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Biomedical subjects

J M Hamilton-Miller

Publications and source records attributed to J M Hamilton-Miller.

At least 145 records · Page 8Linked to original sources

Teicoplanin in patients with chronic renal failure on dialysis: microbiological and pharmacokinetic aspects.

A significant increase in the incidence of methicillin resistance was found in coagulase-negative staphylococci isolated from infected dialysis fluids in 1985 compared with the previous year. Vancomycin and teicoplanin were active against all these isolates, and had similar minimum inhibitory and bactericidal concentrations. The pharmacokinetic behaviour of teicoplanin in 23 dialysis patients was studied. A single, intravenous dose of teicoplanin was given to 11 patients on haemodialysis (HD) and seven patients on chronic ambulatory peritoneal dialysis (CAPD). In five CAPD patients, 40 mg was added to each 2 litre bag of dialysate for a five day period. Twenty such bags were exchanged. The study showed that a) teicoplanin was not removed from the body by HD or CAPD, b) less than 3% of the administered dose appeared in the urine, c) serum levels reached a plateau of 3-4 micrograms/ml after 40 hours and were maintained for at least five days, regardless of the route of administration or form of dialysis. These findings have obvious implications regarding appropriate treatment regimens in dialysis patients.

Adult↗

Effect of amoxicillin-clavulanate and cephradine on the fecal flora of healthy volunteers not exposed to a hospital environment.

A 7-day course of either cephradine or amoxicillin-clavulanate treatment caused no significant change in fecal flora composition, except that staphylococci were virtually eliminated in both groups. Some amoxicillin-resistant coliforms were isolated after treatment in both groups, but cephradine- or amoxicillin-clavulanate-resistant coliforms were rarely isolated.

Amoxicillin↗

Cefonicid, a long acting cephalosporin: in vitro activity compared with three cephalosporins and gentamicin.

Minimum inhibitory concentrations of cefonicid, cefazolin, cefuroxime, ceftazidime and gentamicin were determined against 688 bacterial strains (234 Gram-positive and 454 Gram-negative) from 20 different genera. Cefonicid showed a broader spectrum than cefazolin but was not as active as ceftazidime or gentamicin. Cefonicid most closely resembled cefuroxime in terms of microbiological properties. Disc testing accurately predicted sensitivity to cefonicid except for Staphylococcus aureus (which was sensitive by MIC, but appeared resistant in the disc test) and Proteus vulgaris (which was resistant by MIC but appeared sensitive in the disc test). In combination with gentamicin, synergy or addition was observed in 94% of 35 strains tested by the chequerboard technique. In view of its long half-life and wide range of microbiological activity, cefonicid promises to be a useful addition to the range of cephalosporins already available.

Cefamandole↗

In vitro activity of six antibiotics against multiresistant staphylococci and other gram-positive cocci.

Sixty-two strains of Staphylococcus aureus and coagulase-negative staphylococci, 21 Streptococcus faecalis and 17 other strains of streptococci isolated from cases of endocarditis were tested for sensitivity against rifampicin, teicoplanin, vancomycin, fusidic acid, erythromycin and novobiocin. Only rifampicin, novobiocin and teicoplanin were found to be active against the great majority of these strains. The microbial properties of these antibiotics suggest the necessity of combinations for effective therapy. The combinations rifampicin + novobiocin and rifampicin + teicoplanin were additive and suppressed the emergence of resistant mutants. Thus according to in vitro tests, either of these two combinations would be suitable for prophylactic use in high-risk patients, especially those scheduled to receive prosthetic implants.

Anti-Bacterial Agents↗

A clinical comparison between Macrodantin and trimethoprim for prophylaxis in women with recurrent urinary infections.

Seventy-two patients with a history of at least three attacks of urinary infection in the previous 12 months were assigned randomly to long-term prophylaxis with 100 mg at night of either Macrodantin (34 patients) or trimethoprim (38 patients). The mean interval between symptomatic attacks while on either treatment was increased three-fold compared with the pretreatment period. Macrodantin was significantly more effective (P less than 0.05) at preventing bacteriuria. Prophylaxis was equally effective in patients with and without a radiological abnormality. Side effects were significantly more common (P less than 0.05) in the group taking Macrodantin. In patients taking trimethoprim acquisition of resistance by faecal coliforms occurred at a rate of about 5%/month, and breakthrough infections were almost exclusively caused by trimethoprim-resistant coliforms. No acquisition of resistance occurred in patients taking Macrodantin, and the few breakthrough infections noted were due to sensitive bacteria.

