scholarly journals Comparative study of bactericidal activities, postantibiotic effects, and effects of bacterial virulence of penicillin G and six macrolides against Streptococcus pneumoniae.

1997 ◽  
Vol 41 (4) ◽  
pp. 781-784 ◽  
Author(s):  
K Fuursted ◽  
J D Knudsen ◽  
M B Petersen ◽  
R L Poulsen ◽  
D Rehm
Keyword(s):  
Bactericidal Activity ◽  
Lethal Dose ◽  
Drug Regimen ◽  
Bactericidal Effect ◽  
Penicillin G ◽  
Resistant Strains ◽  
Bactericidal Activities ◽  
Immunocompetent Mice ◽  
Intraperitoneal Inoculation

In this report, we present MIC, bactericidal activity, postantibiotic effect (PAE), and in vivo infectivity data for postantibiotic-phase pneumococci. We compared and evaluated penicillin G and six macrolides, erythromycin, azithromycin, clarithromycin, dirithromycin, roxithromycin, and spiramycin, against 10 strains of pneumococci with various levels of susceptibility to penicillin. All of the agents, except azithromycin, exhibited a bactericidal effect (a > or = 3 log10 decrease in the number of CFU per milliliter) after 4 h of exposure to a concentration equal to 10 times the MIC, displaying the following hierarchy: spiramycin = penicillin G = erythromycin = dirithromycin = clarithromycin = roxithromycin > azithromycin. The bactericidal rate of penicillin G was significantly lower for resistant strains (MIC, > or = 2 microg/ml), while bactericidal rates of macrolides were unaffected by penicillin susceptibility. A PAE was induced in all of the strains by all of the antibiotics after exposure for 1 h to a concentration equivalent to 10 times the MIC. The mean duration of PAEs varied between 2.3 and 3.9 h, showing the following hierarchy: spiramycin = dirithromycin = clarithromycin = erythromycin = roxithromycin > azithromycin > penicillin G. Virulence studies were performed with immunocompetent mice by intraperitoneal inoculation of virulent, penicillin-susceptible serotype 3 pneumococci which had been pre-exposed to penicillin G or a macrolide for 1 h. A significant decrease in the virulence of postantibiotic-phase pneumococci was induced only by erythromycin, azithromycin, dirithromycin, and spiramycin, displaying 5.9-, 7.1-, 4.2-, and 3.6-fold increases in the 50% lethal dose (LD50) compared to a control suspension, respectively. No significant correlation could be demonstrated between the LD50 and the MIC, bactericidal activity, or PAE duration. These results suggest that antimicrobial interaction with host defenses in terms of virulence might be a significant parameter that could influence the drug or drug regimen of choice.

scholarly journals THE THERAPEUTIC ACTIVITY OF PENICILLINS F, G, K, AND X IN EXPERIMENTAL INFECTIONS WITH PNEUMOCOCCUS TYPE I AND STREPTOCOCCUS PYOGENES

1947 ◽  
Vol 85 (2) ◽  
pp. 175-186 ◽  
Author(s):  
Harry Eagle ◽  
Keyword(s):  
Streptococcus Pyogenes ◽  
Bactericidal Activity ◽  
Penicillin G ◽  
Blood Levels ◽  
Type I ◽  
Pneumococcal Infections ◽  
Bactericidal Activities ◽  
Pneumococcus Type

1. The relative bactericidal activities of penicillins F, G, K, and X against Type I pneumococcus in vitro were 60, 100, 180, and 135. The corresponding activities against Streptococcus pyogenes, strain C-203, were 75, 100, 115, and 145, respectively. 2. The total curative doses (CD50) of penicillins F, G, K, and X in pneumococcal infections of white mice (ten injections at 3 hour intervals) were 4.6, 3.8, 20, and 2.4 mg. per kg., respectively, or relative activities of 83, 100, 19, and 160, referred to G as 100. 3. The corresponding curative doses in streptococcal infections of white mice were 2.6, 1.3, 14.0, and 0.5 mg. per kg., or relative activities of 50, 100, 9, and 260. 4. Penicillin K was therefore one-tenth as active in vivo as would be implied by its bactericidal activity in vitro. This probably reflects its rapid inactivation in vivo, evidenced by the low and evanescent blood levels observed in both rabbits and man, and the low urinary recovery of this species of penicillin. 5. Penicillin X was significantly more active therapeutically than its bactericidal activity in vitro would imply. This probably reflects its slower inactivation in vivo, evidenced by the somewhat higher and more prolonged blood levels afforded by this penicillin in comparison with penicillin G. Judged by the mouse infections with the strains here used, penicillin X is the penicillin of choice in the treatment of infections with pneumococcus Type I and hemolytic streptococci. 6. The curative dose of penicillin in streptococcal and pneumococcal infections paralleled the varying susceptibility of these organisms to penicillin in vitro.

