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Biomedical subjects

B Olsson-Liljequist

Publications and source records attributed to B Olsson-Liljequist.

52 records · Page 3Linked to original sources
PubMed1991

Antibiotic susceptibility of 629 bacterial blood and CSF isolates from Swedish infants and the therapeutic implications.

Blood and CSF isolates (n = 629) from Swedish infants up to one year of age were tested in vitro against 13 antimicrobial agents in order to update the guidelines for empiric therapy of septicaemia and meningitis. Ampicillin plus gentamicin provided inadequate empiric therapy for meningitis, due to the poor CSF penetration of the aminoglycoside and the frequent occurrence of bacterial resistance to ampicillin. Ceftazidime and cefuroxime were moderately active, particularly against isolates from small infants. Cefotaxime today seemed to provide the best empiric therapy of septicaemia and meningitis in infants. Because of the occurrence of Listeria and enterococcal infections, ampicillin should initially be added and other combinations are also advisable for the occasional cases of Enterobacter, Citrobacter, Serratia, and Pseudomonas infections. For coagulase-negative staphylococci only vancomycin offered a broad activity (100% at achievable serum levels).

Aminoglycosides↗
PubMed1990

Susceptibility of mycobacteria to fusidic acid.

Fusidic acid was shown to be effective in vitro against 30 clinical isolates of Mycobacterium tuberculosis at concentrations of 32-64 mg/l, concentrations which are readily achieved in serum. All but one of 17 Mycobacterium avium complex strains were resistant to fusidic acid at concentrations up to 64 mg/l. However, synergistic effects were shown for 11 of the 17 strains when fusidic acid was combined with ethambutol. Five of the strains were fully susceptible to the combination of fusidic acid (64 mg/l) and ethambutol (4 mg/l). It is suggested that fusidic acid should be evaluated clinically as a potential supplementary drug for treatment of mycobacterial infections.

Drug Resistance, Microbial↗
PubMed1990

Antimicrobial susceptibility testing of Haemophilus influenzae. Improvement of accuracy of the disc diffusion test.

A national quality control study was performed in 1986 to investigate the standard of performance of the disc diffusion antimicrobial susceptibility testing of Haemophilus influenzae in Sweden. The accuracy of susceptibility interpretations was unacceptably low. A new standardized method for susceptibility testing of H. influenzae was then worked out, and a new method of setting interpretive zone breakpoints was introduced. The susceptibility category of the main population of clinical isolates was determined according to the MIC50 of the strains. The zone histograms of clinical isolates from five reference laboratories were used for the calculation of interpretive breakpoints. For instance, for susceptible strains the mean of the combined zone values from these laboratories +/- 2 S.D. covered the zone range of the susceptible group, and one more S.D. below covered the intermediate/indeterminate group. The new zone breakpoints would place the main population of clinical isolates in the correct susceptibility group, and even make it possible to detect strains with different degrees of reduced susceptibility in the routine test. In a follow-up quality control study in 1988 the interpretive errors for clinical isolates were eliminated for all antibiotics except doxycycline in some laboratories. Laboratory-related zone breakpoints for doxycycline calculated by the single strain regression analysis method led to correct susceptibility interpretations also in these cases.

Diffusion↗
PubMed1990

In vitro activity of norfloxacin and other antibacterial agents against gastro-intestinal pathogens isolated in Sweden.

The in vitro activity of norfloxacin was compared to that of ampicillin, doxycycline, chloramphenicol, trimethoprim in combination with sulfamethoxazole (1/20), and erythromycin, against 272 clinical isolates of gastro-intestinal pathogens. Norfloxacin was the most active compound of those tested with MICs in the range 0.004-2 mg/l. Concentrations inhibiting 90% of the strains (MIC 90) were 0.008 mg/l for Vibrio cholerae, 0.016 mg/l for Aeromonas hydrophila, 0.032 mg/l for Vibrio cholerae non 01, 0.064 mg/l for Vibrio parahaemolyticus, Yersinia enterocolitica 03, enterotoxigenic (ETEC) and enteropathogenic (EPEC) Escherichia coli and Shigella species, 0.125 mg/l for Salmonella species, and 0.5 mg/l for Campylobacter species. Resistance to one or several of the other drugs was seen with higher or lower frequency in all the bacterial species tested. No cross-resistance between any of the other agents and norfloxacin was recorded.

