm. No Staphylococcus aureus infections occurred in the CIP + COL group compared with 10 in the other patients. Two CIP-resistant Gram-negative bacilli were isolated from patients on CIP + COL compared with 13 NEO-resistant Gram-negative bacilli from patients on NEO + COL. Following a subsequent decade of unchanged use of this prophylactic strategy in neutropenic patients, a 2-year follow-up study between 1 January 1998 and 31 December 1999 showed 66 significant infections during 700 [corrected] neutropenic episodes. Thirty-five of the 111 (31%) isolates were ciprofloxacin-resistant, involving 5% of the neutropenic episodes [corrected].

Selective discharge of patients with acute myeloid leukemia during chemotherapy-induced neutropenia

PURPOSE

It is common practice for patients with acute myeloid leukemia (AML) to be observed in hospital during the entire nadir after intensive chemotherapy. In an attempt to lessen the likelihood of developing infections with hospital acquired pathogens, we usually discharge patients upon completion of chemotherapy and follow them as outpatients. They are readmitted if fever develops. We evaluated the feasibility and safety of this practice.

PATIENTS AND METHODS

We studied 29 patients with AML (median age 40 years, range 16-63) who were treated with intensive remission-induction and consolidation chemotherapy. Afebrile patients not receiving antibiotics were discharged immediately following chemotherapy and were followed every 3-4 days at the day care unit. Patients were instructed to return immediately if fever rose to 38.2 degrees C or a fever of 38 degrees C persisted for 2 hr. The 29 patients received a total of 86 courses. Following 50 courses, patients were discharged. These 50 ambulatory nadir periods (ANPs) were monitored.

RESULTS

Median WBC and platelet counts on discharge were 2,900 per cubic millimeter (range 300-8,300) and 137,000 per cubic millimeter (range 17,000-618,000), respectively. Mean traveling time from the hospital by car was 1.6 hr (range 15 min-3 hr). In three of the 50 ANPs (6%), patients were not readmitted during their entire nadir. During 47 of the ANPs, patients returned to the hospital (because of fever in 44 cases), a mean of 7.2 days (range 1.0-12.7 days) after discharge. In 45 ANPs, patients were readmitted in good general condition. Four patients had life-threatening complications. Two patients were admitted in septic shock due to delay in seeking admission, but rapidly recovered. Two other patients died, one of cardiogenic shock within 24 hr of readmission and one 24 days later. Only one of the 11 gram negative bacteria cultured was resistant to mezlocillin and gentamicin. After 45 ANPs, patients were discharged a mean of 12.2 days (range 5-42 days) following readmission. We estimate that approximately 383 hospital days were saved by this policy, a mean of 7.6 days per patient, representing 16% of total inpatient hospital days.

CONCLUSIONS

For AML patients who are reliable and without complicating medical conditions, selected discharge following chemotherapy is a low-risk practice and may reduce the incidence of infection with resistant hospital-acquired pathogens.

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.

Bowel microorganisms--a target for selective antimicrobial control

This article reviews the eight factors that determine the outcome of selective antimicrobial control (SAC) a technique aimed at the clearance of intestinal Gram-negative bacillary carriage by means of lethal faecal anti-microbial concentrations. They are as follows: (i) the carrier state; (ii) compliance; (iii) SAC aiming at prophylaxis vs treatment; (iv) minimum bactericidal concentration (MBC) of the antimicrobial; (v) dosage; (vi) pharmacokinetics; (vii) faecal inactivation; and (viii) microorganisms to be controlled. In the second part, non-absorbable SAC regimens are compared with absorbable trimethoprim/sulphamethoxazole (TMP/SMZ) and the fluoroquinolones in different clinical settings including neutropenia, intensive care, hepatic encephalopathy, liver transplantation and the salmonella carrier state. Ablation of gut carriage and superinfections are the main endpoints reviewed in this article. The newer fluoroquinolones are potent SAC agents to deal with enterobacteria. Pseudomonads are the major gap in their SAC spectrum. TMP/SMZ emerges as a SAC agent of limited value, whilst the newer non-absorbable combination of polymyxin/tobramycin seems to be the most potent SAC programme since it has activity against pseudomonads. In a third part, three current issues--the emergence of resistance, the selectivity and the tissue effect are discussed. Finally, a potent fluoroquinolone combined with oral polymyxin/tobramycin seems to be the most effective SAC programme currently available to control enterobacteria and pseudomonads in patients in whom bacterial translocation is a risk with minimal risk of resistance emerging.

