Randomized comparison of aztreonam and chloramphenicol in treatment of typhoid fever

Patients with clinical typhoid fever plus a blood, bone marrow, or bile positive for Salmonella typhi or Salmonella paratyphi were included in an open clinical trial to compare the efficacy of aztreonam (6 g/day [2 g intravenously every 8 h]) given for 10 days with that of chloramphenicol (50 mg/kg of body weight per day [intravenously or orally]) administered for 14 days. A total of 44 patients, 22 in each group, were included in the study, and both groups were comparable in terms of baseline parameters. All patients randomized to receive chloramphenicol completed the 14 days of treatment, while two patients randomized to receive aztreonam developed an intestinal hemorrhage, and a third patient elected to withdraw from the trial. Defervescence occurred more quickly in the subjects receiving chloramphenicol than in those receiving aztreonam (P < 0.05). All patients in the chloramphenicol group were clinically cured during therapy, while four patients (21%) in the group receiving aztreonam were declared clinical treatment failures. None of the 19 patients receiving aztreonam, compared with 7 of 22 (32%) patients receiving chloramphenicol, had a positive blood culture after 24 h of therapy (P < 0.05). Adverse experiences were unusual and mild. In the study, aztreonam was less effective than chloramphenicol with regard to clinical effectiveness and time of defervescence but was more effective in the elimination of the infecting Salmonella organisms from the bloodstream.

Urticaria caused by sensitization to aztreonam

A 72-year-old woman presented with generalized urticaria after receiving an injection of aztreonam. After successive in vitro and in vivo studies, allergy to aztreonam with a good tolerance of the other beta-lactams was diagnosed.

Comparison of imipenem/cilastatin with the combination of aztreonam and clindamycin in the treatment of intra-abdominal infections

The clinical safety and efficacy of imipenem/cilastatin in the treatment of intra-abdominal infections was compared with the combination of aztreonam and clindamycin in a randomized prospective trial. The severity of illness was determined by means of the Apache II score and a fixed outcome reporting scheme was used. One hundred and four patients were entered into the study, of whom 80 were evaluable. Forty-two patients were treated with imipenem/cilastatin (500 + 500 mg qds) and 38 with aztreonam (600 tds) and clindamycin (1000 mg tds). The study groups were comparable for age and sex. The imipenem/cilastatin group differed from the aztreonam and clindamycin group in having significantly more patients with the diagnosis of acute appendicitis (P < 0.01) and a significantly lower mean Apache score (P < 0.05). The predominate microorganisms isolated in both groups were Escherichia coli and Bacteroides fragilis. Treatment with imipenem/cilastatin proved successful in 71% and failed in 24%, and initial success only was seen in 5%. The numbers in the group treated with aztreonam and clindamycin were 64%, 29% and 7% respectively. Severity of illness, as measured by Apache II score, had no influence on the study outcome. Imipenem/cilastatin as well as the combination of aztreonam and clindamycin were effective in the treatment of abdominal infections and no major adverse reactions were seen.

[Aztreonam as monotherapy in urinary tract infections with a systemic repercussion in patients with a relative contraindication for the use of aminoglycosides]

A comparative study has been performed to evaluate the clinical efficacy and safety of aztreonam in the treatment of urinary tract infections with systemic affectation, in a group of patients who showed a relative contraindication to be treated with aminoglycosides. The group studied was formed by 30 patients (21 females and 9 males). Mean age of said group was 78 years and percentage of patients over 65 years was 93%. Moreover, 53.3% of patients showed nephropathy, 30% diabetes mellitus and 16.6% hearing disorders. Responsible germ of the infection was identified through blood and urine culture in 24 patients (80%) being the most frequent isolated E. Coli (60%). The cure rate was of 76.6% and improvement rate was 13.3%. Three deaths happened on the studied group (10%). In a patient superinfection due to Enterococcus was detected. There were no significative adverse effects (hypersensibility reactions, hematological disorders, nephrotoxicity or hepatotoxicity). Aztreonam could be an efficacious alternative in the treatment of urinary infection with systemic affectation, caused by gram-negative germs, showing low toxicity.

