Investigation of Whether CLSI Broth Microdilution Method is Applicable for MICs Determination of Enterococcus species

ABSTRACT The activity of CEM-101, a fluoroketolide, was compared to those of 11 other antimicrobial agents using the reference broth microdilution method tested against 103 Neisseria meningitidis strains, including ciprofloxacin-nonsusceptible isolates with confirmed gyr A (T91I) mutations. Among the tested isolates, 79.6% were serogroup B or C and all isolates were susceptible to ceftriaxone, azithromycin, minocycline, and rifampin. However, penicillin-nonsusceptible strains were observed (15.5%) and susceptibility to trimethoprim-sulfamethoxazole was only 50.5%. CEM-101 was the most active macrolide-like compound (MIC90, ≤0.015 μg/ml) compared with MIC90s of telithromycin (MIC90, 0.03 μg/ml), azithromycin and clarithromycin (MIC90, 0.12 μg/ml), and erythromycin (MIC90, 0.25 μg/ml). CEM-101 could provide a potent alternative for the prophylaxis of meningococcal disease.

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Ugotavljanje sposobnosti prilagoditve listerij na benzalkonijev klorid z določanjem njegove minimalne inhibitorne koncentracije

Acta agriculturae Slovenica ◽

10.14720/aas.2019.114.1.15 ◽

2019 ◽

Vol 114 (1) ◽

pp. 131

Author(s):

Monika PODPAC ◽

Barbara JERŠEK

Keyword(s):

Pathogenic Bacteria ◽

Growth Curves ◽

Precise Determination ◽

Plate Count ◽

Good Survival ◽

Production Environment ◽

Broth Microdilution ◽

Microdilution Method ◽

Broth Microdilution Method

Bacteria of the genus Listeria pose a problem in the food industry due to their wide distribution and their good survival in adverse conditions. L. monocytogenes (E. Murray et al. 1926) Pirie 1940 is human pathogen, while L. innocua Seeliger (ATCC® 33090™) as not pathogenic bacteria is the most often found listeria in food production environment. Disinfectants represents an important part of Listeria management in food processing environments and benzalkonium chloride (BAC) is used frequently. The purpose of the work was to determine whether strains of listeria can adapt to BAC. To carry out the adaptation, a precise determination of antibacterial activity of BAC was needed. Firstly minimum inhibitory concentration (MICMTP) of BAC was determined with broth microdilution method for each Listeria strain. Then, we checked whether MICMTP was indeed the lowest concentration of BAC, which had an influence on growth of strains with growth curves. We found out that growth inhibitory effect (MICGC) was achieved at concentrations of BAC that were lower than MICMTP (0.1-0.5x of MICMTP values). Adaptation of listeria to BAC was therefore performed by using 0.25x MICGC as the initial BAC concentration. Results showed that 50 % of the strains were able to adapt to BAC, and in L. monocytogenes ŽM500 this adaptation was even stable. The broth microdilution method was useful for approximate assessment of antimicrobial activity of BAC, while for the more precise determination of disinfectant activity it is necessary to determine it by using another method such as plate count method.

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The determination of minimum inhibitory concentrations of selected antimicrobials for porcine Haemophilus parasuis isolates from the Czech Republic

Acta Veterinaria Brno ◽

10.2754/avb201786020175 ◽

2017 ◽

Vol 86 (2) ◽

pp. 175-181

Author(s):

Kateřina Nedbalcová ◽

Monika Zouharová ◽

Daniel Šperling

Keyword(s):

Czech Republic ◽

Antimicrobial Treatment ◽

Haemophilus Parasuis ◽

Broth Microdilution ◽

The Czech Republic ◽

Minimum Inhibitory Concentrations ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Treatment Of Infection

Haemophilus parasuisisolates obtained from pigs in the Czech Republic were tested for their susceptibility to amoxicillin, penicillin, ceftiofur, enrofloxacin, tetracycline, and tulathromycin by determination of minimum inhibitory concentrations using the broth microdilution method. TheH. parasuisisolates were mostly susceptible to majority of tested antimicrobials (amoxicillin 90%, penicillin 73.3%, enrofloxacin 83.3%, and tulathromycin 83.3%). All isolates were susceptible to ceftiofur. On the other hand, no isolate was susceptible to tetracycline, 30% of tested isolates were intermediately susceptible, and 70% were resistant. These findings indicate that tested antimicrobials with the exception of tetracycline should be the preferred option used for the treatment of infection caused byH. parasuisbut due to the potential transmission of resistance from animals to humans, the use of ceftiofur is considered as a last resort option in antimicrobial treatment of animals.

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Determination of minimum inhibitory concentrations of itraconazole, terbinafine and ketoconazole against dermatophyte species by broth microdilution method

Indian Journal of Medical Microbiology ◽

10.4103/0255-0857.167341 ◽

2015 ◽

Vol 33 (4) ◽

pp. 533 ◽

Cited By ~ 11

Author(s):

PC Sharma ◽

VK Bhatia

Keyword(s):

Broth Microdilution ◽

Minimum Inhibitory Concentrations ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Dermatophyte Species

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Drug susceptibiity testing of nontuberculous mycobacteria by broth microdilution method

Indian Journal of Medical Microbiology ◽

10.1016/j.ijmmb.2021.03.015 ◽

2021 ◽

Author(s):

Megha Sharma ◽

Bharti Malhotra ◽

Shreya Khandelwal

Keyword(s):

