Ontogeny of the phagocytic and bactericidal activities of turkey heterophils and their potentiation bySalmonella enteritidis-immune lymphokines

Salmonella enteritidis (SE) is of great concern to the poultry industry due to the organism's ability to penetrate the intestinal mucosa of the laying hen and subsequently colonize the ovaries and yolk membrane. The resultant subclinical infection can lead to SE infection of raw eggs and egg products. Interference with the ability of the organism to invade has been linked to the activation and recruitment of inflammatory polymorphonuclear cells, heterophils, to the lamina propria of the intestinal tract.Recently it has been established that heterophil activation and increased resistance to SE organ invasion can be accomplished by the administration of SE-immune lymphokines (SE-ILK) obtained from supernatants of concanavalin-A stimulated SE immune T lymphocytes from SE hyperimmunized hens. Invasion of SE into the lamina propria provides a secondary signal for directing activated heterophils to the site of SE invasion.

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Faculty Opinions recommendation of Inhibitory activities of 11 antimicrobial agents and bactericidal activities of vancomycin and daptomycin against invasive methicillin-resistant Staphylococcus aureus isolates obtained from 1999 through 2006.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.13485025.14862152 ◽

2012 ◽

Author(s):

George Sakoulas

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Agents ◽

Methicillin Resistant Staphylococcus Aureus ◽

Methicillin Resistant ◽

Inhibitory Activities ◽

Bactericidal Activities

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Green Synthesis of Multifunctional Carbon Dots with Antibacterial Activities

Nanomaterials ◽

10.3390/nano11020369 ◽

2021 ◽

Vol 11 (2) ◽

pp. 369 ◽

Cited By ~ 1

Author(s):

Arumugam Saravanan ◽

Moorthy Maruthapandi ◽

Poushali Das ◽

John H. T. Luong ◽

Aharon Gedanken

Keyword(s):

Carbon Dots ◽

Fluorescence Spectra ◽

Antibacterial Effect ◽

Curcuma Longa ◽

Antibacterial Activities ◽

Blue Color ◽

Mean Size ◽

One Step ◽

Bactericidal Activities ◽

Bright Blue

Carbon dots (CDs) were obtained from medicinal turmeric leaves (Curcuma longa) by a facile one-step hydrothermal method and evaluated for their bactericidal activities against two gram-negative; Escherichia coli, Klebsiella pneumoniae, and two gram-positive counterparts; Staphylococcus aureus, S. epidermidis. The CDs exhibited spherical shapes with a mean size of 2.6 nm. The fluorescence spectra of CDs revealed intense fluorescence at λex/em = 362/429 nm with a bright blue color in an aqueous solution. The CDs showed strong photostability under various environmental conditions (pH, salt, and UV-radiation). The complete bactericidal potency of CDs was 0.25 mg/mL for E.coli and S. aureus after 8 h of exposure, while for K. pneumoniae, and S. epidermidis, the CDs at 0.5 mg/mL good antibacterial effect within 8 h and complete eradication after 24 h of exposure is observed. The release of reactive oxygen species played a crucial role in the death of the bacterial cell. The present study provides a strategy for the preparation of CDs from a medicinal plant and their potential antibacterial activities against four common contagious pathogens.

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Synergistic bactericidal activities of tobramycin with ciprofloxacin and azithromycin against Klebsiella pneumoniae

The Journal of Antibiotics ◽

10.1038/s41429-021-00427-0 ◽

2021 ◽

Author(s):

Huan Ren ◽

Jingyi Zhang ◽

Jingyi Zhou ◽

Congjuan Xu ◽

Zheng Fan ◽

...

