Activity of Four Cephalosporin Antibiotics In Vitro Against Bovine Udder Pathogens and Pathogenic Bacteria Isolated from Newborn Calves

The in vitro activity of chephaloridine, cephalexin, cefatrizine (BL-S640), and cephapirin (BL-P-1322) was evaluated by the serial dilution method against pathogenic gram-positive and gram-negative bacteria isolated from bovine udders and neonatal calf diseases. Cephapirin showed the comparatively greatest activity against the most common streptococcal species associated with bovine mastitis, whereas cephaloridine exhibited the best activity against Staphylococcus aureus. Cefatrizine was more active than the other cephalosporins against the gram-negative bacteria studied. In general, the minimal bactericidal concentration of each cephalosporin was two- to fourfold lower than the comparative value reported in the literature against the same type of pathogen of human origin.     

Antifungal Activity of Propolis Against Yeasts Isolated From Blood Culture: In Vitro Evaluation

Background: Due to the failure of available antifungal agents in the treatment of candidemia and the toxic activities of these drugs, a lot of researches are being conducted to develop new nontoxic and effective antifungal agents for optimal control of fungal pathogens. The aim of this study is to evaluate the in vitro antifungal activity of propolis against yeasts isolated from the blood cultures of intensive care unit patients. Methods: Seventy‐six strains were included in this study. The in vitro antifungal activity of propolis, fluconazole (FLU), and itraconazole (ITR) was investigated by the microdilution broth methods (CLSI guidelines M27‐A3 for yeast). The propolis sample was collected from Kayseri, Turkey. Results: Of the 76 isolates, 33 were identified as Candida albicans while 37 were C. parapsilosis, three were C. tropicalis, and three were identified as C. glabrata. The geometric mean range for MIC (μg/ml) with regard to all isolates was 0.077 to 3 μg/ml for FLU and ITR, and 0.375 to 0.70 μg/ml for propolis. It was shown that propolis had significant antifungal activity against all Candida strains and the MIC range of propolis was determined as 0185 to 3 μg/ml. Conclusion: This study demonstrated that propolis had significant antifungal activity against yeasts isolated from blood culture compared with FLU and ITR. The propolis MIC in azole‐resistant strains such as C. glabrata was found lower than the FLU MIC.     

In Vitro Comparison of Rosamicin and Erythromycin Against Urinary Tract Pathogens

The in vitro activity of rosamicin and erythromycin was compared at various pH values against 311 strains of bacteria representing common urinary tract pathogens. Alkalinization of the media consistently and significantly increased the antibacterial activity of rosamicin against all of the organisms tested. This was also true for erythromycin except when tested against strains of Proteus. At pH 8, rosamicin was two- to sixfold more active than erythromycin against Enterobacteriaceae. The activity of both antibiotics against Pseudomonas aeruginosa was very similar when tested at pH 8. Erythromycin was twice as active as rosamicin at pH 8 against group D streptococci. The activity of both antibiotics was bacteriostatic and inoculum size dependent, regardless of the organism tested or the pH of the test media. The greater activity of rosamicin against Enterobacteriaceae warrants clinical investigation.     

In Vitro Activity of Gepotidacin,a Novel Triazaacenaphthylene Bacterial Topoisomerase Inhibitor,against a Broad Spectrum of Bacterial Pathogens

Gepotidacin inhibits bacterial DNA replication through a mode different from that of fluoroquinolones. Gepotidacin and comparators were tested by broth and agar dilution against clinical isolates. The in vitro activities of gepotidacin were comparable against methicillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA, respectively) isolates (MIC₉₀, 0.5 μg/ml). The gepotidacin MIC₉₀s were as follows (in micrograms per milliliter) for the indicated bacteria: Streptococcus pyogenes, 0.25; Escherichia coli, 2; Moraxella catarrhalis, ≤0.06; Streptococcus pneumoniae (0.25), Haemophilus influenzae, 1; Clostridium perfringens, 0.5; and Shigella spp., 1, including levofloxacin-resistant subsets. Gepotidacin warrants further investigation for clinical development.     

