scholarly journals In Vitro Susceptibilities of Bordetella pertussis and Bordetella parapertussis to Two Ketolides (HMR 3004 and HMR 3647), Four Macrolides (Azithromycin, Clarithromycin, Erythromycin A, and Roxithromycin), and Two Ansamycins (Rifampin and Rifapentine)

1998 ◽  
Vol 42 (4) ◽  
pp. 965-966 ◽  
Author(s):  
Jörg E. Hoppe ◽  
André Bryskier
Keyword(s):  
Bordetella Pertussis ◽  
Active Compound ◽  
Bordetella Parapertussis ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution ◽  
Horse Blood ◽  
Erythromycin A

ABSTRACT When tested by agar dilution on Mueller-Hinton agar supplemented with 5% horse blood, the ketolides HMR 3004 and HMR 3647 were slightly more active (MIC at which 90% of the isolates were inhibited [MIC90], 0.03 μg/ml) against Bordetella pertussis than azithromycin, clarithromycin, erythromycin A, and roxithromycin. Azithromycin (MIC90, 0.06 μg/ml) was the most active compound against B. parapertussis. Rifampin and rifapentine were considerably less active.

scholarly journals In vitro susceptibilities of Bordetella pertussis and Bordetella parapertussis to four fluoroquinolones (levofloxacin, d-ofloxacin, ofloxacin, and ciprofloxacin), cefpirome, and meropenem.

1996 ◽  
Vol 40 (3) ◽  
pp. 807-808 ◽  
Author(s):  
J E Hoppe ◽  
E Rahimi-Galougahi ◽  
G Seibert
Keyword(s):  
Bordetella Pertussis ◽  
Clinical Isolates ◽  
Bordetella Parapertussis ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution ◽  
Horse Blood

The in vitro activities of levofloxacin, ofloxacin, d-ofloxacin, ciprofloxacin, cefpirome, and meropenem against 34 clinical isolates each of Bordetella pertussis and Bordetella parapertussis were determined by agar dilution on Mueller-Hinton agar supplemented with 5% horse blood. Levofloxacin was as active as ciprofloxacin against both species (MIC, 0.06 microgram/ml) and more active than ofloxacin and d-ofloxacin. Cefpirome was more active against B. pertussis (MIC, 1.0 microgram/ml) than against B. parapertussis (MIC, > 2 micrograms/ml), while the reverse was true for meropenem (MIC, 2.0 micrograms/ml against B. pertussis and 1.0 microgram/ml against B. parapertussis).

scholarly journals Antimicrobial susceptibility testing of 230 Helicobacter pylori strains: importance of medium, inoculum, and incubation time.

1997 ◽  
Vol 41 (12) ◽  
pp. 2634-2639 ◽  
Author(s):  
S H Hartzen ◽  
L P Andersen ◽  
A Bremmelgaard ◽  
H Colding ◽  
M Arpi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Incubation Time ◽  
Susceptibility Testing ◽  
Development Of Resistance ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution ◽  
Horse Blood ◽  
Preliminary Study ◽  
H Pylori

No standardized method of susceptibility testing for Helicobacter pylori is currently available, so before a large agar dilution study comprising 230 H. pylori strains belonging to more than 80 genetically different groups was initiated, we performed a relatively small preliminary study to determine the influences of medium, inoculum density, and incubation time. Seven media were investigated and were primarily evaluated on the basis of their abilities to support growth both semiquantitatively and qualitatively; Iso-Sensitest agar supplemented with 10% horse blood was found to be well suited for the purpose; this was closely followed by Mueller-Hinton agar with 10% horse blood, Mueller-Hinton with 10% sheep blood, and finally, 7% lysed horse blood agar. Investigations of two inoculum densities and two incubation times resulted in recommendations for the use of 10(9) CFU/ml (10[6] CFU/spot) as the inoculum and 72 h as the incubation time. A modest inoculum effect was noted for amoxicillin and metronidazole. By the methodology derived from our preliminary study, the susceptibilities of 230 H. pylori strains to six antibiotics were subsequently determined. The results were generally in accord with those of others, and apart from metronidazole, the MIC of which for approximately 25% of the strains tested was >8 microg/ml, resistance was low in Denmark. The situation might, however, quickly change when and if the number of indications for antibiotic therapy for H. pylori infections increase. Consequently, susceptibility testing of all H. pylori strains is recommended in order to survey the development of resistance, and in our hands the described methodology was relatively easy to perform and the results were easy to read.

scholarly journals 1455. Potential Mechanisms of Cefiderocol MIC Increase in Enterobacterales in In Vitro Resistance Acquisition Studies

