scholarly journals Evaluation of the antimicrobial activity of ridinilazole and six comparators against Chinese, Japanese and South Korean strains ofClostridioides difficile

2020 ◽  
Author(s):  
Deirdre A Collins ◽  
Yuan Wu ◽  
Kazuhiro Tateda ◽  
Hee-Jung Kim ◽  
Richard J Vickers ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
South Korea ◽  
Antimicrobial Agents ◽  
Specific Activity ◽  
Fluoroquinolone Resistance ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Clostridioides Difficile ◽  
Ongoing Surveillance ◽  
And Control

Abstract Background Clostridioides difficile is the most common cause of antimicrobial-associated diarrhoea in high-income countries. Fluoroquinolone resistance enabled the emergence and intercontinental spread of the epidemic ribotype (RT) 027 strain ofC. difficile in the early 2000s. Despite frequent inappropriate antimicrobial use in Asia, RT 027 is rarely isolated in the region, but the often fluoroquinolone- and clindamycin-resistant RT 017 strain predominates. Objectives This study evaluated the antimicrobial activity of ridinilazole, a novel antimicrobial agent with highly specific activity forC. difficile, against clinical strains ofC. difficile from Asia. Methods C. difficile strains from Japan (n = 64), South Korea (n = 32) and China (n = 44) were tested by the agar dilution method for susceptibility to ridinilazole, metronidazole, vancomycin, clindamycin, moxifloxacin, rifaximin and fidaxomicin. Results All strains were susceptible to ridinilazole, with low MICs (0.03–0.25 mg/L). Several strains showed multiresistance profiles, particularly RT 017 (100% clindamycin resistant, 91.3% moxifloxacin resistant, 82.6% rifaximin resistant) and RT 369 (94.4% clindamycin resistant, 100% moxifloxacin resistant). Rifaximin resistance was absent in all strains from Japan. Multiresistance to clindamycin, moxifloxacin and rifaximin was found in 19 RT 017 strains (from China and South Korea), 2 RT 001 strains (South Korea) and 1 RT 046 strain (South Korea). Conclusions Ridinilazole showed potent activity against a range of AsianC. difficile strains, which otherwise frequently displayed resistance to several comparator antimicrobial agents. Ongoing surveillance of antimicrobial resistance profiles is required to monitor and control the spread of resistant strains.

scholarly journals Antimicrobial activity of honeys from two stingless honeybee species and Apis mellifera (Hymenoptera: Apidae) against pathogenic microorganisms

2014 ◽  
Vol 44 (2) ◽  
pp. 287-290 ◽  
Author(s):  
Carolinie Batista Nobre da Cruz ◽  
Fabio Alessandro Pieri ◽  
Gislene Almeida Carvalho-Zilse ◽  
Patrícia Puccinelli Orlandi ◽  
Carlos Gustavo Nunes-Silva ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Apis Mellifera ◽  
Antimicrobial Agents ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Therapeutic Approaches ◽  
E Coli ◽  
Agar Dilution ◽  
Amazonas State

Honeys are described possessing different properties including antimicrobial. Many studies have presented this activity of honeys produced by Apis mellifera bees, however studies including activities of stingless bees honeys are scarce. The aim of this study was to compare the antimicrobial activity of honeys collected in the Amazonas State from Melipona compressipes, Melipona seminigra and Apis mellifera against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Chromobacterium violaceum, and Candida albicans. Minimum inhibitory concentrations were determined using the agar dilution method with Müller-Hinton agar (for bacteria) or Saboraud agar (for yeast). Staphylococcus aureus and E. faecalis were inhibited by all honeys at concentrations below 12%, while E. coli and C. violaceum were inhibited by stingless bee honeys at concentrations between 10 and 20%. A. mellifera honey inhibited E. coli at a concentration of 7% and Candida violaceum at 0.7%. C. albicans were inhibited only with honey concentrations between 30 and 40%. All examined honey had antimicrobial activity against the tested pathogens, thus serving as potential antimicrobial agents for several therapeutic approaches.

scholarly journals Antimicrobial Susceptibilities of Clostridium difficile Isolates from 12 Asia-Pacific Countries in 2014 and 2015

2020 ◽  
Vol 64 (7) ◽  
Author(s):  
Tanya Lew ◽  
Papanin Putsathit ◽  
Kyung Mok Sohn ◽  
Yuan Wu ◽  
Kentaro Ouchi ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Asia Pacific ◽  
Fluoroquinolone Resistance ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Content Type ◽  
Amoxicillin Clavulanate ◽  
Ongoing Surveillance ◽  
Susceptibility Profiles ◽  
Hospital Acquired