In Vitro Activity of Voriconazole Against Candida Species

The in vitro activity of voriconazole was compared with that of itraconazole and fluconazole against 181 isolates of Candida albicans, 124 isolates of Candida glabrata, and 20 isolates of Candida krusei obtained from the early 1980s through the mid-1990s. Voriconazole had greater intrinsic activity than fluconazole or itraconazole against all three Candida species. For C. glabrata, C. krusei, and C. albicans, the MIC₅₀ values for voriconazole were 1 μg/mL, 0.5 μg/mL, and 0.01 μg/mL, respectively, compared with fluconazole MIC₅₀ values of 8 μg/mL, 64 μg/mL, and 0.25 μg/mL, respectively. If isolates from AIDS patients were excluded, MIC values for isolates from the 1990s were no higher than those noted for isolates from the 1980s. Voriconazole, a new triazole antifungal agent, appears to have enhanced activity against these three species of Candida; the clinical relevance of these findings should be studied in treatment trials.     

In Vitro Spectrum of Pexiganan Activity When Tested against Pathogens from Diabetic Foot Infections and with Selected Resistance Mechanisms

Pexiganan, a 22-amino-acid synthetic cationic peptide, is currently in phase 3 clinical trials as a topical antimicrobial agent for the treatment of mild infections associated with diabetic foot ulcers. Bacterial isolates from the 2013 SENTRY Antimicrobial Surveillance Program designated as pathogens from diabetic foot infections (DFI) and Gram-negative and -positive pathogens from various infection types that harbored selected resistance mechanisms/phenotypes were tested against pexiganan in reference cation-adjusted Mueller-Hinton broth. The MIC₅₀ and MIC₉₀ against all organisms tested from DFI were 16 and 32 μg/ml, respectively. Escherichia coli, Klebsiella pneumoniae, Citrobacter koseri, Enterobacter cloacae, Acinetobacter species, and Pseudomonas aeruginosa MIC values ranged from 8 to 16 μg/ml. Pexiganan MIC values among Staphylococcus aureus (methicillin-resistant S. aureus [MRSA] and methicillin-susceptible S. aureus [MSSA]), beta-hemolytic streptococci, and Enterococcus faecium ranged from 8 to 32 μg/ml. Pexiganan activity was not adversely affected for members of the family Enterobacteriaceae or P. aeruginosa that produced β-lactamases or resistance mechanisms to other commonly used antimicrobial agents. Decreased susceptibility to vancomycin did not affect pexiganan activity against S. aureus or E. faecium. Enterococcus faecalis appears to be intrinsically less susceptible to pexiganan (MIC, 32 to 256 μg/ml). The “all organism” MIC₉₀ of 32 μg/ml for pexiganan in this study was >250-fold below the pexiganan concentration in the cream/delivery vehicle being developed for topical use.     

Comparative In Vitro Activity of Five Cephalosporins Against Lactobacilli

Of five parenteral cephalosporins tested against 43 lactobacilli, cephaloridine, cefazolin, and cefamandole were the most active inhibitory and bactericidal agents. Timed-kill analysis revealed a slow bactericidal effect, with significant declines in mean minimal bactericidal concentration values at 48 h versus 24 h.     

白藜芦醇体外抗白假丝酵母菌生物膜作用的初步研究

目的 研究白藜芦醇对体外白假丝酵母菌生物膜的影响.方法 采用XTT减低法评价白藜芦醇对白假丝酵母菌生物膜的影响;通过倒置显微镜、扫描显微镜观察该药对白假丝酵母菌生物膜的形态学影响.结果 白藜芦醇对白假丝酵母菌生物膜的SMIC50,SMIC80分别为128,256 μg/ml;当白藜芦醇浓度为256 μg/ml时对白假丝酵母菌的早期黏附及菌丝生长有抑制作用.结论 白藜芦醇对体外白假丝酵母菌生物膜有显著的抑制作用.     

In Vitro Activity of Sodium Fusidate Against Anaerobic Bacteria

The microtiter broth dilution method was employed to determine the in vitro susceptibility of 525 recent clinical isolates of anaerobic bacteria to sodium fusidate. The minimal inhibitory concentrations of sodium fusidate ranged from 相似文献   

In Vitro Activity of Cefotaxime Against Cephalothin-Resistant Clinical Isolates

Cefotaxime is more active than six other cephalosporins against 150 cephalothin-resistant Enterobacteriaceae strains and is the only drug which is more active than ampicillin against Haemophilus. It shows a potentially useful activity against Pseudomonas.     