Ofloxacin versus trimethoprim-sulfamethoxazole for prevention of infection in patients with acute leukemia and granulocytopenia

In a prospective randomized study we evaluated the efficacy and safety of oral ofloxacin (dosage: 200 mg three times daily) versus trimethoprim-sulfamethoxazole (dosage: 960 mg three times daily) as antibacterial prophylaxis in 128 patients with acute leukemia who received aggressive cytotoxic chemotherapy and were granulocytopenic for a median duration of 30 days. Fewer patients receiving ofloxacin were colonized by Enterobacteriaceae (13% versus 90%, p less than 0.001) and Pseudomonas aeruginosa (3% versus 14%, p = 0.025), and developed gram-negative bacterial infection (4% versus 26%, p = 0.002), whereas the incidence of gram-positive bacterial (19% versus 22%) and fungal (7% versus 14%) infections was similar in both groups. Ofloxacin was significantly better tolerated than trimethoprim-sulfamethoxazole, and shortened the duration of fever (p = 0.02) and of parenteral antimicrobial therapy for presumed or documented acquired infection (p = 0.01). Ofloxacin appears to be a safe, effective, well-tolerated alternative to trimethoprim-sulfamethoxazole for preventing gram-negative infection in acute leukemia, but more effective prophylaxis of gram-positive infections is still needed.

Streptococcal bacteremia in adult patients with leukemia undergoing aggressive chemotherapy. A review of 55 cases

We reviewed 55 cases of streptococcal bacteremia in adult patients who received cytotoxic chemotherapy for treatment of acute leukemia. Viridans group streptococci were the most frequent species isolated (45 isolates). Hemolytic streptococci (four isolates), pneumococci (three isolates), and enterococci (three isolates) were infrequent. Clinical features of streptococcal bacteremia included fever, upper and lower respiratory infection, respiratory distress syndrome, soft tissue infection, and septic shock. Forty patients who had only streptococci, but no other organisms isolated from their blood, were compared with 36 cases of gram-negative bacillary bacteremia that occurred during the same study period within the same population at risk. The comparison showed that patients with streptococcal bacteremia had more often received high dose cytosine arabinoside as part of their chemotherapy (17 vs. five), had a longer mean duration of fever (11 vs. seven days, p less than 0.01) needed slightly more days of antibacterial therapy (15 vs. 12 days, p = 0.07, not significant), and were more likely to have been treated with newer quinolones for infection prevention (30 vs. eight). No differences between both groups were found for age, underlying disease, remission status, duration of severe granulocytopenia, and number of superinfections. The overall mortality was 18% in streptococcal bacteremia and 17% in gram-negative bacillary bacteremia. Streptococci, especially viridans group streptococci, should now be regarded as frequent causes of serious life-threatening infections following aggressive chemotherapy in patients with hematologic malignancies.

Ofloxacin versus vancomycin/polymyxin for prevention of infections in granulocytopenic patients

INTRODUCTION

The efficacy and safety of oral ofloxacin were compared with those of vancomycin/polymyxin for prophylaxis of bacterial infections in granulocytopenic patients undergoing chemotherapy for hematologic malignancy.

PATIENTS AND METHODS

Antimicrobial prophylaxis was begun at the time of initiation of chemotherapy. Thirty patients received ofloxacin tablets (300 mg orally every 12 hours) plus a nystatin suspension. Thirty-two patients received vancomycin capsules (500 mg orally every eight hours) and polymyxin capsules (100 mg orally every eight hours) plus a nystatin suspension.

