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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We evaluated the usefulness of a Nested PCR method for detecting Legionella pneumophila. This method resulted in L. pneumophila specific detection as far as we evaluated. The first and second step PCR achieved the sensitivity as small as 10 pg and 10 fg of the target DNA, respectively. In the detection from Legionella seeded sputa, the method could detect 0.1 cfu/ml of the bacteria, and it took about 12 hours to detect the target DNA. We demonstrated that the Nested PCR method was superior in sensitivity and rapidity for isolation of the bacteria to the conventional using low pH treatment and selective media for Legionella.
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PMID:[Detection of Legionella pneumophila using a nested polymerase chain reaction]. 140 13

A patient undergoing esophageal dilatation for carcinoma of the esophagus suffered esophageal perforation and development of an empyema. Culture of pleural fluid yielded multiple organisms, including Legionella pneumophila serogroup 5. Epidemiologic investigation showed that the source of L pneumophila was a tap used by the nursing personnel to fill patients' water pitchers. Whole-cell restriction endonuclease analysis of DNA from the clinical and environmental isolates of L pneumophila serogroup 5 yielded identical patterns. Our findings suggest that L pneumophila was acquired by the patient at least 12 h prior to the procedure causing the esophageal perforation and empyema, suggesting that the organism can persist in an infectious form in the upper aerodigestive tract.
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PMID:Isolation of Legionella pneumophila serogroup 5 from empyema following esophageal perforation. Source of the organism and mode of transmission. 142 1

A Legionella-like organism (strain 214T [T = type strain]) was isolated from a cooling tower in Stratford-upon-Avon, England. This strain required L-cysteine and contained cellular branched-chain fatty acids that are typical of the genus Legionella. Strain 214T produced pink colonies on buffered charcoal-yeast extract agar. Ubiquinone Q-12 was the major quinone. Strain 214T was serologically distinct from other legionellae as determined by a slide agglutination test. The results of DNA hybridization studies showed that strain 214T (= ATCC 49655T) is a member of a new Legionella species, Legionella shakespearei.
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PMID:Legionella shakespearei sp. nov., isolated from cooling tower water. 150 72

The conjugative properties of an indigenous 85 MDa plasmid (designated pCH1) from Legionella pneumophila were studied. To determine if pCH1 was transmissible by conjugation, mating experiments were performed between legionellae that harboured pCH1 and several plasmid-less recipients. Plasmid transfer was monitored by colony hybridization, using a cloned 21.0 kb SalI restriction fragment from pCH1 as a probe. The results from these experiments showed that pCH1 could be conjugatively transferred into several strains of L. pneumophila serogroup 1 but not into strain Bloomington-2 (serogroup 3) or Escherichia coli. Southern hybridization experiments in which pCH1 DNA was used as a probe showed that pCH1 does not share homology with other indigenous L. pneumophila plasmids. There was no detectable DNA homology between pCH1 and L. pneumophila chromosomal DNA. Additional mating experiments revealed that pCH1 was unable to mobilize the L. pneumophila chromosome. The conjugative transfer of pCH1 into plasmid-less avirulent or virulent serogroup 1 strains did not alter the intracellular growth characteristics of these strains in U937 cells, a human-monocyte-like cell line, or in the amoeba Hartmannella vermiformis. These results suggest that pCH1 does not contribute to the ability of L. pneumophila to enter or grow within eukaryotic cells.
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PMID:Isolation and characterization of a conjugative plasmid from Legionella pneumophila. 151 68

The rapid development of biotechnological methods provides the potential of dissecting the molecular structure of microorganisms. In this review the molecular biology of chlamydia is described. The genus Chlamydia contains three species C. trachomatis, C. psittaci, and C. pneumonia which all are important human pathogens. Chlamydia is obligate intracellular bacteria with a unique biphasic life cycle. The extracellularly chlamydial elementary bodies (EB) are small, metabolic inactive, infectious particles with a tight outer cell membrane. After internalization into host cells the chlamydial structure changes, they transform to reticulated bodies (RB) which become larger, metabolically active, and start to replicate. Fourtysix hrs post infection RB reorganizes to EB followed by burst of the inclusion. The structure of the EB outer membrane differs from the membrane of gram-negative bacteria since it is highly cross-linked by S-S bridges. There are, however, also similarities to gram-negative cell walls. The chlamydial major outer membrane protein, Omp1, forms pores and is closely associated with lipopolysaccharide, LPS. LPS, however, is more loosely associated with Omp1 than in other gram negative bacteria since incubation of EB with antibodies against LPS will liberate it from the chlamydial surface. Therefore the surface localized LPS may be important for chlamydial survival. OMP1 varies between the different serovar of C. trachomatis. Several very conserved regions are separated by variable domains. The variable domains are very antigenic and are localized at the surface of EB. After chlamydial internalization into the host cell transition to RB starts. Some of the early proteins are DnaK-like and groEL-like heat-shock proteins. The chlamydial DnaK-like protein is very antigenic. Patient serum samples will recognize the chlamydial DnaK-like protein. From the determined DNA sequence the amino acid sequence was determined. It was 57% homologous to the Eschrichia coli DnaK protein. Also the GroEL-like protein is antigenic and very conserved. Factors of importance for pathogenicity of chlamydia have not yet been found. The adhesin(s) is unknown, and no factor of importance for the inhibition of fusion between phagosome and host cell lysosomes has been described. A protein similar to the mip gene product of Legionella pneumofila may be a possible candidate for a pathogenicity factor. Diagnosis of C. trachomatis infections has been done by chlamydia cultivation in tissue culture cells, by immunofluorescence and by ELISA. A new method based on the polymerase chain reaction (PCR) has been developed. As primers sequences from the common plasmid were used. This method has high sensitivity and specificity and does not require live chlamydia.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The molecular biology and diagnostics of Chlamydia trachomatis. 152 83

