Repurposing an old drug: aztreonam as a new treatment strategy for gonorrhoea.

Objectives: To determine whether aztreonam is still an effective drug for the treatment of gonorrhoea. Methods: Observational study of patients with gonorrhoea diagnosed by urine multiplex PCR, with a past medical history of allergy to ß-lactams or relapse after treatment with a third-generation cephalosporin. Patients received a single 1 g dose of aztreonam in accordance with the manufacturer's instructions. Results: Five patients (four males, one female) were enrolled, comprising two who were allergic to ß-lactams and three previously treated with cephalosporins who relapsed. Median age was 38 years (range 23-51). Following treatment with aztreonam all were cured without any adverse event. All the men were free of symptoms, and the woman tested negative for gonorrhoea 1 month after treatment. Conclusion: Aztreonam appears to be an effective alternative to cephalosporins in the treatment of uncomplicated gonorrhoea, particularly when patients are suspected of being infected by strains with reduced susceptibility to ceftriaxone or are known to be allergic to penicillin.

Efficacy and safety of tigecycline monotherapy compared with vancomycin-aztreonam in the treatment of complicated skin and skin structure infections in patients from India and Taiwan.

BACKGROUND: To compare the monotherapy of tigecycline with vancomycin-aztreonam in hospitalized patients from India and Taiwan with complicated skin and skin structure infections (cSSSIs). METHODS: Safety and efficacy data were analyzed for Indian (n = 86) and Taiwanese (n = 41) patients hospitalized with cSSSIs who participated in two international Phase 3, randomized, double-blind studies. RESULTS: Patients were treated for 5-14 days. Cure rates at the test-of-cure assessment (12-92 days post-therapy) were generally similar between tigecycline and vancomycin-aztreonam in the clinically evaluable populations (India, 83.3% vs. 75.8%; Taiwan, 78.6% vs. 90%) and in the clinical modified intent-to-treat populations (India, 78.6% vs. 66.7%; Taiwan, 73.3% vs. 75.0%). Nausea and vomiting occurred more frequently with tigecycline, but overall safety and tolerability were comparable between the two treatments. CONCLUSIONS: Tigecycline monotherapy is a safe and effective therapy for cSSSIs in geographically distinct populations in Asia.

Efficacy and safety of tigecycline monotherapy compared with vancomycin plus aztreonam in patients with complicated skin and skin structure infections: Results from a phase 3, randomized, double-blind trial.

OBJECTIVES: To compare the effect of tigecycline monotherapy, a first-in-class, expanded broad spectrum glycylcycline, with the combination of vancomycin and aztreonam (V + A) in the treatment of complicated skin and skin structure infections (cSSSI). METHODS: A phase 3, double-blind study conducted in 8 countries enrolled adults with cSSSI who required intravenous (IV) antibiotic therapy for > or =5 days. Patients were randomly assigned (1:1) to receive either tigecycline or V + A for up to 14 days. Primary endpoint was the clinical cure rate at the test-of-cure visit. Secondary endpoints included microbiologic efficacy and in vitro susceptibility to tigecycline of bacteria that cause cSSSI. Safety was assessed by physical examination, laboratory analyses, and adverse event reporting. RESULTS: A total of 596 patients were screened for enrollment, 573 were analyzed for safety, 537 were included in the clinical modified intent-to-treat (c-mITT) population, 397 were clinically evaluable (CE), and 228 were microbiologically evaluable (ME). At test-of-cure, cure rates were similar between tigecycline and V + A groups in the CE population (82.9% versus 82.3%, respectively) and in the c-mITT population (75.5% versus 76.9%, respectively). Microbiologic eradication rates (subject level) at test-of-cure in the ME population were also similar between tigecycline and V + A. Frequency of adverse events was similar between groups, although patients receiving tigecycline had higher incidence of nausea, vomiting, dyspepsia, and anorexia, while increased ALT/SGPT, pruritus, and rash occurred significantly more often in V + A-treated patients. CONCLUSIONS: This study demonstrates that the efficacy of tigecycline monotherapy for the treatment of patients with cSSSI is statistically noninferior to the combination of V + A.

The efficacy and safety of tigecycline in the treatment of skin and skin-structure infections: results of 2 double-blind phase 3 comparison studies with vancomycin-aztreonam.

Two phase 3, double-blind studies in hospitalized adults with complicated skin and skin-structure infections (cSSSI) determined the safety and efficacy of tigecycline versus that of vancomycin-aztreonam. Patients received tigecycline (100 mg, followed by 50 mg intravenously twice daily) or vancomycin (1 g intravenously twice daily) plus aztreonam (2 g intravenously twice daily) for up to 14 days. Populations were as follows: 1116 patients (566 treated with tigecycline, and 550 treated with vancomycin-aztreonam) constituted the modified intent-to-treat (mITT) population, 1057 patients (538 treated with tigecycline, and 519 treated with vancomycin-aztreonam) constituted the clinical mITT (c-mITT) population, and 833 patients (422 treated with tigecycline, and 411 treated with vancomycin-aztreonam) constituted the clinically evaluable population. Clinical responses to tigecycline and vancomycin-aztreonam at test-of-cure were similar: c-mITT, 79.7% (95% confidence interval [CI], 76.1%-83.1%) versus 81.9% (95% CI, 78.3%-85.1%) (P = .4183); and clinically evaluable, 86.5% (95% CI, 82.9%-89.6%) versus 88.6% (95% CI, 85.1%-91.5%) (P = .4233). Adverse events were similar, with increased nausea and vomiting in the tigecycline group and increased rash and elevated hepatic aminotransferase levels in the vancomycin-aztreonam group. Tigecycline monotherapy is as safe and efficacious as the vancomycin-aztreonam combination in treating patients with cSSSI.

