scholarly journals Experiments designed to determine the mechanism of the adjuvant activity of Gram-negative organisms upon antibody production

1962 ◽  
Vol 60 (4) ◽  
pp. 411-426 ◽  
Author(s):  
J. R. Farthing ◽  
L. B. Holt
Keyword(s):  
Antibody Production ◽  
Antibody Formation ◽  
Direct Link ◽  
No Adsorption ◽  
Adjuvant Effect ◽  
Adjuvant Activity ◽  
Gram Negative ◽  
Stress Symptoms ◽  
Gram Negative Organisms ◽  
Characteristic Stress

The characteristics of Gram-negative organisms and some of the underlying reasons for their adjuvant action with diphtheria toxoid are described.The adjuvant effect was shown by an earlier production of antitoxin, with a maintained differential advantage over controls, but with the usual decline in titre with passage of time. The adjuvant effect only occurred with a primary stimulus. There was no adsorption between toxoid and vaccine and mixture of the two was not necessary, but the vaccine had to be given simultaneously with or within 24 hr. following injection of the toxoid. There was evidence for believing that these adjuvants decreased the minimal stimulating dose of antigen and caused hyperplasia of antibody-producing cells. No direct link could be found between the characteristic stress symptoms caused by lipopolysaccharides and their ability to enhance antibody formation.

scholarly journals Linearized esculentin-2EM shows pH dependent antibacterial activity with an alkaline optimum

2021 ◽  
Author(s):  
Erum Malik ◽  
David A. Phoenix ◽  
Timothy J. Snape ◽  
Frederick Harris ◽  
Jaipaul Singh ◽  
...  
Keyword(s):  
Helical Structure ◽  
Food Preservation ◽  
Forming Process ◽  
Gram Positive ◽  
Gram Negative ◽  
Bacterial Membranes ◽  
Gram Positive Bacteria ◽  
Alkaline Conditions ◽  
Ph Dependent ◽  
Gram Negative Organisms

AbstractHere the hypothesis that linearized esculentin 2EM (E2EM-lin) from Glandirana emeljanovi possesses pH dependent activity is investigated. The peptide showed weak activity against Gram-negative bacteria (MLCs ≥ 75.0 μM) but potent efficacy towards Gram-positive bacteria (MLCs ≤ 6.25 μM). E2EM-lin adopted an α-helical structure in the presence of bacterial membranes that increased as pH was increased from 6 to 8 (↑ 15.5–26.9%), whilst similar increases in pH enhanced the ability of the peptide to penetrate (↑ 2.3–5.1 mN m−1) and lyse (↑ 15.1–32.5%) these membranes. Theoretical analysis predicted that this membranolytic mechanism involved a tilted segment, that increased along the α-helical long axis of E2EM-lin (1–23) in the N → C direction, with −  < µH > increasing overall from circa − 0.8 to − 0.3. In combination, these data showed that E2EM-lin killed bacteria via novel mechanisms that were enhanced by alkaline conditions and involved the formation of tilted and membranolytic, α-helical structure. The preference of E2EM-lin for Gram-positive bacteria over Gram-negative organisms was primarily driven by the superior ability of phosphatidylglycerol to induce α-helical structure in the peptide as compared to phosphatidylethanolamine. These data were used to generate a novel pore-forming model for the membranolytic activity of E2EM-lin, which would appear to be the first, major reported instance of pH dependent AMPs with alkaline optima using tilted structure to drive a pore-forming process. It is proposed that E2EM-lin has the potential for development to serve purposes ranging from therapeutic usage, such as chronic wound disinfection, to food preservation by killing food spoilage organisms.

scholarly journals Systemic Antibiotics and Obesity: Analyses from a Population-Based Cohort

2021 ◽  
Vol 10 (12) ◽  
pp. 2601
Author(s):  
So Young Park ◽  
Morena Ustulin ◽  
SangHyun Park ◽  
Kyung-Do Han ◽  
Joo Young Kim ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Adult Population ◽  
Antibiotic Use ◽  
Population Based ◽  
Obesity Risk ◽  
Gram Negative ◽  
Korean Adult ◽  
Korean National Health Insurance ◽  
Gram Negative Organisms ◽  
Systemic Antibiotics

Background: In this study, we analyzed the association between antibiotic use and obesity and metabolic syndrome (MS) in a Korean adult population. Methods: Subjects using the Korean National Health Insurance Service sample cohort were retrospectively analyzed in 2015. The differences in obesity and metabolic syndrome (MS) status were compared and analyzed according to duration of systemic antibiotic treatment in the previous 10 years (non-users, 1st, 2nd, and 3rd tertile). Results: Subjects who used systemic antibiotics for longer periods were older, satisfied more criteria for MS, and had more comorbidities than non-users (non-users vs. 3rd tertile, p < 0.0001 for all). After adjusting for confounding factors, the risk of obesity was higher in subjects who used systemic antibiotics for longer periods than in non-users (non-users vs. 3rd tertile, OR (odds ratio) (95% CI (confidence interval)); 1.20 (1.12–1.38)). The criteria for MS were more satisfied in the 3rd tertile than in non-users. A higher obesity risk was also found in subjects treated with antibiotics targeting Gram-negative organisms than in those targeting Gram-positive organisms. Conclusion: The risk of obesity was higher in subjects who took systemic antibiotics more frequently. The risk was more prominent when they took antibiotics targeting Gram-negative bacteria.