Aztreonam

Aztreonam is the first monobactam and is unique among beta-lactam antibiotics for its spectrum of activity that is exclusively active against gram-negative aerobic bacteria. Broad clinical experience with this agent supports its use in the treatment of adults with severe or complicated urologic infections. Aztreonam may be safely used in patients with penicillin allergy. With a spectrum of activity that is comparable to the aminoglycosides but without the potential for ototoxicity or nephrotoxicity, aztreonam represents a rational choice of therapy for treatment of systemic urinary tract infections due to susceptible organisms.

Aztreonam

Aztreonam is a synthetic monobactam antibiotic that has excellent activity against aerobic gram-negative bacilli. It can be used as a single agent for the treatment of upper urinary tract infections caused by organisms resistant to the cephalosporins and ampicillin. It also can be administered in combination with a drug such as clindamycin for treatment of pelvic inflammatory disease or postoperative pelvic infections.

An open, comparative trial of aztreonam with vancomycin and gentamicin with piperacillin in patients with fulminant hepatic failure

Fifty patients admitted with fulminant hepatic failure and clinically suspected infection were allocated to receive either aztreonam and vancomycin or piperacillin and gentamicin as first line treatment. Fourteen patients died within 48 h of admission and were excluded from the analysis. Of the remaining 36 patients, 16 received aztreonam/vancomycin and 20 piperacillin/gentamicin. There were 18 episodes of infection in the aztreonam/vancomycin group and 24 in the piperacillin/gentamicin group (P = not significant). The most frequent bacterial pathogen was Staphylococcus aureus. Fungal infection developed in 13 patients (nine in the aztreonam/vancomycin group and four in the piperacillin/gentamicin group; P = not significant). Death attributed to infection occurred in 4 (25%) of 16 patients receiving aztreonam/vancomycin and 4 (20%) of 20 receiving piperacillin/gentamicin (P = not significant). Thirteen patients (three in the aztreonam/vancomycin group and ten in the piperacillin/gentamicin group) had clinical and microbiological improvement without addition or substitution of other antibiotics. No side-effects attributed to the study drugs were recorded.

A comparative trial of aztreonam versus gentamicin in the treatment of urinary tract infections

A prospective, randomized trial was conducted to compare the efficacy of aztreonam, a monobactam antibiotic, and gentamicin in the treatment of serious urinary tract infections. Fifty-five patients with a suspected or confirmed infection were randomized, 28 received aztreonam and 27 received gentamicin. Both antibiotics had a high clinical response rate (aztreonam 92%, gentamicin 85%). However, the duration of treatment was significantly shorter (p = 0.037, Wilcoxon Rank Sum Test) when aztreonam was used. There were no cases of toxicity with either antibiotic but 5 patients who received gentamicin required dose alteration. Aztreonam is well tolerated and is no less effective than gentamicin in the treatment of urinary tract infections and has advantages in convenience of use and duration of treatment.

Nephrotoxicity and ototoxicity of aztreonam versus aminoglycoside therapy in seriously ill nonneutropenic patients

A randomized double-blind clinical trial was done of aztreonam versus aminoglycoside therapy for the empiric treatment of seriously ill nonneutropenic patients suspected of aerobic gram-negative bacterial infection. Each patient was treated for greater than or equal to 72 h with the study drug. Nephrotoxicity, defined by greater than or equal to 50% increase in baseline serum creatinine, occurred in 12 (15%) of 92 patients receiving aminoglycoside therapy and 1 (1%) of 92 patients receiving aztreonam (P less than .004). More severe nephrotoxicity, defined by greater than or equal to 100% increase in baseline serum creatinine, occurred in 6 (6.5%) of 92 patients receiving aminoglycoside therapy and in 1 of 92 receiving aztreonam (P less than .11). Patients with an elevated baseline total bilirubin level were most likely to develop nephrotoxicity. Auditory toxicity occurred in 2 (7%) of 28 evaluatable patients receiving aminoglycoside therapy and in 1 (3%) of 33 receiving aztreonam (P less than .58). One patient, who received aminoglycoside, developed vestibular toxicity. In nonneutropenic patients believed to be at increased risk for renal dysfunction, aztreonam is a less toxic alternative to aminoglycoside therapy for treatment of suspected aerobic gram-negative infection.

