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Biomedical subjects

B Wiedemann

Publications and source records attributed to B Wiedemann.

At least 37 records · Page 2Linked to original sources
PubMed2001

Natural antibiotic susceptibility of strains of the Enterobacter cloacae complex.

The natural susceptibility to 70 antibiotics of 104 strains of the Enterobacter cloacae complex was examined using a microdilution procedure in Isosensitest broth. One hundred and one clinical strains designated as 'E. cloacae' were identified as E. hormaechei (n=65), E. asburiae (n=20) and E. cloacae genospecies 1 or 2 (n=16). Apart from fosfomycin susceptibility, there were only minor differences in natural antibiotic susceptibility patterns. All species were naturally sensitive or naturally sensitive and intermediate to numerous beta-lactams (e.g. carbapenems, aztreonam, acylaminopenicillins, ticarcillin, and some 'modern' cephalosporins), quinolones, aminoglycosides, tetracyclines, antifolates, chloramphenicol, and nitrofurantoin. Uniform natural resistance was found in benzylpenicillin, oxacillin, amoxycillin, amoxycillin/clavulanate, cefoxitin, rifampicin, lincosamides, glycopeptides, streptogramins and fusidic acid. Enterobacter hormaechei was the species most susceptible to fosfomycin. beta-Lactam susceptibility patterns pointed to the presence of chromosomally-encoded AmpC enzymes in all taxa of the E. cloacae complex.

Anti-Bacterial Agents↗
PubMed2001

beta-Lactam-susceptibility patterns of Plesiomonas shigelloides strains: importance of inoculum and medium.

The susceptibility of 10 Plesiomonas shigelloides strains to 30 beta-lactam antibiotics was examined. Susceptibility testing was carried out with a microdilution procedure using 3 media (Isosensitest broth, Mueller-Hinton broth and cation-adjusted Mueller-Hinton broth) and 4 inocula [1 x 10(4), 1 x 10(5), 1 x 10(6) and 1 x 10(7) colony-forming units (CFU)/ml]. A high inoculum dependency of MIC values was found for numerous beta-lactams. Each strain showed 2 completely different susceptibility patterns to several cephalosporins and aztreonam, but the same patterns were found with little variation in each strain. Using an inoculum of 1 x 10(4) CFU/ml the strains showed a high susceptibility to aztreonam and to all cephalosporins in all media (pattern 1), whereas they showed a decreased susceptibility to aztreonam and numerous cephalosporins with an inoculum of 1 x 10(7) CFU/ml (pattern 2). Using an inoculum of 1 x 10(6) CFU/ml, 4/10 strains in lsosensitest broth and 2/10 strains in Mueller-Hinton media showed pattern 1. Susceptibility testing of numerous penicillins revealed a medium-independent inoculum dependency, characterized by a step-to-step correlation between MICs and inocula. The beta-lactam susceptibility patterns arising from different inocula point to new beta-lactamase expression and regulation mechanisms in Plesiomonas. The potential to be resistant to a variety of beta-lactams under conceivable testing conditions should question the use of numerous beta-lactams for the treatment of Plesiomonas infections.

Animals↗
PubMed2001

Natural antimicrobial susceptibilities of Plesiomonas shigelloides strains.

The natural susceptibility of 74 Plesiomonas shigelloides strains isolated from humans (n = 50), water (n = 22) and animals (n = 2) to 71 antibiotics was examined. MICs were performed using a microdilution procedure with Mueller-Hinton broth and an inoculum of 1 x 10(6) cfu/mL. Plesiomonas strains were naturally susceptible or naturally susceptible and intermediate to tetracyclines, several aminoglycosides, aminopenicillins in combination with beta-lactamase inhibitors, all cephalosporins except cefoperazone, ceftazidime and cefepime, carbapenems, aztreonam, quinolones, trimethoprim, sulfamethoxazole, azithromycin, chloramphenicol, nitrofurantoin and fosfomycin. Uniform natural resistance was found to all penicillins tested, roxithromycin, clarithromycin, lincosamides, streptogramins, glycopeptides and fusidic acid. Plesiomonas strains were naturally resistant and intermediate to streptomycin, erythromycin and rifampicin. There were two susceptibility patterns to piperacillin/tazobactam, several cephalosporins and aztreonam. In contrast to a previous study with beta-lactam antibiotics, susceptibility testing of non-beta-lactams revealed no alterations of the MICs of most antibiotics, using different inocula and media. A database is described of the natural susceptibility of P. shigelloides strains to a wide range of antibiotics. It can be used for the validation of susceptibility test results of these bacteria.

Animals↗
PubMed2001

In vitro activities of ertapenem (MK-0826) against recent clinical bacteria collected in Europe and Australia.

