Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Approximately 5 million public and private hot tubs, whirlpools, and spas are used in the United States. Extensive spa use combined with inadequate maintenance contribute to recreational water illnesses (RWIs) caused by pathogens such as Pseudomonas spp., Legionella spp., and Mycobacterium spp. In the United States, local environmental health inspectors periodically inspect public spas to determine their compliance with local or state health regulations. During inspections for regulatory compliance, data pertaining to spa water chemistry, filtration and recirculation, and management and operations are collected. This report summarizes spa inspection data from six sites in the United States during May 1-September 1, 2002. The findings underscore the utility of these data for public health decision-making and the need for increased training and vigilance by operators to ensure high-quality spa water for use by the public.
 ...
PMID:Surveillance data from public spa inspections--United States, May-September 2002. 1522 12

Changing regulations to lower disinfectant byproducts in drinking water is forcing utilities to switch disinfection from chlorine to monochloramine. It is generally unknown whether this will impact positively or negatively on the microbiological quality of drinking water. A utility in Florida, using water with relatively high organic carbon levels from deep wells in several wellfields, made the decision to change its disinfection regime from chlorine to chloramine in order to meet the new regulations. To assess the impacts of such a change on the microbiology of its water supplies, it undertook a number of studies before and after the change. In particular, the presence of the opportunistic pathogens Legionella and Mycobacterium, and also the composition of drinking-water biofilms, were examined. A preliminary synthesis and summary of these results are presented here. Legionella species were widely distributed in source waters and in the distribution system when chlorine was the disinfectant. In some samples they seemed to be among the dominant biofilm bacteria. Following the change to monochloramine, legionellae were not detected in the distribution system during several months of survey; however, they remained detectable at point of use, although with less species diversity. A variety of mycobacteria (21 types) were widely distributed in the distribution system when chlorine was the disinfectant, but these seemed to increase in dominance after chloramination was instituted. At point of use, only four species of mycobacteria were detected. Other changes occurring with chloramination included (a) an altered biofilm composition, (b) increased numbers of total coliforms and heterotrophs and (c) nitrification of water storage tanks. The results suggested that consideration should be given to the microbiological effects of changing disinfection regimes in drinking-water and distribution system biofilms.
 ...
PMID:Investigation of opportunistic pathogens in municipal drinking water under different supply and treatment regimes. 1531 91

A range of opportunistic pathogens have been associated with dental unit water systems (DUWS), particularly in the biofilms that can line the tubing. This study therefore aimed to assess the microbiology of DUWS and biofilms in general dental practices across seven European countries, including the United Kingdom (UK), Ireland (IRL), Greece (GR), Spain (ES), Germany (D), Denmark (DK) and the Netherlands (NL). Water supplied by 51% of 237 dental unit water lines exceeded current American Dental Association recommendations of < or = 200 colony-forming units (CFU) ml(-1). Microbiological loading of the source waters was between 0 (Denmark, the Netherlands and Spain) and 4.67 (IRL) log CFU ml(-1); water line samples from the DUWS ranged from 1.52 (ES) to 2.79 (GR) log CFU ml(-1); and biofilm counts ranged from 1.49 (GR) to 3.22 (DK) log CFU.cm(-2). Opportunistic pathogens such as legionellae (DK and ES), including Legionella pneumophila SG1 (DK and GR), and Mycobacterium spp. (DK, NL, GR, D and ES) were recovered occasionally. Presumptive oral streptococci (ES and NL), oral anaerobes (GR), Candida spp. (UK, NL and ES) and blood (GR and IRL) were detected at relatively low frequencies, but their presence indicated a failure of the 3-in-1 antiretraction valve, leading to back siphonage of oral fluids into the water and biofilm phase. These findings confirm that a substantial proportion of DUWS have high levels of microbial contamination, irrespective of country, type of equipment and source water. The study emphasizes the need for effective mechanisms to reduce the microbial burden within DUWS, and highlights the risk of occupational exposure and cross-infection in general dental practice.
 ...
PMID:Microbiological evaluation of dental unit water systems in general dental practice in Europe. 1545 99

Inbred mouse strains have been known for many years to vary in their degree of susceptibility to different types of infectious diseases. The genetic basis of these interstrain differences is sometimes simple but often complex. In a few cases, positional cloning has been used successfully to identify single gene effects. The natural resistance-associated macrophage protein 1 (Nramp1) gene (Slc11a1) codes for a metal transporter active at the phagosomal membrane of macrophages, and Nramp1 mutations cause susceptibility to Mycobacterium, Salmonella, and Leishmania. Furthermore, recent advances in gene transfer technologies in transgenic mice have enabled the functional dissection of gene effects mapping to complex, repeated parts of the genome, such as the Lgn1 locus, causing susceptibility to Legionella pneumophila in macrophages. Finally, complex traits such as the genetically determined susceptibility to malaria can sometimes be broken down into multiple single gene effects. One such example is the case of pyruvate kinase, where a loss-of-function mutation was recently shown by our group to be protective against blood-stage infection with Plasmodium chabaudi. In all three cases reviewed, the characterization of the noted gene effect(s) has shed considerable light on the pathophysiology of the infection, including host response mechanisms.
 ...
PMID:Single gene effects in mouse models of host: pathogen interactions. 1565 50

