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  • American Society for Microbiology  (45)
  • 1990-1994  (45)
Type of Medium
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  • American Society for Microbiology  (45)
Language
Years
  • 1990-1994  (45)
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Subjects(RVK)
  • 1
    Online Resource
    Online Resource
    American Society for Microbiology ; 1991
    In:  Antimicrobial Agents and Chemotherapy Vol. 35, No. 2 ( 1991-02), p. 380-381
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 35, No. 2 ( 1991-02), p. 380-381
    Abstract: The penetration of ofloxacin into lung tissue was studied in 10 patients subjected to pulmonary surgery. Samples of blood and lung tissue were obtained 3 to 8 h (mean, 5 h) after oral administration of 200 mg. The mean level in tissue was 2.17 +/- 0.5 micrograms/g, while the mean level in serum was 0.85 +/- 0.23 micrograms/ml. The mean lung tissue/serum concentration ratio was 2.55 +/- 0.30. The achievable levels of ofloxacin in lung tissue are above the MICs for most pulmonary pathogens.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1991
    detail.hit.zdb_id: 1496156-8
    SSG: 12
    SSG: 15,3
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  • 2
    Online Resource
    Online Resource
    American Society for Microbiology ; 1992
    In:  Antimicrobial Agents and Chemotherapy Vol. 36, No. 3 ( 1992-03), p. 566-572
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 36, No. 3 ( 1992-03), p. 566-572
    Abstract: The autolytic activities, including unstimulated, Triton X-100-stimulated, and daptomycin-induced, of various sets of methicillin-resistant and related methicillin-susceptible strains were compared. Faster rates of autolysis were noted in two heterogeneous methicillin-resistant transductants than in their methicillin-susceptible parental recipients, in a heterogeneous resistant strain than in a susceptible derivative created by chemical mutagenesis, and in a homogeneous resistant strain than in a derivative that had decreased methicillin resistance and was created by transposon Tn551 mutagenesis. These results suggest that the presence of the methicillin resistance region, mec, either directly or indirectly through an interaction with other host genes, confers a faster rate of autolysis on strains. Various auxilliary genes are known to affect methicillin resistance expression, and one of these genes, femA, was necessary for the expression of this faster rate of autolysis. These differences in autolytic activities were not observed in isolated crude cell walls retaining autolytic activities, suggesting different modes of regulation of autolysins in intact cells and isolated walls. In contrast, one homogeneous, highly resistant strain, DU4916, had a lower autolytic activity than did derived heterogeneous resistant and susceptible strains created by chemical mutagenesis and a strain that had decreased resistance and was created by transposon mutagenesis. Our observations suggest that methicillin resistance expression is associated with an enhanced rate of autolysis, in heterogeneous resistant strains at least.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1992
    detail.hit.zdb_id: 1496156-8
    SSG: 12
    SSG: 15,3
    Library Location Call Number Volume/Issue/Year Availability
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  • 3
    Online Resource
    Online Resource
    American Society for Microbiology ; 1992
    In:  Antimicrobial Agents and Chemotherapy Vol. 36, No. 12 ( 1992-12), p. 2617-2621
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 36, No. 12 ( 1992-12), p. 2617-2621
    Abstract: The restriction site polymorphism of the chromosomal femAB region and the first appearance of the regulatory element mecR1-mecI associated with the methicillin resistance determinant (mec) were analyzed in 192 initially methicillin resistant (Mcr) Staphylococcus aureus clinical isolates collected between 1965 and 1990 in the Zurich area. Forty-three of the strains lost the resistance spontaneously. All isolates that were still Mcr hybridized with mecA, the gene for the low-affinity penicillin-binding protein PBP 2'. Mcr strains isolated before 1977 lacked sequences that hybridized with mecR1-mecI, a regulatory element controlling the expression of mecA; exceptions to this were one strain