Protected environments and prophylactic antibiotics. A prospective controlled study of their utility in the therapy of acute leukemia

Effect of systemic antimicrobial prophylaxis on microbial flora

Fifteen patients undergoing intensive chemotherapy for oat cell carcinoma of the lung in a protected environmental unit received antimicrobial prophylaxis with oral trimethoprim-sulfamethoxazole and short courses of parenteral ticarcillin, tobramycin, and miconazole. Altogether, 58 (65%) of 89 strains of aerobic bacteria and 28 (60%) of 47 strains of anaerobic bacteria present before prophylaxis were no longer cultured from stool specimens during prophylaxis. Ten strains of bacteria and four fungi were acquired in the stools during prophylaxis. Most fungi persisted in the throat and stools during prophylaxis. Bacterial infections occurred infrequently, but three patients developed Candida esophagitis. The regimen was well tolerated with minimal side effects.

The oral flor as a source of septicemia in patients with acute leukemia

This study was performed to determine the role of the oral cavity in causing septicemia in patients with acute leukemia. Thirty-three patients with acute nonlymphocytic leukemia were investigated prospectively via clinical, hematologic, and microbiologic techniques. The mouth was the most likely source of septicemia in seven of twelve cases. Necessary dental treatment prior to chemotherapy was accompanied by a significant reduction in the rate of septicemia. The authors conclude that oral sources of bacteremia should be eliminated prior to chemotherapy in patients with acute leukemia.

[Comparative study on the value of selective decontamination of the digestive tract in acute leukemia patients (author's transl)]

A comparative study of infectious morbidity and mortality in neutropenic patients with acute leukemia receiving chemotherapy was undertaken to test the effects of a suppression of endogenous and ambient microorganisms. Patients were allocated to receive [1] oral antibiotics (neomycin, colistin, and nystatin) in conventional ward isolation; [2] no antimicrobial suppression but conventional ward isolation; [3] strict isolation, filtered air, sterilized food and oral antibiotics. Significantly fewer infections with Gram-negative bacilli were seen in patients with strict isolation plus endogenous microbial suppression versus patients receiving selective gut decontamination versus patients without nonabsorbable antibiotics in simple reverse isolation. The death rate from infection was significantly reduced in patients who received antibiotics for gut flora suppression in conventional ward isolation compared with the corresponding control group. In addition, a significant improvement of leukemic remission rate was seen in this group. The protocol for decontamination was well tolerated.

Recontamination after gastrointestinal decontamination with non-absorbable antibiotics

In an attempt to restore the colonization resistance we administered anaerobic microflora to prevent an abnormal colonization of the intestine after antibiotic treatment had been discontinued. After the antibiotics had been discontinued and before the donor flora had been administered and had colonized the intestine, microorganisms present were "unopposed" and expanded to a high density. A mouse model was used to investigate which antibiotics negatively influenced the donor flora and reduced the colonization resistance when administered intraperitoneally. Erythromycin, clindamycin and carbenicillin suppressed the donor flora permanently, as could be seen by the reduced colonization resistance. Benzylpenicillin, ampicillin, doxycycline and the combination gentamicin-cephalothin affected the colonization resistance as long as these agents were present. Gentamicin alone and cephalothin and oxytetracycline had no effect on the colonization resistance.

High-dose combination chemotherapy for acute nonlymphoblastic leukemia in adults

One hundred thirty-nine consecutive unselected adults with acute nonlymphoblastic leukemia were treated with a high-dose chemotherapeutic remission-induction regimen consisting of daunomycin (70 mg/m2 IV on days 1, 2, 3), cytosine arabinoside (100 mg/m2 IV every 12 hours), 6-thioguanine (100 mg/m2 orally every 12 hours), prednisone (40 mg/m2 daily), all given on days 1 through 7, and vincristine (1 mg/m2 IV on days 1 and 7). Supportive care consisted of broad spectrum antibiotics for fever in the presence of granulocytopenia and prophylactic platelet transfusions. The complete remission (CR) rate was 60%. The median number of days to CR was 30. Fifty-eight of 77 (75%) patients under age 50 and 26 of 62 (42%) patients over age 50 attained CR. Despite the use of a relatively large dose of daunomycin and monthly maintenance chemotherapy, the median remission duration was only 39 weeks and the medial survival 64 weeks. Most patients who failed to achieve CR died early-77% of deaths occurred within the first six weeks. Infections accounted for the increase mortality in patients over age 50. Thirty-seven percent of patients over age 50 died of infections whereas only 10% under age 50 did so (P less than 0.001). Seven percent of the patients died of fungal infection during attempted remission induction. The incidence of resistance of the leukemia to the remission-induction regimen was low (8%).