ABSTRACT Clostridium (Clostridioides) difficile causes toxin-mediated diarrhea and pseudomembranous colitis, primarily among hospital inpatients. Outbreaks of C. difficile infection (CDI) have been caused by strains with acquired antimicrobial resistance, particularly fluoroquinolone resistance, including C. difficile ribotype (RT) 027 in North America and Europe and RT 017, the most common strain in Asia. Despite being the most common cause of hospital-acquired infection in high-income countries, and frequent misuse of antimicrobials in Asia, little is known about CDI in the Asia-Pacific region. We aimed to determine the antimicrobial susceptibility profiles of a collection of C. difficile isolates from the region. C. difficile isolates (n = 414) from a 2014 study of 13 Asia-Pacific countries were tested for susceptibility to moxifloxacin, amoxicillin-clavulanate, erythromycin, clindamycin, rifaximin, metronidazole, vancomycin, and fidaxomicin according to the Clinical and Laboratory Standards Institute’s agar dilution method. All isolates were susceptible to metronidazole, vancomycin, amoxicillin-clavulanate, and fidaxomicin. Moxifloxacin resistance was detected in all countries except Australia, all RT 369 and QX 239 strains, and 92.7% of RT 018 and 70.6% of RT 017 strains. All C. difficile RT 012, 369, and QX 239 strains were also resistant to erythromycin and clindamycin. Rifaximin resistance was common in RT 017 strains only (63.2%) and was not detected in Australian, Japanese, or Singaporean isolates. In conclusion, antimicrobial susceptibility of C. difficile varied by strain type and by country. Multiresistance was common in emerging RTs 369 and QX 239 and the most common strain in Asia, RT 017. Ongoing surveillance is clearly warranted.

scholarly journals Evaluation of the Antimicrobial Activity of Some Components of the Essential Oils of Plants Used in the Traditional Medicine of the Tehuacán-Cuicatlán Valley, Puebla, México

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 295
Author(s):  
Sebastián Candelaria-Dueñas ◽  
Rocío Serrano-Parrales ◽  
Marisol Ávila-Romero ◽  
Samuel Meraz-Martínez ◽  
Julieta Orozco-Martínez ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oils ◽  
Qualitative Evaluation ◽  
Bactericidal Effect ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
E Coli ◽  
Gram Positive Bacteria ◽  
Diffusion Technique ◽  
Agar Dilution

In Tehuacán-Cuicatlán valley (Mexico), studies have been carried out on the essential oils of medicinal plants with antimicrobial activity and it was found that they present compounds in common such as: α-pinene, β-pinene, carvacrol, eugenol, limonene, myrcene, ocimene, cineole, methyl salicylate, farnesene, and thymol. The goal of this study was to assess the antimicrobial activity of essential oils’ compounds. The qualitative evaluation was carried out by the Kirby Baüer agar diffusion technique in Gram-positive bacteria (11 strains), Gram-negative bacteria (18 strains), and yeasts (8 strains). For the determination of the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), the agar dilution method was used. All the evaluated compounds presented antimicrobial activity. The compounds eugenol and carvacrol showed the largest inhibition zones. Regarding yeasts, the compounds ocimene, cineole, and farnesene did not show any activity. The compounds eugenol, carvacrol, and thymol presented the lowest MIC; bactericidal effect was observed at MIC level for S. aureus 75MR, E. coli 128 MR, and C albicans CUSI, for different compounds, eugenol, carvacrol, and thymol. Finally, this study shows that the essential oils of plants used by the population of Tehuacán-Cuicatlán valley share compounds and some of them have antibacterial and fungicidal activity.

scholarly journals Comparison of methods for the determination of antimicrobial resistance in Campylobacter spp. human and the food chain isolates

2008 ◽  
Vol 52 (No. 4) ◽  
pp. 169-174
Author(s):  
M. Holasova ◽  
R. Karpiskova ◽  
S. Karpiskova ◽  
V. Babak ◽  
J. Schlegelova
Keyword(s):  
Nalidixic Acid ◽  
Antimicrobial Agents ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Study Results ◽  
Agar Dilution