Allergy to amoxicillin in patients who tolerated benzylpenicillin, aztreonam, and ceftazidime

The usual battery of skin tests employed for determining penicillin allergy may fail to detect allergic reactions to side chain-specific beta-lactam agents. We report the cases of six patients who experienced anaphylactic reactions after treatment and challenge with amoxicillin but who tolerated parenteral challenges with benzylpenicillin, aztreonam, and ceftazidime. Results of skin tests for amoxicillin (10 mg/mL) were positive for four of the six patients.

Toxic epidermal necrolysis possibly linked to aztreonam in bone marrow transplant patients

OBJECTIVE AND SETTING

After instituting aztreonam as part of antibiotic prophylaxis in bone marrow transplant (BMT) patients at the Seattle Department of Veterans Affairs Medical Center, the first two cases of toxic epidermal necrolysis (TEN) occurred in more than 250 BMT patients at this center. We have examined the possible cause-and-effect relationship between aztreonam and TEN.

PATIENTS

The first patient was a 23-year-old man with acute lymphocytic leukemia receiving a BMT from a related mismatched donor. He experienced profound conjunctivitis and superficial bulla covering 60 percent of his body surface area (BSA). The second patient, a 32-year-old man with lymphoma, received a BMT from a matched unrelated donor. He exhibited lymphocytosis, acute conjunctivitis, and bullous lesions covering 60 percent of his BSA.

INTERVENTIONS

Aztreonam was discontinued in both patients. The first patient was treated with pigskin grafting and the second was treated with topical silver sulfadiazine.

RESULTS

Despite stabilization of symptoms, both patients eventually died of infectious complications.

CONCLUSIONS

Histological data in both patients were more consistent with TEN than graft-versus-host disease (GVHD) in that dermal infiltrates were sparse or absent. The onset of cutaneous symptoms was of more acute onset than acute GVHD, and ocular complaints are uncommon in acute GVHD. Furthermore, the onset of TEN bore a closer temporal relationship to aztreonam than to other drugs administered.

A comparative study on aztreonam, ceftazidime and amikacin in the treatment of complicated urinary tract infections

In a prospective, randomized trial, aztreonam (1 g intravenously or intramuscularly, twice daily) was compared with ceftazidime (1 g intravenously or intramuscularly, twice daily) and amikacin (500 mg intravenously or intramuscularly, twice daily) in 76 patients aged 24 to 84 years (mean, 59.7 years) with complicated urinary tract infections. Initial pathogens included Escherichia coli (47.5%), Pseudomonas aeruginosa (22.5%), Klebsiella spp. (9%), Proteus spp. (7.5%) and Enterobacter spp (6%). In four patients initial urine cultures yielded more than one organism. All pathogens were sensitive to the three study drugs. Including performance of 4- to 6-week follow-up cultures, eradication of the pathogens occurred in 72% of patients treated with aztreonam, in 74% of those treated with ceftazidime and in 71% treated with amikacin (p greater than 0.05). Clinical success was observed in 84% of patients treated with aztreonam, in 82% of those treated with ceftazidime and in 85% treated with amikacin (p greater than 0.05). All drugs were well tolerated. It is concluded that aztreonam, ceftazidime and amikacin are equally effective and safe for the treatment of complicated urinary tract infections due to susceptible organisms.