Feces↗

Successful use of reduced dosage of cinoxacin in the treatment of recurrent urinary infection.

Ninety-seven patients with a history of recurrent bacteriuria were treated with cinoxacin in a dosage of either 250 mg (48 patients) or 500 mg (49 patients) 12-hourly for seven days. Both regimens had a success rate in excess of 85% one week after the end of treatment, and only 15% of the patients rendered abacteriuric had relapsed four weeks later. Both dosage regimens of cinoxacin were very well tolerated. Our results show that in patients with recurrent urinary infections the conventional dosage of cinoxacin (500 mg) can be reduced to 250 mg 12-hourly without any loss of efficacy. Consequently patients seen in family practice with uncomplicated lower tract urinary infection can confidently be expected to respond equally well to a dose of 250 mg 12-hourly with the obvious advantages of less toxicity, less chance of producing resistance in the bowel flora and lower cost.

Adult↗

Antimicrobial resistance in coagulase-negative staphylococci.

Patterns of resistance to antimicrobial agents were studied in 193 strains of coagulase-negative staphylococci isolated from hospital patients. Strains isolated from patients with malignant disease were significantly more often resistant to sulphonamide, trimethoprim, gentamicin and methicillin than were strains from other sources. Susceptibility to various beta-lactam antibiotics and aminoglycosides was investigated in members of the two most frequent species: Staphylococcus epidermidis and S. haemolyticus. S. haemolyticus strains were not only more often resistant to methicillin than S. epidermidis strains (respectively 81% and 17%) but they were more highly resistant (mean MICs respectively 85 and 19 mg/L). Methicillin-resistant S. haemolyticus strains were highly resistant to nine other beta-lactam antibiotics, whereas methicillin-resistant S. epidermidis strains showed both lower levels and a narrower spectrum of cross-resistance. Resistance to methicillin in members of both species was "heterogeneous", i.e., only a minority of cells in a culture showed significant resistance. Almost all gentamicin-resistant strains were sensitive to netilmicin and amikacin; rifampicin, vancomycin and teicoplanin were also highly active in vitro.

Aminoglycosides↗

Relationship between adhesion of Escherichia coli to uro-epithelial cells and the pathogenesis of urinary infection: problems in methodology and analysis.

Escherichia coli strains isolated from patients with urinary infections were tested for their ability to adhere to human uro-epithelial cells. In any single experiment, the numbers of bacteria adhering to individual uro-epithelial cells showed great variations; some cells had hundreds of bacteria adhering to them whereas other cells had few or none. This non-Normal distribution of bacterial attachment must be taken into account when carrying out statistical analyses of the results. The wide discrepancies reported in the literature regarding bacterial adhesion to uro-epithelial cells must, in part, be related to the type of statistical analysis used. In many cases, a Normal rather than a non-Normal distribution has been assumed. We found that even when all variables were kept constant, the experiment was still not reproducible. Therefore the technique shows a high degree of both inter- and intra-experimental error. Adhesion depended on such factors as the type of fimbriae produced by the bacteria, differing viability of uro-epithelial cells and varying pH of the medium used for a particular experiment. It is concluded that the results of in-vitro experiments demonstrating adhesion of E. coli to uro-epithelial cells are difficult to relate to bacterial adhesion in vivo but better results could be obtained if more attention were paid to standardisation of methods and their analysis.

Adhesiveness↗

Trimethoprim alone compared to co-trimoxazole in lower respiratory infections: pharmacokinetics and clinical effectiveness.

24 patients, admitted to hospital with lower respiratory tract infection, were treated with either co-trimoxazole (800 mg sulphamethoxazole + 160 mg trimethoprim) or trimethoprim (200 mg) orally twice daily. All showed a clinical improvement and with one exception respiratory pathogens were eliminated. Pharmacokinetics in blood, sputum and saliva were studied in 11 patients taking trimethoprim and 9 taking co-trimoxazole. No sulphamethoxazole was detected in either the sputum or saliva. Trimethoprim was found in higher concentrations in the sputum than in the blood, although there were wide and significant variations in individual patient's sputum pharmacokinetic profiles. Trimethoprim penetrates into the sputum at therapeutic concentrations in patients with chronic respiratory infections.

Adolescent↗