scholarly journals The intestinal flora of colonization-resistant mice

1971 ◽  
Vol 69 (3) ◽  
pp. 413-421 ◽  
Author(s):  
F. Wensinck ◽  
J. G. H. Ruseler-van Embden
Keyword(s):  
Escherichia Coli ◽  
Yeast Extract ◽  
Propionibacterium Acnes ◽  
Intestinal Flora ◽  
Ammonium Phosphate ◽  
Anaerobic Conditions ◽  
Gram Negative ◽  
Gram Negative Organisms

SUMMARYTo facilitate the isolation of anaerobes from cultures in which swarming organisms were present Roux flasks were adapted to provide anaerobic conditions. Using these flasks, five species of anaerobes were isolated from the caecum of mice resistant to colonization withEscherichia coliand other Gram-negative organisms. These species accounted for the majority of organisms seen in films of caecal material. No aerobes were isolated and the flora of these mice apparently consisted of a limited number of anaerobes representing part of the intestinal flora of conventional mice. Three of the species were clostridia and another was identified asPropionibacterium acnes. One species resembledCatenabacteriumbut was not identified. One of theClostridiumspecies could only be isolated when the medium was supplemented with yeast extract and vitamins. This species sporulated on media with ammonium phosphate as the source of nitrogen; tryptone completely suppressed sporulation.

Inactivation of chloramphenicol by Gram-negative microorganisms

1968 ◽  
Vol 14 (8) ◽  
pp. 891-899 ◽  
Author(s):  
David Sompolinsky ◽  
Ruth Ziegler-Schlomowitz ◽  
Dora Herczog
Keyword(s):  
Escherichia Coli ◽  
Growth Medium ◽  
Minimal Medium ◽  
Resistance Factor ◽  
The Other ◽  
Gram Negative ◽  
Resistant Strains ◽  
Gram Negative Organisms ◽  
High Level ◽  
Level Resistance

Two derivative strains of Escherichia coli with high-level resistance to chloramphenicol, one carrying an episomal resistance factor and the other a chromosomal mutant, were both shown to be potent inactivators of the drug. When 1 mM chloramphenicol was added to an exponential culture in minimal medium, growth was halted until 85–90% of the drug was inactivated by acylation. At this state the drug was essentially monoacylated. During and after growth, esterification of the second alcoholic group occurred, though at a slower rate. Arylamines, in amounts up to 10% of chloramphenicol equivalents, were demonstrated in the growth medium after 1–3 days' incubation.With an acetateless mutant of Escherichia coli K12, carrying a resistance factor, it was shown that 5–6 moles of acetate was consumed for every mole of chloramphenicol acylated.Inactivation of chloramphenicol by Gram-negative organisms from infections in hospitalized patients was also examined. Among 103 strains susceptible to chloramphenicol, none produced considerable amounts of chloramphenicol esters. The same was the case with 14 resistant strains of Pseudomonas. Of 134 other resistant organisms examined, including strains of Escherichia, Proteus, Klebsiella, Salmonella, and Shigella, 133 were producers of chloramphenicol esters, and in most cases the drug was partly or entirely diacylated.

scholarly journals Polar Localization of the Autotransporter Family of Large Bacterial Virulence Proteins

2006 ◽  
Vol 188 (13) ◽  
pp. 4841-4850 ◽  
Author(s):  
Sumita Jain ◽  
Peter van Ulsen ◽  
Inga Benz ◽  
M. Alexander Schmidt ◽  
Rachel Fernandez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Shigella Flexneri ◽  
Bacterial Pathogen ◽  
Gram Negative ◽  
Virulence Proteins ◽  
Host Interactions ◽  
Polar Localization ◽  
Associated Proteins ◽  
Molecular Information ◽  
Gram Negative Organisms

