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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The resistence of different microorganisms to formaldehyde was determined. As test objects served gram-negative and gram-positive vegetative germs (Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella paratyphi-B, Staphylococcus aureus, Streptococcus faecalis), bacterial spores (Bacillus cereus, Bacillus pumilus, Bacillus stearothermophilus, Bacillus subtilis), fungi (Aspergillus niger, Candida albicans), bacteriophages (Escherichia coli phages, T1, T2, T3), and viruses (adenovirus, poliomyelitis virus, vaccinia virus). For the studies, suspensions of germs were exposed at identical temperature (20 degrees C) and pH (7.0). The microbicidal effect of formaldehyde was measured by the decrease of the proportion of germs capable of multiplication in the suspension (lg (N/N0); where: N0 equals initial number of germs capable of multiplication; N equals number of germs capable of multiplication after exposure to formaldehyde). For all germs the dependence of the microbicidal effect on the concentration of formaldehyde was determined. In all experiments, the duration of exposure was two hours. Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella paratyphi-B were found to be more susceptible than Staphylococcus aureus (vf. Fig. 1 A). The strains of Pseudomonas aeruginosa used were widely varying as to their susceptibility. To obtain equal microbicidal effects, concentrations of formaldehyde almost three times as high had to be used for the most resistant strain than were necessary for the most susceptible strain of Pseudomonas aeruginosa. All strains of Klebsiella pneumoniae examined were found to have an identical resistence to formaldehyde. Streptococcus faecalis was even more resistant to formaldehyde than Staphylococcus aureus. In the case of Streptococcus faecalis, a concentration of formaldehyde about three times as high had to be used to obtain microbicidal effects of identical magnitude. For the killing of Candida albicans cells concentrations of formaldehyde not higher than those needed for the killing of vegetative gram-negative bacteria were necessary. The conidia of Aspergillus niger were found to be more resistant than the cells of Candida albicans but did not require any higher concentrations than for the killing of Staphylococcus aureus (see Fig. 1 B). In the case of bacterial spores, a special phenomenon was observed. If the spores had been exposed to a temperature of 80 and 95 degrees C, respectively (depending on the species involved) for one or two hours following exposure to formaldehyde, a considerably higher number of spores was found to be capable of germination and colony formation than without such treatment (heat activation: cf. Fig. 2A and Fig. 2B). The spores of Bacillus cereus had only a relatively low resistance to formaldehyde. To reduce the proportion of the spores capable of colony formation to 1/10000, a 2.9% formaldehyde concentration was necessary without heat activation and one of 10.8% with heat activation...
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PMID:[Microbial resistance to formaldehyde. I. Comparative quantitative studies in some selected species of vegetative bacteria, bacterial spores, fungi, bacteriophages and viruses]. 19 Aug 25

A 4.1. Kb large DNA fragment of a E. coli plasmid pVU 3695, on which the genes for formaldehyde-resistance are located, was used as a DNA probe to identify bacteria that carry this segment among formaldehyde-resistant bacteria. It was shown by Southern Blot-, Dot Blot-, and Colony Blot- Hybridization studies that the DNA of all formaldehyde-resistant E. coli, Serratia marcescens, Enterobacter cloacae, Citrobacter freundii and Klebsiella pneumoniae strains tested hybridize with the DNA probe from E. coli. In contrast the E. coli DNA probe does not hybridize with the DNA from formaldehyde-resistant Pseudomonas aeruginosa strains.
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PMID:Formaldehyde-resistance in Enterobacteriaceae and Pseudomonas aeruginosa: identification of resistance genes by DNA-hybridization. 190 32