isolated in 1966 and one strain isolated in 1972. The size of the EcoRV fragment carrying femA, a chromosomally encoded factor involved in pentaglycine side chain formation of the peptidoglycan and essential for the expression of methicillin resistance, was conserved in all strains but one, which was susceptible to methicillin even though it carried a functional mecA gene. The methicillin susceptibility of this particular strain was presumably due to a spontaneous femA-like mutation. The 192 strains belonged to seven different EcoRV restriction fragment patterns recognizable with a 10.5-kb probe covering the femAB region. Some 93% of the 149 Mcr strains belonged to pattern A, and the remaining Mcr strains shared patterns A' and B. The 42 isolates which spontaneously lost their resistance upon storage and revival represented all seven different patterns. This strong conservation of femA suggests an important role for femA in cell wall metabolism and methicillin resistance.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1992
    detail.hit.zdb_id: 1496156-8
    SSG: 12
    SSG: 15,3
    Library Location Call Number Volume/Issue/Year Availability
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  • 4
    Online Resource
    Online Resource
    American Society for Microbiology ; 1990
    In:  Antimicrobial Agents and Chemotherapy Vol. 34, No. 3 ( 1990-03), p. 494-495
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 34, No. 3 ( 1990-03), p. 494-495
    Abstract: Using an agar dilution assay, for 66 of 104 (63.5%) clinical isolates of Acinetobacter calcoaceticus biovar anitratus, the MIC of ciprofloxacin was greater than or equal to 1.0 micrograms/ml. Cross resistance was demonstrable to ciprofloxacin and gentamicin (P less than 0.001), amikacin (P less than 0.01), cefotaxime (P less than 0.001), azlocillin (P less than 0.001), ceftazidime (P less than 0.001), trimethoprim-sulfamethoxazole (P less than 0.001), and minocycline (P less than 0.05). The mean MIC of ciprofloxacin for drug-susceptible isolates was consistently lower than that for resistant isolates; however, these differences were significant only for amikacin (P = 0.036).
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1990
    detail.hit.zdb_id: 1496156-8
    SSG: 12
    SSG: 15,3
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  • 5
    Online Resource
    Online Resource
    American Society for Microbiology ; 1994
    In:  Antimicrobial Agents and Chemotherapy Vol. 38, No. 4 ( 1994-04), p. 724-728
    In: Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 38, No. 4 ( 1994-04), p. 724-728
    Abstract: Characteristic for methicillin-resistant (Mcr) staphylococci is the heterogeneous expression of the intrinsic methicillin resistance. The majority of the cells express resistance to low concentrations of methicillin, and a minority of the cells express resistance to much higher concentrations. We show here (i) that the presence of the mecA encoding region on plasmid pBBB79 was sufficient to render a methicillin-susceptible (Mcs) Staphylococcus aureus strain heteroresistant and (ii) that this Mcr strain segregated highly resistant subclones which retained the high-resistance phenotype under nonselective growth conditions. The Mcr strain with only mecA on plasmid pBBB79 thus behaved identically to a Mcr strain carrying the complete mec determinant integrated at its proper chromosomal site. (iii) Curing a such highly resistant subclone from plasmid pBBB79 yielded an Mcs strain that was as susceptible as the original Mcs parent strain. (iv) Comparisons were made between the original parent and the cured Mcs strain by backcrossing pBBB79 into them and looking at their progeny. Transductants derived from the formerly highly resistant cured strain became resistant to high concentrations of methicillin, whereas transductants derived from the original parent strain were resistant to lower concentrations of methicillin and showed the typical heterogeneous resistance. We deduced therefrom that the high-level resistance expressed by the minority of the population of Mcr S. aureus was due to a chromosomal mutation(s) (chr*) involving neither mecA nor the additional 30 kb of mec-associated DNA. Moreover, we could show that this postulated mutation chr* was not linked to the femAB operon, which is known to affect methicillin resistance levels.
