Mupirocin-resistant Staphylococcus aureus.
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Administration, Topical↗
Biomedical subjects
R Wise
Publications and source records attributed to R Wise.
Concentrations of temafloxacin in serum and bronchial mucosa.
The bronchial mucosal concentrations of temafloxacin hydrochloride were determined in specimens obtained at fibreoptic bronchoscopy and compared with simultaneous serum concentrations. The 18 patients studied were given an oral dose of 400 mg b.i.d for three days to achieve steady state levels. The mean serum concentration was 6.9 mg/l (SD 2.5 mg/l) and the mean bronchial mucosal concentration 12.2 mg/kg (SD 4 mg/kg). The mucosal levels exceeded those required to inhibit most of the common respiratory pathogens, including Streptococcus pneumoniae and Pseudomonas aeruginosa. These data support the use of temafloxacin for therapy of bronchial infections.
4-Quinolones↗
A comparison between imipenem and metronidazole prophylaxis against sepsis following appendicectomy.
A single preoperative dose of imipenem/cilastatin was compared with metronidazole for the prevention of infectious sequelae following emergency appendicectomy. Patients with established sepsis received in addition 72 h of either intravenous imipenem or ampicillin, gentamicin and metronidazole postoperatively. Two hundred and sixty-eight patients were studied. Wound infection rate in low-risk patients was 9% for metronidazole and 8% for imipenem. When sepsis was already established intraperitoneally the wound infection rate was 24% for the triple therapy regimen and 8% for imipenem. There was no statistically significant difference between the infection rates in the two groups of treatment whatever the state of the appendix, but there was a trend in favour of imipenem in those patients with a perforated appendix.
Adolescent↗
Mycobacterium chelonei isolation from broncho-alveolar lavage fluid and its practical implications.
Mycobacterium chelonei was isolated from the broncho-alveolar lavage fluid of seven patients on eight occasions over a 6-month period. The same bacterium was identified in the hospital water supply. Despite the use of a recommended disinfection procedure, it proved impossible to eradicate the organism until the bronchoscopes were treated with ethylene oxide and the use of tap water in rinsing was abandoned.
Aged↗
The accumulation of five quinolone antibacterial agents by Escherichia coli.
The accumulation of five radiolabelled quinolone antibacterial agents by Escherichia coli KL16 was examined using a vacuum filtration method. Preliminary experiments were performed to determine the optimum quinolone concentration, inoculum of cells, filter washing regimen and filter type. All five quinolones showed a similar biphasic pattern of accumulation with high radioactive counts cell-associated during the first ten seconds of the assay, followed by steadily increasing accumulation over 30 min. Analysis of the mean accumulation after 30 min for each quinolone showed that there was no direct relationship between quinolone accumulation and antibacterial activity (as quantified by the MIC or bactericidal activity). Mechanistic investigations showed that accumulation was decreased by low reaction temperatures, acid pH and the presence of the metabolic inhibitors 2,4-dinitrophenol, potassium cyanide and sodium azide. These results suggest that quinolone accumulation by E. coli KL16 is partly dependent on cell metabolism and may proceed by an active transport mechanism. Treatment of cells with EDTA was found not to increase quinolone accumulation, suggesting that the outer membrane of E. coli KL16 does not act as a permeability barrier to these quinolones. The implication of these results in terms of possible mechanisms of bacterial resistance to quinolones is discussed.
4-Quinolones↗
Penetration of cefpirome into prostatic tissue.
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Aged↗
The in-vitro activity of cefpodoxime: a comparison with other oral cephalosporins.
