EUCAST MIC broth microdilution of Streptococcus spp. and Haemophilus influenzae. Evaluation of broth with and without beta-NAD and with different concentrations of lysed horse blood

2016 ◽  
Author(s):  
Erika Matuschek
Keyword(s):  
Haemophilus Influenzae ◽  
Broth Microdilution ◽  
Horse Blood ◽  
Lysed Horse Blood

scholarly journals Effect of Polysorbate 80 on Oritavancin Binding to Plastic Surfaces: Implications for Susceptibility Testing

2008 ◽  
Vol 52 (5) ◽  
pp. 1597-1603 ◽  
Author(s):  
Francis F. Arhin ◽  
Ingrid Sarmiento ◽  
Adam Belley ◽  
Geoffrey A. McKay ◽  
Deborah C. Draghi ◽  
...  
Keyword(s):  
Clinical Isolates ◽  
Polysorbate 80 ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Drug Concentrations ◽  
Broth Microdilution Method ◽  
Horse Blood ◽  
Lysed Horse Blood ◽  
Susceptibility Assay

ABSTRACT Oritavancin, a semisynthetic lipoglycopeptide with activity against gram-positive bacteria, has multiple mechanisms of action, including the inhibition of cell wall synthesis and the perturbation of the membrane potential. Approved guidelines for broth microdilution MIC assays with dalbavancin, another lipoglycopeptide, require inclusion of 0.002% polysorbate 80. To investigate the potential impact of polysorbate 80 on oritavancin susceptibility assays, we quantified the recovery of [14C]oritavancin from susceptibility assay plates with and without polysorbate 80 and examined the effect of the presence of polysorbate 80 on the oritavancin MICs for 301 clinical isolates from the genera Staphylococcus, Enterococcus, and Streptococcus. In the absence of polysorbate 80, [14C]oritavancin was rapidly lost from solution in susceptibility assay test plates: 9% of the input drug was recovered in broth at 1 h when [14C]oritavancin was tested at 1 μg/ml. Furthermore, proportionately greater losses were observed at lower oritavancin concentrations, suggesting saturable binding of oritavancin to surfaces. The inclusion of 0.002% polysorbate 80 or 2% lysed horse blood permitted the recovery of 80 to 100% [14C]oritavancin at 24 h for all drug concentrations tested. Concordantly, oritavancin MIC90s for streptococcal isolates, as determined in medium containing 2% lysed horse blood, were identical with and without polysorbate 80. In stark contrast, polysorbate 80 reduced the oritavancin MIC90s by 16- to 32-fold for clinical isolates of enterococci and staphylococci, which are typically cultured without blood. The results presented here provide evidence that the MIC data for oritavancin in the current literature significantly underestimate the potency of oritavancin in vitro. Moreover, the combination of data from MIC and [14C]oritavancin recovery studies supports the revision of the oritavancin broth microdilution method to include polysorbate 80 throughout the assay.

scholarly journals Myeloperoxidase Selectively Binds and Selectively Kills Microbes

2010 ◽  
Vol 79 (1) ◽  
pp. 474-485 ◽  
Author(s):  
Robert C. Allen ◽  
Jackson T. Stephens
Keyword(s):  
Streptococcus Pyogenes ◽  
Direct Evidence ◽  
Minimal Bactericidal Concentration ◽  
Viridans Streptococci ◽  
E Coli ◽  
Horse Blood ◽  
Valid Comparison ◽  
Relationship Of ◽  
The Relationship ◽  
Lysed Horse Blood

ABSTRACTMyeloperoxidase (MPO) is reported to selectively bind to bacteria. The present study provides direct evidence of MPO binding selectivity and tests the relationship of selective binding to selective killing. The microbicidal effectiveness of H2O2and of OCl−was compared to that of MPO plus H2O2. Synergistic microbicidal action was investigated by combiningStreptococcus sanguinis, a H2O2-producing microbe showing low MPO binding, with high-MPO-bindingEscherichia coli,Staphylococcus aureus, orPseudomonas aeruginosawithout exogenous H2O2, with and without MPO, and with and without erythrocytes (red blood cells [RBCs]). Selectivity of MPO microbicidal action was conventionally measured as the MPO MIC and minimal bactericidal concentration (MBC) for 82 bacteria includingE. coli,P. aeruginosa,S. aureus,Enterococcus faecalis,Streptococcus pyogenes,Streptococcus agalactiae, and viridans streptococci. Both H2O2and OCl−destroyed RBCs at submicrobicidal concentrations. Nanomolar concentrations of MPO increased H2O2microbicidal action 1,000-fold. Streptococci plus MPO produced potent synergistic microbicidal action against all microbes tested, and RBCs caused only a small decrease in potency without erythrocyte damage. MPO directly killed H2O2-producingS. pyogenesbut was ineffective against non-H2O2-producingE. faecalis. The MPO MICs and MBCs forE. coli,P. aeruginosa, andS. aureuswere significantly lower than those forE. faecalis.The streptococcal studies showed much higher MIC/MBC results, but such testing required lysed horse blood-supplemented medium, thus preventing valid comparison of these results to those for the other microbes.E. faecalisMPO binding is reportedly weak compared to binding ofE. coli,P. aeruginosa, andS. aureusbut strong compared to binding of streptococci. Selective MPO binding results in selective killing.

