Antimicrobial agents and chemotherapy
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Antimicrob. Agents Chemother. · Jun 1981
Effect of ionized calcium and soluble magnesium on the predictability of the performance of Mueller-Hinton agar susceptibility testing of Pseudomonas aeruginosa with gentamicin.
The soluble and ionized calcium and magnesium contents of 18 lots of Mueller-Hinton agar medium from three different manufacturers were analyzed, and the results were correlated with medium performance. A standardized disk diffusion test, with Pseudomonas aeruginosa (ATCC 27853) and a 10-microgram gentamicin disk, served as an indicator of medium performance. Zone diameters correlated well with the ionized calcium values and the sum of the ionized calcium and soluble magnesium values in the different lots (r = -0.88 for both). ⋯ Adjustment of deficient lots of Mueller-Hinton agar medium with ionized calcium or soluble magnesium or both (as the gluconate salts), to match the concentrations in lots that provided satisfactory zone sizes (17 to 19 mm), resulted in performance comparable to that of the control lots. Sixteen strains of Pseudomonas aeruginosa, ranging from resistant to susceptible, responded to cation adjustment in the same manner as the ATCC quality control strain. Satisfactory medium performance can obviously be assured by biological means in aminoglycoside susceptibility testing of Pseudomonas aeruginosa on Mueller-Hinton medium; however, cation adjustment of medium to predetermined levels of ionized calcium and soluble magnesium can now also provide desirable performance levels for P. aeruginosa on Mueller-Hinton medium.
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Antimicrob. Agents Chemother. · Jun 1980
Randomized Controlled Trial Clinical TrialSulfamethoxazole- trimethoprim versus ampicillin in treatment of acute invasive diarrhea in adults.
Twenty-seven Navajo adults with moderate to severe acute inflammatory diarrhea were hospitalized and randomly given ampicillin or sulfamethoxazole-trimethoprim. All patients had invasive diarrhea as defined by sheets of fecal leukocytes, seen on methylene blue wet-slide preparations, and significant clinical symptoms, including postural hypotension from dehydration or fever (temperature greater than 100 degrees F [or 37.8 degrees C]). Patients were followed daily for 5 days in the hospital. ⋯ Three of the eight patients successfully treated with sulfamethoxazole-trimethoprim had ampicillin-resistant organisms. The three patients with ampicillin-resistant organisms who were treated with ampicillin appeared to do less well; one was a clinical and bacteriological failure at 72 h and subsequently improved after sulfamethoxazole-trimethoprim therapy. As predicted by in vitro susceptibility studies and by studies in children, sulfamethoxazole-trimethoprim was highly effective in treating adult patients with shigellosis and appears to be the treatment of choice in areas where ampicillin resistance among Shigella is common.
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Antimicrob. Agents Chemother. · Jun 1979
Randomized Controlled Trial Clinical TrialRelationship between aminoglycoside-induced nephrotoxicity and auditory toxicity.
We have reviewed our data from 391 patients entered into three prospective, double-blind studies of aminoglycosides and evaluated 127 cases to determine whether aminoglycoside-induced auditory toxicity and nephrotoxicity are independent events. The cases selected for evaluation included all patients treated for greater than 3 days (mean, 7.7 days) who had serial creatinine determinations and were able to cooperate with serial bedside audiograms (250 to 8,000 Hz). Patients received either gentamicin, tobramycin, or amikacin. ⋯ The incidence of auditory toxicity in the nephrotoxic group (18.2%) was not significantly different from that in the nonnephrotoxic group (15.2%) (P = 0.75; Fisher exact test). There was no statistical difference between the nephrotoxic and auditory toxic groups in patient age, total dose of aminoglycoside, initial creatinine level, duration of therapy, or concurrent use of furosemide or cephalothin. We conclude that aminoglycoside-induced auditory toxicity and nephrotoxicity are independent events when the drug is administered for approximately 7 days and when aminoglycoside levels are maintained within a predefined range.