Preparatory to development of in situ disinfection of implanted catheters, silicone rubber tubing colonized by incubation with Staphylococcus aureus, Staphylococcus epidermidis, or Klebsiella pneumoniae was used to test the efficacy of various chemicals in vitro. Protocols sterilizing all segments colonized for 24 h (n = 30) were immersion into 50% povidone iodine for 5 and 60 min, 100% povidone iodine for 5, 15, and 60 min, 1.2 x 10(3) ppm chlorine dioxide for 15 and 60 min, and 1.2 x 10(3) ppm chlorine dioxide buffered to pH 5.1 for 60 min. Immersion in up to 2% chlorhexidine, 7.4% formaldehyde, or 6% sodium hypochlorite for up to 60 min failed to sterilize all segments. None of 117 control segments were sterilized. Segments colonized for seven days were sterilized by immersion into 100% povidone iodine for 15 or 60 min. Use of 1.2 x 10(3) ppm chlorine dioxide for 60 min sterilized 97% of segments tested. Lower concentrations and shorter exposure times failed to sterilize all segments. Eighteen silicone rubber catheters, colonized on the outer surface, were all sterilized within 24 h by a chlorine dioxide solution placed in the lumen and diffusing through the wall to kill the bacteria.
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PMID:Sepsis of vascular catheters. II: In vitro disinfection of colonized tubing. 240 73

Voltammetric techniques (differential pulse polarography (DPP) and differential pulse anodic stripping voltammetry (DPASV)) were evaluated for their capability to distinguish, without prior separation of the solid phase (e.g. filtration, centrifugation), between dissolved and particulate concentrations of Zn(II), Pb(II) and Cu(II), and to measure the extent of binding of these metals to the surface of a bacterium (Klebsiella pneumonia, formaldehyde treated). From titration curves of bacterial cell suspensions with metals the specific adsorption of metals was determined and quantified in terms of average surface complex formation constants and differential equilibrium functions. The following stability sequence for surface complexes was found: Cu2+ greater than Pb2+ greater than Zn2+ much greater than Ca2+. Simultaneous analytical determination permitted the measurement of both the binding of Cu(II) to the cell surface, and the binding to the solute exudate ligands. The affinity of the metal ions for the functional groups of the cell surface is strongly pH-dependent, and, at a given pH, decreases with increasing metal loading of the bacterial surfaces. This indicates that metal ions bind first to the highest affinity surface ligands and subsequently to those of lesser activity. Copper(II) appears to form stronger surface complexes with the high affinity ligands of the bacterial surface than with the functional groups of hydrous oxides.
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PMID:Metal ion binding by biological surfaces: voltammetric assessment in the presence of bacteria. 355 Oct 69

The occurrence and characteristics of hemagglutinins were investigated in 310 Klebsiella strains (195 K. pneumoniae- and 115 K. oxytoca-strains). Mannose-sensitive (MS)-hemagglutinins as well as Mannose-resistant (MR/K)-hemagglutinins could be demonstrated, only 13 Klebsiella-strains were not able to hemagglutinate. MS-hemagglutinins were much more often found in K. pneumoniae- than in K. oxytoca-strains, whereas the MR/K-hemagglutinin-frequency was equally high. Features (resistance to formaldehyde, trypsin, pronase, glycosidases, sodium metaperiodate and heating) and pathogenic significance of these hemagglutinins (fimbriae) were discussed.
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PMID:Hemagglutinins of Klebsiella pneumoniae and Klebsiella oxytoca. 636 75