RESULTS

In the group of patients receiving ofloxacin, there were a lower number of acquired gram-negative bacillary organisms per patient (0.13 versus 1.37, p less than 0.00005), fewer patients with documented infection (11 of 30 versus 21 of 32, p = 0.04), and fewer cases of gram-negative septicemia (zero of 30 versus five of 32, p = 0.05). Ofloxacin was also better tolerated (24 of 30 versus 10 of 32 patients highly compliant, p = 0.01) and associated with fewer gastrointestinal side effects (one of 30 versus nine of 32 patients with gastrointestinal side effects, p = 0.01) than vancomycin/polymyxin. However, except for a reduction of Staphylococcus aureus colonization and infection by ofloxacin, neither ofloxacin nor vancomycin/polymyxin was effective in eliminating colonization or infection with viridans group streptococci, coagulase-negative staphylococci, or other gram-positive organisms. Only three isolates of ofloxacin-resistant gram-negative bacteria (Pseudomonas fluorescens, Pseudomonas putida, and Enterobacter aerogenes) were isolated from surveillance cultures, but none caused infection.

CONCLUSION

These results suggest that oral ofloxacin is a more tolerable and efficacious alternative to vancomycin/polymyxin for prevention of serious gram-negative bacillary infections in granulocytopenic patients. More effective prophylaxis of gram-positive infections, however, is still needed.

Prevention of infection in acute leukemia

In a randomized study comparing cotrimoxazole plus colistin with ciprofloxacin, each in combination with nonabsorbable antimycotics, the incidence of major infections in terms of septicemias and pneumonias as well as of minor infections and episodes of unexplained fever (FUO) was higher in patients treated with ciprofloxacin. In cases of microbiologically documented infections, gram-positive cocci dominated by far. In surveillance cultures of oral washings and of feces, gram-negative enterobacteria were only rarely detected; however, large numbers of cultures were positive for Acinetobacter species. There were four cases of documented Pneumocystis carinii pneumonia in patients not receiving cotrimoxazole. The incidence of documented mycotic infections as well as the detection of fungi in surveillance cultures was similar in both treatment groups. A decrease in the number of adverse events, especially of allergic reactions, could not be achieved by the administration of ciprofloxacin. In conclusion, cotrimoxazole plus colistin in combination with nonabsorbable antimycotics remains the standard regimen for prevention of infection in patients with acute leukemia undergoing aggressive remission induction therapy. A detailed analysis of study II will be prepared for publication.

Prevention of infection and graft-versus-host disease by suppression of intestinal microflora in children treated with allogeneic bone marrow transplantation

The effect of suppression with antimicrobial agents of the intestinal microflora of paediatric bone marrow graft recipients on severe bacterial and fungal infections and on moderate to severe acute graft-versus-host disease was studied retrospectively. Data on 65 cases of bone marrow transplantation for either severe bone marrow failure or leukaemia, performed in a strict protective environment with either complete or selective gastrointestinal decontamination, were evaluated. All bone marrow grafts were from HLA-identical siblings and were not depleted of T-lymphocytes. Twenty percent of the recipients had one or more episodes of septicaemia during the granulocytopenic period after transplantation, mostly due to gram-positive bacteria. Only five children died due to infection, in each case caused by a microorganism originating from the endogenous flora. Complete gastrointestinal decontamination was superior to selective gastrointestinal decontamination in preventing infectious complications (p less than 0.001). The same was the case for the prevention of acute graft-versus-host disease of grade II or higher, which was observed in 7 of 40 (17.5%) completely decontaminated children versus 9 of 18 (50%) selectively decontaminated children evaluable for graft-versus-host disease (p less than 0.01). It is concluded that complete gastrointestinal decontamination in a strict protective environment is a feasible and very effective method for preventing severe infections and acute graft-versus-host disease after allogeneic bone marrow transplantation in children and adolescents; it resulted in a low transplantation-related mortality of 26% and a good quality of survival in 69% of the graft recipients.

Prevention of bacterial and fungal infections in granulocytopenic patients

Granulocytopenic patients are at high risk for infections caused by gram-negative bacteria mostly originating from the gastro-intestinal tract. Several antimicrobial prophylactic regimens are used for prevention of bacterial infections. Prophylaxis with absorbable antimicrobial agents such as trimethoprim-sulfamethoxazole or new fluorinated quinolones seems to be superior to non-absorbable drugs such as polymyxin, vancomycin and gentamicin. The most promising results are obtained with new quinolones. Use of prophylaxis in neutropenic patients leads to changes in the spectrum of infections from gram-negative towards gram-positive.