ABSTRACT Autotransporters are an extensive family of large secreted virulence-associated proteins of gram-negative bacteria. Secretion of such large proteins poses unique challenges to bacteria. We demonstrate that autotransporters from a wide variety of rod-shaped pathogens, including IcsA and SepA of Shigella flexneri, AIDA-I of diffusely adherent Escherichia coli, and BrkA of Bordetella pertussis, are localized to the bacterial pole. The restriction of autotransporters to the pole is dependent on the presence of a complete lipopolysaccharide (LPS), consistent with known effects of LPS composition on membrane fluidity. Newly synthesized and secreted BrkA is polar even in the presence of truncated LPS, and all autotransporters examined are polar in the cytoplasm prior to secretion. Together, these findings are consistent with autotransporter secretion occurring at the poles of rod-shaped gram-negative organisms. Moreover, NalP, an autotransporter of spherically shaped Neisseria meningitidis contains the molecular information to localize to the pole of Escherichia coli. In N. meningitidis, NalP is secreted at distinct sites around the cell. These data are consistent with a model in which the secretion of large autotransporters occurs via specific conserved pathways located at the poles of rod-shaped bacteria, with profound implications for the underlying physiology of the bacterial cell and the nature of bacterial pathogen-host interactions.

Infections caused by Gram-negative bacteria

2017 ◽  
Author(s):  
Philippa C. Matthews
Keyword(s):  
Escherichia Coli ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Treatment And Prevention ◽  
Clinical Syndromes ◽  
Causes Of Disease ◽  
Gram Negative Organisms ◽  
The Tropics

This chapter consists of short notes, diagrams, and tables to summarize Gram-negative organisms that are significant causes of disease in the tropics and subtropics. This includes Escherichia coli, Shigella, and Salmonella species (including typhoid and paratyphoid), Brucella, melioid, Campylobacter, and meningococci. For ease of reference, each topic is broken down into sections, including classification, epidemiology, microbiology, pathophysiology, clinical syndromes, diagnosis, treatment, and prevention.

Improved Enrichment for Recovery of Shigella sonnei from Foods

1985 ◽  
Vol 68 (3) ◽  
pp. 552-555 ◽  
Author(s):  
Ira J Mehlman ◽  
Aida Romero ◽  
Barry A Wentz
Keyword(s):  
Escherichia Coli ◽  
Methylene Blue ◽  
Tween 80 ◽  
Anaerobic Conditions ◽  
Macconkey Agar ◽  
Brussels Sprouts ◽  
Enrichment Broth ◽  
Gram Negative ◽  
Shigella Species ◽  
Food Portion

Abstract Shigella species were recovered from foods by the procedure described in the Bacteriological Analytical Manual, 5th Ed. The method is effective if Shigella species are present at about 106 cells/g. A 25 g food portion was incubated in Gram-negative (GN) and selenite cystine broths for 16 h at 35°C and streaked onto MacConkey, Levine's eosin methylene blue, desoxycholate citrate, and xylose lysine desoxycholate agars. 5. sonnei cells were recovered quantitatively at 44.5°C, and along with other Shigella species, were grown with Escherichia coli in a tryptone broth under anaerobic conditions. Shigella species were also grown in a mixed microflora from foods. 5. sonnei cells were inoculated into an enrichment broth containing 20 g tryptone, 2 g K2HPO4, 2 g KH2PO4, 1 g glucose, 5 g NaCl, 1.5 mL Tween 80, and 0.5 mg novobiocin/L (pH 7.0) and incubated for 20 h at 44°C. Enrichments were streaked onto MacConkey agar and the plates were incubated 20 h at 35°C. Suspect Shigella colonies were screened in glucose, tryptone, and lysine broths and in triple sugar iron and motility agars. The sensitivity varied from 0.3 to 1000 bacteria/g. The method has been examined with artificially inoculated lettuce, celery, brussels sprouts, mushrooms, and hamburger. It is also applicable to S. flexneri if incubation is conducted at 42°C.

