scholarly journals Medium-term influence of tetracyclines on total and specific microbial biomass in cultivated soils of Galicia (NW Spain)

2020 ◽  
Vol 10 ◽  
Author(s):  
V. Santás-Miguel ◽  
M. Díaz-Raviña ◽  
A. Martín ◽  
E. García-Campos ◽  
A. Barreiro ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Bacterial Biomass ◽  
Similar Response ◽  
Medium Term ◽  
Gram Positive ◽  
Gram Negative ◽  
The Relationship ◽  
Higher Doses ◽  
Tetracycline Group ◽  
Cultivated Soils

This work examines the results of a soil incubation experiment in the laboratory, under controlled conditions of humidity and temperature. The purpose was to determine the medium-term influence of the presence of antibiotics on the total and specific microbial biomass, determined by means of the phospholipid fatty acids (PLFAs) analysis (total microbial biomass, and specific fungal, bacterial, actinobacterial, Gram-negative bacterial and Gram-positive bacterial biomass), as well as the relationship between some of these groups (fungal biomass/bacterial biomass, Gram-negative-bacterial /Gram-positive bacterial). The experiment was performed with four different cultivated soils with a similar pH but different organic matter (OM) content, to which eight doses of three antibiotics of the tetracycline group (tetracycline, oxytetracycline and chlorotetracycline) were added. Microbial biomass measurements (total and specific groups) were performed after 42 days of incubation. As expected, the total and specific microbial biomass values were different in the four soils studied. Both the total and the specific microbial biomass showed a similar response to the presence of antibiotics, although in several cases the data were inconsistent and difficult to interpret. In general, in all soils the addition of chlorotetracycline and tetracycline slightly modified or increased, to a greater or lesser extent, the values of both total and specific microbial biomass, particularly at higher doses. However, in certain cases, biomass values decreased due to the addition of the highest dose of oxytetracycline. With regard to fungal/bacterial and Gram<sup>-</sup>bacteria/Gram<sup>+</sup> bacterial biomass ratios, values slightly changed after the addition of the antibiotics.

scholarly journals Exploring the relationship between structure and activity in BODIPYs designed for antimicrobial phototherapy

2020 ◽  
Vol 18 (13) ◽  
pp. 2416-2431 ◽  
Author(s):  
Benjamin F. Hohlfeld ◽  
Burkhard Gitter ◽  
Keith J. Flanagan ◽  
Christopher J. Kingsbury ◽  
Nora Kulak ◽  
...  
Keyword(s):  
Gram Positive ◽  
Gram Negative ◽  
Highly Effective ◽  
The Relationship ◽  
Structure And Activity

A series of BODIPYs were evaluated for their phototoxic activity against Gram-positive S. aureus and Gram-negative P. aeruginosa. Specifically, carbohydrate/dibromosubstituted BODIPYs showed a highly effective inactivation of S. aureus.

Homologous and cross-reacting antibodies in the sera of gnotobiotic rats

1978 ◽  
Vol 24 (4) ◽  
pp. 365-371 ◽  
Author(s):  
Joy C. McLeod ◽  
Edward Balish
Keyword(s):  
Gram Negative Bacteria ◽  
Sprague Dawley ◽  
Gram Positive ◽  
Passive Hemagglutination ◽  
Gram Negative ◽  
E Coli ◽  
Sprague Dawley Rats ◽  
Antibody Titers ◽  
The Relationship ◽  
Reactive Antibody

Sera from Sprague–Dawley rats monoassociated with Clostridium perfringens, C. tertium, C. bifermenlans, Staphylococcus aureus, Escherichia coli, Proteus mirabilis, or Klebsiella pneumoniae for 4 weeks were assayed for homologous and cross-reacting antibodies against antigens on a variety of bacteria. A passive hemagglutination assay, with the antigen(s) consisting of bacteria conjugated to tanned sheep red blood cells, was used to assess antibody titers. Both homologous and cross-reacting antibodies were detected in sera that were collected from the monoassociated animals. Sera from monoassociated rats had agglutinating antibody to genera of bacteria that had not colonized their gastrointestinal tract. Although S. aureus shared some antigens with three species of Clostridium, the relationship was not reciprocal. Sera from rats monoassociated with E. coli, P. mirabilis, or K. pneumoniae had cross-reactive antibody against gram-positive and gram-negative bacteria, but did not have antibodies that could agglutinate H. influenzae type b. Monoassociation with C. perfringens resulted in the production of antibodies against a variety of gram-positive and gram-negative bacteria, but it did not induce cross-reactive antibodies against Corynebacterium diphtheriae, streptococci (groups A, C, and G), or Staphylococcus epidennidis.

scholarly journals Probing the relationship between Gram-negative and Gram-positive S1 proteins by sequence analysis

2009 ◽  
Vol 37 (16) ◽  
pp. 5578-5588 ◽  
Author(s):  
Philippe Salah ◽  
Marco Bisaglia ◽  
Pascale Aliprandi ◽  
Marc Uzan ◽  
Christina Sizun ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Gram Positive ◽  
Gram Negative ◽  
The Relationship

Antibacterial activity in the haemocytes of the shore crab,Carcinus maenas

1992 ◽  
Vol 72 (3) ◽  
pp. 529-542 ◽  
Author(s):  
June R. S. Chisholm ◽  
Valerie J. Smith
Keyword(s):  
Antibacterial Activity ◽  
Divalent Cations ◽  
Carcinus Maenas ◽  
Shore Crab ◽  
Gram Positive ◽  
Gram Negative ◽  
Heat Stable ◽  
Gram Negative Organisms ◽  
The Relationship ◽  
Selection Of