Evaluation of a protective environment in the management of granulocytopenic patients: a comparative study

Fever, clinical infection, bacteriologically documented infection, and death from infection were evaluated in 95 consecutive uninfected patients with severe granulocytopenia (less than 0.5 x 10(6)/liter). Patients were randomly allocated to reverse isolation and prophylactic oral nonabsorbable antibiotics or to open ward care. The microbiologic surveillance of air samples and stool cultures showed reduction of pathogenic organisms in patients treated in protective environment units. There was a statistically significant reduction in the incidence of fever (80% vs. 39.6%; P less than 0.001), clinical infections (55.3% vs. 25%; P less than 0.01), bacteriologically documented infections (53.2% vs. 20.8%; P less than 0.01), and deaths from infections (25.5% vs. 8.3%; P = 0.02) in patients treated in a protective environment as compared with patients treated on the open ward.

A four-year experience with anthracycline, cytosine arabinoside, vincristine and prednisone combination chemotherapy in 325 adults with acute leukemia

Combination chemotherapy with an anthracycline, Adriamycin or rubidazone, cytosine arabinoside, vincristine and prednisone resulted in a complete remission rate of 62% in 325 consecutive unselected adults with acute leukemia. The results by morphologic categories were 58% for acute myelogenous leukemia (AML), 70% for acute undifferentiated leukemia (AUL), and 77% for acute lymphoblastic leukemia (ALL). The median survival was 43 weeks. Ten percent of all patients are projected to be alive and in remission at five years. The median remission duration for the whole group was 51 weeks, durations being significantly longer for AML (60 wks) than ALL (30 wks) and AUL (21 wks). Central nervous system involvement was uncommon in AML (4%), but much more common in patients with AUL (37%) and ALL (32%). One in five complete responders with AML is projected to be in their first remission at five years off all chemotherapy. Age, sex, morphology, cytogenetic pattern, temperature of presentation, and presence of a documented preceding hematologic abnormality are found to be significant variables for response and survival.

Protected environment - prophylactic antibiotic program for malignant sarcomas: randomized trial during remission induction chemotherapy

Fifty-one valuable patients with malignant sarcomas were randomly allocated to receive three courses of remission induction chemotherapy with cyclophosphamide, vincristine, Adriamycin, and dimethyl triazeno imidazole carboxamide (CYVADIC) on the protected environment-prophylactic antibiotic for the control group (P = 0.22). The response rates (complete plus partial) were 71% and 67%, respectively. The durations of response were similar for both groups of patients, but the PEPA patients survived substantially longer (median, 84 weeks vs. 58 weeks). The frequency of infection was significantly lower among the PEPA patients, and the doses of CYVADIC could be escalated more often among these patients. Dosage escalation was associated with a higher complete remission rate and lower fatality rate.

Bacteriological aspects of selective decontamination of the digestive tract as a method of infection prevention in granulocytopenic patients

We describe the bacteriological results of a controlled clinical trial of selective decontamination of the digestive tract as a method of infection prevention in granulocytopenic patients. Selective elimination of Enterobacteriaceae and Pseudomonadaceae species was accomplished by the oral administration of nalidixic acid, co-trimoxazole, or polymyxin. Yeasts were eliminated selectively by amphotericin B or nystatin treatment. The drugs used in this study were chosen because of their capacities to selectively eliminate gram-negative rods and yeast without affecting the anaerobic part of the gut flora which is responsible for colonization resistance. Compared with the control group, the selectively decontaminated patients had significantly fewer (P less than 0.0005) gram-negative rods or yeasts or both in their throat swab cultures and in their feces. This reduction may explain the clinical effectiveness of selective decontamination.