scholarly journals In VitroandIn VivoStudies of Monoclonal Antibodies with Prominent Bactericidal Activity against Burkholderia pseudomallei and Burkholderia mallei

2011 ◽  
Vol 18 (5) ◽  
pp. 825-834 ◽  
Author(s):  
Shimin Zhang ◽  
Shaw-Huey Feng ◽  
Bingjie Li ◽  
Hyung-Yong Kim ◽  
Joe Rodriguez ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Bactericidal Activity ◽  
Burkholderia Pseudomallei ◽  
Protective Efficacy ◽  
Lethal Dose ◽  
Burkholderia Mallei ◽  
Content Type ◽  
Bactericidal Activities

ABSTRACTOur laboratory has developed more than a hundred mouse monoclonal antibodies (MAbs) againstBurkholderia pseudomalleiandBurkholderia mallei. These antibodies have been categorized into different groups based on their specificities and the biochemical natures of their target antigens. The current study first examined the bactericidal activities of a number of these MAbs by anin vitroopsonic assay. Then, thein vivoprotective efficacy of selected MAbs was evaluated using BALB/c mice challenged intranasally with a lethal dose of the bacteria. The opsonic assay using dimethyl sulfoxide-treated human HL-60 cells as phagocytes revealed that 19 out of 47 tested MAbs (40%) have prominent bactericidal activities againstB. pseudomalleiand/orB. mallei. Interestingly, all MAbs with strong opsonic activities are those with specificity against either the capsular polysaccharides (PS) or the lipopolysaccharides (LPS) of the bacteria. On the other hand, none of the MAbs reacting to bacterial proteins or glycoproteins showed prominent bactericidal activity. Further study revealed that the antigenic epitopes on either the capsular PS or LPS molecules were readily available for binding in intact bacteria, while the epitopes on proteins/glycoproteins were less accessible to the MAbs. Ourin vivostudy showed that four MAbs reactive to either the capsular PS or LPS were highly effective in protecting mice against lethal bacterial challenge. The result is compatible with that of ourin vitrostudy. The MAbs with the highest protective efficacy are those reactive to either the capsular PS or LPS of theBurkholderiabacteria.

scholarly journals Antigiardial Effect of Kramecyne in Experimental Giardiasis

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Leticia Eligio-García ◽  
Elida Pontifez-Pablo ◽  
Salúd Pérez-Gutiérrez ◽  
Enedina Jiménez-Cardoso
Keyword(s):  
Side Effects ◽  
High Efficiency ◽  
Morphological Changes ◽  
Lethal Dose ◽  
Expression Of Genes ◽  
Antigiardial Activity ◽  
Resistant Strains ◽  
Polymerase Chain

A variety of drugs are used in giardiasis treatment with different levels of efficiency, presence of side effects, and even formation of resistant strains, so that it is important to search new only-one-dose treatments with high efficiency and less side effects. Kramecyne, an anti-inflammatory compound isolated from methanolic extract ofKrameria cytisoides, does not present toxicity, even at doses of 5,000 mg/kg. The objective was to determine the antigiardial effect of kramecyne overGiardia intestinalis in vitroandin vivoand analyze the expression of genes ERK1, ERK2, and AK on kramecyne treated trophozoites by Real Time Polymerase Chain Reaction (RTPCR). The median lethal dose (LD50) was 40 μg/mL and no morphological changes were observed by staining with blue trypan and light microscopy; experimental gerbil infection was eliminated with 320 μg/Kg of weight. After treatment there were no differences between intestines from treated and untreated gerbils. Kramecyne did not have significant effect over ERK1 and AK, but there are differences in ERK2 expression (p=0.04). Results show antigiardial activity of kramecyne; however the mode of action is still unclear and the evaluation of ultrastructural damage and expressed proteins is an alternative of study to understand the action mechanism.

scholarly journals Reg4 defenses the intestine against Salmonella infection via binding the flagellin