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S730-S730
Author(s):  
Yoshinori Yamano ◽  
Rio Nakamura ◽  
Miki Takemura ◽  
Roger Echols
Keyword(s):  
Iron Transport ◽  
Resistance Mechanisms ◽  
Altered Expression ◽  
Carbapenem Resistant ◽  
Mueller Hinton ◽  
Two Component ◽  
Mueller Hinton Agar ◽  
Related Proteins

Abstract Background Cefiderocol (CFDC) is a novel siderophore, iron-chelating cephalosporin, which is transported into bacteria via iron transporters. CFDC has potent in vitro and in vivo activity against all aerobic Gram-negative bacteria, including carbapenem-resistant strains. To date, clinical isolates with cefiderocol MIC >4 µg/mL have been found infrequently, in which the presence of a few β-lactamases or altered iron transport was found. We investigated potential new mechanisms causing CFDC MIC increases in non-clinical studies. Methods The mutation positions were determined by whole genome sequencing using four K. pneumoniae mutants including two KPC producers and one NDM producer that had shown CFDC MIC increases in previous in vitro resistance-acquisition studies. The mutant strains were obtained at the frequency of 10-7 to < 10-8 by spreading bacteria on standard Mueller‒Hinton agar medium containing CFDC at concentrations of 10× MIC, with or without apo-transferrin (20 μg/mL). CFDC MIC was determined by broth microdilution using iron-depleted cation-adjusted Mueller-Hinton broth based on Clinical and Laboratory Standards Institute guidelines. The emergence of MIC increase mutants was also assessed by in vitro chemostat models under humanized plasma pharmacokinetic exposures of CFDC. Results The possible resistance mechanisms were investigated. Mutation of baeS or envZ, sensors of two-component regulation systems, were found in three or two mutants among the tested four isolates, respectively, and caused the MIC to increase by 4–32-fold. The altered expression level of specific genes by the baeS or envZ mutation could affect CFDC susceptibility, but the specific genes have not been identified. In addition, the mutation of exbD, an accessory protein related to iron transport, was identified in one case and caused the MIC to increase by >8-fold. In vitro chemostat studies using two isolates (one NDM producer and one KPC producer) showed no resistance acquisition during 24-hour exposure. Table. Overview of mutation emergence in five isolates of K. pneumoniae Conclusion The mutation of two-component regulation systems (BaeSR and OmpR/EnvZ) and iron transport-related proteins were shown to be possible mechanisms causing CFDC MIC increases, but these mutants did not appear under human exposures. Disclosures Yoshinori Yamano, PhD, Shionogi & Co., Ltd. (Employee) Rio Nakamura, BSc, Shionogi & Co., Ltd. (Employee) Miki Takemura, MSc, Shionogi & Co., Ltd. (Employee) Roger Echols, MD, Shionogi Inc. (Consultant)

scholarly journals Helicobacter pylori: Primary Susceptibility to Clarithromycin in vitro in Nova Scotia

1997 ◽  
Vol 11 (4) ◽  
pp. 298-300 ◽  
Author(s):  
Linda M Best ◽  
David JM Haldane ◽  
Gregory S Bezanson ◽  
Sander JO Veldhuyzen
Keyword(s):  
Helicobacter Pylori ◽  
Nova Scotia ◽  
Antimicrobial Agents ◽  
Primary Resistance ◽  
Susceptibility Data ◽  
Mueller Hinton ◽  
Agar Diffusion Test ◽  
Mueller Hinton Agar ◽  
H Pylori

Resistance to antimicrobial agents is a major determinant of the efficacy of regimens to eradicateHelicobacter pylori. Clarithromycin (CLA) has become one of the most commonly used antibiotics for treatment ofH pyloriinfection. In this study, the rate of primary resistance to CLA inH pyloriisolated from patients was determined. One hundred sixty-two strains were recovered from patients before treatment. Strains were grown and inoculated onto Mueller-Hinton agar with 7% sheep blood. CLA epsilometer gradient agar diffusion test (E test) strips were used to test for susceptibility. Appropriate control organisms were tested to validate the assay. Plates were incubated at 37°C in a microaerophilic atmosphere for up to five days. E test results were easy to interpret. Strains were considered resistant if the minimum inhibitory concentration (MIC) was 2 µg/mL or greater. Three strains were resistant (two strains with MIC 8 µg/mL and one strain with MIC 12 µg/mL), and 159 strains were sensitive (MICs ranged from less than 0.016 to 0.38 µg/mL). Ninety per cent of the strains had MICs of 0.023 µg/mL. Primary resistance was 1.8%. These susceptibility data support the use of CLA for the treatment ofH pyloriin the Nova Scotia population.

scholarly journals In vitro activity of RU 64004, a new ketolide antibiotic, against gram-positive bacteria.