A comparison of trimethoprim-sulfamethoxazole plus nystatin with gentamicin plus nystatin in the prevention of infections in acute leukemia

Fifty-three profoundly granulocytopenic patients with relapsed acute leukemia who were undergoing reinduction chemotherapy were prospectively randomized to receive either trimethoprim-sulfamethoxazole plus nystatin or gentamicin plus nystatin for prevention of infections. The acquisition of new organisms per patient during the total study period was similar in both groups. Thirty-five symptomatic infections (five of which were bacteremias) occurred in patients receiving trimethoprim-sulfamethoxazole plus nystatin, whereas 31 infections (eight bacteremias) occurred in patients receiving gentamicin plus nystatin. Four deaths related to infection occurred in patients taking trimethoprim-sulfamethoxazole, and eight occurred in patients taking gentamicin. We conclude that trimethoprim-sulfamethoxazole plus nystatin was approximately as effective as gentamicin plus nystatin for prophylaxis against infection in relapsed acute leukemia. Furthermore, side effects were fewer and compliance was better with trimethoprim-sulfamethoxazole plus nystatin.

The value of protective isolation in preventing nosocomial infections in high risk patients

Since infection is a major cause of death in the patient whose immune responses have been compromised (immunocompromised patient), considerable attention has been focused on developing methods for the prevention of infection. This has primarily been directed at suppressing or eliminating the host's endogenous microbial burden and in decreasing the acquisition of new organisms. The prevention techniques which have been employed vary in complexity from single-room isolation to elaborate systems utilizing air-filtration and decontamination. The most sophisticated of these regimens is the total protected environment (TPE) consisting of a high-efficiency-particulate-air (HEPA)-filtered laminar air flow room which is surface disinfected and in which the patient is fully decontaminated with oral nonabsorbable antibiotics, cutaneous antisepsis, orificial antibiotics and a semisterile diet. The cumulative data to data have shown that the TPE affords a significant (albeit incomplete) reduction in the incidence of serious infections in severely compromised patients. Such protection from infection permits the delivery of novel therapies which might have been precluded because of consequent hematologic or immunologic toxicity. Nonetheless, the TPE is also elaborate, cumbersome and expensive, and its utilization for patients with immunodeficiency syndromes, bone marrow failure states and cancer depends heavily on the success of available therapy (e.g., immunoreconstitution, transplantation, intensive chemotherapy) for the patient's underlying disorder. Critical evaluation of the TPE and alternative prevention strategies are imperative to assure the effective and appropriate utilization of limited hospital resources.

A study of the value of simple protective isolation in patients with granulocytopenia

To assess the value of simple protective isolation, we prospectively compared it with standard hospital care in 43 episodes of severe granulocytopenia, most occurring in patients with acute nonlymphocytic leukemia. Sterilized food and prophylactic oral antibiotics were not used. Twenty episodes in 17 patients were randomized to simple protective isolation (437 days), and 23 episodes in 20 patients to standard care (611 days). No statistically significant differences were observed in the overall incidence of infection, time to onset of first infection, or days with fever. Twenty-seven infections occurred in recipients of standard care (4.42 per 100 days), and 28 infections in isolated patients (6.41 per 100 days). Except for a threefold higher rate of bacteremia in patients in isolation (2.06 vs. 0.65 per 100 days), the profile of infection was similar in the two groups. Neither response to antileukemic therapy nor survival was improved by isolation. We conclude that protective isolation alone, as practiced in most hospitals, appears not to benefit granulocytopenic patients.

Protected environments in cancer chemotherapy: design and function of a large unit

The construction of a new hospital building permitted the design of a new protected environment unit. The design and operating procedures of this unit are described. Microbiological monitoring has been conducted using air sampling, floor sampling, and settling plates. Microbial contamination is substantially lower in the protected environment unit than in comparable locations elsewhere in the hospital.

Adult acute nonlymphocytic leukemias

For the first two decades, leukemic chemotherapy had little impact on survival. In the past 10 years, however, remission induction therapy has generated complete remissions which last approximately one year in about half to three fourths of those treated, with a seventh in some series alive at 5 years.