Bacteria↗
PubMed1989

In-vitro synergistic activity between ethambutol and fluorinated quinolones against Mycobacterium avium complex.

Ciprofloxacin, ofloxacin and norfloxacin were ineffective at clinically relevant concentrations against the Mycobacterium avium complex (MAC) in vitro as measured by radiometric respirometry. Only two of 30 clinical isolates of MAC were susceptible to any of the tested quinolones. By contrast good antibacterial activity was obtained when any of the quinolones was combined with ethambutol. The synergistic effect was most pronounced for the combination of ethambutol and ciprofloxacin, to which 76 of 100 strains were susceptible. It is suggested that the synergism is based on an enhanced penetration of the quinolones by ethambutol.

Anti-Infective Agents↗
PubMed1985

Comparative in-vitro activity of Sch 34343 and other antimicrobial agents against anaerobic bacteria.

The activity of Sch 34343 was determined against 575 strains of anaerobic bacteria by an agar-dilution method. Its activity was compared with that of benzylpenicillin, piperacillin, cefoxitin, imipenem, clindamycin, metronidazole, chloramphenicol, vancomycin, fusidic acid and bacitracin. Sch 34343 and imipenem were the most active agents tested. Based on these results, Sch 34343 appears to be a promising antimicrobial agent for anaerobic infections and warrants further clinical investigations.

Anti-Bacterial Agents↗
PubMed1985

Scandinavian quality surveys of gentamicin assays 1978-1983.

During 1978-1983 44 Scandinavian laboratories participated in 7 quality surveys of gentamicin serum assays. In each survey 2 test solutions of gentamicin were distributed. In the first 4 surveys very few non-microbiological assays were used while in the 7th survey almost half the laboratories had access to enzyme immunoassay (EMIT). The gentamicin survey mean (SM) concentrations, which did not differ significantly from the intended concentrations, were used as target values. In survey 1, 65% of the results of either of the 2 test solutions were outside the SM +/- 25% and 16% were outside SM +/- 50% ("highly misleading"). In surveys 5 and 7 the corresponding figures were 27 and 5% and 18 and 0%, respectively. The EMIT performed excellently in all surveys. Agar well diffusion assays using Diagnostic Sensitivity Test agar (Oxoid) performed better than other plate diffusion assays. Laboratories participating regularly performed better than others. It is concluded that the survey program, which continues, provides an external facility for unbiased control of commercially available as well as non-commercial assay techniques and that it has been instrumental in the improvement of gentamicin assay standard. It is stressed that the surveys cannot replace internal quality control, best performed by daily measurement and regular statistical evaluation of samples of known potency.

Biological Assay↗
PubMed1985

Beta-lactamases in anaerobic bacteria.

The known mechanisms of beta-lactam resistance in anaerobic bacteria involve production of beta-lactamases, alteration of penicillin-binding proteins and blocked penetration of beta-lactams through the outer membranes. The most important factor in beta-lactam resistance is production of beta-lactamase. Beta-lactamases in various Bacteroides, Fusobacterium and Clostridium species have been described. Beta-lactam resistance in Bacteroides fragilis is most commonly mediated by beta-lactamase production mainly of cephalosporinase character. Recent studies have also shown that B. fragilis can produce a penicillinase which inactivates piperacillin and carbenicillin. Enzymes inactivating cefoxitin and imipenem have also been isolated from B. fragilis. The Bacteroides non-fragilis species produce beta-lactamases of mainly penicillinase character. Recently a penicillinase from Fusobacterium nucleatum has been characterized. Among the clostridia, Clostridium butyricum, C. clostridiiformis and C. ramosum have been shown to produce penicillinases.

Bacteria, Anaerobic↗
PubMed1984

Antimicrobial susceptibility of anaerobic bacteria in Sweden in 1983.

This review is concerned with anaerobic bacteria and antimicrobial susceptibility. Data on the susceptibility to different antimicrobials of anaerobic isolates in Sweden during 1983 is presented. Among the different bacterial groups, Clostridium perfringens, propionibacteria, anaerobic cocci and curved rods were found to be susceptible to beta-lactam antibiotics, clindamycin and chloramphenicol. C. difficile was susceptible to benzylpenicillin and imipenem, but resistant to cefoxitin. Most C. difficile strains were also susceptible to clindamycin and fusidic acid, while all strains were susceptible to metronidazole and vancomycin. The majority of the fusobacteria were susceptible to beta-lactam antibiotics, clindamycin, metronidazole and chloramphenicol. However, some strains were found to be resistant to penicillins. Against the Bacteroides fragilis group, clindamycin, chloramphenicol, metronidazole and imipenem had the best activity, whereas piperacillin and cefoxitin showed good activities. Most Bacteroides non-fragilis strains were susceptible to the antimicrobials tested. However, an increasing number of isolates were found to be resistant especially to penicillins when comparing with data from the last five years.

