High level of resistance to aztreonam and ticarcillin in Pseudomonas aeruginosa isolated from soil of different crops in Brazil.

Pseudomonas aeruginosa can be found in water, soil, plants and, human and animal fecal samples. It is an important nosocomial pathogenic agent characterized by an intrinsic resistance to multiple antimicrobial agents and the ability to develop high-level (acquired) multidrug resistance through some mechanisms, among them, by the acquisition of plasmids and integrons, which are mobile genetic elements. In this study, 40 isolates from Brazilian soil were analyzed for antibiotic resistance, presence of integrons and plasmidial profile. The results demonstrated that the vast majority of the isolates have shown resistance for aztreonam (92.5%, n=37) and ticarcillin (85%, n=34), four isolates presented plasmids and eight isolates possess the class 1 integron. These results demonstrated that environmental isolates of P. aeruginosa possess surprising antibiotic resistance profile to aztreonam and ticarcillin, two antimicrobial agents for clinical treatment of cystic fibrosis patients and other infections occurred by P. aeruginosa.

Drug-induced retinal toxicity in albino rabbits: the effects of imipenem and aztreonam.

PURPOSE: To test the toxic action of two antibiotics, imipenem and aztreonam, on the functional and morphologic integrity of the albino rabbit retina. METHODS: Two commercial drugs were used--Tienam, which contains imipenem, and Azactam, which contains aztreonam. Different doses of these drugs were injected intravitreally. Retinal function was assessed from the electroretinogram (ERG) and the visual evoked potential (VEP). Retinal structure was examined at the light microscopic level. RESULTS: Imipenem did not affect the ERG and the VEP responses or the morphology of the retina up to a total injected dose of 0.98 mg (2 mg Tienam). Aztreonam was not toxic to the albino rabbit retina up to a total injected dose of 2.8 mg (5 mg of Azactam). Severe functional and morphologic retinal damage was seen when 10 mg of Azactam was injected. A similar degree of damage was seen when a dose of 5 mg L-arginine, an ingredient of Azactam, was injected into the vitreous. CONCLUSIONS: Imipenem and aztreonam are nontoxic to the albino rabbit retina at concentrations that are 500-fold higher than their effective dose against bacterial infection. Azactam is highly toxic at high levels (more than 10 mg injected into the vitreous). Most of the toxicity could be explained by the L-arginine content of the drug.

A comparative efficacy and safety study of teicoplanin plus aztreonam versus gentamicin plus piperacillin in haematology oncology patients with clinically diagnosed septicaemia.

Infections due to Gram-positive bacteria, especially coagulase-negative staphylococci, have been increasing in immunocompromised patients during the last 5 years because of an increased use of Hickman catheters and oral gut decontamination with quinolones. Teicoplanin, a new glycopeptide antibiotic, has a long plasma half-life which allows once-a-day bolus administration, making it a 'user friendly' agent. A randomized comparative evaluation of teicoplanin plus aztreonam versus gentamicin plus piperacillin in leukaemic patients with a clinical diagnosis of septicaemia was undertaken. The objectives of this study were (1) to evaluate the efficacy and safety of teicoplanin and aztreonam in comparison to a 'standard antibiotic' regimen and (2) to assess the local and systemic tolerance of these drugs. Results of the study in more than 70 patients to date are presented, and the role of anti-Gram-positive antibiotics in the management of severe sepsis in immunocompromised patients is discussed.

Safety and toxicity profile of aztreonam.

Aztreonam is the first monocyclic beta-lactam antibiotic released for clinical use. Extensive toxicity and safety data for aztreonam in animals, healthy volunteers and adult patients have been accumulated previously; recently these studies have been extended to children. Overall the incidence of adverse clinical reactions caused by aztreonam is similar to or lower than that caused by comparison drugs. There is no evidence that aztreonam causes significant ototoxicity or nephrotoxicity; biochemical and hematologic abnormalities are rarely significant. Compared with the broad spectrum cephalosporins, aztreonam causes less disruption of normal gastrointestinal flora and consequently a lower incidence of diarrhea. Aztreonam does not displace bilirubin from albumin and penetrates readily into cerebrospinal fluid. Because of negligible immunologic cross-reactivity with other beta-lactams, aztreonam has been safely administered to patients with IgE-mediated penicillin hypersensitivity. These data suggest that aztreonam should be safe and well-tolerated in infants and children with infections caused by susceptible Gram-negative bacteria.

Clinical evaluation of aztreonam for serious gram-negative bacterial infections.

In an open study aztreonam was evaluated for efficacy and safety in 20 hospital in-patients presenting with presumptive or confirmed hospital acquired aerobic gram-negative infections. The overall clinical cure rate was 100% (19/19) with a corresponding microbiological cure rate of 100% in those patients in whom an organism was isolated initially (17/17). Reinfection with enterococcus occurred in 2 patients with UTI within a week of stopping aztreonam and one patient developed superinfection during treatment, but none were given any additional therapy. No evidence of drug-associated toxicity was found on any of the laboratory evaluations. One patient developed diarrhea 3 days after starting therapy, was withdrawn from the study and subsequently excluded from the analysis. One other patient remained febrile despite evidence of clinical and microbiological cure. Both these incidents were thought to be possibility drug-related. This study confirms aztreonam as a safe and effective way to treat patients with serious gram-negative infections.

Efficacy and safety of aztreonam in the treatment of serious gram-negative bacterial infections.

Aztreonam was used in the initial treatment of infection of the urinary tract (23 cases), respiratory tract (17 cases), skin and soft tissue (12 cases), abdominal cavity (three cases), endocarditis (two cases), septicemia (eight cases), and osteomyelitis (two cases). In 26 of 60 evaluable infectious episodes, aztreonam was used alone. Clinical cure was observed in 35 of 60, improvement in 24 of 60, and failure in one of 60 cases. Ten patients developed subsequent superinfection. Aztreonam was well tolerated, although one case of exfoliative dermatitis and one of pseudomembranous colitis occurred. However, these cases were complicated by proximal administration of other antibiotics.