Ertapenem (MK-0826, L-749,345) is a 1-beta-methyl carbapenem with a long serum half-life. Its in vitro activity was determined by broth microdilution against 3,478 bacteria from 12 centers in Europe and Australia, with imipenem, cefepime, ceftriaxone, and piperacillin-tazobactam used as comparators. Ertapenem was the most active agent tested against members of the family Enterobacteriaceae, with MICs at which 90% of isolates are inhibited (MIC(90)s) of < or =1 microg/ml for all species. Ertapenem also was more active than imipenem against fastidious gram-negative bacteria and Moraxella spp.; on the other hand, ertapenem was slightly less active than imipenem against streptococci, methicillin-susceptible staphylococci, and anaerobes, but its MIC(90)s for these groups remained < or =0.5 microg/ml. Acinetobacter spp. and Pseudomonas aeruginosa were also much less susceptible to ertapenem than imipenem, and most Enterococcus faecalis strains were resistant. Ertapenem resistance, based on a provisional NCCLS MIC breakpoint of > or =16 microg/ml, was seen in only 3 of 1,611 strains of the family Enterobacteriaceae tested, all of them Enterobacter aerogenes. Resistance was also seen in 2 of 135 anaerobes, comprising 1 Bacteroides fragilis strain and 1 Clostridium difficile strain. Ertapenem breakpoints for streptococci have not been established, but an unofficial susceptibility breakpoint of < or =2 microg/ml was adopted for clinical trials to generate corresponding clinical response data for isolates for which MICs were as high as 2 microg/ml. Of 234 Streptococcus pneumoniae strains tested, 2 required ertapenem MICs of 2 microg/ml and one required an MIC of 4 microg/ml, among 67 non-Streptococcus pyogenes, non-Streptococcus pneumoniae streptococci, single isolates required ertapenem MICs of 2 and 16 microg/ml. These streptococci also had diminished susceptibilities to other beta-lactams, including imipenem as well as ertapenem. The Etest and disk diffusion gave susceptibility test results in good agreement with those of the broth microdilution method for ertapenem.

Anti-Bacterial Agents↗
PubMed2001

Natural antibiotic susceptibilities of Edwardsiella tarda, E. ictaluri, and E. hoshinae.

The natural antibiotic susceptibilities to 71 antibiotics of 102 Edwardsiella strains belonging to E. tarda (n = 42), E. ictaluri (n = 41), and E. hoshinae (n = 19) were investigated. MICs were determined using a microdilution procedure according to NCCLS criteria and German standards. All edwardsiellae were naturally sensitive to tetracyclines, aminoglycosides, most beta-lactams, quinolones, antifolates, chloramphenicol, nitrofurantoin, and fosfomycin. Edwardsiella species were naturally resistant to macrolides, lincosamides, streptogramins, glycopeptides, rifampin, fusidic acid, and oxacillin. Although slight species-dependent differences in natural susceptibilities to some antibiotics (e.g., macrolides and cefaclor) were seen, differences in natural susceptibility affecting clinical assessment criteria were only seen with benzylpenicillin. Whereas E. tarda was naturally resistant to benzylpenicillin, E. hoshinae was naturally sensitive. Natural sensitivity and resistance to this penicillin were found among the strains of E. ictaluri. The observed oxacillin sensitivity of E. ictaluri was attributed to the failure of the species to grow at higher salt concentrations found in oxacillin-containing microtiter plates. The present study describes a database concerning the natural susceptibility of Edwardsiella species to a wide range of antibiotics, which can be applied to validate forthcoming antibiotic susceptibility tests of these microorganisms.

Anti-Bacterial Agents↗
PubMed2001

The German cystic fibrosis quality assurance project: clinical features in children and adults.

Cystic fibrosis (CF) is a complex disease which requires interdisciplinary care in specialized CF centres. In Germany, 97 paediatric and adult outpatient clinics agreed to report clinical data of their patients to a newly established registry, the Cystic Fibrosis Quality Assurance (CFQA) project. This article characterizes the design of the CFQA and the health status of the patients enrolled by the end of 1997. Data from 4,306 patients reported to the CFQA project were analysed. Nutritional status and lung function of the patients were examined as well as the use of specific therapeutic interventions. Mean age of all 4,182 patients alive by the end of 1997 was 15.7 yrs (maximum, 58 yrs), and 35.8% of patients were > 18.0 yrs of age. One-third of the CF population were treated in the nine largest centres (each caring for > 100 patients). Abnormal nutritional status (weight-for-height >90% of predicted or body mass index < 19.0 kg m2, respectively) was observed in 26.8% of children and adolescents and in 38.3% of adults. Lung function was abnormal (forced expiratory volume in one second < 80% predicted) in the majority of adults (83.9%) and in 42.5% of the younger patients. The mortality rate was 1.4 of 100 patients in 1997. No clear association of clinical status with centre size was observed. The clinical features of patients treated in German cystic fibrosis centres were generally comparable to those reported from other countries, although improvements are certainly warranted. The Cystic Fibrosis Quality Assurance project represents an important tool for future progress in the quality of cystic fibrosis care.

Adolescent↗