The haploid social soil amoeba Dictyostelium discoideum has been established as a host model for several pathogens including Pseudomonas aeruginosa, Cryptococcus neoformans, Mycobacterium spp. and Legionella pneumophila. The research areas presently pursued include (i) the use of Dictyostelium wild-type cells as screening system for virulence of extracellular and intracellular pathogens and their corresponding mutants, (ii) the use of Dictyostelium mutant cells to identify genetic host determinants of susceptibility and resistance to infection and (iii) the use of reporter systems in Dictyostelium cells which allow the dissection of the complex host-pathogen cross-talk. The body of information presented in this review demonstrates that the availability of host cell markers, the knowledge of cell signalling pathways, the completion of the genome sequencing project and the tractability for genetic studies qualifies Dictyostelium for the study of fundamental cellular processes of pathogenesis.
 ...
PMID:Dictyostelium as host model for pathogenesis. 1567 34

Moxifloxacin (Bay 12-8039) is a new 8 methoxy quinolone antibacterial. The MIC90 values are < or = 0.25 mg/l for Streptococcus pneumoniae (irrespective of penicillin susceptibility), Haemophilus influenzae (beta-lactamase positive or negative), Morexella catarrhalis, Bordetella pertussis, Legionella sp., Mycoplasma pneumoniae, Clamydia pneumoniae, Mycobacterium tuberculosis, methicillin-sensitive Staphylococcus aureus, beta-haemolytic streptococci (macrolide-sensitive or -resistant), Listeria sp., most Enterobacteriaceae, Salmonella sp., Shigella sp., Neisseria gonorrhoeae, N. menigitidis, Pasteurella spp., Vibrio spp. and Yersinia enterocolitica. For Mycobacterium intracellularae, methicillin-resistant S. aureus (MRSA), ciprofloxacin-resistant S. aureus, Citrobacter freundii, Providencia sp., Serratia sp., P. aeruginosa and other non-fermentive Gram-negative rods, MIC90s are in the range 0.5-4 mg/l. For anaerobic bacteria species, MIC90s are also in the range 0.25-4 mg/l. Moxifloxacin is bactericidal at concentrations 2- to 4-fold higher than the MIC and is rapidly bactericidal against most common pathogen groups at concentrations achieved in serum with a 400 mg dose that is between 0.5-4 mg/l. There is a post-antibiotic effect against Gram-positive and -negative bacteria. Resistant mutants are at present difficult to select in the laboratory but in general, moxifloxacin has poorer activity against strains resistant to ciprofloxacin compared to those which are susceptible. Animal and laboratory pharmacodynamic models indicate that the MIC and area under the serum concentration time curve predict outcome. Various animal models mainly of respiratory tract infection indicate equivalent or superior results compared to existing or other developmental agents. Human pharmacokinetics in healthy volunteers indicate linear pharmacokinetics over the dose range 50-800 mg/day. A single dose of 400 mg produces a maximum serum concentration of 2.5-4.5 mg/l, half-life of 11-15 h, AUC of 25-40 mg x h/l and volume of distribution of 2.5-3.5 L/kg. Protein binding is about 50% and two metabolites have been identified (M-1 and M-2). Bioavailability is > 85% and a minority of clearance is via the kidneys. No dose modification is required in renal impairment. Extra vascular penetration, where studied, is comparable to that of other quinolones. At present undergoing clinical trials, with a focus on respiratory tract infection, it is likely that moxifloxacin will provide effective therapy for pathogens with MICs of < or = 0.25-0.5 mg/l. The safety profile in a large number of human subjects is awaited.
 ...
PMID:Moxifloxacin (Bay 12-8039): a new methoxy quinolone antibacterial. 1599 72

Multiple-antibiotic-resistant Salmonella enterica serotype Typhimurium is a food-borne pathogen that has been purported to be more virulent than antibiotic-sensitive counterparts. The paradigm for this multiresistant/hyperpathogenic phenotype is Salmonella enterica serotype Typhimurium phage type DT104 (DT104). The basis for the multiresistance in DT104 is related to an integron structure designated SGI1, but factors underlying hyperpathogenicity have not been completely identified. Since protozoa have been implicated in the alteration of virulence in Legionella and Mycobacterium spp., we attempted to assess the possibility that protozoa may contribute to the putative hypervirulence of DT104. Our study reveals that DT104 can be more invasive, as determined by a tissue culture invasion assay, after surviving within protozoa originating from the bovine rumen. The enhancement of invasion was correlated with hypervirulence in a bovine infection model in which we observed a more rapid progression of disease and a greater recovery rate for the pathogen. Fewer DT104 cells were recovered from tissues of infected animals when protozoa were lysed by preinfection chemical defaunation of the bovine or ovine rumen. The protozoan-mediated hypervirulence phenotype was observed only in DT104 and other Salmonella strains, including serovars Agona and Infantis, possessing SGI1.
 ...
PMID:Exposure to rumen protozoa leads to enhancement of pathogenicity of and invasion by multiple-antibiotic-resistant Salmonella enterica bearing SGI1. 1604 Sep 79

