Effects on oral and intestinal microfloras of norfloxacin and pefloxacin for selective decontamination in bone marrow transplant patients

We monitored the modifications of oral and intestinal microfloras of 10 allogeneic bone marrow recipients who received randomly either norfloxacin or pefloxacin (400 mg three times a day) as selective decontamination for infection prevention. After 1 week of treatment, in all patients members of the family Enterobacteriaceae were no longer detectable and in all but one pefloxacin-treated patient enterococci were also eliminated in the intestine. The anaerobic flora was not affected, with the exception of Bacteroides spp., markedly reduced after treatment with pefloxacin. In most patients the most striking effect was the increase in staphylococcal counts. These strains were found to be resistant to both quinolones in the study. Less consistent changes were observed in oral flora. No relevant difference could be demonstrated between the two regimens on bacterial counts either in feces or in saliva. This study shows the efficacy of both quinolones in eradicating gram-negative bacilli in the alimentary tract of bone marrow transplant patients; however, the finding of the overgrowth of resistant gram-positive organisms during treatment with these agents deserves further evaluation.

Teicoplanin in the treatment of gram-positive-bacterial endocarditis

Intravenous teicoplanin has been used to treat 23 cases of gram-positive-bacterial endocarditis, usually with 3 to 7 mg/kg every 12 h on the first day, followed by 3 to 7 mg/kg every 24 h. For some cases (staphylococcal and enterococcal endocarditis), the dosage was 8 to 14.4 mg/kg per day and/or other antibiotics were given. The mean duration was 48.2 days (range, 23 to 130 days). Of 23 patients, 21 (91.3%) had negative cultures or were cured. A total of 18 patients were treated with teicoplanin alone; of these, 4 had surgery, and all (except 2 who relapsed) were cured. Teicoplanin was combined with one or more antibiotics in five cases; in all cases appropriate cultures were negative, but three patients died during therapy or follow-up. Mild renal impairment was seen in two patients; both were receiving teicoplanin in combination with an aminoglycoside. We conclude that intravenous teicoplanin administered once a day at doses of 7 to 14 mg/kg per day is well tolerated, easy to administer, and may represent an efficacious therapy for gram-positive-bacterial endocarditis.

Aspergillus colonization of the nose and pulmonary aspergillosis in neutropenic patients: a retrospective study

Fungal infections are definitely increasing in neutropenic patients with hematologic malignancies. In view of a previous report on a likely correlation between nose cultures positive for Aspergillus spp. and pulmonary aspergillosis, a retrospective study on 306 consecutive neutropenic patients was performed. Twenty-six patients had one or more nose cultures positive for Aspergillus: thirteen of them developed pulmonary aspergillosis. On the other hand, only twenty out of the remaining 280 patients with negative nose cultures developed this fungal pneumonia (p less than 0.00001). Even if negative results do not obviously exclude the possibility of invasive aspergillosis, nose cultures positive for Aspergillus might prove helpful in predicting this fungal infection in febrile neutropenic patients.

Antimicrobial susceptibilities of Streptococcus species that cause septicemia in neutropenic patients

Sixty-three consecutive streptococcal blood isolates from neutropenic patients, represented mainly by viridans group streptococci, were evaluated in vitro for antibiotic susceptibility. Of these isolates, 79.3% were highly susceptible to penicillin (MIC, less than or equal to 0.12 microgram/ml). Overall, imipenem was the most active agent, followed by teicoplanin and vancomycin. All other agents showed decreased activity against streptococcal isolates that were not highly susceptible to penicillin.

Comparative in vitro activities of new fluorinated quinolones and other antibiotics against coagulase-negative Staphylococcus blood isolates from neutropenic patients, and relationship between susceptibility and slime production

We evaluated the in vitro antibiotic susceptibilities of 31 coagulase-negative Staphylococcus isolates causing septicemia in neutropenic patients undergoing norfloxacin prophylaxis. All the strains but one were resistant to 1 microgram of norfloxacin per ml. At the same concentration, ciprofloxacin, ofloxacin, imipenem, and pefloxacin were inhibitory for 19 (61%), 19 (61%), 18 (58%), and 14 (45%) of the evaluated strains, respectively. Imipenem had an MBC/MIC ratio of greater than or equal to 32 against 19 (61%) of the evaluated isolates, and resistant subpopulations were detected at 5 micrograms/ml in 16 of 17 oxacillin-resistant strains and in 3 of 14 oxacillin-susceptible or -tolerant strains. Resistance to gentamicin was seen with increased frequency among slime-producing strains.

Invasive Fusarium solani infections in patients with acute leukemia

Two cases of disseminated hyalohyphomycosis due to Fusarium solani in patients with acute nonlymphocytic leukemia were studied. The clinical features in both patients included fever, fungemia, severe myalgias, disseminated ecthyma gangrenosum-like skin lesions, ocular symptoms, and a fatal outcome despite systemic administration of amphotericin B in the setting of profound, persistent granulocytopenia. In vitro studies showed the resistance of both F. solani isolates to amphotericin B, 5-fluorocytosine, and imidazoles. This investigation confirmed the emergence of F. solani infection in immunosuppressed hosts.

Clostridium difficile colitis in leukemia patients

Leukemia patients with diarrhea or other abdominal symptoms have been investigated for the presence of Clostridium difficile and its cytotoxin in stools. Of the patients studied 19% had C. difficile, in most cases together with cytotoxin. All patients but one had received antibiotics, while one had been treated with cytotoxic agents only. Symptoms of colitis were most often abdominal pain and distension rather than diarrhea. Owing to the not infrequent fatal evolution, it is recommended that routine search for C. difficile in leukemia patients with abdominal symptoms be performed and appropriate therapy started immediately.