Biologic characteristics and treatment of acute nonlymphocytic leukemia in children. Report of the ANLL Strategy Group of the Childrens Cancer Study Group

Today approximately 75 per cent of children with ANLL can be induced into a complete remission and approximately 40 per cent will have an event-free survival for more than 3 years, irrespective of whether they received a bone marrow transplantation or chemotherapy after induction. In order to achieve these results very intensive therapy is required. The morbidity and mortality of treatment are high. The length of therapy needed after induction of remission is not known. Whether or not maintenance therapy is required is perhaps related most directly to the intensity of the therapy employed. Similarly, the role of bone marrow transplantation in patients in first remission, treatment of CNS leukemia, and treatment of chloromas are controversial. There is general agreement that WBCs over 100,000, acute monoblastic leukemia in infants less than 2 years of age, and certain chromosomal abnormalities are associated with a poor prognosis. Although there has been a dramatic improvement in the treatment of ANLL over the past 15 years, stratification of therapy based on biologic parameters, and alteration of treatment based on the early responses to treatment may be required before further advances will be made.

Ciprofloxacin and norfloxacin for selective decontamination in patients with severe granulocytopenia

In a randomized multicenter study, ciprofloxacin and norfloxacin, each in two different dose regimens and in combination with non-absorbable antimycotics, were administered to 51 patients with acute leukaemia undergoing aggressive remission induction chemotherapy for infection prevention. Both drugs showed an effective elimination of gram-negative potential pathogens and Staphylococcus aureus not affecting the anaerobic flora of the gastrointestinal tract. A low incidence of side effects and a satisfactory patient compliance could be observed. A daily dosage of 1,000 mg ciprofloxacin or 800 mg norfloxacin is recommended for infection prevention in severely granulocytopenic patients.

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.

Colonization resistance of the digestive tract--mechanism and clinical consequences

Potentially pathogenic bacteria and yeasts meet a number of resistance factors. These colonization resistance (CR) determining factors control the growth density of potentially pathogenic microorganisms in the various parts of the alimentary canal. The CR of the digestive tract is to be seen partially of host origin but to a greater extent due to direct and indirect activity of the (anaerobic) indigenous microflora. This implies that the CR mechanism is vulnerable to antibiotics which affect the indigenous flora during treatment. A decreased CR enhances colonization by microorganisms that are resistant to the antibiotic(s) used for therapy. Increased population densities of potentially pathogenic bacteria ("overgrowth") may correlate with invasion of the mucosal tissues often followed by translocation to remote lymphatic organs. Overgrowth also may correlate with development or acquisition of resistance to the antibiotic applied. By screening in experimental animals antibiotics have been selected which do not affect the CR. Such antimicrobial drugs have successfully been used to selectively eliminate potentially pathogenic bacteria and yeast in neutropenic patients.

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).

Norfloxacin versus vancomycin/polymyxin for prevention of infections in granulocytopenic patients

Selective antimicrobial decontamination with norfloxacin was compared with vancomycin/polymyxin for prophylaxis of bacterial infections in granulocytopenic patients. In the group of patients receiving norfloxacin, there were a lower number of acquired gram-negative bacillary organisms per patient (0.88 versus 1.86, p = 0.002), fewer patients with documented infection (16 of 36 versus 20 of 30, p = 0.12), and fewer cases of gram-negative septicemia (0 of 36 versus five of 30, p = 0.02). Norfloxacin was better tolerated (30 of 36 versus 16 of 30 patients highly compliant, p = 0.02), and associated with fewer gastrointestinal side effects (eight of 36 versus 14 of 36 patients, p = 0.07). These results suggest that norfloxacin is a more tolerable and efficacious oral antimicrobial agent than vancomycin/polymyxin for the prevention of serious gram-negative bacillary infections in granulocytopenic patients.