scholarly journals 1554. Epidemiology of Adult Bacterial Hand Infections at Two Urban Hospitals

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S777-S778
Author(s):  
Arsheena Yassin ◽  
Christine Stavropoulos ◽  
Krystina L Woods ◽  
Jiashan Xu ◽  
Justin Carale ◽  
...  
Keyword(s):  
New York ◽  
Staphylococcus Aureus ◽  
Antibiotic Regimen ◽  
Gram Positive ◽  
Gram Negative ◽  
Streptococcus Species ◽  
Urban Hospitals ◽  
Haemophilus Parainfluenzae ◽  
Empiric Antibiotic ◽  
Gram Negative Organisms

Abstract Background Hand infections represent a major source of morbidity, which can result in hand stiffness and amputation. Early appropriate empiric antibiotic regimen may reduce the associated morbidity, hence the importance to examine local epidemiology. The aim of this study was to define the current epidemiology of adult hand infections at two urban hospitals in New York City. Methods We performed a double center, retrospective study of adult patients hospitalized from March 2018 to May 2020. Patients with positive cultures associated with the hand infections were included. Retrospectively, 100 patients were reviewed. Data on baseline demographic, clinical, surgical, microbiology, and treatment parameters were collected. Results Of the 100 patients, 76% were male, with median age of 47.5 years (35, 58.25) and average C-reactive protein (CRP) of 50.66 mg/L (± 64.64) on admission (see Table 1). Previous hospitalization within 1 year (38%), previous surgical procedures (39%) and recent IV medication use (26%) were common. 130 bacterial isolates were identified (see Table 2). The most frequent organisms were Gram-positive, with Methicillin susceptible Staphylococcus aureus (MSSA, 25.38%), Streptococcus species (20.08%), and Methicillin resistant Staphylococcus aureus (MRSA, 15.38%) being the most common. Gram-negative organisms were infrequent, with Haemophilus parainfluenzae (3.85%), Enterobacter cloacae (3.85) and Pseudomonas aeruginosa (3.08%) being the most prevalent. Of the 100 patients, 27% had polymicrobial infections, associated with trauma (6%), illicit IV use (6%) and unknown (7%) etiologies. Table 1: Baseline demographics and co-morbid conditions Table 2: Types and numbers of organisms in relation to etiologies Conclusion Within our population, the most common organisms associated with hand infections were Gram-positive, with Staphylococcus aureus and Streptococcus species being the most prevalent. Gram-negative pathogens were infrequently isolated. The results within this study can provide guidance to clinicians on assessing the appropriate empiric antibiotic regimen in patients with hand infections, and can serve as a basis for further studies identifying risk factors associated with isolation of organisms associated with hand infections. Disclosures All Authors: No reported disclosures

scholarly journals Endotoxemia as a Diagnostic Tool for Patients with Suspected Bacteremia Caused by Gram-Negative Organisms: a Meta-Analysis of 4 Decades of Studies

2015 ◽  
Vol 53 (4) ◽  
pp. 1183-1191 ◽  
Author(s):  
James C. Hurley ◽  
Piotr Nowak ◽  
Lars Öhrmalm ◽  
Charalambos Gogos ◽  
Apostolos Armaganidis ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Meta Analysis ◽  
Inclusion Criteria ◽  
Summary Receiver Operating Characteristic ◽  
Detection Rates ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Patient Groups ◽  
Gram Negative Organisms

The clinical significance of endotoxin detection in blood has been evaluated for a broad range of patient groups in over 40 studies published over 4 decades. The influences of Gram-negative (GN) bacteremia species type and patient inclusion criteria on endotoxemia detection rates in published studies remain unclear. Studies were identified after a literature search and manual reviews of article bibliographies, together with a direct approach to authors of potentially eligible studies for data clarifications. The concordance between GN bacteremia and endotoxemia expressed as the summary diagnostic odds ratios (DORs) was derived for three GN bacteremia categories across eligible studies by using a hierarchical summary receiver operating characteristic (HSROC) method. Forty-two studies met broad inclusion criteria, with between 2 and 173 GN bacteremias in each study. Among all 42 studies, the DORs (95% confidence interval) were 3.2 (1.7 to 6.0) and 5.8 (2.4 to 13.7) in association with GN bacteremias withEscherichia coliand those withPseudomonas aeruginosa, respectively. Among 12 studies of patients with sepsis, the proportion of endotoxemia positivity (95% confidence interval) among patients withP. aeruginosabacteremia (69% [57 to 79%];P= 0.004) or withProteusbacteremia (76% [51 to 91%];P= 0.04) was significantly higher than that among patients without GN bacteremia (49% [33 to 64%]), but this was not so for patients bacteremic withE. coli(57% [40 to 73%];P= 0.55). Among studies of the sepsis patient group, the concordance of endotoxemia with GN bacteremia was surprisingly weak, especially forE. coliGN bacteremia.

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