With a microdilution method, using the commercial diagnostic test Sensititre Susceptibility Plates for Campylobacter MIC (Trek Diagnostic Systems, Cleveland, OH, USA), disk diffusion and agar dilution method, resistance to six antimicrobial agents were examined in a reference strain <i>Campylobacter jejuni</i> ATCC 33560 and 73 thermo-tolerant isolates of <i>Campylobacter</i> spp. For the microdilution method and all tested antimicrobial agents, our determined values of microbiological breakpoints of resistant strains were suggested as the minimum inhibitory concentration (MIC<sub>R</sub>) for ciprofloxacin &ge; 0.5, erythromycin &ge; 4, gentamicin &ge; 4, nalidixic acid &ge; 32 and tetracycline &ge; 4 &mu;g/ml. On the basis of our study results, strains resistant to clindamycin were MIC<sub>R</sub> &ge; 2 &mu;g/ml for the dilution methods and a zone diameter R ≤ 16 mm for the disk diffusion method. Comparison of the results of the resistance examination, a microdilution method and disk diffusion method with the reference agar dilution method, showed that all compared methods yielded identical results with the exception of the resistance determination in erythromycin and nalidixic acid. The errors were mostly the result of the interpretation criteria for MIC<sub>R</sub> of agar dilution method and different conditions of cultivation used. However, the compared methods, provide results comparable with the reference method having greater convenience of measurement.

scholarly journals Chemical Compositions and Antimicrobial Activity of the Essential Oils of Piper abbreviatum, P. erecticaule and P. lanatum (Piperaceae)

2014 ◽  
Vol 9 (12) ◽  
pp. 1934578X1400901 ◽  
Author(s):  
Wan Mohd Nuzul Hakimi Wan Salleh ◽  
Farediah Ahmad ◽  
Khong Heng Yen
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oils ◽  
Antimicrobial Agents ◽  
Antimicrobial Activities ◽  
Dilution Method ◽  
Chemical Compositions ◽  
Gram Positive Bacteria ◽  
Aerial Parts ◽  
Ms Analysis ◽  
Weak Activity

The study was designed to examine the chemical composition and antimicrobial activities of essential oils extracted from the aerial parts of three Piper species: Piper abbreviatum, P. erecticaule and P. lanatum, all from Malaysia. GC and GC/MS analysis showed qualitative and quantitative differences between these oils. GC and GC-MS analysis of P. abbreviatum, P. erecticaule and P. lanatum oils resulted in the identification of 33, 35 and 39 components, representing 70.5%, 63.4% and 78.2% of the components, respectively. The major components of P. abbreviatum oil were spathulenol (11.2%), ( E)-nerolidol (8.5%) and β-caryophyllene (7.8%), whereas P. erecticaule oil mainly contained β-caryophyllene (5.7%) and spathulenol (5.1%). Borneol (7.5%), β-caryophyllene (6.6%) and α-amorphene (5.6%) were the most abundant components in P. lanatum oil. Antimicrobial activity was carried out using disc diffusion and broth micro-dilution method against nine microorganisms. All of the essential oils displayed weak activity towards Gram-positive bacteria with MIC values in the range 250–500 μg/mL. P. erecticaule oil showed the best activity on Aspergillus niger (MIC 31.3 μg/mL), followed by P. lanatum oil (MIC 62.5 μg/mL). This study demonstrated that the essential oils have potential as antimicrobial agents and may be useful in the pharmaceutical and cosmetics industries.

Antimicrobial susceptibility of Clostridioides difficile isolated from diarrhoeal stool specimens of Canadian patients: summary of results from the Canadian Clostridioides difficile (CAN-DIFF) surveillance study from 2013 to 2017

2020 ◽  
Vol 75 (7) ◽  
pp. 1824-1832
Author(s):  
James A Karlowsky ◽  
Heather J Adam ◽  
Melanie R Baxter ◽  
Christopher W Dutka ◽  
Kim A Nichol ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Surveillance Study ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
In Vitro Susceptibility ◽  
Ribotype 027 ◽  
Clostridioides Difficile ◽  
Vancomycin Mics ◽  
Stool Specimens