Keyword(s):

Klebsiella Pneumoniae ◽

Bactericidal Activities

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Urinary Excretion and Bactericidal Activities of a Single Oral Dose of 400 Milligrams of Fleroxacin versus a Single Oral Dose of 800 Milligrams of Pefloxacin in Healthy Volunteers

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.7.1659 ◽

1998 ◽

Vol 42 (7) ◽

pp. 1659-1665 ◽

Cited By ~ 15

Author(s):

Kurt G. Naber ◽

Ursula Theuretzbacher ◽

Martina Kinzig ◽

Orlin Savov ◽

Fritz Sörgel

Keyword(s):

Oral Dose ◽

Healthy Volunteers ◽

Single Oral Dose ◽

E Coli ◽

Wide Range ◽

The Mean ◽

Bactericidal Activities ◽

Tract Infections ◽

Time Kill ◽

Randomized Crossover Study

ABSTRACT Twelve healthy volunteers participated in this randomized crossover study to compare the concentrations and recovery levels of fleroxacin and pefloxacin in urine and to assess their bactericidal activities against 12 strains of urinary pathogens with different susceptibilities over a wide range of MICs. The volunteers received a single oral dose of 400 mg of fleroxacin or 800 mg of pefloxacin. The mean cumulative renal excretion of unchanged fleroxacin,N-demethyl-fleroxacin, and N-oxide-fleroxacin accounted for 67, 7, and 6% of the total dose, respectively. The total urinary recovery of pefloxacin and the active metabolite norfloxacin was 34%. In the time-kill and the urinary bactericidal titer (UBT) studies, only the subjects’ urine not supplemented with broth was used. With most tested organisms and both quinolones it took more than 8 h to achieve a reduction in CFU of 99.9% (3 log units). Overall, there was a good correlation between UBTs and MICs for the strains. Against Escherichia coli ATCC 25922 the median UBTs were similar for both antibiotics and at least 1:8 for 96 h; against the E. coli strain for which the MIC was 0.5 μg/ml the UBT was at least 1:4 for 48 h. The UBTs of both drugs against Klebsiella pneumoniae were at least 1:16 for 72 h. The UBTs for Staphylococcus aureus (the MIC for which was 16 μg/ml) of both antibiotics were low, and in some of the samples, no bactericidal titers were observed. UBTs for Proteus mirabilis of pefloxacin are significantly higher than those of fleroxacin. For Pseudomonas aeruginosa the median UBTs were present for the 24-to-48-h interval. The same is true forEnterococcus faecalis. Against Staphylococcus saprophyticus, UBTs were present for at least 48 h with both quinolones. Overall, a single oral dose of 400 mg of fleroxacin exhibits UBTs comparable to those of 800 mg of pefloxacin. Therefore, it may be expected that half of the dose of fleroxacin gives comparable results in the treatment of urinary tract infections; this should be substantiated in comparative clinical trials.

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Acylation of SC4 dodecapeptide increases bactericidal potency against Gram-positive bacteria, including drug-resistant strains

Biochemical Journal ◽

10.1042/bj20031393 ◽

2004 ◽

Vol 378 (1) ◽

pp. 93-103 ◽

Cited By ~ 57

Author(s):

Nathan A. LOCKWOOD ◽

Judith R. HASEMAN ◽

Matthew V. TIRRELL ◽

Kevin H. MAYO

Keyword(s):