The in-vitro activity of cefpodoxime was studied in 529 clinical isolates and compared with the activity of other oral beta-lactams. Amongst the Enterobacteriaceae cefpodoxime was very active (MIC90 less than or equal to 1 mg/l--other than genera commonly possessing chromosomal beta-lactamases). Against these strains cefpodoxime was comparable in activity to cefixime and about eight-fold more active than cefuroxime and 8-16-fold more active than cefaclor and cephalexin. Staphylococcus aureus strains were moderately susceptible (MIC90 4 mg/l) to cefpodoxime in comparison with cefixime (16 mg/l). The respiratory pathogens, Haemophilus influenzae, Streptococcus pneumoniae and Branhamella catarrhalis were susceptible to less than or equal to 0.5 mg/l cefpodoxime. An increase in inoculum from 10(4) to 10(6) cfu had little effect upon activity. Studies in beta-lactamase hydrolysis of cefpodoxime showed it to be stable to TEM-1, SHV-1 and BRO-1 enzymes but with high affinity for the P99 enzyme. The primary target of cefpodoxime is PBP3 (I50 1 mg/l) in Escherichia coli K12. The protein binding of the agent to human serum was 14.3-18.3% at 1 and 5 mg/l respectively.
Administration, Oral↗
Pharmacokinetics and tissue penetration of cefprozil.
The pharmacokinetics of cefprozil after a single 500 mg oral dose were studied, measuring plasma, inflammatory fluid and urine concentrations. Mean peak plasma concentrations of 9.6 mg/l (measured by bioassay) were achieved at a mean time of 1.9 h after administration. The mean plasma elimination half-life was 1.4 h; 63.6% of the dose was eliminated in urine by 24 h. Mean peak levels in inflammatory fluid reached 4.9 mg/l after 3.5 h. Mean plasma levels remained 2 mg/l for almost 5 h post dose and more than 6 h in inflammatory fluid. These data suggest that infections caused by highly susceptible pathogens might respond to a twice daily dosing regimen and less susceptible pathogens might require a higher dose or more frequent administration.
Adult↗
Cefepime concentrations in bronchial mucosa and serum following a single 2 gram intravenous dose.
The concentrations of cefepime in bronchial mucosa were measured after intravenous administration of a single 2 g dose in 20 patients undergoing diagnostic fibreoptic bronchoscopy. These concentrations were compared with simultaneous serum concentrations. The mean bronchial mucosal concentration was 24.1 mg/kg (s.d. 17.8 mg/kg) and the mean serum concentration was 40.4 mg/l (s.d. 28.1 mg/l). The mean percentage penetration was 59.8% (s.d. 12.5%). We conclude that a twice daily dosing of cefepime would be adequate for most respiratory infections although an 8-hourly dose may be necessary in pseudomonal infections.
Biological Assay↗
Macrolide progress.
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Anti-Bacterial Agents↗
In-vitro comparison of the post-antibiotic effect of vancomycin and teicoplanin.
The post-antibiotic effect (PAE) of teicoplanin was compared with that of vancomycin for five selected Gram-positive cocci. Two concentrations of each antibiotic were investigated, with the test organisms being exposed to each for both 1 and 2 h. At a concentration of 25 mg/l, teicoplanin had a greater PAE than vancomycin for the methicillin resistant staphylococci and Enterococcus faecalis strains tested. At a concentration of 5 mg/l, teicoplanin gave equal effects to those of vancomycin except for the strain of methicillin-resistant Staphylococcus aureus (MRSA) tested. The variation in the antibiotic exposure time gave only small changes in the PAE, except for the MRSA tested.
Enterococcus faecalis↗
Ceftibuten--in-vitro activity against respiratory pathogens, beta-lactamase stability and mechanism of action.
The in-vitro activity of ceftibuten against respiratory pathogenic bacteria was studied and compared with that of other oral beta-lactam agents. Ceftibuten displayed high activity against Haemophilus influenzae and Branhamella catarrhalis. There was reduced activity against Streptococcus pneumoniae (MIC90 16 mg/l). The protein binding of ceftibuten was 77% and the primary target site PBP 3. A high degree of stability to beta-lactamase hydrolysis was observed.
Anti-Bacterial Agents↗
Disc sensitivity testing to ofloxacin.
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Drug Resistance, Microbial↗
The pharmacokinetics and inflammatory fluid penetration of orally administered azithromycin.