1997 ◽  
Vol 41 (5) ◽  
pp. 1196-1202 ◽  
Author(s):  
T Schülin ◽  
C B Wennersten ◽  
R C Moellering ◽  
G M Eliopoulos
Keyword(s):  
Vitro Activity ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Agar Dilution ◽  
Resistant Strains ◽  
Erythromycin A

The comparative in vitro activity of RU 64004 (also known as HMR 3004), a new ketolide antibiotic, was tested by agar dilution against approximately 500 gram-positive organisms, including multiply resistant enterococci, streptococci, and staphylococci. All streptococci were inhibited by < or = 1 microg of RU 64004 per ml. The ketolide was more potent than other macrolides against erythromycin A-susceptible staphylococci and was generally more potent than clindamycin against erythromycin A-resistant strains susceptible to this agent. Clindamycin-resistant staphylococci (MIC, > 128 microg/ml) proved resistant to the ketolide, but some erythromycin A- and clindamycin-resistant enterococci remained susceptible to RU 64004.

scholarly journals Uji Daya Hambat Isolat Actinomycetes sebagai Antibakteri terhadap Pertumbuhan Pseudomonas aeruginosa ATCC 27853 secara In Vitro

2021 ◽  
Vol 10 (1) ◽  
pp. 16
Author(s):  
Saskia Arientika Wahyuningrum ◽  
Meiskha Bahar ◽  
Andri Pramesyanti Pramono
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibition Zone ◽  
Diffusion Method ◽  
P Value ◽  
Gram Positive Bacteria ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
The One ◽  
One Way Anova

Pneumonia is a lung parenchymal infection caused by Pseudomonas aeruginosa.It is Gram negative bacteria that have developed antibiotic resistance. Actinomycetes are Gram-positive bacteria that produce secondary metabolites which have the ability as antimicrobial. Objectives: To identified the ability of Actinomycetes isolates to inhibit the growth of the bacterium Pseudomonas aeruginosa ATCC 27853. The samples in this experiment were from Kebun Raya Bogor that had been rejuvenated on Starch Casein Agar (SCA). Methods: Six dilution series 10-1; 10-2; 10-3; 10-4; 10-5; 10-6 Actinomycetes isolates were used to observe the inhibition zone of P.aeruginosa growth on Mueller Hinton Agar (MHA) media by diffusion method. Results: The effective incubation time occurred at 24 hours, and then it resulted in the average clear zone diameter of 14.70 mm, 10.57 mm, 8.53 mm, 8.47 mm, 6.97 mm, and 5.30 mm. The results of the One – Way Anova test with p-value = 0.000 (p < 0.005) showed some differences at each concentration to inhibit the growth of P.aeruginosa ATCC 27853 at 24 hours incubation period. Conclusion: The most effective concentration of Actinomycetes isolates that can potentially be antibacterial was the concentration of 10-1 with potential solid inhibitory power.Keywords: Actinomycetes, antibacterial, Pseudomonas aeruginosa

scholarly journals In vitro evaluation of antibacterial activity in ethanolic extract of whole plant Sphaeranthus indicus Linn.

2020 ◽  
Vol 9 (11) ◽  
pp. 1730
Author(s):  
Preeja K. Sundaresan ◽  
Kala P. Kesavan
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Resistance ◽  
Ethanolic Extract ◽  
Human Pathogens ◽  
Traditional System ◽  
Whole Plant ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Sphaeranthus Indicus

Background: Sphaeranthus indicus Linn is a widely used medicinal plant in Indian traditional system of medicine against human pathogens. Alarming bacterial resistance is urging scientist to search for newer anti-microbial substances from the medicinal plants. The objective of the study was to evaluate the antibacterial activity of ethanolic extract of the whole plant Sphaeranthus indicus Linn (Asteraceae).Methods: The antibacterial activity of ethanolic extract of whole plant of Sphaeranthus indicus Linn was done against Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis and Staphylococcus aureus in Mueller Hinton Agar (MHA) and compared with ciprofloxacin as standard by disc diffusion method.Results: The study revealed that there was no zone of inhibition in doses of 100 mcg, 200 mcg and 300 mcg of ethanolic whole plant extract of Sphaeranthus indicus in MHA plates compared with ciprofloxacin 30 mcg.Conclusions: Ethanolic extract of Sphaeranthus indicus does not have antibacterial activity. Further studies are needed in different extracts and parts of the plant. Simultaneous studies can be done in different places to evaluate environmental factors and regional variations.

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