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

A chemically defined medium containing 21 amino acids and inorganic salts was developed which supported the growth of four isolates of Legionnaires disease bacterium (Legionella pneumophila). Growth in liquid defined medium at 37 degrees C with shaking approximated the generation time and growth kinetics observed for growth in complex media. After a 3-h lag, the culture grew exponentially with a generation time of 6 h and reached a maximum optical density of 230 Klett units (170 Klett units corrected for pigment). A soluble brown pigment was first observed as the culture entered late exponential to early stationary phase of growth. Morphologically, L. pneumophila grew in the liquid defined medium with extensive filamentation and numerous intracellular lipid granuoles. L-Serine, L-methionine, and L-cysteine were required for optimum growth. The latter amino acid could be replaced by L-cystine or reduced glutathione but not by D-cysteine, thiomalate, thioglycollate, or 2-mercaptoethanol. Ferric iron was needed for maximum growth, but supplemental iron was not an essential growth requirement. Carbohydrates (i.e., glucose) or organic acids did not stimulate growth. In fact, pyruvate, acetate, and citrate all gave varying degrees of inhibition (69, 37, and 0% of control growth, respectively).
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PMID:Growth of Legionnaires disease bacterium (Legionella pneumophila) in chemically defined medium. 50 Jul 95

Indole-3-propionic acid (IPA), a phytohormone derivative, is a potent inhibitor of growth of Legionella pneumophila cultivated extracellularly in a chemically defined hypotonic medium and intracellularly in human monocytes. The inhibitory activity turns into bactericidal activity with increasing concentrations. The susceptibility of the microorganism to IPA was more evident in "fast-growing" cultures (under conditions of vigorous shaking) than in static cultures growing under an atmosphere of 5% CO2-95% air, which resulted in a decreased growth rate. The MIC, after incubation with the drug for 48 h and as determined by counting of the CFU, was 1.58 microM for fast-growing cultures and 2.64 microM for those grown under static conditions. The MBCs were 5.28 and 26.43 microM, respectively. Tryptophan (Trp) at 150 microM prevented the inhibition caused by 2.64 microM IPA, increased the MIC about 3-fold, and increased the MBC by 10-fold. The effect of Trp was less remarkable in "slow-growing" cultures. The susceptibility of L. pneumophila proliferating in human monocytes was markedly lower than that when it was cultivated extracellularly in the chemically defined hypotonic medium. The MIC after incubation for 48 h was 5.28 microM, and a decrease in viable count was achieved with 105.70 microM. The lower susceptibility was apparently due (at least partially) to the presence of Trp (24.50 microM) in the RPMI 1640 medium that was used for the monocyte cultures. The effect of IPA was time dependent, and prolonged exposure enhanced the bactericidal activity and turned the inhibitory dose into a bactericidal dose. The present data demonstrate that IPA is a potent anti-L. pneumophila factor, although it has a markedly lower activity against bacteria growing intracellularly compared with its activity against extracellularly proliferating microorganisms.
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PMID:Susceptibility of Legionella pneumophila grown extracellularly and in human monocytes to indole-3-propionic acid. 181 Jan 85

Ten liquid media were compared under standard conditions for their ability to support the growth of Legionella pneumophila. Modified gonococcal-ferric cysteine broth (without sodium chloride) supplemented with 1% yeast extract yielded the best overall growth of the one strain of L. pneumophila examined. Growth rates were independent of pH changes which occurred during incubation. The growth rates of 10 different strains of L.pneumophila were compared in this medium. There appeared to be little difference in the growth rates of strains passaged frequently or infrequently, or between environmental and clinical isolates. Moderate aeration resulted in a faster growth rate and in approximately a 1 log10 higher final cell concentration as compared to a static broth culture. These experiments demonstrate that there are moderate to marked differences among the various media described in the literature and that no liquid medium yet developed supports rapid growth of L. pneumophila incubated without shaking.
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PMID:Comparison of liquid growth media for Legionella pneumophila. 703 31

This study aimed to determine the aetiology of community-acquired pneumonia (CAP) by adding polymerase chain reaction (PCR) to conventional methods and to describe the clinical and laboratory features between patients with bacterial pneumonia (BP) and viral pneumonia (VP). Adults with CAP admitted from November 2009 to October 2010 were included. Demographics, comorbidities, severity and clinical features were recorded. Conventional microbiological methods included blood and sputum cultures, acute and convalescent serologic samples, and antigen urinary detection. New methods included multiplex PCR for Mycoplasma pneumoniae, Legionella pneumophila, Chlamydophila pneumoniae, Bordetella pertussis and 15 respiratory viruses. A total of 169 patients were included. Using conventional methods, we identified a pathogen in 51 % of cases. With PCR, up to 70 % of cases had an aetiological diagnosis. Forty-five patients had BP (34 %), 22 had VP (17 %) and 25 (19 %) had co-infection (BP and VP). Pneumococci and respiratory syncytial virus (RSV) were the most frequently identified pathogens. Procalcitonin (PCT) and C-reactive protein (CRP) median values were significantly higher in BP than in VP patients. Shaking chills, higher CURB score and shock were significantly more frequent in BP. A viral infection was identified in more than one-third of patients with CAP. Clinical and laboratory features could help to differentiate between VP and BP and to guide empirical therapy.
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PMID:Aetiology of community-acquired pneumonia among adults in an H1N1 pandemic year: the role of respiratory viruses. 2254 30