The presence of antibacterial activity in the haemocytes of the shore crab,Carcinus maenas(L.) (Crustacea: Decapoda), was investigated using a selection of Gram-positive and Gram-negative bacteria from geographically diverse waters. Preliminary investigations into the relationship between this activity and the prophenoloxidase activating system (proPO) were also carried out. Antibacterial activity against both Gram-positive and Gram-negative organisms were found to reside exclusively in the granular haemocytes and eight of the twelve bacteria tested were susceptible to this effect. Additional studies, usingPsychrobacter immobilis(=Moraxellasp.), revealed that the factor (or factors) responsible was 90% effective within 60 min and was also heat stable, independent of divalent cations, and non-lytic in character. Although antibacterial activity resides in the same cell population that carries the proPO system, there appears to be no relationship between antibacterial activity and phenoloxidase itself. Other components of the proPO system, however, may be involved.

scholarly journals Value of Time to Positivity of Blood Culture in Children with Bloodstream Infections

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Fen Pan ◽  
Wantong Zhao ◽  
Hong Zhang
Keyword(s):  
Bacterial Species ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Drug Resistant ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Microbiological Characteristics ◽  
The Mean ◽  
The Relationship

Objective. This study was to investigate the microbiological characteristics and the relationship between the time to positivity (TTP) of blood cultures and different bacterial species and to assess the clinical value of TTP in children with bloodstream infections (BSIs). Methods. The TTP of all the blood cultures from children with suspected BSIs was retrospectively collected in 2016. The microbiological characteristics and the relationship between the TTP of blood cultures and different bacterial species were also analyzed. Results. A total of 808 strains were isolated from 15835 blood cultures collected, and 145 (17.9%) were Gram-negative, 636 (78.7%) were Gram-positive, and 27 (3.3%) were fungi. The bacteria were divided into definite pathogens (174), possible pathogens (592), fungi (27), and contaminants (15). The average TTP of all positive blood cultures was 30.97 and ranged from 3.23 h to 92.73 h. The TTP of Gram-negative strains was significantly shorter than that of Gram-positive strains (P<0.001) and fungi (P = 0.032). The mean TTP for E. coli (15.60 h) was shortest within the group of Gram-negative isolates, and the mean TTP for Streptococcus (17.34 h) within the group of Gram-positive isolates. Significant difference of the TTP was detected in methicillin-resistant vs methicillin-susceptible S. aureus, extended-spectrum beta-lactamases (ESBLs) positive vs negative Enterobacteriaceae, and extensive drug-resistant and non-XDR A. baumannii. The median TTP in patients with BSI was significantly shorter than in those without it (P<0.001). ROC curve analysis indicated that the TTP cutoff value of CoNS, S. aureus, E. coli, and K. pneumoniae was 22.72 h, 19.6 h, 18.58 h, and 16.43 h, respectively, with most sensitive and specific predictor of BSIs. Conclusions. Our data acknowledged that TTP is a valuable index for the early prognosis of BSIs. TTP not only provides additional utility as a general predictor of bacteria with smear result but also provides the implication of drug-resistant organisms.

scholarly journals Pharmacodynamic Profiling of Ceftobiprole for Treatment of Complicated Skin and Skin Structure Infections

2009 ◽  
Vol 53 (8) ◽  
pp. 3371-3374 ◽  
Author(s):  
Holly Kimko ◽  
Xu Xu ◽  
Partha Nandy ◽  
Mahesh N. Samtani ◽  
Richard S. Strauss ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Clinical Cure ◽  
Therapeutic Outcome ◽  
Gram Positive ◽  
Gram Negative ◽  
Skin Structure ◽  
Complicated Skin ◽  
Intent To Treat ◽  
The Relationship ◽  
Treat Analysis

ABSTRACT Ceftobiprole, a broad-spectrum cephalosporin with activity against methicillin (meticillin)-resistant staphylococci, was statistically noninferior to a combination of vancomycin plus ceftazidime in patients with complicated skin and skin structure infections (cSSSI). This analysis used data from this clinical trial to determine the relationship between therapeutic outcome and the percentage of time that the unbound ceftobiprole concentration exceeds the MIC (percent T>MIC). From the trial of ceftobiprole (500 mg every 8 h, 2-h infusion) for cSSSI due to gram-positive and/or gram-negative bacteria, data from 309 patients in the microbiological intent-to-treat analysis set with measured ceftobiprole concentrations and baseline MICs were used to assess the relationship between percent T>MIC and therapeutic outcome. Individual pharmacokinetic (PK) profiles were obtained from a three-compartment population PK model. The relationship between percent T>MIC and a clinical cure was determined. For the clinical trial dosing regimen, individual percent T>MICs were used to calculate fractional target attainment rates (TARs) for ≥30 and ≥50% T>MIC targets at various MICs. There was a statistically significant relationship between achieving a ≥30 or ≥50% T>MIC and a clinical cure (P = 0.003 and P = 0.007, respectively; Pearson's χ2 test). The fractional TAR was greater than 90% at a MIC of ≤4 mg/liter for patients with normal renal function. A relationship between percent T>MIC and a clinical cure with ceftobiprole was demonstrated. A ceftobiprole regimen of 500 mg every 8 h as a 2-h infusion has a high probability of achieving a target of ≥30 or ≥50% T>MIC for patients with cSSSI due to gram-positive and gram-negative pathogens.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

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