The efficiency of strict reverse isolation and antimicrobial decontamination in remission induction therapy of acute leukemia

The efficiency of strict reverse isolation and antimicrobial decontamination in remission induction therapy of acute leukemia was studied retrospectively in 47 patients who were treated with a standardized aggressive chemotherapy of daunorubicin and cytosine arabinoside. Twenty-two patients were treated in strict reverse isolation with antimicrobial decontamination and 25 patients in the open ward without any measures against infections. In the patients in isolation the incidence of new infections per patient was 0.77 compared to 1.42 in the control group. The rate of complete remissions was 77% in the patients in isolation vs. 56% in the control patients.

Treatment of acute leukemia in protected environment units

Thirty evaluable patients with acute leukemia (AL), aged 14 to 48-year-old received remission induction chemotherapy on a protected environment-prophylactic antibiotic program. Twenty-seven (90%) of these patients achieved complete remission and 17 remained in complete remission for 1 to 22 months. Although these patients spent 36% of their time with neutrophil counts less than 100/mm3, they spent only 20% of their time with fever. Major infection was present during only 7% of the days when neutrophil count was less than 100/mm3. No patient died of an infectious complication during remission induction therapy.

Infectious episodes in severely granulocytopenic patients

In a prospective study, 40 episodes of granulocytopenia (granulocytes less than 500/mm3) in 34 patients were analyzed. During 52.5% of these episodes there was proven infection; these infections were present for only 24.4% of the 1,435 granulocytopenic days. The risk of infection and mortality were closely linked with extreme granulocytopenia (granulocytes less than 100/mm3). Of the episodes with severe granulocytopenia (granulocytes 100-500/mm3) only a small number were associated with infections, and mortality was virtually absent in this category. These results implicated a restricted use of supportive measures (e.g. granulocyte transfusions) especially when granulcotye counts are higher than 100 mm3.

Attempts to control clothes-borne infection in a burn unit, 3. An open-roofed plastic isolator or plastic aprons to prevent contact transfer of bacteria

An open-roofed plastic isolator was built in a single patient isolation room in a burn unit. It was designed to prevent contact contamination only, as this had been shown to be the important route of cross-colonization in the unit. To exclude any possible effect on airborne transfer of bacteria, the isolator was first examined by means of an airborne particle tracer of the same size as bacteria-carrying particles. Such experiments indicated that the isolator might prevent some transfer out of but not into the isolator. This was not confirmed in simulated nursing experiments nor in a patient study, where the air counts of bacteria were practically the same inside and outside the isolator wall. Two patients only were nursed in the isolator. Both patients acquired exogenous colonizations from other patients, one with Ps. aeruginosa and the other with S. aureus. Nursing in the isolator was difficult and staff-demanding. In simulated nursing experiments, plastic aprons and gauntlets as the only protective measures against contact contamination gave as much protection to a mock patient as did the isolator. S. aureus were released from nurses' clothes more easily during work with the isolator than in open nursing with aprons and gauntlets. In conclusion, the isolator did not seem to be a realistic alternative to impermeable clothes such as plastic aprons as a means of preventing clothes-borne cross-contamination between burn patients.

A prospective controlled investigation of prophylactic trimethoprim/sulfamethoxazole in hospitalized granulocytopenic patients

Oral trimethoprim/sulfamethoxazole (TMP/SMZ) therapy was investigated in the prophylaxis of infections in granulocytopenia. Hospitalized granulocytopenic patients were allocated at random to receive TMP/SMZ (group 1) or to a control group (group 2). The percentage of febrile granulocytopenic days was significantly reduced in group 1, 19 per cent compared to 39 per cent in group 2 (P less than 0.01). In group 1, there were no bacteremias in 59 episodes of granulocytopenia (909 days). In group 2, there were nine bacteremias in 52 episodes of granulocytopenia (796 days)(P = 0.001). Disseminated candidiasis developed in two patients in each group. Candida occurred in similar numbers in surveillance cultures in both groups; Staphylococcus aureus and Pseudomonas aeruginosa were slightly decreased, and Enterobacteriaceae resistant to TMP slightly increased in group 1. This study suggest that oral prophylactic TMP/SMZ therapy is an effective, well tolerated, easily administered alternative to "gut sterilization" with nonabsorbable antibiotics.