Fatty Acid ◽

Fluorescence Spectroscopy ◽

Bactericidal Activity ◽

Bacterial Cell ◽

Membrane Surface ◽

Peptide Amphiphiles ◽

Helical Conformation ◽

Gram Positive ◽

Bacterial Membranes ◽

Bactericidal Activities

We have conjugated dodecyl and octadecyl fatty acids to the N-terminus of SC4, a potently bactericidal, helix-forming peptide 12-mer (KLFKRHLKWKII), and examined the bactericidal activities of the resultant SC4 ‘peptide-amphiphile’ molecules. SC4 peptide-amphiphiles showed up to a 30-fold increase in bactericidal activity against Gram-positive strains (Staphylococcus aureus, Streptococcus pyogenes and Bacillus anthracis), including S. aureus strains resistant to conventional antibiotics, but little or no increase in bactericidal activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Fatty acid conjugation improved endotoxin (lipopolysaccharide) neutralization by 3- to 6-fold. Although acylation somewhat increased lysis of human erythrocytes, it did not increase lysis of endothelial cells, and the haemolytic effects occurred at concentrations 10- to 100-fold higher than those required for bacterial cell lysis. For insight into the mechanism of action of SC4 peptide-amphiphiles, CD, NMR and fluorescence spectroscopy studies were performed in micelle and liposome models of eukaryotic and bacterial cell membranes. CD indicated that SC4 peptide-amphiphiles had the strongest helical tendencies in liposomes mimicking bacterial membranes, and strong membrane integration of the SC4 peptide-amphiphiles was observed using tryptophan fluorescence spectroscopy under these conditions; results that correlated with the increased bactericidal activities of SC4 peptide-amphiphiles. NMR structural analysis in micelles demonstrated that the two-thirds of the peptide closest to the fatty acid tail exhibited a helical conformation, with the positively-charged side of the amphipathic helix interacting more with the model membrane surface. These results indicate that conjugation of a fatty acid chain to the SC4 peptide enhances membrane interactions, stabilizes helical structure in the membrane-bound state and increases bactericidal potency.

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In Vivo Pharmacodynamics of Ceftobiprole against Multiple Bacterial Pathogens in Murine Thigh and Lung Infection Models

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01273-07 ◽

2008 ◽

Vol 52 (10) ◽

pp. 3492-3496 ◽

Cited By ~ 57

Author(s):

W. A. Craig ◽

D. R. Andes

Keyword(s):

Serum Levels ◽

Lung Infection ◽

Lung Model ◽

Dose Fractionation ◽

Time Curve ◽

Gram Negative ◽

Infection Models ◽

Bactericidal Activities

ABSTRACT Ceftobiprole medocaril is the parenteral prodrug of ceftobiprole, a novel pyrrolidinone broad-spectrum cephalosporin with in vitro and in vivo bactericidal activities against methicillin-resistant Staphylococcus aureus (MRSA) and penicillin-resistant Streptococcus pneumoniae (PRSP). We have used murine thigh and lung infection models in neutropenic and normal mice to characterize the in vivo pharmacokinetic (PK)-pharmacodynamic (PD) activities of ceftobiprole against multiple strains of S. aureus (including MRSA), S. pneumoniae (including PRSP), and gram-negative bacilli. Serum levels of ceftobiprole following the administration of multiple doses were determined by a microbiological assay. In vivo bactericidal activities and postantibiotic effects (PAEs) of ceftobiprole against MRSA and PRSP strains were determined from serial CFU/thigh values following single doses of ceftobiprole (40 and 160 mg/kg of body weight). Dose fractionation studies were used to determine which PK-PD index correlated best with activity. Magnitudes of the PK-PD indices were calculated from MICs and PK parameters. A sigmoid dose-response model was used to estimate the dose (mg/kg/24 h) required to achieve a static and 2-log10 kill effects over 24 h. PK results showed area under the concentration-time curve/dose values of 1.8 to 2.8 and half-lives of 0.29 to 0.51 h. MICs ranged from 0.015 to 2 μg/ml. Ceftobiprole demonstrated time-dependent killing; its in vivo PAEs varied from 3.8 h to 4.8 h for MRSA and from 0 to 0.8 h for PRSP. The time above MIC (T > MIC) correlated best with efficacy for both MRSA and PRSP. The T > MIC values required for the static doses were significantly longer (P < 0.001) for Enterobacteriaceae (36 to 45%) than for S. aureus (14 to 28%) and S. pneumoniae (15 to 22%). The drug showed activities in the lung model similar to those in the thigh model. The presence of neutrophils significantly enhanced the activity of ceftobiprole against S. pneumoniae but only slightly against Klebsiella pneumoniae. Based on its PD profile, ceftobiprole is a promising new β-lactam agent with activity against gram-negative and gram-positive organisms including MRSA and PRSP.

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