    Type of Medium: Online Resource
    ISSN: 0066-4804 , 1098-6596
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1994
    detail.hit.zdb_id: 1496156-8
    SSG: 12
    SSG: 15,3
    Library Location Call Number Volume/Issue/Year Availability
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  • 6
    Online Resource
    Online Resource
    American Society for Microbiology ; 1992
    In:  Journal of Clinical Microbiology Vol. 30, No. 10 ( 1992-10), p. 2686-2691
    In: Journal of Clinical Microbiology, American Society for Microbiology, Vol. 30, No. 10 ( 1992-10), p. 2686-2691
    Abstract: The Diaslide urine culture device consists of a hinged case containing two opposing agar media separated by a sampler with a handle at one end and two bent sampler tips at the opposite end. The tips of the sampler are first dipped into the urine. The sampler is then pulled out through the casing, simultaneously inoculating both agar surfaces with a streaking dilution. As a result, individual colonies can be observed even when bacterial concentrations exceed 10(6) CFU/ml. The number of colonies on the Diaslide correlated linearly with CFU per milliliter as determined by dilution plating. The clinical performance of the Diaslide was compared with those of ordinary dipslides and conventional cultures with a sample of 473 prescreened hospital urine specimens. The sensitivity, specificity, and positive predictive value of Diaslide versus those of culture at the 10(4)-CFU/ml cutoff level were 97.5, 98.3, and 98.3%, respectively, compared with 98.8, 95.7, and 97.2%, respectively, for dipslide versus culture. Similar results were found at the 10(5)-CFU/ml cutoff level. Only 5.5% of the Diaslides required subculturing, compared with 14.7 and 9.4% of the dipslides and conventional cultures, respectively. The Diaslide proved more convenient than an ordinary dipslide for sampling low volumes of urine. These data suggest that the Diaslide is a simple, effective device for culturing of urine specimens.
    Type of Medium: Online Resource
    ISSN: 0095-1137 , 1098-660X
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1992
    detail.hit.zdb_id: 1498353-9
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    American Society for Microbiology ; 1994
    In:  Journal of Bacteriology Vol. 176, No. 12 ( 1994-06), p. 3646-3660
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 176, No. 12 ( 1994-06), p. 3646-3660
    Abstract: The Agrobacterium tumefaciens virB gene products are proposed to assemble into a transport system capable of exporting complexes of DNA and protein across the bacterial envelope en route to plant cells. Nonpolar null mutations were constructed in each of the 11 virB genes of the A. tumefaciens pTiA6NC plasmid. In tumorigenicity assays, delta virB1 mutants exhibited severely attenuated virulence and delta virB2 through delta virB11 mutants exhibited avirulence. NdeI restriction sites introduced at the predicted translational start sites of the virB genes were used to subclone each of the virB genes downstream of the lacZ or virB promoter on broad-host-range plasmids. virB gene expression plasmids were used to define promoter and general sequence requirements for genetic complementation of the deletion mutations. Whereas virB1 and virB2 complemented delta virB1 and delta virB2, respectively, only when expressed in trans from the virB promoter, virB3 through virB11 complemented the corresponding deletion mutations when expressed in trans from either the lacZ or virB promoter. Several virB genes required additional upstream or downstream sequences for complementation: (i) virB2 complemented the delta virB2 mutation only when the complementing plasmid coexpressed virB1 and virB2, (ii) virB6 and virB9 complemented the delta virB6 and delta virB9 mutations only when the complementing plasmids carried at most 55 and 230 bp of sequences residing 5' of these genes, respectively, and (iii) virB7 and virB8 complemented the delta virB7 and delta virB8 mutations only when the complementing plasmid coexpressed virB7 and virB8. These studies established that virB1 is an accessory virulence determinant and virB2 through virB11 are absolutely essential for the A. tumefaciens infection process.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1994
    detail.hit.zdb_id: 1481988-0
    SSG: 12
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  • 8
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 173, No. 23 ( 1991-12), p. 7416-7422