Infections due to Escherichia coli and Other Enteric Gram-Negative Bacilli

2016 ◽  
Author(s):  
Allison Mah ◽  
Inna Sekirov ◽  
Theodore S Steiner
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Antimicrobial Resistance ◽  
Clinical Manifestations ◽  
Gram Negative ◽  
The Family ◽  
Enteric Infections ◽  
Gram Negative Organisms ◽  
Tract Infections

This review describes infections caused by Escherichia coli and related members of the family Enterobacteriaceae, excluding other genera that principally cause enteric infections. Infections caused by Salmonella, Shigella, and Yersinia are described in the review “Gastrointestinal Tract Infections," found elsewhere in this publication. The purpose of this review is to examine the specific epidemiology, clinical manifestations, and treatment of individual members of the Enterobacteriaceae. The emerging concern of antimicrobial resistance amongst enteric gram-negative organisms and the approach to treatment in the setting of infection with these resistant organisms are discussed in the review “Antimicrobial Resistance in Enteric Gram-Negative Organisms,” found elsewhere in this publication. Figures illustrate the mechanisms of antimicrobial resistance in Enterobacteriaceae. A table lists the clinical, epidemiologic, pathogenetic, and therapeutic aspects of infection with various pathotypes of Escherichia coli. This review contains 6 highly rendered figures, 1 table, and 79 references.

Changing Patterns of Resistance to Ampicillin/Sulbactam

1995 ◽  
Vol 11 (4) ◽  
pp. 153-155
Author(s):  
Sally Usdin Yasuda ◽  
Princy N Kumar ◽  
Mary A Young ◽  
Joseph G Timpone ◽  
Helen C Turner ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Susceptibility ◽  
Nosocomial Infections ◽  
Educational Program ◽  
University Teaching ◽  
Gram Negative ◽  
Appropriate Prescribing ◽  
Changing Patterns ◽  
Observational Design ◽  
Gram Negative Organisms

Objective: To report on methods to halt the increasing resistance of gram-negative organisms to ampicillin/sulbactam. Design: A before-after observational design was used to evaluate susceptibility of organisms to ampicillin/sulbactam. Setting: A university teaching hospital. Interventions: An educational program regarding appropriate prescribing of ampicillin/sulbactam and restriction of the use of ampicillin/sulbactam. Main Outcome Measures: Antimicrobial susceptibility to ampicillin/sulbactam. Results: The trend in increasing resistance was halted for Escherichia coli and Enterobacter. Emerging resistance of other organisms was not observed. Conclusions: The trend in increasing resistance was halted by restrictions on prescribing and by providing education regarding rational prescribing of ampicillin/sulbactam. We recommend that this combination not be used empirically to treat nosocomial infections or for bacteria against which ampicillin alone is effective.

scholarly journals The changing aetiology of paediatric bacteraemia in England and Wales, 1998–2007

2010 ◽  
Vol 59 (2) ◽  
pp. 213-219 ◽  
Author(s):  
Katherine L. Henderson ◽  
Alan P. Johnson ◽  
Berit Muller-Pebody ◽  
André Charlett ◽  
Ruth Gilbert ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Annual Reports ◽  
Coagulase Negative Staphylococci ◽  
Gram Negative ◽  
England And Wales ◽  
Threatening Condition ◽  
Life Threatening ◽  
Catch Up ◽  
Gram Negative Organisms ◽  
Over Time

Bacteraemia in children is a potentially life-threatening condition. The objective of this study was to determine trends in the aetiology of bacteraemia in children aged 1 month–15 years in England and Wales by collecting data voluntarily reported by National Health Service hospital microbiology laboratories. Over the 10-year period 1998–2007, a total of 51 788 bacteraemia cases involving 105 genera/species of bacteria were reported. Total annual reports of bacteraemia increased from 4125 to 6916, with a mean increase of 6.5 % per year (95 % CI: 1.3–12.1 %). In 2007, just over half the cases were accounted for by four groups of organisms: coagulase-negative staphylococci (28 %), Staphylococcus aureus (10 %), non-pyogenic streptococci (9 %) and Streptococcus pneumoniae (7 %). These organisms along with a further 13 species/genera accounted for 90 % of the cases. The commonest Gram-negative organisms were Neisseria meningitidis and Escherichia coli, which each accounted for 5 % of total bacteraemia reports in 2007. There was a significant decrease in reports of bacteraemia due to the three vaccine-preventable pathogens Haemophilus influenzae, N. meningitidis and Strep. pneumoniae, following the introduction of each vaccine programme or catch-up campaign. This study identified the commonest causes of bacteraemia in children in England and Wales, and highlighted the shifts in trends observed over time.

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