Comparative epileptogenic properties of two monobactam derivatives in C57, Swiss and DBA/2 mice.

The behavioural and electrocortical effects of two monobactam derivatives were studied after intraperitoneal (ip) administration in DBA/2 mice, a strain genetically susceptible to sound-induced seizures, and in C57 and Swiss mice, two strains not prone to seizure. DBA/2 mice were more susceptible than Swiss and C57 mice to seizures induced by aztreonam or carumonam. No significant differences were observed between seizures elicited by aztreonam and carumonam in animals (DBA/2 only) administered intracerebroventricularly or ip. Although the main mechanism for seizure-like activity of monobactams cannot be easily determined, we believe that several mechanisms may be involved. An increased excitation of the central nervous system (CNS) by inhibition of GABA binding to receptors and a slow clearance of aztreonam and carumonam from the CNS may be postulated.

[Clinical efficacy of aztreonam in patients with complicated urinary tract infections].

Aztreonam (AZT) (2 g daily) was intravenously administered for 5 to 7 days to 65 patients with complicated urinary tract infections (UTI). Ninety one organisms were isolated from these patients' urine. Among them 66 organisms were eliminated following AZT administration. The elimination rate for Gram negative organisms was 94.7% and that for Gram positive organisms was 33.3%. Thirty one organisms appeared newly by the replacement of organisms. Among them, 12 organisms were E. faecalis. The efficacy rate of AZT in single infection and in mixed infection was 55.8% and 13.7%, respectively. The overall clinical efficacy rate of AZT in the present study was 41.5%. As side effects, skin rash and itching were observed in 3 patients and slight elevations in blood chemistry were observed in 10 patients. The results indicate that AZT is an effective drug for the treatment of patients with complicated UTI, especially those caused by Gram negative organisms.

Controlled trial of aztreonam vs. tobramycin and azlocillin for acute pulmonary exacerbations of cystic fibrosis.

The efficacy of aztreonam was compared to that of standard therapy consisting of tobramycin and azlocillin in the treatment of acute pulmonary exacerbations of cystic fibrosis in a randomized, open trial. Fifteen patients were randomized to each treatment. Responses were assessed based on changes in pulmonary and clinical scores, white blood cell counts, pulmonary function tests and quantitative bacteriology of sputum which were performed before, every 5 to 7 days during and on the last day of therapy. Patients in both groups responded to therapy and there were no statistically significant differences in changes in the above indicators of response with therapy between the two groups (P greater than 0.05). The incidence of detection of Pseudomonas aeruginosa isolates resistant to all three study antibiotics increased with therapy. Side effects were limited to transient elevations of liver enzymes (both groups) and rash and fever in one patient treated with azlocillin. Aztreonam represents effective therapy for pulmonary exacerbations of cystic fibrosis associated with susceptible pathogens.

Aztreonam therapy for serious gram-negative infections in children.

Fifty-nine children were enrolled in an open trial of aztreonam, a monocyclic beta-lactam, therapy for serious gram-negative infections. Thirty-six infections were microbiologically evaluable and received five or more days of therapy. Patients' ages ranged from 3 days to 12 years, and diagnoses included pyelonephritis or cystitis (20), deep soft tissue or joint infection (seven), septicemia (four), pneumonia (three), peritonitis, and epiglottitis. Causative bacteria included Escherichia coli and other Enterobacteriaceae, Pseudomonas aeruginosa, and Haemophilus influenzae. The standard regimen was 30 mg/kg every six or eight hours intravenously. All isolates were aztreonam-susceptible and were eradicated during therapy. Two patients had microbiologic relapses: a patient with Salmonella choleraesuis meningitis who was initially treated for only ten days and a patient with E coli pyelonephritis. Clinical cure was achieved in 31 of 36 children. Pharmacokinetic studies performed in six children demonstrated no difference in serum concentrations or pharmacokinetic variables between day 1 and day 7 of therapy. Although several patients had transient eosinophilia (eight), elevated levels of aminotransferase (seven), or thrombocytosis (ten), no clinically significant adverse effects were noted. In this initial, uncontrolled study, aztreonam was effective and safe in the treatment of a variety of serious gram-negative infections in children.

Empiric antimicrobial therapy with aztreonam or ceftazidime in gram-negative septicemia.

In an open, comparative study, 225 patients with severe underlying diseases and suspected gram-negative bacillary septicemia were randomly assigned to receive aztreonam or ceftazidime empirically, 2 g intravenously three times daily. Twenty-five patients in the aztreonam group and 22 in the ceftazidime group had blood cultures that grew aerobic gram-negative bacilli and were evaluable for response to therapy. All pathogenic strains were sensitive to treatment. In the aztreonam group, 22 (88 percent) patients had cures, three (12 percent) had failures, and seven (28 percent) had development of superinfections (five were caused by gram-positive cocci and two by fungi). In the ceftazidime group, 18 (82 percent) patients had cures, one had improvement, three (14 percent) had failures, and three had superinfections. The median peak serum bactericidal activity was 1:2,048 after aztreonam administration and 1:512 after ceftazidime administration. Failures were not related to resistant strains or to low serum bactericidal activity.