2021 ◽  
Author(s):  
Yongtao Xiao ◽  
weipeng wang ◽  
Ying lu ◽  
xinbei tian ◽  
shanshan chen ◽  
...  
Keyword(s):  
Salmonella Typhimurium ◽  
Bactericidal Activity ◽  
Intestinal Inflammation ◽  
Bactericidal Effect ◽  
Intestinal Epithelia ◽  
Food Borne ◽  
Negative Impacts ◽  
First Time

Salmonella Typhimurium is gram-negative flagellated bacteria that can cause food-borne gastroenteritis and diarrhea in humans and animals. The regenerating islet-derived family member 4 (Reg4) is overexpressed in the gastrointestinal tract during intestinal inflammation. However, the role of Reg4 in the intestinal inflammation induced by Salmonella Typhimurium is largely unknown. In this study, we reported for the first time that Reg4 has bactericidal activity against intestinal infection caused by Salmonella Typhimurium. In vivo, Reg4 could reduce the colonization of Salmonella Typhimurium and attenuate intestinal inflammation in the Salmonella Typhimurium-infected model. Additionally, the mice with the epithelial cell specific deletion of Reg4 (Reg4ΔIEC) exhibited more severe intestinal inflammation and more colonization of Salmonella Typhimurium. However, the administration of Reg4 could reverse these negative impacts. In vitro, Reg4 protein was showed to inhibit the growth of Salmonella Typhimurium. We further investigate the function motif of Reg4 and find that the "HDPQK" motif in Reg4 is essential to its bactericidal activity. Reg4 exerted the bactericidal effect by binding to the flagellin of Salmonella Typhimurium and suppressing its motility, adhesion, and invasion to the intestinal epithelia. In conclusion, our findings identify Reg4 as a novel antimicrobial peptide against infection by Salmonella Typhimurium and explore its possible mechanism, which may be of great significance for developing novel agents against flagellated micro pathogens.

scholarly journals Bactericidal Activity of Octenidine to Various Genospecies of Borrelia burgdorferi, Sensu Lato Spirochetes in Vitro and in Vivo

2017 ◽  
Vol 66 (2) ◽  
pp. 259-263 ◽  
Author(s):  
Stanisława Tylewska-Wierzbanowska ◽  
Urszula Roguska ◽  
Grażyna Lewandowska ◽  
Tomasz Chmielewski
Keyword(s):  
Borrelia Burgdorferi ◽  
Bactericidal Activity ◽  
Reliable Method ◽  
Bactericidal Effect ◽  
Sensu Stricto ◽  
Borrelia Burgdorferi Sensu Lato ◽  
Bactericidal Action ◽  
Speed Up

The aim of our studies was to invent a reliable method for detection of bactericidal activity of disinfectants against Borrelia burgdorferi in suspension (in vitro) and in cell line cultures (in vivo). In the suspension method, 0.01 % octenidine at 20°C and 35°C was bactericidal to Borrelia afzeli; Borrelia garini, B. burgdorferi sensu stricto after 5 minutes treatment. Increase of the temperature to 35°C speed up the bactericidal effect to 1 minute. The bactericidal action of octenidine towards B. burgdorferi spirochetes growing in fibroblasts was less effective and needed a longer time to kill them than in the suspension.

scholarly journals Comparative bactericidal activity of ceftazidime against isolates of Pseudomonas aeruginosa as assessed in an in vitro pharmacodynamic model versus the traditional time-kill method.

1997 ◽  
Vol 41 (11) ◽  
pp. 2527-2532 ◽  
Author(s):  
M Manduru ◽  
L B Mihm ◽  
R L White ◽  
L V Friedrich ◽  
P A Flume ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Drug Exposure ◽  
Growth Conditions ◽  
Pharmacodynamic Model ◽  
Drug Concentrations ◽  
Bactericidal Activities ◽  
Time Kill ◽  
In Vivo Pharmacokinetics

Bactericidal activity, historically assessed by in vitro tests which employ fixed drug concentrations, may also be evaluated in in vitro pharmacodynamic models in which in vivo pharmacokinetics and bacterial growth conditions can be simulated. However, systematic comparisons between the two methods are lacking. We evaluated the bactericidal activities of ceftazidime, at two different concentration/MIC ratios (C/MICs), against 10 clinical isolates of Pseudomonas aeruginosa in a two-compartment model with continuous-infusion conditions and a 2-h half-life. These values were compared to those determined by traditional 24-h time-kill (TTK) methods at the same C/MICs. Bactericidal activities were compared by using area under the colony count-time curves. Antibiotic exposure (area under the drug concentration-time curve) was also evaluated. Although bactericidal activity appeared greater by the TTK method (P = 0.05), when it was normalized for drug exposure, these differences disappeared (P = 0.2). This disparity was likely due to differences in drug exposure in the TTK method and in the peripheral compartment of the model (site of bacteria) over the first 8 h of the experiment, during which the antibiotic accumulated to target concentrations. This suggests that the bactericidal effects with constant antibiotic concentrations are similar in the two methods; however, this may not hold true with fluctuating drug concentrations. Further, results from the pharmacodynamic model may theoretically be more relevant, as in vivo pharmacokinetics and bacterial growth conditions call be more faithfully simulated.