scholarly journals Activities of Trovafloxacin, Gatifloxacin, Clinafloxacin, Sparfloxacin, Levofloxacin, and Ciprofloxacin against Penicillin-Resistant Streptococcus pneumoniae in an In Vitro Infection Model

2000 ◽  
Vol 44 (3) ◽  
pp. 598-601 ◽  
Author(s):  
Ellie Hershberger ◽  
Michael J. Rybak
Keyword(s):  
Streptococcus Pneumoniae ◽  
Fibrin Clot ◽  
Infection Model ◽  
Significant Activity ◽  
Time Curve ◽  
Horse Blood ◽  
Bactericidal Activities ◽  
Lysed Horse Blood ◽  
Fibrin Clots

ABSTRACT We adapted an in vitro pharmacodynamic model of infection to incorporate infected fibrin clots. The bactericidal activities of various fluoroquinolones against two strains of penicillin-resistantStreptococcus pneumoniae were studied over a 48-h period. Bacteria were prepared in Muller-Hinton broth by using colonies from a 24-h tryptic soy agar plus 5% sheep blood plate and were added to a mixture of cryoprecipitate (80%) and thrombin (10%) to achieve approximately 106 CFU of organism per fibrin clot. The fibrin clots were suspended into the models and removed, in triplicate, at various time points over 48 h. Control models were also conducted to characterize the growth of S. pneumoniae in the growth medium without antibiotic. Trovafloxacin, gatifloxacin, clinafloxacin, sparfloxacin, levofloxacin, and ciprofloxacin were administered to simulate their pharmacokinetic profiles in humans. Fibrin clot samples were also plated onto antibiotic-containing tryptic soy agar plus 5% lysed horse blood to detect resistance. The newer fluoroquinolones demonstrated better activity than ciprofloxacin against both isolates. In conclusion, the newer quinolones demonstrated significant activity against penicillin-resistant S. pneumoniae, with standard dosing resulting in area under the concentration-time curve/MIC ratios and peak concentration/MIC ratios that resulted in 99.9% killing against these isolates.

scholarly journals THE IMMUNOBIOLOGICAL ACTIVITY OF THE COMPLEX PREPARATION AGAINST HAEMOPHILUS INFLUENZAE INFECTION

2019 ◽  
Vol 1 (1) ◽  
pp. 111-115
Author(s):  
N. E. Yastrebova ◽  
M. M. Tokarskaya ◽  
S. I. Elkina ◽  
N. N. Ovechko ◽  
S. A. Baranovskaya
Keyword(s):  
Haemophilus Influenzae ◽  
Capsular Polysaccharide ◽  
Infectious Agent ◽  
Enzyme Linked Immunosorbent Assay ◽  
Control Group ◽  
Infectious Process ◽  
Complex Preparation ◽  
Horse Blood ◽  
Almost All ◽  
Number Of Bacteria

Aim.To study the immunobiological activity of the complex preparation for Haemophilus influenzae infections prevention.Materials and methods.We used the complex preparation, containing 1 mcg of lipooligosaccharide and 10 mcg of protein-containing fraction, lipooligosaccharide and protein-containing fraction monopreparations, and capsular polysaccharide preparation. For studying cross-protective activity of the complex preparation white outbread mouses (weight 14-16 g) were intramuscularly immunized with a dose 0,5 ml. 10 days later the animals were inoculated with H. influenzae encapsulated and non-typed strains culture inoculum in a dose 5*109 microbial cells/mouse. The immunized animals specific antibodies level was determined by means of indirect enzyme-linked immunosorbent assay (ELISA). For studying complex preparation’s influence on the development of the infectious process immunized mouses were intranasally inoculated with H. influenzae encapsulated and non-encapsulated strains. The mouses dissections were performed in 3, 24 and 72 hours after inoculation. Sterile samples (lung tissue) were homogenized, titrated and plated onto 5% horse blood agar; then after 18-20 growth hours we counted the number of colonies and recalculated its number for one mouse.Results.Our investigations have shown that the complex preparation provided 90-100% animals’ defence from used in this experiment infectious agent strains. Mouses immunization with the preparation induced significant increase in the level of antibodies, revealed by means of indirect ELISA. Beginning with the third day after intranasal inoculation there was a pathogen multiplica112 tion in control group mouses lungs. In the same time immunized mouses had almost indetectable number of bacteria. Almost all animals from control group contained pathogen in lymph nodes and mesentery; though pathogen’s presence in immune mouses viscera was rather occasional.Conclusion. The complex preparation protected animals from all H. influenzae strains, used in our experiment. The dynamic of the infectious process directly depended on the development of immune response on the complex preparation injection. 