Aztreonam-induced myelosuppression during treatment of Pseudomonas aeruginosa pneumonia

Aztreonam is a synthetic, monobactam antibiotic structurally related to the beta-lactam class of drugs. It has inhibitory activity against many aerobic gram-negative bacteria, although it does not inhibit gram-positive or anaerobic bacteria. Administration of aztreonam occasionally is associated with minimal and transient adverse effects. This case report describes a patient we believe experienced bone marrow suppression approximately ten days after aztreonam was given for treatment of pneumonia caused by Pseudomonas aeruginosa. This untoward effect primarily was manifested as neutropenia, although normochromic, normocytic anemia and thrombocytopenia were noted as well. One week after aztreonam was discontinued, the patient's bone marrow suppression resolved spontaneously. Although the mechanism responsible for myelosuppression is unclear, aztreonam may be implicated as the offending agent based on the temporal relationship between the development of neutropenia and its administration, and the resolution of neutropenia upon its discontinuation.

Efficacy of aztreonam in the treatment of neonatal sepsis

In Greece the majority of infections that affect the neonatal population are caused by gram-negative bacteria rather than by group B streptococci as in the United States. The present study investigated the efficacy of aztreonam, a beta-lactam antibiotic that is effective against gram-negative organisms, in this population. Fifty-five neonates aged 2 hours to 36 days who had sepsis were enrolled in this open study. Laboratory tests were extensive, and follow-ups were detailed. Aztreonam (90-125 mg/[kg.d]) administered in two or three doses was given in combination with penicillin (100,000 U/[kg.d]) for 6-15 days. Fifty-two infants were cured, one improved, and two did not improve and received other, more effective regimens. Adverse effects were minimal, and tolerance of aztreonam was excellent.

Aztreonam plus clindamycin versus tobramycin plus clindamycin in the treatment of intraabdominal infections

In a multicenter, randomized clinical trial, aztreonam and tobramycin were compared for efficacy and safety in the treatment of intraabdominal infections. Patients were randomly assigned to one of the drug regimens, and all but two patients were treated concomitantly with clindamycin. Efficacy of treatment could not be evaluated for 107 of the 316 patients enrolled in the study. Among the 209 patients who could be evaluated (104 treated with aztreonam and 105 with tobramycin), microbiologic cure was achieved in 93% and 86%, respectively, and a favorable clinical response was noted in 85% of the patients in both groups. The frequency of adverse drug reactions in the two groups was similar. In this study, the efficacy and safety profiles of aztreonam plus clindamycin were comparable to those of tobramycin plus clindamycin.

Infections in patients in intensive care units: can the combination of a monobactam and a penicillin replace the classic combination of a beta-lactam agent and an aminoglycoside?

An open, comparative, randomized study was performed in two medical intensive care units to compare the efficacy of the combination of aztreonam and either cloxacillin or oxacillin [(cl)oxacillin] with that of the combination of tobramycin and a cephalosporin. Of the 92 patients who were included in the study, 76 were evaluable. All patients suffered from severe, mostly pulmonary, infections and received ventilatory support. The aztreonam combination yielded an 80% rate of clinical cure; mortality was 15%. Use of the aminoglycoside combination resulted in a 51% rate of clinical cure; mortality was 23%. The difference in cure rate between the two combinations was statistically significant. Adverse effects were negligible in patients who received the aztreonam combination, and superinfection was seen in only 2%. Of the patients who received the aminoglycoside combination, 20% developed a superinfection and 11% developed a new renal insufficiency. Therefore, the combination of aztreonam and (cl)oxacillin is a valuable alternative to the combination of an aminoglycoside and a cephalosporin.