Natural and induced bactericidal activities in the hemolymph of the lobster, Homarus americanus: products of hemocyte–plasma interaction

1972 ◽  
Vol 18 (9) ◽  
pp. 1499-1509 ◽  
Author(s):  
James E. Stewart ◽  
B. M. Zwicker
Keyword(s):  
Bactericidal Activity ◽  
Heat Stability ◽  
Homarus Americanus ◽  
Temperature Dependent ◽  
A Value ◽  
Inactive Form ◽  
Probable Presence ◽  
Bactericidal Activities ◽  
Physiological Value

The salient features of this study of the enhancement of bactericidal activity in the hemolymph of the American lobster were as follows: (a) increase in response to a number of non-pathogens isolated from the lobster's intestinal tract (several pseudomonads, an Achromobacter and Sarcina lutea), (b) one isolate identified as Pseudomonas perolens was used for the bulk of the studies, (c) apparent bactericidal activity of the hemolymph increased severalfold with reduction of the pH of the assay system from the physiological value of 7.6 to a value of 6.0, (d) the extent of the enhancement in vivo was roughly proportional to the concentration of the vaccine, (e) the bactericidal activity's enhancement in vivo was temperature dependent, (f) heat-stability trials indicated the probable presence of more than one bactericidin, (g) the bactericidal principle(s) exists in vivo in an inactive form until activated by material contained within the hemocytes, (h) no protection against Gaffkya homari was conferred on the lobster by prior treatment with vaccines prepared from P. perolens, G. homari, or S. lutea.

scholarly journals Efficacy of Cethromycin, a New Ketolide, against Streptococcus pneumoniae Susceptible or Resistant to Erythromycin in a Murine Pneumonia Model

2006 ◽  
Vol 50 (9) ◽  
pp. 3033-3038 ◽  
Author(s):  
E. Azoulay-Dupuis ◽  
J. Mohler ◽  
J. P. Bédos ◽  
C. Barau ◽  
B. Fantin
Keyword(s):  
Streptococcus Pneumoniae ◽  
Survival Rates ◽  
Administration Route ◽  
Serum Protein Binding ◽  
In Vitro Activity ◽  
Serotype 1 ◽  
Resistant Strains ◽  
Immunocompetent Mice

ABSTRACT Cethromycin is a ketolide with in vitro activity against macrolide-sensitive and -resistant strains of Streptococcus pneumoniae. We compared its in vivo efficacy to erythromycin in a mouse model of acute pneumonia induced by two virulent clinical strains: a serotype 3 susceptible strain (P-4241) (MICs: erythromycin, 0.03 μg/ml; cethromycin, 0.015 μg/ml) and a serotype 1 strain resistant to erythromycin (P-6254; phenotypically MLSB constitutive) (MICs: erythromycin, 1,024 μg/ml; cethromycin, 0.03 μg/ml). Immunocompetent mice were infected with 105 CFU of each strain. Six treatments given either subcutaneously (s.c.) or per os (p.o.) at 12-h intervals were initiated at 6 or 12 h after infection. Against P-4241, cethromycin given s.c. at 25 or 12.5 mg/kg protected 100% of the animals, with lungs and blood completely cleared of bacteria. Given p.o., cethromycin maintained its efficacy with 100 and 86% survival at 25 and 12.5 mg/kg, respectively. Erythromycin, given s.c. at 50 or 37.5 mg/kg, provided 50 and 38% survival rates, respectively. Against P-6254, cethromycin was effective at 25 mg/kg (100% survival) regardless of the administration route, whereas only 25 and 8% of animals survived after a 75-mg/kg erythromycin treatment given s.c. and p.o., respectively. The serum protein binding levels of cethromycin were 94.8 and 88.5% after doses of 12.5 and 25 mg/kg, respectively. The higher in vivo activity of cethromycin compared to erythromycin could be explained by favorable pharmacokinetic/pharmacodynamic indexes against P-6254 but not against P-4241.