Abstract Objectives To summarize data generated by the Canadian Clostridioides difficile (CAN-DIFF) surveillance study from 2013 to 2017. Methods Isolates of C. difficile (n = 2158) were cultured from toxin-positive diarrhoeal stool specimens submitted by eight hospital laboratories to a coordinating laboratory. Antimicrobial susceptibility testing was performed according to the CLSI agar dilution method (M11, 2018). Isolate ribotypes were determined using an international, standardized, high-resolution capillary gel-based electrophoresis protocol. Results Of the 2158 isolates of C. difficile, 2133 (98.8%) had vancomycin MICs ≤2 mg/L [i.e. were vancomycin susceptible (EUCAST breakpoint tables, v 9.0, 2019) or WT (CLSI M100, 29th edition, 2019)]. Fidaxomicin MICs were lower than those of all other agents tested (MIC90, 0.5 mg/L); however, one isolate with a fidaxomicin MIC of &gt;8 mg/L was identified. Metronidazole MICs ranged from 0.12 to 4 mg/L; all isolates were metronidazole susceptible by the CLSI breakpoint (≤8 mg/L) compared with 96.8% susceptible by the EUCAST breakpoint (≤2 mg/L). In total, 182 different ribotypes were identified from 2013 to 2017. The most common ribotypes identified were 027 (19.3% of isolates) and 106 (8.2%). Ribotype 027 isolates were frequently moxifloxacin resistant (87.3% of isolates) and MDR (48.6%), associated with vancomycin (10/25, 40.0%) and metronidazole (58/69, 84.1%) resistance and from patients aged ≥80 years. The prevalence of ribotype 027 decreased significantly (P &lt; 0.0001) from 2013 (27.5%) to 2017 (9.0%) and was replaced by increases in ribotype 106 (P = 0.0003) and multiple less common ribotypes. Conclusions Periodic surveillance is required to monitor clinical isolates of C. difficile for changes to in vitro susceptibility testing profiles and ribotype evolution.

scholarly journals Novel Antibiotic Susceptibility Tests by the ATP-Bioluminescence Method Using Filamentous Cell Treatment

1998 ◽  
Vol 42 (6) ◽  
pp. 1406-1411 ◽  
Author(s):  
Noriaki Hattori ◽  
Moto-O Nakajima ◽  
Koji O’Hara ◽  
Tetsuo Sawai
Keyword(s):  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Test Model ◽  
The Novel ◽  
Gram Negative ◽  
Atp Bioluminescence ◽  
Filamentous Cell ◽  
Bioluminescence Method

ABSTRACT Antimicrobial susceptibility testing by the ATP-bioluminescence method has been noted for its speed; it provides susceptibility results within 2 to 5 h. However, several disagreements between the ATP method and standard methodology have been reported. The present paper describes a novel ATP method in a 3.5-h test which overcomes these deficiencies through the elimination of false-resistance discrepancies in tests on gram-negative bacteria with β-lactam agents. In our test model using Pseudomonas aeruginosa and piperacillin, it was shown that ATP in filamentous cells accounted for the false resistance. We found that 0.5% 2-amino-2-methyl-1,3-propanediol (AMPD) extracted ATP from the filamentous cells without affecting normal cells and that 0.3 U of adenosine phosphate deaminase (APDase)/ml simultaneously digested the extracted ATP. We used the mixture of these reagents for the pretreatment of cells in a procedure we named filamentous cell treatment, prior to ATP measurements. This novel ATP method with the filamentous cell treatment eliminated false-resistance discrepancies in tests on P. aeruginosa with β-lactam agents, including piperacillin, cefoperazone, aztreonam, imipenem-cilastatin, ceftazidime, and cefsulodin. Furthermore, this novel methodology produced results which agreed with those of the standard microdilution method in other tests on gram-negative and gram-positive bacteria, including P. aeruginosa, Escherichia coli,Staphylococcus aureus, and Enterococcus faecalis, for non-β-lactam agents, such as fosfomycin, ofloxacin, minocycline, and aminoglycosides. MICs obtained by the novel ATP method were also in agreement with those obtained by the agar dilution method of susceptibility testing. From these results, it was shown that the novel ATP method could be used successfully to test the activities of antimicrobial agents with the elimination of the previously reported discrepancies.

scholarly journals Synthesis, antimicrobial and antioxidative activity of some new isatin derivatives

2014 ◽  
Vol 79 (11) ◽  
pp. 1347-1354 ◽  
Author(s):  
Gavrilo Sekularac ◽  
Jasmina Nikolic ◽  
Predrag Petrovic ◽  
Branko Bugarski ◽  
Boban Djurovic ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antioxidative Activity ◽  
Primary Amines ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Spectroscopic Methods ◽  
Significant Activity ◽  
Agar Dilution ◽  
Different Strains ◽  
Isatin Derivatives

The isatin derivatives, Schiff bases, were synthesized by the reaction of isatin and various substituted primary amines and characterized by several spectroscopic methods. Investigation of the antimicrobial activity of the synthesized compounds was performed by the agar dilution method, against different strains of bacteria and one fungi. The antioxidative activity of the synthesized compounds was also determined. Some of the compounds have shown the significant activity against the selected strains of microorganisms and the antioxidative activity.

scholarly journals In Vitro Antimicrobial Susceptibility Testing of Bacterial Enteropathogens Causing Traveler's Diarrhea in Four Geographic Regions