Clinical use of reverse isolation in a protected environment

The therapeutic method of reverse isolation in patients using an aseptic environment in the Life Island or Laminar Air Flow Unit apparatus systems is described on the basis of data from the literature and the authors' experience. A historical summary of views on treatment in an aseptic environment is followed by a description of the method of work with the system of reverse isolation, including important technical, operational and other data. The main indications for treatment are given and the authors' experience with the reverse isolation of 36 patients suffering from blood diseases who were treated in this way over the past four years is evaluated. The experience gained confirms data from the literature that reverse isolation is unequivocally successful in reducing the number of infections in immunologically weakened persons. Other aspects have not yet been definitely assessed.

Protected environment-prophylactic antibiotic program for malignant lymphoma. Randomized trial during chemotherapy to induce remission

Fifty-eight patients with malignant lymphoma were randomly allocated to receive three courses of chemotherapy to induce remission with CHOP-Bleo on the protected environment-prophylactic antibiotic (PEPA) program (30 patients) or as controls (28 patients). The complete remission rate for all patients was 74 per cent, for patients with diffuse histiocytic lymphoma 78 per cent and for patients with nodular poorly differentiated lymphocytic lymphoma 65 per cent. There were no significant differences in response rates and duration of responses between those on the PEPA program and control patients. The frequency of infection was significantly lower among the patients on the PEPA program, and dosage escalation of the chemotherapeutic agents was accomplished more often among these patients. Dosage escalation did not increase the complete remission rate, but it did reduce the relapse rate and signficantly reduced the fatality rate. The duration of remission and survival was significantly longer for those patients who received dosage escalation.

The use of a laminar airflow isolation system for the treatment of major burns

A laminar airflow isolation burn ward was designed which would maintain a sterile environment and also allow unrestricted burn care and rehabilitation to be performed. A very low rate of sepsis and sepsis-related complications have been found in the 115 patients treated in the unit. Patient cross contamination has been completely controlled under laminar airflow conditions. The incidence of burn colonization and infection by virulent gram-negative organisms, namely pseudomonas, serratia, klebsiella, and proteus, in these patients has been extremely low, particularly in comparison with burn patients managed in a non-laminar flow intensive care environment.

Co-trimoxazole for prevention of infection in acute leukaemia

30 patients with acute leukaemia being treated with cytotoxic drugs were investigated in a randomised trial to determine whether oral administration of co-trimoxazole in addition to non-absorbable antibiotics would reduce the rate of infection. Three significant differences were observed between the co-trmoxazole and the control groups: (i) 15 of the 16 (94%) control patients but only 8 of the 14 (57%) patients on co-trimoxazole developed infections and required additional antibiotics intravenously; (ii) although the duration of severe neutropenia (neutrophils less than 0.1 times 10(9)/1) was similar in the two groups, control patients required intravenous antibiotics on average after 2 days of neutropenia, whereas patients receiving co-trimoxazole required these only after 12 days; and (iii) the only 2 patients who died of infection were in the control group. Prophylaxis with co-trimoxazole is important in preventing or delaying the development of infection in neutropenic patients receiving therapy for acute leukaemia.

Protective isolation and antimicrobial decontamination in patients with high susceptibility to infection. A prospective cooperative study of gnotobiotic care in acute leukaemia patients. III: The quality of isolation and decontamination

In a cooperative study, the quality of protective isolation and of antibiotic decontamination of the digestive tract was studied in patients with acute leukaemia by (bio)-typing of Enterobacteriaceae species, Pseudomonas aeruginosa and Staphylococcus aureus isolated from oral washings and faecal samples. These samples were collected before and during treatment of 82 patients who were either isolated and decontaminated for which latter purposes a combination of neomycin, polymyxin, bacitracin and nystatin was used (group A); isolated without decontamination (Group B) or treated on the ward without decontamination (Group C). The results indicated that protective isolation had only been completely successful during the entire (remission induction) treatment period in one of the 32 patients in Group B. In Group A patients, who underwent antibiotic decontamination in addition, successful isolation was achieved in 57% of 28 patients. Successful antibiotic decontamination of the digestive tract for the entire treatment period as far as all potentially pathogenic species are concerned, was realized in 4 (14%) of the 28 patients of Group A. Bacteriologically confirmed infections occurred in 50% of Group A patients, in 59% Group B patients and in 64% of Group C patients. It is concluded that the quality of isolation had in general been insufficient but that it was improved by oral nonabsorbable antibiotics and, furthermore, that the antibiotic decontamination procedure also requires improvement.