Efficacy and safety of low-dose aztreonam in the treatment of moderate to severe infections due to gram-negative bacilli

One hundred fifty-three patients with moderate to severe infections due to gram-negative bacilli, including septicemia (60 cases), lower respiratory tract infection (32 cases), intraabdominal infection (40 cases), and urinary tract infection (21 cases), were treated with aztreonam (1 g every 12 h). This dosage is lower than usual. Criteria for inclusion in the study included documented infection due to gram-negative bacilli and a measurement of severity of disease of less than 12 (as defined by a Simplified Acute Physiology Score for the 115 cases of community-acquired infection). Other than aztreonam, no antibiotic active against gram-negative bacilli was allowed to be used for treatment. Seventy-one patients in whom gram-positive or anaerobic organisms were detected or suspected were given additional agents effective against the organisms. One hundred forty-one patients (92.2%) were cured; the mean duration of treatment was 10.9 +/- 4.0 days. None of the gram-negative bacilli initially isolated became resistant to aztreonam. Colonization, generally by a gram-positive organism, was observed in 27 patients and superinfection was observed in five. Aztreonam was well tolerated. This study suggests that a dosage of 2 g daily of aztreonam should be appropriate in the treatment of moderate to severe infections due to susceptible gram-negative bacilli.

Evaluation of the immunologic cross-reactivity of aztreonam in patients with cystic fibrosis who are allergic to penicillin and/or cephalosporin antibiotics

The immunogenicity, allergenicity, and cross-reactivity of aztreonam were investigated in 19 patients with cystic fibrosis (CF) who are allergic to beta-lactam antibiotics. Skin tests with benzyl-penicilloyl polylysine (BPO), minor determinant mixture, and the drug responsible for the previous allergic reaction were positive for 26%, 53%, and 79% of the patients, respectively. Serum IgG, but not IgE, antibodies to BPO were detected in nine of 14 patients. Eighteen patients whose skin tests with aztreonam were negative were treated. One developed bronchospasm. The others tolerated aztreonam, with an improvement in clinical score greater than or equal to 1 month after treatment (P less than .001). One patient without previous exposure had positive aztreonam skin tests and was later treated uneventfully after iv desensitization. Treatment with aztreonam did not result in IgG or IgE antibody responses in vitro. However, two patients had anaphylactic reactions on reexposure. In patients with CF, allergy to beta-lactam antibiotics is primarily drug-specific. But despite reduced immunogenicity and cross-reactivity, aztreonam should be administered cautiously to patients with CF who are allergic to other beta-lactam antibiotics because it is potentially allergenic with repeated use.

Treatment of gram-negative peritonitis with aztreonam in patients undergoing continuous ambulatory peritoneal dialysis

In a multicenter open study, intraperitoneal aztreonam was used together with vancomycin, cloxacillin, or flucloxacillin for initial empiric treatment of peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD). Monotherapy with aztreonam was continued in 34 episodes of gram-negative peritonitis in 28 patients. The microorganisms isolated included Escherichia coli, Acinetobacter species, Pseudomonas species, and Klebsiella species. In three episodes, two organisms were cultured. Microbiologic assessment revealed cure in 27 episodes, cure with relapse in two, cure with superinfection in one, and treatment failure in four (with resistance to aztreonam in three). As assessed by clinical criteria, 27 episodes were cured, five failed to respond, and two responded partially. No adverse reactions to aztreonam were observed. Comparison of these 34 episodes with 35 episodes in historical controls (treated mainly with aminoglycosides and/or trimethoprim-sulfamethoxazole) showed significantly higher rates of cure (84% vs. 51%) and of survival (97% vs. 86%) as well as lower rates of catheter removal (65% vs. 87%) with aztreonam. Thus aztreonam is a safe and efficient agent for the treatment of peritonitis caused by gram-negative organisms in patients undergoing CAPD.