By using Taq polymerase, DNA amplification of a specific fragment of the macrophage infectivity potentiator (mip) gene from Legionella pneumophila was used to detect Legionella spp. in bronchoalveolar lavage (BAL) fluid specimens. We were able to detect DNAs from all 30 L. pneumophila strains tested (serogroups 1 to 14), L. micdadei, and L. bozemanii serogroup 1. DNA from bacteria of other species tested and DNA from human leukocytes were not amplified by this procedure. After optimization of the conditions for DNA extraction from BAL fluid, a 2-ml sample of BAL fluid seeded with 25 CFU/ml tested positive after DNA amplification. A total of 68 frozen BAL fluid specimens sent to the laboratory because of suspected legionellosis were tested in a retrospective study. The eight culture-positive samples were all positive after specific DNA amplification. Among 60 culture-negative samples, 7 were positive after amplification. Of these seven samples, four were from patients who had presented a typical clinical history of legionellosis; the samples had antibody titer increases of 2 dilutions. For the three remaining samples, serological diagnosis of legionellosis in the patients from whom the samples were obtained could not be documented, and although the causative agent of these pulmonary infections was not determined, the clinical features of the patients were in accordance with legionellosis.
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PMID:Detection of Legionella spp. in bronchoalveolar lavage fluids by DNA amplification. 157 78

Restriction enzyme profiles of chromosomal DNA obtained from 96 Legionella pneumophila strains isolated from environmental and clinical isolates and digested with Hind III have been analyzed. A method to obtain chromosomal DNA to be use in restriction studies and its electrophoretic analysis have been developed. Studying the fragments showing higher differences when comparing the profiles obtained, 5 subtypes are defined and correlated with the isolation areas. There are similar restriction profiles independent of the plasmid contents.
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PMID:[Molecular epidemiological markers of Legionella pneumophila in the Valencian Community (II). Restriction enzyme profiles of chromosomal DNA]. 167 19

The ability to examine the bacterial genome directly eliminates the problems associated with the variable expression of proteins which may be encountered with protein-based typing or 'fingerprinting' techniques. Bacterial DNA is extracted by a rapid method, digested with a restriction endonuclease and the resulting fragments separated by gel electrophoresis to give a characteristic banding pattern. The choice of restriction endonuclease for a particular bacterial species is critical; an enzyme which cuts frequently results in an indistinct pattern which is difficult to interpret. A banding pattern consisting of a readily discernible number of discrete bands, usually about 20 or less in number, is preferable. Fragments in the 1-10 kb size range enable short separation times while larger fragments are desirable if interpretation is complicated by the presence of plasmid bands. This approach has enabled differentiation of isolates within Staphylococcus aureus (including methicillin-resistant S. aureus), non-typable Haemophilus influenzae, Neisseria meningitidis, Moraxella catarrhalis, Legionella pneumophila and enterococci, indistinguishable by conventional methods. Restriction enzyme digestion of chromosomal DNA provides a highly discriminatory method of bacterial characterization suitable for epidemiological studies.
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PMID:Restriction enzyme analysis of chromosomal DNA and its application in epidemiological studies. 167 12

A series of strains, presumptively identified as legionellas on the basis of their nutritional requirements and biochemical reactivity, were isolated from two unrelated environmental sources in the UK. Representatives of each of these series had a restriction endonuclease digest pattern indistinguishable from that of the Legionella quinlivanii type strain (1442-AUS-E) and the identity of these strains was confirmed by DNA homology studies. Serological examination of the two strains showed that they were distinct from the type strain 1442-AUS-E but indistinguishable from each other. A second serogroup, L. quinlivanii serogroup 2 (type strain LC870; NCTC 12434), is proposed to accommodate these strains.
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PMID:Second serogroup of Legionella quinlivanii isolated from two unrelated sources in the United Kingdom. 168 88

Methods were developed for the detection of Legionella in environmental water sources, based upon the polymerase chain reaction (PCR) and gene probes. All species of Legionella, including all 15 serogroups of L. pneumophila tested, were detected by PCR amplification of a 104 bp DNA sequence that codes for a region of 5S rRNA followed by radiolabelled oligoprobe hybridization to an internal region of the amplified DNA. Strains of L. pneumophila (all serogroups) were specifically detected based upon amplification of a portion of the coding region of the macrophage infectivity potentiator (mip) gene. Pseudomonas spp. that exhibit antigenic cross-reactivity in serological detection methods did not produce positive signals in the PCR-gene probe method using Southern blot analyses. Single cell, single gene Legionella detection was achieved with the PCR-gene probe methods.
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PMID:Detection of Legionella with polymerase chain reaction and gene probe methods. 169 56


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