Prospective randomized trial of antibiotic prophylaxis in acute leukemia

Patients undergoing initial remission induction chemotherapy for acute leukemia in a protected environment unit were randomly assigned to parenteral antibiotic prophylaxis or oral and parenteral antibiotic prophylaxis. Complete remissions were obtained in 82 percent of the 45 patients receiving oral and parenteral antibiotic prophylaxis and 76 percent of the 41 patients receiving parenteral antibiotic prophylaxis. Approximately 20 percent of the patients in both groups have had a continuous complete remission for more than five years. The episodes of fever of unknown origin and major infection were significantly more common in patients receiving parenteral antibiotic prophylaxis, although the episodes of local infection were similar in both groups. The duration of remission and survival was similar in both groups. Hence, the oral and parenteral antibiotic regimen was more effective for infection prophylaxis, but had no effect on response to antileukemic chemotherapy.

The digestive tract in immunocompromised patients: importance of maintaining its resistance to colonization, especially in hospital in-patients and those taking antibiotics

The colonization resistance (CR) of the gastrointestinal tract to potential pathogens depends partly on factors within the host but to a greater extent on the normal (anaerobic) gut flora. Its strength varies between individuals. These individual differences in resistance to colonization by pathogenic microorganisms may explain differences in susceptibility to infection. CR is lowered by remission-inducing treatment (radiation and/or chemotherapy) in leukaemia, but more severely by certain antibiotics. Development (by selection or transfer) of resistance to these antibiotics may lead to overgrowth and penetration of the mucosal lining by the overgrowing (potentially) pathogenic bacteria. Other antibiotics however, if sufficiently dosed, have been found to eliminate (potential) pathogens selectively without decreasing CR. This selective decontamination of the gastrointestinal tract has been successfully used prophylactically in neutropenic patients but needs to be monitored bacteriologically. It should perhaps be used more widely in the hospital to control development and spread of antibiotic-resistant strains.

Myelosuppression associated with co-trimoxazole as a prophylactic antibiotic in the maintenance phase of childhood acute lymphocytic leukemia

Thirty-seven children with acute lymphocytic leukemia in clinical remission for at least 6 months completed a 1-year trial in which they were randomly assigned in a double-blind fashion to receive co-trimoxazole twice daily for 6 months followed by placebo for 6 months (18 patients) or placebo followed by co-trimoxazole (19 patients). Total amounts of maintenance chemotherapy administered during both periods were similar. During administration of co-trimoxazole significant reductions were documented in the patients' average total white blood count (P less than 0.001), absolute neutrophil count (P less than 0.001), absolute lymphocyte count (P = 0.009), and platelet count (P = 0.002) compared with values obtained during the placebo period. Patients had on the average 1.6 infections during the co-trimoxazole period compared with 2.5 infections during placebo administration (P = 0.008). It is concluded that, although co-trimoxazole is an effective prophylactic antibiotic in children with acute lymphocytic leukemia, the resultant myelosuppression could potentially hamper the administration of maintenance cancer chemotherapy.

Symposium on infectious complications of neoplastic disease (Part II). Chemoprophylaxis of bacterial infections in granulocytopenic patients

Several prospectively randomized trials have shown that the administration of prophylactic oral nonabsorbable antibiotics may be beneficial in decreasing the incidence of infection in granulocytopenic patients, whereas others have not. Intolerable nausea and vomiting have prevented the prolonged use of these agents in some studies. Discontinuation of therapy while patients are still granulocytopenic has carried the risk of life-threatening infections, often with aminoglycoside-resistant gram-negative organisms. The benefit of selective decontamination with trimethoprim/sulfamethoxazole used prophylactically remains controversial. The use of trimethoprim/sulfamethoxazole may also be associated with the development of resistant, potentially pathogenic, organisms or prolonged neutropenia. These regimens do not appear to be indicated when patients are anticipated to be neutropenic for less than three weeks. Even in patients with prolonged neutropenia, the risks of such treatment must be weighed against potential benefits.