The pharmacokinetics of azithromycin were determined during a 24 h period following oral administration of a single 500-mg dose to each of six male volunteers. Concentrations in serum, urine and cantharides-induced inflammatory fluid were determined by microbiological assay. The mean peak serum concentration of 0.45 mg/l was obtained at a mean time of 2.6 h post-administration. The elimination half-life from serum was seen to increase with time post-dose; the mean elimination half-life at 16 h post-dose was 9.6 h. Inflammatory fluid was penetrated rapidly, with the mean peak concentration of 0.13 mg/l achieved at a mean time of 3.25 h post-dose. After this peak, levels initially decreased, but after 8 h from drug administration until the end of the trial period, inflammatory fluid concentrations remained relatively constant. The mean inflammatory fluid penetration up to the end of the study period was 74%. The mean urinary recovery of azithromycin, during the initial 24 h post-dose, was 6%.
Administration, Oral↗
Problems with Iso-Sensitest agar.
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Agar↗
In-vitro activity of sparfloxacin, a new quinolone antimicrobial agent.
The in-vitro activity of sparfloxacin (AT-4140), a new difluorinated quinolone, was compared with those of ciprofloxacin, temafloxacin and selected members of other groups of antimicrobial agents, against 651 recent distinct clinical isolates and strains with known mechanisms of resistance. Three strains of Chlamydia trachomatis were also studied. The MICs for 90% of the Enterobacteriaceae were between 0.06 and 1 mg/l; for Pseudomonas aeruginosa the MIC90 was 2 mg/l. Sparfloxacin was 16-fold more active against Acinetobacter spp. than ciprofloxacin. For Staphylococcus spp., Streptococcus, spp. and Enterococcus faecalis the MIC90 was between 0.25 and 1 mg/l; sparfloxacin was four-fold more active against Str. pneumoniae than ciprofloxacin. Ninety percent of strains of Haemophilus influenzae, Branhamella catarrhalis and Neisseria spp. were inhibited by less than 0.03 mg/l; for Bacteroides fragilis the MIC90 was 1 mg/l. The three strains of Chl. trachomatis were susceptible to 0.06-0.12 mg/l sparfloxacin, which was 16-fold more active than ciprofloxacin. There was cross resistance among the quinolones, but not between the quinolones and other groups of antimicrobials. The protein binding of sparfloxacin was 40% and serum had little effect on its activity.
Anti-Bacterial Agents↗
A comparison of the mechanisms of decreased susceptibility of aztreonam-resistant and ceftazidime-resistant Enterobacteriaceae.
Twenty five strains of Enterobacteriaceae (five each of Enterobacter cloacae, Citrobacter freundii, Serratia marcescens, Morganella morganii and Providencia stuartii) were exposed to aztreonam and ceftazidime at 1/2 and 1 x MIC in liquid medium for 22 h, and also to 3, 5 and 10 x MIC and 16 mg/l of each agent in agar. Any putative mutant with an increase in the MIC of greater than or equal to 4 fold was examined for beta-lactamase expression and outer membrane protein profile. Mutants were selected on agar at approximately 10(7); however in liquid medium not all strains yielded mutants. Mutants lacking an outer membrane protein (OMP) with a molecular weight of 40,000 (+/- 5000) were selected with both agents, as were mutants expressing constitutive Richmond and Sykes Class 1 beta-lactamase. For the Ent. cloacae mutants increased beta-lactamase gave rise to MICs above the breakpoint of both agents, whereas with the other species ceftazidime susceptibility was more affected. Strains that were OMP- rarely had MICs above the breakpoint, unless there was also increased beta-lactamase expression, as in species such as M. morganii. Hence the major mechanism of resistance in these strains would appear to be beta-lactamase mediated rather than due to altered expression of outer membrane proteins.
Aztreonam↗
In-vitro activity of cefodizime against respiratory pathogens.
The in-vitro activity of cefodizime was studied against respiratory pathogens and was compared with the activity of other beta-lactams, ciprofloxacin and erythromycin. Cefodizime displayed high activity against Haemophilus influenzae (MIC90 0.008 mg/l), Branhamella catarrhalis and Streptococcus pneumoniae (MIC90 0.5 mg/l). Klebsiella spp. were less susceptible (MIC90 2 mg/l). It was concluded that cefodizime should be a useful agent in the therapy of respiratory tract infections.
Anti-Bacterial Agents↗