2001 ◽  
Vol 45 (1) ◽  
pp. 212-216 ◽  
Author(s):  
Harumi Gomi ◽  
Zhi-Dong Jiang ◽  
Javier A. Adachi ◽  
David Ashley ◽  
Brett Lowe ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Moderate Activity ◽  
Traveler’S Diarrhea ◽  
The World ◽  
Traveler's Diarrhea ◽  
Susceptibility Patterns

ABSTRACT The emergence of resistant enteropathogens has been reported worldwide. Few data are available on the contemporary in vitro activities of commonly used antimicrobial agents against enteropathogens causing traveler's diarrhea (TD). The susceptibility patterns of antimicrobial agents currently available or under evaluation against pathogens causing TD in four different areas of the world were evaluated. Pathogens were identified in stool samples from U.S., Canadian, or European adults (18 years of age or older) with TD during 1997, visiting India, Mexico, Jamaica, or Kenya. MICs of 11different antimicrobials were determined against 284 bacterial enteropathogens by the agar dilution method. Ciprofloxacin, levofloxacin, ceftriaxone, and azithromycin were highly active in vitro against the enteropathogens, while traditional antimicrobials such as ampicillin, trimethoprim, and trimethoprim/sulfamethoxazole showed high levels and high frequencies of resistance. Rifaximin, a promising and poorly absorbable drug, had an MIC at which 90% of the strains tested were inhibited of 32 μg/ml, 250 times lower than the concentration of this drug in the stools. Amdinocillin, nalidixic acid, and doxycycline showed moderate activity. Fluoroquinolones are still the drugs of choice for TD in most regions of the world, although our study has a limitation due to the lack of Escherichia coli samples from Kenya and possible bias in selection of the patients for evaluation. Azithromycin and rifaximin should be considered as promising new agents. The widespread in vitro resistance of the traditional antimicrobial agents reported since the 1980s and the new finding of resistance to fluoroquinolones in Southeast Asia are the main reasons for monitoring carefully the antimicrobial susceptibility patterns worldwide and for developing and evaluating new antimicrobial agents for the treatment of TD.

scholarly journals Telithromycin- and Fluoroquinolone-Resistant Streptococcus pneumoniae in Taiwan with High Prevalence of Resistance to Macrolides and β-Lactams: SMART Program 2001 Data

2003 ◽  
Vol 47 (7) ◽  
pp. 2145-2151 ◽  
Author(s):  
Po-Ren Hsueh ◽  
Lee-Jene Teng ◽  
Tsu-Lan Wu ◽  
Dine Yang ◽  
Wen-Kuei Huang ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Random Amplified Polymorphic Dna ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Time Period ◽  
High Prevalence ◽  
Agar Dilution ◽  
Different Parts

ABSTRACT There is a high prevalence of β-lactam- and macrolide-resistant Streptococcus pneumoniae in Taiwan. To understand the in vitro susceptibilities of recent isolates of S. pneumoniae to fluoroquinolones and telithromycin (which is not available in Taiwan), the MICs of 23 antimicrobial agents for 936 clinical isolates of S. pneumoniae isolated from different parts of Taiwan from 2000 to 2001 were determined by the agar dilution method. Overall, 72% of isolates were not susceptible to penicillin (with 61% being intermediate and 11% being resistant) and 92% were resistant to erythromycin. Telithromycin MICs were ≥1 μg/ml for 16% of the isolates, and for 99% of these isolates the MICs of all macrolides tested were ≥256 μg/ml; all of these isolates had the constitutive macrolide-lincosamide-streptogramin B phenotype. Eighty-eight percent of the isolates were resistant to three or more classes of drugs. The ciprofloxacin MICs were ≥4 μg/ml for six (0.6%) isolates from five patients collected in 2000 and 2001, and the levofloxacin MICs were ≥8 μg/ml for five of these isolates. Seven isolates for which ciprofloxacin MICs were ≥4 μg/ml, including one isolate recovered in 1999, belonged to three serotypes (serotype 19F, five isolates; serotype 23A, one isolate; and serotype 23B, one isolate). The isolates from the six patients for which ciprofloxacin MICs were ≥4 μg/ml had different pulsed-field gel electrophoresis profiles and random amplified polymorphic DNA patterns, indicating that no clonal dissemination occurred over this time period. Despite the increased rate of fluoroquinolone use, the proportion of pneumococcal isolates for which ciprofloxacin MICs were elevated (≥4 μg/ml) remained low. However, the occurrence of telithromycin resistance is impressive and raises concerns for the future.

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