Susceptibility of 324 Nonfermentative Gram-Negative Rods to 6 Cephalosporins and Azthreonam

Abstract

Susceptibility of 324 isolates of nonfermentative gram-negative bacteria to cephalothin, cefamandole, cefoxitin, ceftriaxone, ceftazidime, cefsulodin, and azthreonam was determined by agar dilution and disc diffusion techniques. With the exception of Moraxella species, first- and second-generation cephalosporins were minimally active against nonfermenters tested. Cefsulodin and azthreonam were mainly active against Pseudomonas aeruginosa. In contrast, ceftazidime and ceftriaxone exhibited wider activity spectra. Cefsulodin and ceftazidime were the most active against P. aeruginosa, followed by azthreonam and ceftriaxone. Ceftazidime was the only drug with significant activity against Pseudomonas maltophilia and Pseudomonas fluorescens/ Pseudomonas putida, and was also the most active against Pseudomonas cepacia. Acine-tobacter calcoaceticus and Alcaligenes strains were most sensitive to ceftazidime, followed by ceftriaxone and azthreonam. Ceftriaxone was the most active against moraxellas, followed by cefamandole/cefoxitin, ceftazidime, cephalothin, cefsulodin, and azthreonam. Ceftazidime was the most active against uncommonly isolated nonfermenters. Results observed in this study reflect a potential use for ceftazidime in therapy of infections caused by most gram-negative nonfermenters; therapy with cefsulodin and azthreonam in nonfermenter infections should be restricted to those caused by P. aeruginosa, and that with ceftriaxone reserved for non-P. aeruginosa infections.

Antimicrobial susceptibility of Bordetella avium and Bordetella bronchiseptica isolates

“…The results of the MIC determinations correlate closely with recent reports (1,4,5,8,12), and similar results with disk diffusion methods were observed (9). Although, we report slightly lower trimethoprim-sulfamethoxazole and tetracycline MICs for 90% of isolates than Kurzynski and associates, the range of MICs is essentially the same (8).…”

“…Infected young turkeys experience oculonasal discharge, tracheal collapse, and decreased weight gains; but mortality is usually low (10). No comprehensive epidemiological studies on the incidence of B. avium infection are available.To date, in vitro antimicrobial susceptibility studies with these two organisms have been conducted with either small numbers of isolates (4) or against panels with limited numbers of antimicrobial agents (1,12 tested against all study isolates at the indicated ranges of concentrations: penicillin, 0.015 to 2.0 ,ug/ml; ampicillin, 0.25 to 16 ,ug/ml; ampicillin-sulbactam, 0.03/0.015 to 16/8 ,ug/ml; ticarcillin, 4 to 64 ,ug/ml; mezlocillin, 2 to 4 ,ug/ml; piperacillin, 1 to 64 ,ug/ml; gentamicin, 1 to 8 ,ug/ml; tobramycin, 1 to 8 ,uglml; amikacin, 2 to 32 ,ug/ml; cephalothin, 1 to 16 ,ug/ml; cefuroxime, 0.5 to 32 ,ug/ml; cefoperazone, 2 to 32 ,ug/ml; ceftazidime, 0.5 to 32 ,ug/ml; cefotaxime, 0.5 to 32 ,ug/ml; ceftriaxone, 0.5 to 32 pug/ml; chloramphenicol, 0.25 to 16 ,ug/ml; erythromycin, 0.12 to 8 ,uglml; rifampin, 0.015 to 4 ,ug/ml; trimethoprim-sulfamethoxazole, 0.5/9.5 to 32/608 ,ug/ mnl; and tetracycline, 0.25 to 16 ,ug/ml.The inoculum was a suspension of the organism in …”

Human infections associated with Bordetella bronchiseptica

“…Only one small portion of tissue showed respiratory tract epithelium, and bacteria associated with the ciliated epithelium were not demonstrated by careful search of Gram-and toluidine blue-stained VOL. 4 Cultures of the sinus material for anaerobes, mycobacteria, and fungi were negative. By the Automicrobic System, the B. bronchiseptica isolate was susceptible to carbenicillin, gentamicin, tetracycline, tobramycin, and trimethoprim-sulfamethoxazole and was resistant to ampicillin, cefamandole, cefoxitin, cephalothin, and chloramphenicol.…”

“…Tuomanen and associates (162) (11,13,71,88,92 VOL. 4,1991 animal erythrocytes and is distinctly independent from lipopolysaccharide endotoxin (87). This toxin produces turbinate atrophy accompanied by bone loss and chronic inflammation when applied intranasally or injected parenterally into young swine.…”

“…It is possible that the upper respiratory tract illnesses in the family were of viral etiology and that the recovery of B. bronchiseptica represented the incidental VOL. 4,1991 detection of colonization in people closely exposed to sick farm animals.…”