    Abstract: The DNA sequence located between mecA, the gene that codes for penicillin-binding protein PBP2', and insertion sequence-like element IS431mec has been termed hypervariable because of its length polymorphism among different staphylococcal isolates. We sequenced and characterized the hypervariable region of the methicillin resistance determinant (mec) isolated from Staphylococcus aureus BB270. Within the 2,040-bp hypervariable region, we identified an unusual accumulation of long direct repeats. Analysis of the DNA sequence revealed a minimal direct repeat unit (dru) of 40 bp which was repeated 10 times within 500 bp. The dru sequences are responsible for the length polymorphism of mec. Moreover, we identified an open reading frame that codes for 145 amino acids (ORF145), whose deduced amino acid sequence showed 57% amino acid sequence similarity to the N terminus of the glycerophosphoryl diester phosphodiesterase (UgpQ) of Escherichia coli.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1991
    detail.hit.zdb_id: 1481988-0
    SSG: 12
    Library Location Call Number Volume/Issue/Year Availability
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  • 9
    Online Resource
    Online Resource
    American Society for Microbiology ; 1992
    In:  Journal of Clinical Microbiology Vol. 30, No. 2 ( 1992-02), p. 359-361
    In: Journal of Clinical Microbiology, American Society for Microbiology, Vol. 30, No. 2 ( 1992-02), p. 359-361
    Abstract: Skin biopsy specimens from the peripheral aspect of erythema migrans lesions (site 1) and from clinically normal perilesional areas (site 2) were compared as sources of Borrelia burgdorferi. This spirochete was isolated from the skin of 18 of 21 (86%) patients with untreated early Lyme disease at one or both biopsy sites. Site 1 specimens were superior to site 2 specimens for the isolation of B. burgdorferi. Site 1 specimens from 18 (86%) patients were culture positive, and site 2 specimens from 12 (57%) patients were culture positive. For patients whose site 2 specimens were culture positive, site 1 specimens were also found to be culture positive. B. burgdorferi was isolated from two patients with atypical lesions and from two patients with erythema migrans lesions that were less than 5 cm in diameter. This study demonstrates that the cultivation of B. burgdorferi from skin biopsy specimens from cutaneous lesions thought to be erythema migrans can be an efficacious procedure for confirming the diagnosis of Lyme disease and that the spirochete is present in clinically normal appearing perilesional skin.
    Type of Medium: Online Resource
    ISSN: 0095-1137 , 1098-660X
    RVK:
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1992
    detail.hit.zdb_id: 1498353-9
    SSG: 12
    Library Location Call Number Volume/Issue/Year Availability
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  • 10
    Online Resource
    Online Resource
    American Society for Microbiology ; 1990
    In:  Journal of Bacteriology Vol. 172, No. 8 ( 1990-08), p. 4399-4406
    In: Journal of Bacteriology, American Society for Microbiology, Vol. 172, No. 8 ( 1990-08), p. 4399-4406
    Abstract: The ntrA gene of Thiobacillus ferrooxidans was cloned by complementation of an Escherichia coli ntrA mutant that was unable to produce gas via the sigma 54 (NtrA)-dependent formate hydrogenlyase pathway. Analysis of the DNA sequence showed that the T. ferrooxidans ntrA gene coded for a protein of 475 amino acids (calculated Mr, 52,972). The T. ferrooxidans NtrA protein had 49, 44, 33, and 18% amino acid similarity with the NtrA proteins of Klebsiella pneumoniae, Azotobacter vinelandii, Rhizobium meliloti, and Rhodobacter capsulatus, respectively. The ability of the T. ferrooxidans NtrA protein to direct transcription from sigma 54-dependent promoters was demonstrated in E. coli by using fdhF-lacZ and nifH-lacZ fusions. An open reading frame coding for a protein of 241 amino acids (calculated Mr, 27,023) was situated 12 base pairs upstream of the T. ferrooxidans ntrA gene. Comparison of this protein with the product of the open reading frame ORF1, located upstream of the R. meliloti ntrA gene, showed that the two proteins had 55% amino acid similarity. The cloned T. ferrooxidans ntrA gene was expressed in E. coli from a promoter located within the ORF1 coding region.
    Type of Medium: Online Resource
    ISSN: 0021-9193 , 1098-5530
    Language: English
    Publisher: American Society for Microbiology
    Publication Date: 1990
    detail.hit.zdb_id: 1481988-0
    SSG: 12
    Library Location Call Number Volume/Issue/Year Availability
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