The in vitro activities of mupirocin, quinupristin/dalfopristin, linezolid, eperezolid, sitafloxacin, clinafloxacin, moxifloxacin, amoxycillin, metronidazole and clarithromycin were tested at pH 7.4 against 57 strains of Helicobacter pylori. The most active agents (mupirocin, sitafloxacin and clinafloxacin) were also tested for activity at pH 5.4 against the same strains. Mupirocin was very active at pH 7.4 and 5.4 (MIC90 0.25 and 0.12 mg/L, respectively). Quinupristin/dalfopristin, linezolid and eperezolid had low activity (MIC90 4, 8 and 4 mg/L, respectively). Sitafloxacin (MIC90

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...

Corynebacterium group D2 (CGD2) is involved in urinary tract infections in patients with underlying predisposing factors. This microorganism is highly resistant to a number of antimicrobial agents. We tested the activities of 79 antimicrobial agents against CGD2. (8-Lactams, aminoglycosides, and macrolides were ineffective. Fluorinated quinolones showed irregular activities, ofloxacin being the most active one. Doxycycline, rifampin, and mainly glycopeptides (vancomycin and teicoplanin) were the most active antibiotics against CGD2.Corynebacterium group D2 (CGD2) is involved in the etiology of urinary tract infections (UTIs) in patients with underlying predisposing factors, such as urinary tract instrumentation, surgery, or malignancy (1). CGD2 has also been involved in the origin of phosphate-encrusted cystitis (10, 11) and in sepsis in compromised hosts (3). This group has been shown to be resistant to most antibiotics used for the treatment of UTIs (9), the utilization of glycopeptides being frequently necessary.We studied the in vitro activities of 79 antimicrobial agents against CGD2 in order to find therapeutic alternatives useful for the treatment of UTIs caused by this microorganism.The antibiotics tested, kindly provided by their manufacturers, were penicillin, ampicillin, amoxicillin, carbenicillin, ticarcillin, azlocillin, mezlocillin, piperacillin, cloxacillin, mecillinam, temocillin, amoxicillin-clavulanic acid, sulbactam-ampicillin, piperacillin-tazobactam, ticarcillin-clavulanic acid, cefazolin, cefamandole, cefuroxime, cefotetan, cefonicid, cefaclor, cefoxitin, cefotaxime, cefsulodin, cefetamet, cefterame, latamoxef, ceftizoxime, cefoperazone, cefbuperazone, cefpirome, CGP-31608/WS (Ciba-Geigy), CGP-22495 (Ciba-Geigy), CGP-31523 (Ciba-Geigy), ICI-194008 lysed horse blood was used). The inoculum was prepared in Mueller-Hinton broth from a 48-h growth on Mueller-Hinton 5% sheep blood agar, adjusted to a turbidity equivalent to that of a 0.5 McFarland standard, and diluted 1:10. The inoculation of the agar plates was performed by using a Steer's replicator, the final inoculum on the media being approximately 104 CFU per spot. Plates were incubated for 48 h at 35°C in room air, since after 24 h of incubation, the control plates (the same strains inoculated on the same blood agar without antibiotics) occasionally showed very faint growth or had no visible growth. The growth on these plates after 48 h was always satisfactory. The MIC was defined as the lowest concentration of antibiotic that suppressed visible bacterial growth. Single colonies, faint hazes, and skip plates were disregarded.Results are shown in Table 1 and confirm the high resistance of CGD2 to a wide number of antimicrobial agents (6). CGD2 was resistant to all of the penicillins and combinations of penicillin and ,B-lactamase inhibitor tested. No strain was inhibited by any of these compounds and combinations at 128 ,ug/ml. To all of the cephalosporins, including the most recently developed ones and those active against other gram-...

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