Infection in acute leukemia patients receiving oral nonabsorable antibiotics

During a 20-month period all acute nonlymphocytic patients (87 patient trials) receiving cytotoxic chemotherapy were placed on an oral nonabsorbable antibiotic regimen consisting of gentamicin, vancomycin, and nystatin in addition to an intensive program of infection prevention aimed at reducing exogenously acquired and body-surface potential pathogens. Although side effects of anorexia, diarrhea, and nausea were common, gentamicin-vancomycin-nystatin was ingested 80% of the study time. Microbial growth in gingival and rectal cultures was substantially reduced. The incidence of bacteremias and other serious infections was low. Pseudomonas aeruginosa, other gram-negative bacilli, and Candida species caused few infections along the alimentary canal, whereas infections of the skin (especially Staphylococcus aureus) were not reduced compared with those occurring in former years. A total of the 104 acquired gram-negative bacilli were gentamicin resistant; 5 subsequently caused infection. Thus, despite certain definite drawbacks, the use of oral nonabsorbable antibiotics to suppress alimentary tract microbial flora in combination with other infection prevention techniques in granulocytopenic cancer patients has proven feasible and tolerable and has been associated with a low order of life-threatening infections.

Protective isolation and antimicrobial decontamination in patients with high susceptibility to infection. A prospective cooperative study of gnotobiotic care in acute leukemia patients. II. Organizational and statistical concept

The organizational and statistical concept of the cooperative randomized controlled clinical trial on gnotobiotic care and its effect in acute leukamia patients is described. The purpose is the clarification of the concept of the study and the comparison with other studies on the same subject. It is concluded that the value of the results and of the decisions based on them depend mainly on the statistical design, the protocol, and the performance of a study. The performance of a controlled study depends on its organizational details, its monitoring, documentation, and appropriate biometric evaluation. In this particular study it proved fruitful that a statistician was engaded in the evaluation and also in developing the protocol and in carrying out the study.

A controlled study of the efficacy of granulocyte transfusions in patients with neutropenia

A randomized clinical trial to determine the efficacy of granulocyte transfusions in neutropenic patients with infection was conducted. Criteria for patient selection included a proved infection, a granulocyte count of less than 300/mm3, availability of a suitable donor and failure to respond to at least 72 horus of appropriate antibiotic therapy. Thirty patients were assigned at random to receive either granulocyte transfusions or to serve as a control group. Antibiotic therapy was continued in both groups. Responses were judged by the degree of diminution of infectious episodes and survival. The results showed that 11 of 13 control patients failed to respond during the period of observation, whereas 10 of 17 patients given transfusions responded. The results were statistically significantly different (p less than 0.05). The median survival was 22.5 days in the group given transfusions (group 2) and 7.7 in the control group (group 1) (p less than 0.01). The granulocyte transfusions were most effective in patients with hypocellular marrows who failed to recover during the period of observation. These results indicate that granulocyte transfusions are effective in the short-term control of infections in neutropenic patients.

Early deaths in acute myelogenous leukemia

In a series of 84 patients with acute myelogenous leukemia, 24 died within 6 weeks of starting treatment. Twenty of the 24 patients had failed to achieve remission at the time of death. Death was due to infection in 20 patients and in 17 of these to septicemia; but whereas severe local infection with septicemia accounted for 12 deaths, only five patients died of septicemia without local infection. Bleeding was the direct cause of death in only four patients and an associated terminal event in another three; of these four patients three had disseminated intravascular coagulopathy. Surprisingly, in this group of patients age and overall clinical status at the time of admission were of no prognostic value in the first 6-week period. The importance of drug resistent disease associated with intractable local infection as a major cause of early death is emphasized.