Anti-Bacterial Agents↗
PubMed1984

Anaerobic bacteria and beta-lactam antibiotics.

This review is concerned with anaerobic bacteria and beta-lactam antibiotics. Data on the susceptibility to beta-lactam antibiotics of anaerobic isolates in Sweden during 1983 is presented. Among the different bacterial groups, Clostridium perfringens, anaerobic cocci and curved rods were found to be very susceptible to the beta-lactams tested. C. difficile was susceptible to benzylpenicillin, piperacillin and imipenem, but resistant to the second and third generation of cephalosporins. Most fusobacteria were susceptible to the beta-lactam antibiotics investigated. However, some strains were found to be resistant to the penicillins. Against the Bacteroides fragilis group, imipenem had the best activity whereas moxalactam, piperacillin and cefoxitin had good activities. The majority of the Bacteroides non-fragilis strains were still susceptible to beta-lactam antibiotics. However, an increasing number of isolates were found to be resistant, especially to the penicillins when comparing with data from the last five years. The known mechanisms of beta-lactam resistance in anaerobic bacteria involve production of beta-lactamases, alteration of penicillin-binding proteins and blocked penetration of beta-lactams through the outer membranes of anaerobes. The presence of beta-lactamases in various Bacteroides and Clostridium species is reported as well as the characteristics of the different beta-lactamases encountered. The role of penicillin-binding proteins and penetration barrier in beta-lactam resistance is also discussed.

Anti-Bacterial Agents↗
PubMed1981

In vitro susceptibility of anaerobic bacteria to nitroimidazoles.

The in vitro susceptibility of 355 Swedish clinical isolates of anaerobic bacteria to three nitroimidazole drugs was determined by the agar dilution method. The drugs were metronidazole, tinidazole and ornidazole. In addition the in vitro susceptibility of 32 strains of clostridium difficile to metronidazole was determined. Gram-negative rods and clostridia were inhibited by 4 microgram/ml or less of all three compounds except one strain of C. difficile, which was not inhibited by 16 microgram/ml of metronidazole. Against strains of the Bacteroides fragilis group, tinidazole was slightly more active than metronidazole and ornidazole. Only about 70% of anaerobic cocci (peptococci and peptostreptococci) were inhibited by 4 microgram/ml of the three drugs, whereas the remaining isolates were resistant (minimum inhibitory concentration greater than or equal to 8 microgram/ml). Anaerobic streptococci were not included in this material. Actinomyces, arachnia and propionibacteria were resistant to the nitroimidazole drugs. At achievable serum levels, nitroimidazoles inhibited the majority of anaerobic bacteria found with greatest frequency in anaerobic infections.

Anaerobiosis↗
PubMed1980

Characterization of three different beta-lactamases from the Bacteroides fragilis group.

beta-Lactamases from five strains of Bacteroides fragilis and two strains of Bacteroides uniformis, all resistant to beta-lactam antibiotics, were compared by means of isoelectric focusing and enzyme kinetic measurements. beta-Lactamases from the five B. fragilis strains were identical, whereas those from the two B. uniformis strains were distinguished from each other and also from the B. fragilis enzymes. The two B. uniformis strains were relatively resistant to cefoxitin (minimal inhibitory concentration, 32 micrograms/ml), but only one of the strains, B. uniformis 2986, was found to rapidly inactivate cefoxitin. This apparently enzymatic inactivation of cefoxitin seemed to be of minor importance, and the main factor for cefoxitin resistance was considered to be a decreased permeability of the drug. Transfer of resistance to beta-lactam antibiotics from these beta-lactamase-producing strains of B. fragilis and B. uniformis to a non-beta-lactamase-producing strain of Bacteroides distasonis was attempted, but with these isolates no transfer of resistance to beta-lactam antibiotics was demonstrated.

Bacteroides fragilis↗