Search PubMed⌕ Search

Biomedical subjects

N A Westerdaal

Publications and source records attributed to N A Westerdaal.

24 records · Page 2Linked to original sources
PubMed1984

New, simple medium for selective recovery of Klebsiella pneumoniae and Klebsiella oxytoca from human feces.

A culture medium was developed which selectively favored the growth of Klebsiella pneumoniae and Klebsiella oxytoca in Escherichia coli-rich fecal cultures, without the use of antibiotics. The discriminative capacity of this medium was based on the presence of only two carbon sources, citrate and inositol, which can be utilized by nearly all K. pneumoniae and K. oxytoca strains but not by E. coli. The medium consisted of Simmons citrate agar (SCA) with 1% inositol (SCAI). Klebsiella strains from fecal samples subcultured on SCAI grew unhampered as yellow, dome-shaped, often mucoid colonies, whereas E. coli appeared as tiny, watery colonies. Apart from some Enterobacter strains, no other types of bacteria were found to mimic the typical appearance of klebsiellae. Recovery experiments from stool samples revealed a limiting ratio of Klebsiella to E. coli of 1:10(6) or more when samples were plated on SCAI versus ratios of 1:10(2) to 1:10(3) on blood agar or Macconkey agar. Compared with an existing Klebsiella culture method, the combination of SCA and MacConkey-inositol-carbenicillin (MIC) agar, Klebsiella yields with SCAI were not lower than those with the combination of MIC and SCA. Furthermore, the efficiency of the SCAI method was twice that of the latter combination. The SCAI plate could be a valuable tool in studies on the epidemiology of K. pneumoniae and K. oxytoca, for example in nosocomial infections, especially those concerning immunocompromised patients.

Citrates↗
PubMed1982

Activity and synergy of ureido penicillins and aminoglycosides against Pseudomonas aeruginosa.

The in vitro activities of piperacillin, azlocillin, mezlocillin, sulbenicillin and ticarcillin were compared with those of carbenicillin using 88 clinical isolates of Pseudomonas aeruginosa. The minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) were determined by standard techniques. The MIC for 90% of the strains was 7.5 mg/l for piperacillin, 10.0 mg/l for azlocillin, 26.5 mg/l for mezlocillin, 48.4 mg/l for sulbenicillin, 50.0 mg/l for ticarcillin and more than 100 mg/l for carbenicillin. The MBC/MIC ratio was 1.3 for piperacillin, 1.9 for ticarcillin, 2.1 for sulbenicillin, 3.3 for mezlocillin and 4.5 for azlocillin. The susceptibilities of the same strains to four aminoglycosides were tested. The MIC for 90% of the strains was 0.3 mg/l for sisomicin and tobramycin, 1.5 mg/l for amikacin, and 2.2 mg/l for gentamicin. The effect of combining piperacillin, azlocillin and mezlocillin with gentamicin, tobramycin, sisomicin and amikacin was studied using checkerboard titration. The highest degrees of synergy were found with the combinations of piperacillin and an aminoglycoside. Strong potentiation was observed in 85% of the strains with piperacillin - sisomicin and in 50% with piperacillin - gentamicin. The synergistic effects of azlocillin and mezlocillin in combination with an aminoglycoside (observed in 30-65% of the strains) were for the most part moderate or slight. No antagonism was observed.

Aminoglycosides↗
PubMed1979

In vitro susceptibility of pseudomonas to four beta-lactamantibiotics (ampicillin, cephalothin, carbenicillin, piperacillin), to four aminoglycosides (kanamycin, amikacin, gentamicin, tobramycin) and to colimycin.

Of 97 well-defined strains of Pseudomonas, isolated from sputum of patients with cystic fibrosis (CF), the minimum inhibitory concentration (MIC) of several antibiotics was determined with a broth dilution method. The majority of the strains were resistant to ampicillin and cephalothin, moderately susceptible to carbenicillin (70% to 100 microgram/ml) and highly susceptible to piperacillin (100% to 25 microgram/ml, 88% to 6.25 microgram and 60% to 3.12 microgram/ml). If the pharmacological properties of piperacillin are comparable with those of carbenicillin, it can be expected that the sputum level of this drug will be adequate to treat Pseudomonas pulmonary infections. At the lowest concentration tested (0.78 microgram/ml) 3% of the strains were susceptible to kanamycin, 85,5% to amikacin, 95% to gentamicin, 98% of tobramycin, and 80% to colimycin. With regard to clinically attainable concentrations, 98.9% of the strains were susceptible to gentamicin and tobramycin 97.9% to amikacin, 96.9% to colimycin, 88.6% to piperacillin, 38% to carbenicillin, 25.7% to kanamycin, 12.3% to ampicillin, and 1% to cephalothin.

Amikacin↗
PubMed1979

Piperacillin dosage.

Explore the source record for details and available documents.

Bacterial Infections↗
PubMedDate not supplied

Effects of various coryneforms on mononuclear phagocyte system function and on production of tumour necrosis factor in mice.

Vaccines of 6 strains of the genera Corynebacterium and Propionibacterium were tested for induction of hepatosplenomegaly and stimulation of clearance of injected colloidal carbon and viable Listeria monocytogenes. These effects were compared with the ability of these strains to support the endotoxin-induced liberation of tumour necrosis factor, interferon and heat-stable cytostatic factors in mouse circulation. Five strains caused good stimulation of macrophage functions and induced high levels of all factors. One strain was nearly lacking in macrophage stimulatory capacity and also failed to support factor production. These data are discussed in relation to the production mechanisms of the factors.

Animals↗