Pollution by pathogenic bacteria was examined in 150 French metalworking fluid samples. Gram-negative micro-organisms such as Salmonella spp., Shigella spp., and Vibrio spp. as well as Gram-positive cocci were never isolated. Nevertheless opportunistic pathogens such as Pseudomonas aeruginosa and Klebsiella pneumoniae still contaminated these fluids with an isolation frequency of 17% of samples for each. These two micro-organisms failed to grow or even survive in vitro in sterile cutting fluids protected by biocides. Preliminary growth of other micro-organisms such as Pseudomonas putida or Pseudomonas fluorescens, which are the major part of the indigenous microflora, seemed to be a prerequisite for their growth. These former two Pseudomonas could resist three different classes of biocides and, at least in the case of formaldehyde-releasers, adaptation was followed by biocide deterioration. Resistance magnification was observed in the presence of the three different types of biocides and, in the case of formaldehyde releasers the resistance and deterioration levels were close to those recommended by the manufacturers. This is probably the reason why the preliminary growth of Pseudomonas putida allowed in vitro differed growth of Klebsiella pneumoniae and Pseudomonas aeruginosa. Due to relatively high isolation frequencies of opportunistic pathogens (17% of samples) periodical microbiological examination of cutting fluids should be carried out in order to evaluate risks for human health. Wearing masks and gloves is still recommended, at least in France.
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PMID:Pollution of modern metalworking fluids containing biocides by pathogenic bacteria in France. Reexamination of chemical treatments accuracy. 748 67

Aerobic gram-negative methylotrophs oxidize methanol to formaldehyde by using a methanol dehydrogenase that has pyrroloquinoline quinone (PQQ) as a prosthetic group. Seventy-two mutants which are unable to grow on methanol unless the growth medium is supplemented with PQQ have been isolated in the facultative methanol utilizer Methylobacterium extorquens AM1. In addition, 12 previously isolated methanol oxidation mutants of M. extorquens AM1 were shown to be able to grow on methanol in the presence of PQQ. These putative PQQ biosynthesis mutants have been complemented by using previously isolated clones containing M. extorquens AM1 DNA, which were known to contain genes necessary for oxidation of methanol to formaldehyde (mox genes). Subcloning and transposon mutagenesis experiments have assigned these mutants to five complementation groups in two gene clusters. Representatives of each complementation group were shown to lack detectable PQQ in the growth medium and in cell extracts and to contain methanol dehydrogenase polypeptides that were inactive. Therefore, these mutants all appear to be defective in PQQ biosynthesis. PQQ biosynthesis mutants of Methylobacterium organophilum DSM 760 and M. organophilum XX were complemented by using M. extorquens AM1 subclones, and PQQ biosynthesis mutants of M. extorquens AM1 and M. organophilum XX were complemented by using M. organophilum DSM 760 subclones. This analysis suggested that a total of six PQQ biosynthesis complementation groups were present in M. extorquens AM1 and M. organophilum DSM 760. A 2-kb M. extorquens AM1 DNA fragment that complemented the MoxO class of PQQ biosynthesis mutants was sequenced and found to contain two complete open reading frames and the N-terminal sequence of a third. These genes designated pqqDGC, had predicted gene products with substantial similarity to the gene products of corresponding pqq genes in Acinetobacter calcoaceticus and Klebsiella pneumoniae. pqqD encodes a 29-amino-acid peptide which contains a tyrosine residue and glutamate residue that are conserved in the equivalent peptides of K. pneumoniae, PqqA (23 amino acids), and A. calcoaceticus, PqqIV (24 amino acids), and are thought to be the precursors for PQQ biosynthesis. The organizations of a cluster of five PQQ biosynthetic genes appear to be similiar in four different bacteria (M. extorquens AM1, M. organophilum DSM 760, K. pneumoniae, and A. calcoaceticus). Our results show that a total of seven pqq genes are present in M. extorquens AM1, and these have been designated pqqDGCBA and pqqEF.
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PMID:Isolation, phenotypic characterization, and complementation analysis of mutants of Methylobacterium extorquens AM1 unable to synthesize pyrroloquinoline quinone and sequences of pqqD, pqqG, and pqqC. 813 70