Cefaclor: In Vitro Spectrum of Activity and Beta-Lactamase Stability

The in vitro activity of cefaclor against 556 clinical isolates of gram-positive and gram-negative bacteria was compared with that of other cephalosporins. Cefaclor had activity similar to that of cephalexin against gram-positive bacteria. It showed greater activity against Haemophilus strains than did cephalexin and inhibited β-lactamase-producing Haemophilus isolates. Cefaclor was more active than cephalexin or cephalothin against Escherichia coli, Salmonella, and Shigella isolates but did not act against Serratia, Acinetobacter, indole-positive Proteus, or Bacteroides isolates. Cefaclor was resistant to type III (TEM) β-lactamases but was destroyed by type I β-lactamases and, to a lesser degree, by type IV and type V β-lactamases.     

In Vitro Activity of Rosamicin Against Neisseria and Haemophilus, Including Penicillinase-Producing Strains

Rosamicin was significantly more active against Haemophilus and Neisseria than are many antibiotics currently used to treat or prevent infection caused by these organisms. This enhanced activity was also observed against penicillinase-producing strains.     

Comparative In Vitro Activity of Pirbenicillin, Ticarcillin, and Carbenicillin Against Pseudomonas aeruginosa

Pirbenicillin, a semisynthetic penicillin, showed greater in vitro activity against 68 recent isolates of Pseudomonas aeruginosa than did ticarcillin or carbenicillin. The median minimum inhibitory concentration of each of these three compounds, respectively, was 3.1, 12.5, and 25 mug/ml when a 10(-4) dilution of an overnight culture (about 10(5) colony-forming units [CFU]/ml) was used as inoculum, but these differences were less striking when larger inocula were used: at 10(7) CFU/ml these values were 6.25, 12.5, and 50 mug/ml, and at 10(8) to 10(9) CFU/ml these values were 50, 50, and 100 mug/ml. All three compounds showed greater inhibitory activity at pH 6 than at pH 8. This pH effect was greatest with pirbenicillin, for 6.25 mug of pirbenicillin per ml inhibited 7, 11, and 57% of the strains at pH 6, 7, and 8, respectively; these values were 4, 4, and 11% with ticarcillin and 0, 0, and 7% with carbenicillin. At sufficient inhibitory concentrations, the rates of bacterial killing of the three compounds were similar. The observed differences in anti-pseudomonad activity were not due to differences in stability to pseudomonad beta-lactamases, but all three compounds were more stable than were cefazolin, cephaloridine, and benzylpenicillin.     

In Vitro Activity of Cinoxacin, Ampicillin, and Chloramphenicol Against Shigella and Nontyphoid Salmonella

The in vitro antibacterial activity of cinoxacin was compared with that of ampicillin and chloramphenicol against 26 strains of nontyphoid Salmonella and 44 strains of Shigella. Cinoxacin was found to have a lower minimal inhibitory concentration than ampicillin and chloramphenicol against all Salmonella and Shigella sonnei strains. Cinoxacin had minimal inhibitory concentrations similar to those of chloramphenicol but lower than those of ampicillin against Shigella flexneri and S. boydii strains.     

Telavancin In Vitro Activity against a Collection of Methicillin-Resistant Staphylococcus aureus Isolates,Including Resistant Subsets,from the United States

Telavancin had MIC₅₀, MIC₉₀, and MIC₁₀₀ values of 0.03, 0.06, and 0.12 μg/ml, respectively, against methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and non-multidrug-resistant (non-MDR) and MDR subsets. MRSA with elevated MIC values for vancomycin (2 to 4 μg/ml) or daptomycin (1 to 2 μg/ml) had telavancin MIC₅₀ (0.06 μg/ml) values 2-fold higher than those of isolates with lower MIC results (MIC₅₀, 0.03 μg/ml). However, telavancin had MIC₉₀ and MIC₁₀₀ results of 0.06 and 0.12 μg/ml (100% susceptible), respectively, regardless of the MRSA subset.     