Randomized controlled trial comparing trimethoprim/sulfamethoxazole and trimethoprim for infection prophylaxis in hospitalized granulocytopenic patients

The clinical and microbiologic efficacy of trimethoprim alone and trimethoprim/sulfamethoxazole for infection prevention was evaluated in 75 patients during 92 episodes of granulocytopenia. Ultimately, 60 patients were evaluable during 77 episodes of granulocytopenia, 36 episodes in the trimethoprim group and 41 episodes in the trimethoprim/sulfamethoxazole group. The incidence of infection was higher in the trimethoprim group (50 percent) than in the trimethoprim/sulfamethoxazole group (39 percent), but this did not reach statistical significance. Trimethoprim did not appear to be as protective as trimethoprim/sulfamethoxazole when the granulocyte count was less than 100/mm3. In patients receiving trimethoprim/sulfamethoxazole, aerobic gram-negative bacilli cleared from fecal surveillance cultures more often and new aerobic gram-negative bacilli were acquired less often than in those receiving trimethoprim alone (p less than 0.05). More myelosuppression was observed among patients receiving trimethoprim/sulfamethoxazole (p less than 0.001). These observations suggest that trimethoprim alone may not be optimal for preventing colonization and infection in granulocytopenic patients and that combination with other agents may be necessary to increase the spectrum of activity. Trimethoprim/sulfamethoxazole itself may predispose toward an increased risk of infection by prolonging myelosuppression.

Prophylaxis of fever and infection in adult cancer patients. A placebo-controlled trial of oral trimethoprim-sulfamethoxazole plus erythromycin

Oral trimethoprim-sulfamethoxazole (Bactrim) plus erythromycin (TMZ-E) was tested versus placebo (P) as prophylaxis for bacterial infection in a randomized, double-blind trial in adult cancer patients receiving cytotoxic chemotherapy expected to result in significant neutropenia. The incidence of adverse reactions attributable to TMZ and/or E was higher in drug-treated episodes (18 of 28 vs 3 of 29 for P, P less than 0.0005) resulting in poorer compliance. The incidence of fever was not significantly different between episodes treated with TMZ-E (18/27) and those treated with P (17/29), nor was there a significant difference in the median interval between the onset of neutropenia and the onset of fever. However, 14 of 18 fevers in TMZ-E recipients were without a documented infectious source compared with only 6 of 17 in P recipients (P less than 0.05). The same patterns were apparent even when episodes in which compliance with the regimen was either excellent or good were considered separately. There was no significant difference in the number of deaths from infection between TMZ-E and P recipients (3/27 vs 1/29). It is concluded that TMZ-E prophylaxis is of no practical benefit, may mask the cause of infection in febrile neutropenic cancer patients, and is associated with substantial toxicity.

Outbreak of co-trimoxazole- and gentamicin-resistant Klebsiella aerogenes bacteremia in neutropenic patients receiving oral co-trimoxazole prophylaxis

Over a five-day period, three neutropenic patients developed bacteremia with an identical strain of Klebsiella aerogenes (serotype K16) resistant to co-trimoxazole and gentamicin. All three patients had received prophylaxis with oral co-trimoxazole before the onset of bacteremia. This report outlines some of the problems associated with co-trimoxazole prophylaxis.

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

In a prospective study the efficacy of two regimens for selective decontamination of the digestive tract was studied in patients with acute leukaemia during remission induction therapy. Seventy-eight patients were randomized to receive either a combination of cotrimoxazole, polymyxin B and nystatin (group A) or a combination of nalidixic acid, polymyxin B, neomycin and nystatin. With both regimens the gastrointestinal tract could be decontaminated equally effectively from potential pathogens. In the oropharyngeal region the decontamination from Enterobacteriaceae was significantly better in group A (P less than 0.01). In both groups less than 10% of the acquired infections were caused by gram-negative bacilli and no gram-negative septicaemia occurred in either group. The median time interval until the first acquired infection was 17 days in group A and 36 days in group B, respectively (P less than 0.05). It is concluded that regimen A might be more effective than regimen B though both regimens prevent reliably severe gram-negative infections.

Penetration of trimethoprim and sulfamethoxazole into skin blister fluid

In 32 patients the concentrations of sulfamethoxazole and trimethoprim in whole blood, plasma and skin blister fluid were studied in the course of treatment with co-trimoxazole and trimethoprim alone. Measurements were taken on the fourth day of treatment, 3 h after administration of the morning dose of the drug. The blood contained a lower concentration of sulfamethoxazole than plasma. About 70% of the sulfonamide penetrated into the exudate from plasma. Trimethoprim administered conjointly with sulfamethoxazole to a higher degree penetrated skin blister fluid to a greater extent than when given alone.