The Antimicrobial Implications of the Pharmacokinetics of Cotrimoxazole in CAPO Patients

1987 ◽  
Vol 7 (2) ◽  
pp. 74-77 ◽  
Author(s):  
Otegbola Ojo ◽  
Colina Jones ◽  
Donald L. Stevens
Keyword(s):  
Bactericidal Activity ◽  
Optimal Combination ◽  
Single Organism ◽  
Staphylococcus Epidermis ◽  
Spent Dialysate ◽  
Agar Dilution ◽  
Horse Blood ◽  
Antimicrobial Synergy ◽  
Susceptibility Tests ◽  
Lysed Horse Blood

Cotrimoxazole (TMP/SMX) has been used to treat continuous ambulatory peritoneal dialysis (CAPD) associated peritonitis. It is considered bactericidal for some species. The most common single organism responsible for this type of peritonitis is Staph. epidermidis (SE). When the drug is given orally, the typical ratio of TMP to SMX achieved in the peritoneal fluid is 1:5, which is different from the optimal combination for antimicrobial synergy of 1:19. This study investigated the antimicrobial activity of TMP alone and TMP/SMX by agar dilution at ratios of 1:19, 1:10 and 1:5 against 99 strains of Staphylococcus epidermis (SE). The majority of strains were susceptible to TMP and to all ratios of TMP/SMX by the routine agar dilution methods. We studied the bactericidal activity of TMP/SMX against one strain each of SE and of Staph. aureus (SA) in pooled uninfected spent dialysate by killing curve experiments. TMP at concentrations of 0.5 to 2.0 μg/ml was bacteriostatic. TMP/SMX became slowly bactericidal when 5 % lysed horse blood, a source of thymidine phosphorylase, was added to the dialysate. It is concluded that susceptibility tests of inhibition do not predict bactericidal activity of TMP/SMX in recovered dialysate. Inhibition of TMP/ SMX is most likely due to thymidine present in dialysate. TMP alone was as effective against SE as TMP/ SMX. Until it is shown that bactericidal activity is not required for cure of CAPD-related peritonitis, cotrimoxazole should not be used routinely for its treatment.

scholarly journals In vitro activity of BAY 12-8039, a novel 8-methoxyquinolone, compared to activities of six fluoroquinolones against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis.

1997 ◽  
Vol 41 (7) ◽  
pp. 1594-1597 ◽  
Author(s):  
A B Brueggemann ◽  
K C Kugler ◽  
G V Doern
Keyword(s):  
Streptococcus Pneumoniae ◽  
Haemophilus Influenzae ◽  
Moraxella Catarrhalis ◽  
Ambient Air ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Broth Microdilution ◽  
Agar Dilution ◽  
Resistant Strains

The in vitro activity of a novel 8-methoxyquinolone, BAY 12-8039, against recent clinical isolates of Streptococcus pneumoniae (n = 404), Haemophilus influenzae (n = 330), and Moraxella catarrhalis (n = 250) was evaluated. Activity was compared to those of six other fluoroquinolones: ciprofloxacin, clinafloxacin, levofloxacin, ofloxacin, sparfloxacin and trovafloxacin. BAY 12-8039 and clinafloxacin had the highest levels of activity against S. pneumoniae, both with a MIC at which 90% of the isolates were inhibited (MIC90) of 0.06 microg/ml. Trovafloxacin and sparfloxacin were the next most active agents versus S. pneumoniae (MIC90s = 0.12 microg/ml). No differences in activity against penicillin-susceptible, -intermediate, or -resistant strains of S. pneumoniae were noted for any of the fluoroquinolones tested. MIC90s for the seven fluoroquinolones ranged from 0.008 to 0.06 microg/ml versus H. influenzae and from 0.008 to 0.12 microg/ml for M. catarrhalis. The MICs for two strains of S. pneumoniae and one strain of H. influenzae were noted to be higher than those for the general population of organisms for all of the fluoroquinolones tested. Finally, the activity of BAY 12-8039 versus S. pneumoniae was found to be diminished when MIC determinations were performed with incubation of agar dilution plates or broth microdilution trays in 5 to 7% CO2 versus ambient air.

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