We investigated the in vitro influence of HAF on the antibacterial activity of moxifloxacin against Escherichia coli ATCC 10798, Escherichia coli K-12, Proteus rettgeri (Sanelli), Staphylococcus ...aureus ATCC 25923 Staphylococcus aureus NCTC 1808 and Staphylococcus epidermidis ATCC 12228. Human ascitic fluid was obtained from 6 cirrhotic patients by paracentesis. The interaction effect was evaluated by the checkerboard technique. Our results indicate the ability of human ascitic fluid to reduce minimum inhibitory concentrations of moxifloxacin against Gram-negative bacteria, but not against Gram-positives.
Representing the major part of the human colon microflora, members of the Bacteroides fragilis group are frequently involved in mixed aerobic and anaerobic infections. Recent studies show an ...increased resistance of the B. fragilis group against several antimicrobial agents. The aim of the present study was to determine the susceptibility of 87 B. fragilis group strains isolated in 2003/2004 in Western Austria against eight antimicrobial agents by Etest. Furthermore, the resistance patterns were compared with those of 45 B. fragilis group strains isolated in 1992 and referred to the world wide trend towards increased resistance. In 1992 as well as in 2003/2004, all strains were susceptible against metronidazole and imipenem. However, comparing the MIC-values of the B. fragilis group strains collected 1992 with data from 2003/2004, a significant increase in resistance was found for clindamycin (p<0.01). Regarding cefoxitin, a similar trend could be observed. However, this difference was not yet significant (p=0.144). Our findings underline the emerging resistance of the B. fragilis group against antimicrobial agents and underscore the importance of susceptibility testing of anaerobes even in routine laboratories.
Objectives Though used for infections of the central nervous system, the pharmacodynamics of antimicrobial agents is commonly evaluated only in commercially available bacterial growth media. In the ...present study, the effects of cerebrospinal fluid (CSF) on bacterial killing by cefepime and rifampicin were investigated. Methods CSF was collected from patients who did not receive antibiotics. Time–kill curves were performed over 24 h using drug concentrations of 0.25-, 0.5-, 1-, 2-, 4- and 8-fold the respective MIC for the Staphylococcus aureus test strain. Killing curves were performed in Mueller–Hinton broth (MHB), in CSF incubated in ambient air (CSFAIR) and in CSF in air with 5% CO2 (CSFCO2). CO2 served to adjust the pH of CSF to physiological values. Results Sustained bacterial killing was achieved by cefepime at lower drug concentrations in CSFCO2 than in MHB. In contrast, rifampicin concentrations above the MIC were required to exert sustained killing in CSFCO2. Both drugs were least effective in CSFAIR. Conclusions Standard susceptibility tests may lead to over- or underestimation of the activity of distinct antibiotics in CSF. Evaluation of the antimicrobial activity in pH-adjusted CSF can provide useful information on drugs considered for the treatment of bacterial infections residing in CSF.
BCG vaccines are the oldest vaccines in use today, but the protective effect of the vaccination is still controversial. The risk of contracting tuberculosis is low compared with the possible ...complications after this vaccination. In Austria the formerly used BCG vaccine was not available in the required amount and another vaccine was released by the drug authorities. This product, with a more virulent strain, was used between August and December 1990, and this increased the incidence of complications. Eighty four of 1950 vaccinated newborn babies developed severe suppurative lymphadenitis three to 28 weeks after the vaccination, and surgical treatment was found to be necessary. Isoniazid treatment did not prove to be successful when the lymph node exceeded a certain size. Culture was successful in 46% up to week 20; after 20 weeks no culture became positive. All cultured bacteria were isoniazid sensitive. The question of general vaccination is raised and several points were considered before we came to the conclusion that except for high risk groups a general vaccination programme for neonates is not justified in Western countries.
to assess the in vitro activity of ceftobiprole and comparators against a recent collection of Gram-positive and Gram-negative pathogens, in order to detect potential changes in susceptibility ...patterns, and to evaluate the Etest assay for ceftobiprole susceptibility testing.
