Actinomyces meyeri is rarely isolated in cases of actinomycosis. We present a case of disseminated actinomycosis due to A. meyeri; the patient had an abscess of the lung, osteomyelitis of the tibia, and multiple skin abscesses. Cure was achieved with surgical debridement and administration of intravenous penicillin, followed by oral penicillin, for 1 year. A concomitant gram-negative bacillus, Actinobacillus actinomycetemcomitans, was also isolated. Review of the literature revealed only 26 well-documented cases of infection with A. meyeri. Male adults are mainly affected, and alcoholism is frequently the underlying condition in these patients. Associated bacteria were isolated in two-thirds of these cases. In contrast to other species of Actinomyces, A. meyeri often causes pulmonary infection and shows a tendency for hematogenous dissemination. Even though multiple organs are involved, the outcome for these patients is excellent when penicillin is administered for several months and surgical procedures are performed when necessary.

No abstract

Blood and urine concentrations of a new aminoglycoside, tobramycin, were compared with those of gentamicin after intravenous and intramuscular administration in healthy adult volunteers. Serum concentrations for the two antibiotics were the same after an intravenous infusion of 100 mg for the first haur (about 4.75 p.g per milliliter), during the steady state attained by infusing 30 mg per hour for the next 2 haurs (about 3.85 p.g per milliliter), and during the elimination phase after the antibiotics were stopped. After a single intramuscular injection of 100 mg, the blood level curves were equal and the peak concentrations at 20 to 45 minutes were the same as those obtained after intravenous infusion of the same dose for 1 hour. Between 80% and 90% of each of the two antibiotics was recovered in the urine within 24 hours. Plasma clearance was not significantly higher than renal clearance, and glomerular filtration seemed to be the main pathway of elimination. The two aminoglycosides had an apparent volume of distribution of about 30% total body weight. Each had a half‐life of 2 hours.

Ampicillin and amoxicillin (a-amino-p-hydroxybenzyl penicillin) were administered orally in 500-mg doses to eight fasting volunteers in a comparative study in which pharmacokinetic techniques were used. The absorption of amoxicillin was significantly better, as demonstrated by a higher mean peak serum concentration of 7.6 Ag/ml as compared to 3.2 ,ug/ml for ampicillin, an average "area under the curve"that was approximately double that of ampicillin, and an 8-hr urinary recovery for amoxicillin of 60% as compared to 34% for ampicillin. Serum half-lives were the same for the two antibiotics, with values of 60.3 (±3.3) min for ampicillin and 61.3 (±5.6) min for amoxicillin. The latter drug gave measurable concentrations in the blood at 8 hr in all of eight volunteers, as compared to only three of eight with ampicillin.Amoxicillin (BRL-2333, a-amino-p-hydroxybenzyl penicillin) is a semisynthetic penicillin that is comparable to ampicillin in antibacterial spectrum and in vitro activity but yields higher concentrations in the blood after equivalent oral doses (3,(16)(17)(18). Neu and Winsheil reported an average peak concentration in serum of 7.6 ,g/ml after oral administration of 500 mg of amoxicillin to volunteers, as compared to 3.8 Aug/ml for ampicillin (17). Considerably higher peak blood concentrations, 10.8 ,g/ml for amoxicillin and 6.3 ,ug/ml for ampicillin, were found with the same doses in another study (3). Further, only a 20% difference in the urinary recovery of the two agents was noted in one of the studies, as compared with 37% in the other (3,17). Peak serum concentrations of ampicillin attained after 500 mg orally as reported in the literature have ranged from 1.5 to 6.3 jAg/ml (2, 3,8,[13][14][15]17). Because of these inconsistencies and the desire to get more complete information regarding the precise pharmacokinetics of these two ampicillins, including the comparative half-lives, the present study was carried out. MATERIALS AND METHODSEight healthy adult male volunteers received two 250-mg capsules of amoxicillin and of commercially available ampicillin (Beecham Pharmaceuticals) in crossover fashion, with an interval of 7 days or more between the two parts of the study. The volunteers reported to the laboratory after an overnight fast and were instructed to empty their bladders. They were then given the antibiotic capsules with 100 ml of water, and were allowed no food during the first 3 hr of the experiment. Blood samples taken at 0, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, and 8 hr, and samples of urine collected between 0 to 4 and 4 to 8 hr, were assayed for antibiotic content by use of a previously described agar-well diffusion technique, with Bacillus stubtilis as the test organism (1). Appropriate standards were prepared in pooled human serum and urine on the morning of each study, with the use of antibiotic powders provided by Beecham Research Laboratories. Specimens and standards were frozen at -20 C, and all assays were carried out within a few days of collection of the samples.The serum levels of...

Aminoglycoside antibiotics seem to accumulate and persist in the kidney. For a better understanding of this problem, groups of six rats received a single 4 mg/kg i.p. injection of sisomicin and were sacrificed repeatedly from 30 min to 28 days later. Sisomicin concentrations (bioassay) decreased rapidly in the serum, lung and other tissues. There was only a trace at six hours. The situation was totally different for the kidney. Concentrations in the cortex increased up to six hours with a maximum of 99 mug/g, 11 times higher than the peak value in the serum then decreased very slowly to 56, 18, and 7 mug/g, 2, 14 and 28 days, respecitvely, after injection. The concentrations in the medulla were lower than in the cortex but also showed an accumulation and persistence. Similar results were observed with gentamicin. In another experiment, daily injections of sisomicin or gentamicin during seven days demonstrated that the concentrations of both antibiotics six hours after the last injection were nearly three times higher in the cortex and twice as high in the medulla than after a single injection. These data explain why the nephrotoxicity of sisomicin or gentamicin involves chiefly the cortex, increases with the length of the treatment and can persist for several weeks after the last injection. Therapeutic implications need further studies.