In order to estimate the distribution of bacteria and fungi with an elevated level of resistance to antimicrobial substances, we have analyzed water samples and surveyed institutions presumably concerned with analyses of microbial resistance (university institutes for hygiene, health authorities) by means of questionnaire. A total of 41 water samples was drawn from various aquatic biotopes in the region of Heidelberg. The samples originated from the effluents of a community sewage treatment plant, from the Neckar river, from drinking water supplies and from public swimming pools. The following substance groups were included in a search for bacteria with an elevated resistance to antiseptics and disinfectants: Aldehydes, biguanides, quaternary ammonium compounds (QAC), phenols and halogen. Upon determination of the maximal tolerated concentrations to these antimicrobial agents, samples of treated wastewater effluents showed a considerably higher prevalence of bacteria resistant to formaldehyde, chlorhexidine and QAC. The highest levels of resistance were found in Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas fluorescens and Enterobacter species. The maximal tolerated level of 0.06 percent formaldehyde by weight was considerably higher than the levels tolerated by the corresponding ATCC reference strains. The highest levels of resistance to a biguanid/QAC preparation were seen in isolates of Alcaligenes species and Providencia species, with a maximal tolerated level of 0.5 volume percent. In addition, several isolates of E. coli and Klebsiella species were observed which showed a considerably higher level of resistance to the biguanide preparation as compared to the corresponding ATCC reference strains. A questionnaire was mailed to a series of institutions and companies presumably concerned with problems of microbial resistance. Responses were in accordance with our own observations, both with regard to the spectrum of bacteria observed and to the antimicrobial substances concerned.
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PMID:[Epidemiology of microbial resistance to biocides]. 857 12

Giardia lamblia is recognized as one of the most common agents for diarrhea world wide. To date, microscopical examination of stool samples is the gold standard for giardiasis diagnosis. However, intermittence of the Giardia cycle and some medications may cause temporary disappearance of cysts from stools, thus giving false negative results. In the present study, we evaluated a commercially available enzyme immunoassay kit (GiardEIA) for the detection of Giardia copro-antigens and compared the results with those of the merthiolate-iodine-formaldehyde concentration (MIFC) microscopical examination technique. Sixty-nine fecal samples from children 2-12 years old were emulsified and allowed to react with a Giardia specific antibody, then with an enzyme conjugated antibody and the reaction was developed colorimetrically. Seventy-four percent of the parasitologically positive Giardia cases were also positive by GiardEIA while 26% of the microscopically negative cases were positive by the assay. GiardEIA gave negative results with 82% and 100% of stools with helminthic and protozoan (other than Giardia) infections, respectively. Similarly, no cross-reactivity was found with any of the bacterial agents including Shigella flexneri, pathogenic E. coli, Klebsiella spp. and Salmonella typhi. GiardEIA is a simple assay that can diagnose 24 samples in less than an hour without the need for any special equipment and can be useful in epidemiological surveys and in giardiasis outbreaks.
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PMID:Evaluation of GiardEIA kit for giardiasis diagnosis. 858 58

OutB is a component of the Erwinia chrysanthemi Out secretion machinery. Homologues of OutB have been described in two other bacteria, Klebsiella oxytoca and Aeromonas hydrophila, but their requirement in the secretion process seems to be different. Study of OutB topology with the BlaM topology probe suggests that it is an inner-membrane protein with a large periplasmic domain. However, fractionation experiments indicate that it could be associated with the outer membrane through its C-terminal part. The secretion deficiency of an Erw. chrysanthemi outB mutant can be reversed by the addition of an inducer of the kdgR regulon. It was shown that this effect results from the increased expression of the secretin OutD and that secretion can be restored in an outB mutant by introducing the outD gene on a plasmid. Several experiments suggest an interaction between OutB and OutD. In Erw. chrysanthemi, the presence of OutD stabilizes OutB. OutD expressed in Escherichia coli can be protected from proteolytic degradation by the coexpression of OutB. This effect does not require the N-terminal, transmembrane segment of outB. OutB can be cross-linked with OutD by formaldehyde. These results indicate that OutB could act with OutD in the functioning of the Out secretion machinery.
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PMID:Overproduction of the secretin OutD suppresses the secretion defect of an Erwinia chrysanthemi outB mutant. 1074 67


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