Cefotaxime plus amikacin as empiric therapy in the treatment of febrile episodes in neutropenic patients with hematologic malignancies

Between October 1980 and October 1981, cefotaxime plus amikacin were used in the treatment of 131 febrile episodes that occurred in 108 neutropenic patients with hematologic malignancies. The overall clinical response was 86.2%. Fevers of unknown origin and clinically or microbiologically documented infections responded in 88.8 and 84.4% of the cases, respectively. Renal toxicity occurred in 3.8% of the cases. In vitro studies showed that cefotaxime and amikacin were active against 78.7 and 94.7% of the pathogens, respectively, despite the high frequency (31%) of multiply resistant strains of Pseudomonas aeruginosa (defined as in vitro simultaneously resistant to carbenicillin, gentamicin, tobramycin and sisomicin) isolated from blood and infected sites. Synergy studies performed against 35 gram-negative bacilli isolated from blood revealed the presence of synergism between cefotaxime and amikacin in 54% of the cases. The peak levels of bactericidal activity in the serum of patients receiving cefotaxime plus amikacin showed median values of 1:128 and 1:8 against Escherichia coli and P. aeruginosa septicemias, respectively.

Serum bactericidal activity as a therapeutic guide in severely granulocytopenic patients with gram-negative septicemia

The peak and trough levels of bactericidal activity of the serum of 74 severely granulocytopenic patients (less than or equal to 500 polymorphonucleates per microliter) with hematologic malignancies and Gram-negative septicemia were measured using the patient's infectious organism and serum containing the given antibiotics. When the peak titer of bactericidal activity in the serum was greater than 1:8 the septicemia was cured in more than 90% of the cases. However, in order to achieve a satisfactory rate of cure, patients with less than 100 polymorphonucleates/microliter required higher peak levels than patients with 100-500 polymorphonucleates/microliter. Serum bactericidal activity was influenced by the in vitro susceptibility of the offending pathogen and by the presence of in vitro synergism between the given antibiotics. These two variables showed a correlation with the clinical outcome that proved to be increasing with the degree of granulocytopenia. Furthermore, synergistic combination of the antibiotics appeared essential when the in vitro susceptibility shown by the offending pathogen was moderate. These data suggest (i) that determination of the bactericidal activity of the serum may prove to be a useful method to predict the clinical outcome in severely granulocytopenic patients with Gram-negative septicemia; and (ii) under the same conditions, antibiotic combinations that have demonstrable in vitro synergy against the offending pathogen should be given the utmost consideration.

Superinfections during antimicrobial treatment with betalactam-aminoglycoside combinations in neutropenic patients with hematologic malignancies

The frequency, etiology and risk factors of superinfections during and/or within one week after antibiotic therapy with betalactam-aminoglycoside combinations were evaluated in 631 patients with hematologic malignancies admitted to the Institute of Hematology of Rome from January 1982 to December 1984. 356 patients (56%) developed 402 episodes of proven or presumed infection. Of these patients, 78 developed 102 superinfections. Overall, superinfections responded less satisfactorily to antibiotic therapy than the primary febrile episodes (63% vs. 85%). The distribution of etiologic agents of superinfections differed from those responsible for primary infections, since fungi and anaerobes (especially Clostridium difficile) were mostly isolated after antibiotic therapy had begun. Moreover, among aerobic bacteria, frequently antibiotic-resistant species, such as Pseudomonas aeruginosa, Streptococcus faecalis and Staphylococcus epidermidis were the leading etiologic agents of superinfection. The risk of superinfection appeared to increase with the depth and persistence of granulocytopenia. On the other hand, the length of hospitalization, length of previous antibiotic therapy, previous chemoprophylaxis and presence of indwelling venous catheter did not affect the risk of superinfection.

Comparative in vitro activity of aztreonam, other beta-lactam antibiotics and aminoglycosides against Pseudomonas aeruginosa

Aztreonam, ceftriaxone, moxalactam, cefotaxime, cefsulodin, cefoperazone, piperacillin, azlocillin, carbenicillin, amikacin, gentamicin, tobramycin, sisomicin and dibekacin were tested by broth dilution against 161 isolates of Pseudomonas aeruginosa. Seventy-one of these strains were selected for their resistance to carbenicillin and aminoglycosides and classified as "multiply resistant" strains. Over all, aztreonam showed the greatest antipseudomonal activity by far, followed by ceftriaxone, moxalactam, cefotaxime and amikacin. Piperacillin, azlocillin, cefsulodin, and cefoperazone were highly active against carbenicillin and/or aminoglycoside-susceptible P. aeruginosa strains, but were also poorly inhibitory against multiply resistant isolates.

Cotrimoxazole prophylaxis in patients with leukemia and prolonged granulocytopenia

Sixty-three patients with acute nonlymphoid leukemia (ANLL) under cytostatic treatment were investigated in a randomized trial to determine whether oral administration of cotrimoxazole (TMP/STX) would reduce the rate of infection. Four significant differences were observed between the group given TMP/STX (30 patients) and the control group (33 patients): 1) the mean duration of severe granulocytopenia (less than or equal to 500 PMN/mm3) before the first febrile episode was longer in prophylaxis group, 14.26 days versus four in the control group (p less than 0.001); 2) the number of febrile episodes was 37 in TMP/STX group and 69 in control group (p less than 0.01); 3) 23 patients on prophylaxis presented at least one febrile episode versus 33 in the control group (p less than 0.01); 4) deaths due to infection were two in the TMP/STX group versus 11 in control group (p less than 0.05). Prophylaxis with TMP/STX appears to be useful since by reducing the number of febrile episodes and deaths due to infection, it increases the survival of leukemia patients under cytostatic drugs. Nevertheless, further studies on a larger number of patients are necessary in order to confirm the true efficacy of the drug in the reduction of sepsis and death due to infection.