In Vitro Activity of Josamycin Against Aerobic Gram-Positive Cocci and Anaerobes

Josamycin, a new macrolide antibiotic, was compared with ampicillin, erythromycin, and clindamycin in vitro against 25 isolates each of pneumococci, enterococci, Staphylococcus aureus, S. epidermidis, and nonenterococcal hemolytic streptococci and against 25 anaerobes including 10 Bacteroides fragilis. Minimal inhibitory concentration and minimal bactericidal concentration data were obtained for the aerobic organisms, using serial twofold tube dilutions in Mueller-Hinton broth. Minimal inhibitory concentrations were determined for the anaerobes by the agar dilution technique. Josamycin was comparable to erythromycin and clindamycin in activity against the pneumococci, streptococci, and staphylococci and was more active than clindamycin against enterococci. It was somewhat less active than ampicillin against enterococci and S. epidermidis and showed its greatest in vitro activity against anaerobes, being comparable to clindamycin.     

In Vitro Activity of 5-Fluorocytosine Against Candida and Torulopsis Species

One hundred yeasts were studied. Tests included detailed identification and determination of 24- and 48-hr minimal inhibitory concentrations and minimal fungicidal concentrations of 5-fluorocytosine (5-FC). Final identifications included 57 isolates of Candida albicans, 15 isolates of C. tropicalis, 13 isolates of C. parapsilosis, 7 isolates of Torulopsis glabrata, 3 isolates of C. guilliermondii, 2 isolates each of C. stellatoidea and Cryptococcus neoformans, and 1 isolate of Candida krusei. Twenty-three original identifications were in error; these involved mostly C. albicans, C. tropicalis, C. parapsilosis, and T. glabrata. Inhibitory end point readings based on 24 hr of incubation were misleading. Whereas 79 of 91 isolates of Candida appeared to be inhibited at 24 hr by 12.5 mug or less of 5-FC/ml, only 52 were inhibited at 48 hr; whereas only 12 isolates appeared to be resistant to 100 mug/ml after 24 hr, 37 were resistant after 48 hr. Susceptibility varied amount the different species. C. tropicalis was the most susceptible, with 10 of 15 isolates (66.7%) being inhibited by 12.5 mug or less/ml and 7 (46.7%) being killed by 100 mug or less/ml. C. albicans was similarily susceptible; 33 of 57 isolates (57.9%) were inhibited by 12.5 mug or less/ml and 25 (43.9%) were killed by 100 mug or less/ml. C. parapsilosis was quite resistant, as only 4 of 13 isolates (30.8%) were inhibited by 12.5 mug or less/ml and 3 (23.1%) were killed by 100 mug or less/ml.     

In Vitro Activity of Spectinomycin Against Recent Urinary Tract Isolates

The susceptibilities to spectinomycin of 303 recent urinary tract isolates were determined and compared to the susceptibilities of those strains to ampicillin, tetracycline, and gentamicin. Based on minimal inhibitory concentrations, 84% of Escherichia coli, Klebsiella, and Enterobacter, 31% of other Enterobacteriaceae, 7% of Staphylococcus aureus and Streptococcus (including enterococci), and 0% of Pseudomonas aeruginosa were susceptible to concentrations of spectinomycin that are easily surpassed in serum (相似文献   

Comparative In Vitro Activity of Five Cephalosporin Antibiotics Against Salmonellae

The in vitro activities of five cephalosporin antibiotics against 121 strains of salmonellae were compared. Cefamandole and cefaclor were more potent than cefazolin, and these three drugs were more active than cephalothin and cephalexin.     

Comparative In Vitro Activity of Newer Cephalosporins Against Anaerobic Bacteria

The in vitro susceptibilities of 408 recent clinical isolates of anaerobic bacteria against cefaclor, cephalexin, cephalothin, cefazolin, cefamandole, and cefoxitin were compared by an agar dilution technique. Against gram-positive bacteria, especially peptococci, peptostreptococci, and propionibacteria, cephalexin and cefaclor were significantly less active than cephalothin (P < 0.05). Cephalexin was also less active than cephalothin against clostridia and lactobacillus (P < 0.05). Against gram-negative bacteria, major differences were observed primarily with Bacteroides fragilis, against which cephalexin, cefazolin and cefoxitin were all significantly more active than cephalothin (P < 0.001). At concentrations of 16 μg per ml, however, all cephalosporins showed high in vitro activity, except against Lactobacillus species and B. fragilis. Cephalothin, cefazolin and cefamandole were considerably more active against the former, whereas cefoxitin was distinctly more active against the latter.