scholarly journals Evaluation of Antibacterial Activity of Essential Oil of Ziziphora clinopodioides and Achillea wilhelmsii on Antibiotic-resistant Strains of Staphylococcus aureus

2017 ◽  
Vol 2 (2) ◽  
pp. 49 ◽  
Author(s):  
Abolfazl Jafari-Sales ◽  
Ahmadreza Shahniani ◽  
Reza Fathi ◽  
Parviz Malekzadeh ◽  
Haedeh Mobaiyen ◽  
...  
Keyword(s):  
Essential Oil ◽  
Essential Oils ◽  
Bacterial Resistance ◽  
Medical Science ◽  
Antibacterial Properties ◽  
Bactericidal Effect ◽  
Antimicrobial Effects ◽  
Resistant Strains ◽  
Achillea Wilhelmsii

AbstractIntroduction and aim: The use of drugs to treat diseases led to the emergence of resistant strains of bacteria. Bacterial resistance to antibiotics is the most common problems in medical science. This study is done to evaluate the antimicrobial effects of Essential Oil of Ziziphora clinopodioides and Achillea wilhelmsii on against resistant clinical strains of Staphylococcus aureus.Material and methods: After collecting plants and validate its scientific name by botanists of Agricultural Organization and after drying in shade, Essential Oil of Ziziphora clinopodioides and Achillea wilhelmsii, extracted with steam distillation method by Clevenger and antimicrobial effects of Essential Oil by well diffusion on above mentioned bacteria were interpreted. Amount of Essential Oil were injected to gas chromatography linked to mass spectrometry (GC / Ms), and the amount and type compounds of the Essential Oils were identified.Results:The results showed that the extracted essence Essential Oil from the Ziziphora clinopodioides and Achillea wilhelmsii has bactericidal effect. In the obtained results by GC/Ms chromatography, in Ziziphora clinopodioides and Achillea wilhelmsii Essential Oils, 22 and 18 compounds, were identified respectively.Conclusion: The results of this study show that can be taken Ziziphora clinopodioides and Achillea wilhelmsii in herbals groups with antibacterial properties and after evaluating their effects in vivo condition and to identify the active ingredients, as an alternative to synthetic drugs that commonly used to treat infections are used.

Bactericidal Activity of Isothiocyanate against Pathogens on Fresh Produce†

2000 ◽  
Vol 63 (1) ◽  
pp. 25-30 ◽  
Author(s):  
CHIA-MIN LIN ◽  
JEONGMOK KIM ◽  
WEN-XIAN DU ◽  
CHENG-I WEI
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Bactericidal Activity ◽  
Bactericidal Effect ◽  
Escherichia Coli O157 ◽  
Methyl Isothiocyanate ◽  
E Coli ◽  
Log Reduction ◽  
Iceberg Lettuce ◽  
Resistant Strains

The bactericidal activity of allyl and methyl isothiocyanate (AITC and MITC) was tested with a rifampicin-resistant strain of Salmonella Montevideo and streptomycin-resistant strains of Escherichia coli O157:H7 and Listeria monocytogenes Scott A. Iceberg lettuce inoculated with high (107 to 108 CFU/g) and low (103 to 104 CFU/g) concentrations of bacterial pathogens was treated with AITC and MITC in sealed containers at 4°C for 4 days. AITC showed stronger bactericidal activity than MITC against E. coli O157:H7 and Salmonella Montevideo, whereas MITC showed stronger activity against L. monocytogenes than E. coli O157:H7 and Salmonella Montevideo. Up to 8-log reduction occurred with E. coli O157:H7 and Salmonella Montevideo on lettuce following treatment with vapor generated from 400 μl of AITC for 2 and 4 days, respectively. AITC was used to treat tomatoes inoculated with Salmonella Montevideo on stem scars and skin and apples inoculated with E. coli O157:H7 on stem scars. The bactericidal effect of AITC varied with bacteria species and exposure time. Salmonella Montevideo inoculated on tomato skin was more sensitive to AITC than that on stem scars. Treatment with vapor generated from 500 μl of AITC caused an 8-log reduction in bacteria on tomato skin but only a 5-log reduction on tomato stem scars. The bactericidal activity of AITC was weaker for E. coli O157:H7 on apple stem scars; only a 3-log reduction in bacteria occurred when 600 μl of AITC was used.

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