Clinical experience with aztreonam for treatment of infections in children

The in vitro activity, pharmacokinetics, bactericidal activity, and tissue penetration of aztreonam suggest that it may play a role in therapy for serious gram-negative bacterial infections in children. Several thousand children throughout the world received aztreonam during open or comparative clinical trials for treatment of infections including pyelonephritis, bacteremia, meningitis, skeletal infection, pneumonia, and peritonitis. Cure rates have ranged from 92% to 100%, with relapses seen mainly in children with obstructive renal lesions and those with infections caused by Salmonella. A comparative trial of aztreonam for treatment of neonatal sepsis showed it to be at least as effective as amikacin for this infection. Aztreonam yielded clinical results comparable to those of conventional combined therapy for pulmonary infection in patients with cystic fibrosis. Adverse effects in pediatric trials have been uncommon; fever, diarrhea, or rash occurred in less than 2% of treated children. Reversible laboratory abnormalities have occasionally been noted. On the basis of these data, aztreonam is considered an appropriate alternative agent for the treatment of serious gram-negative bacterial infections in neonates and children. Further comparative clinical trials will delineate specific indications.

Aztreonam in the treatment of gram-negative bacterial meningitis

Aztreonam was administered to 122 patients with presumptive or confirmed gram-negative bacillary meningitis in an open, multinational study. The antibiotic was administered at a dosage of 1-2 g to adults, 50 mg/kg to children greater than 2 years old, and 30 mg/kg to infants three or four times daily. Seventy-seven patients had microbiologically confirmed gram-negative meningitis due to an aztreonam-susceptible organism and received aztreonam for at least 48 hours. Haemophilus influenzae was the most frequently recovered pathogen (40 patients), followed by Enterobacteriaceae (16 patients), Neisseria meningitidis (15 patients), and Pseudomonas species (six patients). All but four patients were microbiologically cured. Microbiologic failure was associated with either a persistent intracerebral abscess (one patient) or a foreshortened course of therapy before microbiologic reevaluation and death (at 48 hours, 48 hours, and 72 hours after initiation of treatment, respectively). These data suggest that aztreonam is effective in the treatment of gram-negative bacillary meningitis caused by susceptible organisms.

Efficacy of aztreonam in the treatment of skeletal infections due to Pseudomonas aeruginosa

Twenty-eight patients with skeletal infections due to Pseudomonas aeruginosa were treated with aztreonam during two open, noncomparative, multicenter clinical trials. Ten patients with septic arthritis received 2 g of aztreonam three times a day (modal) for 30 days (mean). The mean follow-up period was 4 weeks. Microbiologic cure was achieved in all 10 patients; complete clinical cure, in eight; and partial clinical cure, in two. Eighteen cases of osteomyelitis were treated with 2 g of aztreonam three times a day (modal) for 40 days (mean), with a mean follow-up period of 6 months. Microbiologic cure was achieved in 17 patients. Relapse occurred 1 month after therapy in one patient. Complete clinical cure was achieved in 13 and partial clinical cure was achieved in five patients. The most common adverse reactions to aztreonam were a transient elevation in levels of hepatic enzymes and transient eosinophilia. Three superinfections and one subsequent infection occurred. These results support use of aztreonam for the treatment of skeletal infections due to P. aeruginosa.

Retrospective clinical study of hypersensitivity reactions to aztreonam and six other beta-lactam antibiotics in cystic fibrosis patients receiving multiple treatment courses

A total of 2,793 courses of treatment with seven beta-lactam antibiotics were administered to 121 cystic fibrosis patients chronically infected with Pseudomonas aeruginosa, and the patients were evaluated with respect to clinical hypersensitivity reactions. Seventy-five patients (62%) experienced 125 reactions, for an overall frequency (based on the number of courses) of 4.5%. Immediate reactions occurred in 34 patients (28.1%) during 53 courses (1.9%). The highest rate of reactions involved piperacillin (50.9% of patients), and the lowest rate involved imipenem and aztreonam (4.0% and 6.5% of patients, respectively); intermediate reaction rates were noted for carbenicillin (23.6% of patients), azlocillin (20.8%), cefsulodin (17.1%), and ceftazidime (13.0%). Cross-reactivity did not appear to be a major problem. Reactions to aztreonam seemed to be restricted to a small group of patients with a high propensity for beta-lactam hypersensitivity.