Susceptibility of
            <i>Nocardia asteroides</i>
            to 45 Antimicrobial Agents In Vitro

Bach, Michael C.; Sabath, L. D.; Finland, Maxwell

doi:10.1128/aac.3.1.1

Cited by 86 publications

(48 citation statements)

References 8 publications

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“…Confirming the observations of Wilson and Williams (13), we found ampicillin to be the most active of the currently available penicillins and cephalosporins, but only less than half of the strains tested were inhibited by 25 Mg/ml in the first two tests, and the MICs of ampicillin in the third test were 50 to 200 ig/iml for most of the strains at 48 and 72 h. As previously shown by Sanford and co-workers (9), we also found erythromycin to be active in low concentrations against a large proportion of strains, but many of them required higher concentrations or were not inhibited by 100 ,g of that antibiotic per ml (2). Considering differences in media, time of incubation (48 h in most instances), and the differences in the sources and maintenance of the organisms tested by different workers, the results have been reasonably consistent and compatible with those presented here with respect to the individual antibiotics.…”

Section: Resultssupporting

confidence: 61%

Synergistic Action of Ampicillin and Erythromycin Against Nocardia asteroides: Effect of Time of Incubation

Finland

Bach

Garner

et al. 1974

Antimicrob Agents Chemother

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Ampicillin and erythromycin were shown to act synergistically in vitro against the majority of strains of Nocardia asteroides tested. With these strains, the minimal inhibiting concentration (MIC) of each drug when combined was reduced 4-to more than 512-fold as compared with the MIC of each antibiotic acting individually against the same strains. The combined action against other strains was at least additive, and occasionally indifferent, but antagonism was not observed. The duration of incubation greatly influenced the MIC of erythromycin but had less effect on the action of ampicillin. Synergistic action was still demonstrable, although less frequently, when the period of incubation was increased from 48 to 72 h.We recently encountered pulmonary nocardiosis in a recipient of a renal transplant in whom treatment with trisulfapyrimidines had to be stopped because of severe drug reactions before the progress of the infection was arrested. In vitro tests with the Nocardia asteroides strain from that patient showed ampicillin and erythromycin to be the most active of the antimicrobials tested. Treatment with both of these antibiotics in moderate doses eliminated Nocardia for the first time from the patient's sputum, and the pulmonary lesion regressed. In another patient with similar symptoms, in whom treatment with various sulfonamides in large doses failed to control the infection, minocycline (not used in the tests with the straip from the first patient) was most active in vitro against the strain of N. asteroides isolated and proved similarly effective in the therapy of that patient. The clinical and laboratory findings in these two patients are reported in detail elsewhere (1).The observations in these two cases prompted an extensive study of the in vitro activity of a large number of strains of N. asteroides to most of the antimicrobials currently available for therapy and to several which were still under investigation. Minocycline proved to be the most uniformly active of the 45 drugs tested; ampicillin and the chemically related amoxicillin were the most active of the penicillins and cephalosporins; and erythromycin in a concen-1 Present address: Department of Medicine, Toronto General Hospital, Toronto, Ontario, Canada. tration of 0.8 gg or less per ml inhibited 40% of strains, and 25 gg/ml inhibited 53% of the strains.We report here the results of studies in which strains of N. asteroides were tested simultaneously for susceptibility to erythromycin and ampicillin, separately and in combination, by an agar-dilution method. MATERIALS AND METHODSThe strains of N. asteroides were selected from the same collection of cultures that had been used previously (2), except that two additional clinical isolates were included. The methods were essentially the same as those used previously. Preparation of the cultures involved initial cultivation in an enrichment broth and selection of those strains which grew heavily within 6 days at 37 C; these were subcultured in Mueller-Hinton broth (Difco), and only strains tha...

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Section: Resultssupporting

confidence: 61%

Synergistic Action of Ampicillin and Erythromycin Against Nocardia asteroides: Effect of Time of Incubation

Finland

Bach

Garner

et al. 1974

Antimicrob Agents Chemother

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“…Many in vitro studies of the sensitivities of Nocardia to antimicrobials have been reported; however, in most of them the investigators have used N. asteroides or other Nocardia species as the test organism or have included few (n Ͻ 20) N. brasiliensis strains (2,3,4,5,29,31,34,35). In the present work we studied the sensitivities of local N. brasiliensis strains to a wide range of antimicrobials.…”

Section: Discussionmentioning

confidence: 99%

In Vitro and In Vivo Activities of Antimicrobials against Nocardia brasiliensis

Gomez-Flores

Welsh

Said‐Fernández³

et al. 2004

Antimicrob Agents Chemother

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In Mexico mycetomas are mostly produced by Nocardia brasiliensis, which can be isolated from about 86% of cases. In the present work, we determined the sensitivities of 30 N. brasiliensis strains isolated from patients with mycetoma to several groups of antimicrobials. As a first screening step we carried out disk diffusion assays with 44 antimicrobials, including aminoglycosides, cephalosporins, penicillins, quinolones, macrolides, and some others. In these assays we observed that some antimicrobials have an effect on more than 66% of the strains: linezolid, amikacin, gentamicin, isepamicin, netilmicin, tobramycin, minocycline, amoxicillin-clavulanic acid, piperacillin-tazobactam, nitroxolin, and spiramycin. Drug activity was confirmed quantitatively by the broth microdilution method. Amoxicillin-clavulanic acid, linezolid, and amikacin, which have been used to treat patients, were tested in an experimental model of mycetoma in BALB/c mice in order to validate the in vitro results. Linezolid showed the highest activity in vivo, followed by the combination amoxicillin-clavulanic acid and amikacin.

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“…Only minocycline and amikacin are active against >90%o of strains (1,8), and both of these drugs have potential toxicities. Cefamandole is unlike--ly, however, to be useful in treating diseases of the central nervous system.…”

Section: Resultsmentioning

confidence: 99%