contemporary Gram-positive and Gram-negative isolates (excluding extended-spectrum β-lactamase-producing isolates) from across Europe and the Middle East were collected, and their susceptibility to ceftobiprole, vancomycin, teicoplanin, linezolid, ceftazidime and cefepime was assessed using the Etest method. Quality testing using Etest and broth microdilution (BMD) was conducted at a central reference laboratory.
some 5041 Gram-positive and 4026 Gram-negative isolates were included. Against Gram-positive isolates overall, ceftobiprole had the lowest MIC50 (0.5 mg/L), compared with 1 mg/L for its comparators (vancomycin, teicoplanin and linezolid). Against methicillin-resistant Staphylococcus aureus, all four agents had a similar MIC90 (2 mg/L), but ceftobiprole had a 4-fold better MIC90 (0.5 mg/L) against methicillin-susceptible strains. Only 38 Gram-positive isolates were confirmed as ceftobiprole resistant. Among Gram-negative strains, 86.9%, 91.7% and 95.2% were susceptible to ceftobiprole, ceftazidime and cefepime, respectively. Pseudomonas aeruginosa was less susceptible to all three antimicrobials than any other Gram-negative pathogen. There was generally good agreement between local Etest results and those obtained at the reference laboratory (for ceftobiprole: 86.8% with Gram-negatives; and 94.7% with Gram-positives), as well as between results obtained by BMD and Etest methods (for ceftobiprole: 98.2% with Gram-negatives; and 98.4% with Gram-positives).
ceftobiprole exhibits in vitro activity against a wide range of Gram-positive and Gram-negative pathogens, including multidrug-resistant strains. No changes in its known susceptibility profile were identified.
The major drawback in effective use of polymerase chain reaction (PCR) for detecting Mycobacterium tuberculosis (MTB) in clinical samples is the presence of PCR inhibitors and unique cell components ...of the organism that complicate DNA extraction and subsequent PCR amplification. A PCR assay with a unique multistep DNA extraction method that minimizes these problems was compared in a prospective study to acid-fast bacilli stain (AFBS) and culture for detecting MTB in clinical samples. A total of 254 clinical specimens in two separate studies were processed for MTB by these techniques. While PCR and culture were 100% sensitive and specific, culture required up to 8 weeks of incubation and additional time to perform biochemical testing to identify the isolated micro-organism. Acid-fast bacilli stain had a specificity of about 87% and did not differentiate among Mycobacterial species. In contrast, the results from PCR were available within 48 h and did not require additional testing to attain a final result. Polymerase chain reaction was highly reliable for detection and confirmation and interpretation of positive AFBS results. The assay was easy to perform with a turn around time of about 2 days.
Bactericidal activity of herbal extracts Thuille, Nikolaus; Fille, Manfred; Nagl, Markus
International journal of hygiene and environmental health,
06/2003, Letnik:
206, Številka:
3
Journal Article
Recenzirano
The antimicrobial activity of total herbal extracts has been investigated. The MIC of extracts of Evodia rutaecarpa and grape kernel ranged between 0.25 and 1 mg/ml against gram-positive cocci and P. ...aeruginosa. Cocci were killed after 30 – 90 min of incubation in grape kernel extract (0.5 – 1.5 mg/ml), and after 8 h in evodia extract (0.5 – 1 mg/ml), respectively. C. albicans was only susceptible to evodia (MIC 0.5 mg/ml).
The organic solvents of the preparations contributed to the antibacterial effect of herbal extracts with MICs of ethanol between 4 and 10 vol% and those of methanol between 6 and 10 vol%. Taking this into consideration, mastic and thyme extracts exerted hardly any microbicidal activity, while grape kernel extract and evodia were still effective at 2- to 6-fold dilutions below the MIC of the solvent. Because of the weak antimicrobial activity of total herbal extracts we recommend to give preference to preparations of single or more purified compounds.
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