Susceptibility testing of fastidious and unusual pathogens

Thornsberry, Clyde; Swenson, Jana M.; Baker, C N; McDougal, Linda K.; Stocker, Sheila A.; Hill, Bertha C.

doi:10.1016/0738-1751(87)90026-8

Cited by 6 publications

(2 citation statements)

References 23 publications

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“…Here, we report the results of the effect of inoculum density (103, 104, and (17). The culture medium was Mueller-Hinton agar (Oxoid Ltd., Basingstoke, England) supplemented with 1% hemoglobin (bioMerieux, Charbonnieres les Bains, France) and 1% PoliViteX (bio Merieux).…”

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confidence: 99%

Lack of effective bactericidal activity of new quinolones against Brucella spp

Garcı́a-Rodrı́guez

Sánchez

Trujillano

1991

Antimicrob Agents Chemother

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The in vitro activities of six fluoroquinolones against 43 Brucella spp. were compared by testing three different inocula at two medium pH values. The influence of the test conditions was moderate. The activities of all quinolones were lower at pH 5 and with a high inoculum size. Results indicate the lack of effective bactericidal activity of quinolones against most strains of Brucella spp., particularly B. abortus.Although brucellosis is primarily a disease of domestic animals, it is a public health problem in many countries, especially the Mediterranean countries. The treatment of brucellosis requires combined regimens of antibiotics and is conditioned by the fact that brucellae are intracellular pathogens; thus, agents with a good capacity to penetrate macrophages are required for successful treatment. The regimen recommended for the treatment of brucellosis is a combination of oral tetracycline (or doxycycline) plus intramuscular streptomycin. Another regimen used is doxycycline plus rifampin (1, 13). Each of these regimens has disadvantages (13). The necessity of combined treatment, the length of treatment, and the proportion of therapeutic failures with some regimens oblige us to look for new drugs for the treatment of brucellosis. Fluoroquinolones, as a class, exhibit a broad spectrum of antibacterial activity (18). Their oral bioavailabilities, high tissue concentrations, evidence of intracellular penetration (fluoroquinolones appear to achieve intracellular concentrations in phagocytic cells significantly in excess of extracellular concentrations) (4-6, 14), and in vitro activities against Brucella spp. (2, 3, 7, 9, 10, 12, 13) make these antimicrobial agents attractive for use against infections caused by intracellular bacteria such as Brucella spp.The purpose of the present study was to determine the effect of the pH of the medium and inoculum size on the MICs and MBCs of ciprofloxacin, ofloxacin, lomefloxacin, temafloxacin, fleroxacin, and sparfloxacin against Brucella spp. Here, we report the results of the effect of inoculum density (103, 104, and (17). The culture medium was Mueller-Hinton agar (Oxoid Ltd., Basingstoke, England) supplemented with 1% hemoglobin (bioMerieux, Charbonnieres les Bains, France) and 1% PoliViteX (bio Merieux). The antimicrobial stock solutions were prepared at concentrations of 1,280 mg/liter and were stored frozen in small volumes in sterile polypropylene vials at -70°C. Serial twofold dilutions of antimicrobial agents were made in Mueller-Hinton broth supplemented with 1% PoliViteX. The range of concentrations assayed for each antibiotic was 0.008 to 4 mg/liter. In all cases, we considered the directions provided by the drug manufacturers as a part of these general recommendations. Brucella inocula were dilutions of 48-h broth cultures which were inoculated from a stock brucella slant that was stored frozen. Standard Brucella inocula were carried out by touching the top of four to five colonies of a single type and inoculating them into a tube containing 3.0 ml of b...

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confidence: 99%

Lack of effective bactericidal activity of new quinolones against Brucella spp

Garcı́a-Rodrı́guez

Sánchez

Trujillano

1991

Antimicrob Agents Chemother

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“…A color change to deep red within 10 min, at room temperature, was regarded as a positive result. As generally recommended (18), the time for reading was prolonged up to lh with Haemophilus, Neisseria and Branhamella.…”

Section: Fl-lactamase Detectionmentioning

confidence: 99%

Circulation in Italy of ?-lactamase-producing strains within the major groups of bacterial pathogens

et al. 1990

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A multicenter study was undertaken in Italy to assess the circulation of beta-lactamase-producing organisms and their current incidence within the major groups of bacterial pathogens. Almost four thousand strains, all freshly isolated from clinical material, were examined at four centers serving different areas of Italy. Despite some significant center-to-center differences, this survey documented the occurrence of a large overall circulation of beta-lactamase-producing organisms among clinical bacterial isolates. In particular, ampicillin resistance was recorded in one third to one half of the isolates of some Enterobacteriaceae, including Escherichia coli, Proteus, and Citrobacter species, and 80-90% of these resistant strains proved to be beta-lactamase producers. Both ampicillin resistance and beta-lactamase production were almost the rule in other Enterobacteriaceae, including Klebsiella, Enterobacter, and Serratia species. beta-lactamase was also produced by about 80% of glucose-non-fermenting gram-negative bacteria and Aeromonas hydrophila strains, by all of the isolates of Branhamella catarrhalis manifesting ampicillin resistance (i.e. more than half the total number of isolates), and by about two thirds of the ampicillin-resistant Haemophilus strains (which accounted for 20-25% of all Haemophilus isolates examined). In contrast, no beta-lactamase producers were observed among Neisseria gonorrhoeae isolates.

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In vitro activity of nonsteroidal antiinflammatory agents, phenotiazines, and antidepressants againstBrucella species

Muñoz-Criado¹,

Muñoz‐Bellido²,

Garcı́a-Rodrı́guez³

1996

Eur. J. Clin. Microbiol. Infect. Dis.

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The in vitro antimicrobial activity of streptomycin, rifampicin, tetracycline, seven nonsteroidal anti-inflammatory agents (acetyl-salicylic acid, piroxicam, indomethacin, ibuprofen, ketoprofen, sulindac, and diclofenac), and eight phenotiazine derivatives and antidepressant agents (clorpromazine, fluphenazine, amitryptiline, clomipramine, imipramine, maprotiline, sertraline, and diazepam) against 62 strains of Brucella spp. was tested. Diclofenac was the most active of the anti-inflammatory agents (MIC90 = 16 micrograms/ml). The activity of the phenotiazines and antidepressants was heterogeneous, with MIC90s ranging from 16 micrograms/ml for sertraline and 32 micrograms/ml for fluphenazine and clomipramine to > 512 micrograms/ml for diazepam. When the six most active anti-inflammatory agents and the six most active psychiatric drugs were tested at pH 5 and pH 4, the MICs remained unchanged except for those of fluphenazine; the MIC50 and MIC90 of this agent increased by one dilution.

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Susceptibility testing of fastidious and unusual pathogens

Cited by 6 publications

References 23 publications

Lack of effective bactericidal activity of new quinolones against Brucella spp

Lack of effective bactericidal activity of new quinolones against Brucella spp

Circulation in Italy of ?-lactamase-producing strains within the major groups of bacterial pathogens

In vitro activity of nonsteroidal antiinflammatory agents, phenotiazines, and antidepressants againstBrucella species

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