Microbiological analysis allows us to identify the etiology of pneumonia and its in vitro susceptibility pattern. Antibiotic treatment directed against a known pathogen enables us to narrow antibacterial spectrum of action, and to reduce costs, drug adverse effects risk and antibiotic resistance. However it is unnecessary to perform extended microbiological studies in all patients with community acquired pneumonia (CAP). Etiological studies must be based in pneumonia severity, epidemiological risk factors and clinical response to empirical treatment. Routine microbiological analysis for ambulatory patients is not recommended. In patients with persistent cough and worsening in their general conditions, a sputum sample must be obtained to perform an acid-fast smear and Mycobacterium culture. The risk of complications and death of patients hospitalized with CAP justifies basic microbiological exploration (sputum Gram staining and culture, blood cultures, pleural fluid culture) intending to obtain a more accurate etiology of pulmonary infection and to guide specific antibiotic treatment. Paired serum samples obtained to document atypical pathogen infections (Mycoplasma pneumoniae, Chlamydia pneumoniae) and urine sample to detect Legionella pneumophila antigenuria are recommended in all CAP severely ill patients that are admitted to ICU, in those not responding to betalactamic drug treatment and in selected patients with specific epidemiological risks. A microbiological study would be useful in management of patients with severe CAP pneumonia outbreaks with clinical-epidemiological particular characteristics, and in-patients with empirical antimicrobial treatment failure.
 ...
PMID:[Microbiologic diagnosis of community-acquired pneumonia in adults]. 1616 17

The shell-vial culture assay is performed routinely in our laboratory. Recently we revisited our experience of using the shell-vial culture assay for the isolation of microorganisms from various clinical samples. Over a 13-year period, we have isolated 580 bacterial strains (5%) from 11,083 clinical samples tested. Over the same period, 285 isolates of rickettsiae, bartonellae, or Coxiella burnetii were cultured from a total of 7,102 samples tested. These isolates include 55 Rickettsia sp. isolates, 95 Coxiella burnetii isolates, and 135 Bartonella sp. isolates. Based on our experience with the growth of fastidious microorganisms, we have used a centrifugation shell-vial technique called JNSP, for "je ne sais pas" ("I don't know [what I am growing]") for the isolation of other microorganisms. A total of 173 isolates were cultured from the 3,861 clinical samples tested using the JNSP method. Of these, 40 isolates had not been grown before on usual axenic medium. These include 2 Staphylococcus aureus isolates, 7 isolates of Streptococcus sp. and related genera, 6 Mycobacterium sp. isolates, 1 Nocardia asteroides isolate, 1 Actinomyces sp. isolate, 1 Brucella melitensis isolate, 2 Francisella tularensis isolates, 1 Mycoplasma pneumoniae isolate, and 1 Legionella pneumophila isolate. Using this protocol, we have also cultured intracellular bacteria such as Chlamydia trachomatis and we have performed the first culture and establishment of Trophyrema whipplei. Applied in our laboratory, the shell-vial culture generally exhibits a low rate of success. However, in some cases, this technique allowed microbial diagnosis when classical agar procedure and PCR were negative.
 ...
PMID:Use of shell-vial cell culture assay for isolation of bacteria from clinical specimens: 13 years of experience. 1620 53

Most water utilities use chlorine or chloramine to produce potable water. These disinfecting agents react with water to produce residual oxidants within a water distribution system (WDS) to control bacterial growth. While monochloramine is considered more stable than chlorine, little is known about the effect it has on WDS biofilms. Community structure of 10-week old WDS biofilms exposed to disinfectants was assessed after developing model biofilms from unamended distribution water. Four biofilm types were developed on polycarbonate slides within annular reactors while receiving chlorine, chloramine, or inactivated disinfectant residual. Eubacteria were identified through 16S rDNA sequence analysis. The model WDS biofilm exposed to chloramine mainly contained Mycobacterium and Dechloromonas sequences, while a variety of alpha- and additional beta-proteobacteria dominated the 16S rDNA clone libraries in the other three biofilms. Additionally, bacterial clones distantly related to Legionella were found in one of the biofilms receiving water with inactivated chlorine residual. The biofilm reactor receiving chloraminated water required increasing amounts of disinfectant after 2 weeks to maintain chlorine residual. In contrast, free chlorine residual remained steady in the reactor that received chlorinated water. The differences in bacterial populations of potable water biofilms suggest that disinfecting agents can influence biofilm development. These results also suggest that biofilm communities in distribution systems are capable of changing in response to disinfection practices.
 ...
PMID:Population diversity in model potable water biofilms receiving chlorine or chloramine residual. 1652 41


<< Previous 1 2 3 4 5 6 7 8 9 10