Nontuberculous Mycobacteria ◽

Broth Microdilution ◽

Microdilution Method ◽

Broth Microdilution Method

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Antimicrobial Essential Oil Combinations to Combat Foot Odour

Planta Medica ◽

10.1055/a-0592-8022 ◽

2018 ◽

Vol 84 (09/10) ◽

pp. 662-673 ◽

Cited By ~ 4

Author(s):

Ané Orchard ◽

Alvaro Viljoen ◽

Sandy van Vuuren

Keyword(s):

Antimicrobial Activity ◽

Essential Oil ◽

Essential Oils ◽

Antimicrobial Efficacy ◽

Juniperus Virginiana ◽

Broth Microdilution ◽

Synergistic Interactions ◽

Microdilution Method ◽

Broth Microdilution Method

AbstractFoot odour (bromodosis) is an embarrassing and perplexing condition mostly caused by bacteria of the Brevibacterium species. Essential oils are a credible option as an affordable treatment of odour and contribute towards antimicrobial efficacy. Therefore, this study sets out to investigate the antimicrobial activity of essential oil combinations against odour-causing bacteria. The broth microdilution method was used to investigate the antimicrobial activity of 119 essential oil combinations, and the fractional inhibitory index was calculated to determine the interactive profile. Combinations that resulted in synergy in 1 : 1 ratios were further evaluated in different concentrations, and isobolograms were plotted to determine the influence of the ratio on overall activity. Numerous combinations could be identified as having synergistic interactions against the Brevibacterium spp. and no antagonism was observed. The combination of Juniperus virginiana (juniper) and Styrax benzoin (benzoin) demonstrated synergy against all three Brevibacterium spp. tested and J. virginiana was the essential oil responsible for the majority of the synergistic interactions. The results reported here confirm the promising potential of the majority of these oils and selected combinations in treating and controlling bromodosis.

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Standartization of broth microdilution method for Mycobacterium tuberculosis

Memórias do Instituto Oswaldo Cruz ◽

10.1590/s0074-02762000000100021 ◽

2000 ◽

Vol 95 (1) ◽

pp. 127-129 ◽

Cited By ~ 22

Author(s):

Clarice Queico Fujimura Leite ◽

Ana Laura Remédio Zeni Beretta ◽

Ivone Shizuko Anno ◽

Maria Alice da Silva Telles

Keyword(s):

Mycobacterium Tuberculosis ◽

Broth Microdilution ◽

Microdilution Method ◽

Broth Microdilution Method

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In Vitro Activities of the Novel Oxazolidinones DA-7867 and DA-7157 against Rapidly and Slowly Growing Mycobacteria

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00763-06 ◽

2006 ◽

Vol 50 (12) ◽

pp. 4027-4029 ◽

Cited By ~ 18

Author(s):

Lucio Vera-Cabrera ◽

Barbara A. Brown-Elliott ◽

Richard J. Wallace ◽

Jorge Ocampo-Candiani ◽

Oliverio Welsh ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Clinical Isolates ◽

Nontuberculous Mycobacterium ◽

The Novel ◽

Broth Microdilution ◽

Reference Species ◽

Microdilution Method ◽

Broth Microdilution Method ◽

Aerobic Actinomycetes

ABSTRACT DA-7867 and DA-7157 are oxazolidinones active against pathogenic aerobic actinomycetes including Nocardia spp. and Mycobacterium tuberculosis. However, the activity of these drugs against nontuberculous mycobacterium (NTM) species is not known. In this work, we compared the susceptibilities of 122 clinical isolates and 29 reference species of both rapidly growing and slowly growing mycobacteria to linezolid, DA-7867, and DA-7157 by the broth microdilution method. The MICs for 50 and 90% of the strains tested (MIC50s and MIC90s, respectively) of DA-7867 and DA-7157 were lower than those of linezolid. In all of the cases, a MIC90 of <8 μg/ml was observed for all of the species tested in both groups of NTM. For M. kansasii and M. marinum isolates, the MIC90s of both DA-7867 and DA-7157 were less than 0.5 μg/ml. These results demonstrate the potential of these compounds to treat NTM infections.

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Susceptibility of Filamentous Fungi to Voriconazole in Malaysia Tested by Sensititre YeastOne and CLSI Microdilution Methods

10.21203/rs.3.rs-199013/v1 ◽

2021 ◽

Author(s):

Xue Ting Tan ◽

Stephanie Jane Ginsapu ◽

Fairuz binti Amran ◽

Salina binti Mohamed Sukur ◽

Surianti binti Shukor

Keyword(s):

Filamentous Fungi ◽

Susceptibility Testing ◽

Rhizopus Oryzae ◽

Antifungal Susceptibility ◽

Sporothrix Schenckii ◽

Rank Test ◽

Broth Microdilution ◽

Syncephalastrum Racemosum ◽

Microdilution Method ◽

Broth Microdilution Method

Abstract Background: Voriconazole is a trizaole antifungal to treat fungal infection. In this study, the susceptibility pattern of voriconazole against filamentous fungi was studied using Sensititre® YeastOne and Clinical & Laboratory Standards Institute (CLSI) M38 broth microdilution method. Methods: The suspected cultures of Aspergillus niger, A. flavus, A. fumigatus, A. versicolor, A. sydowii, A. calidoutus, A. creber, A. ochraceopetaliformis, A. tamarii, Fusarium solani, F. longipes, F. falciferus, F. keratoplasticum, Rhizopus oryzae, R. delemar, R. arrhizus, Mucor sp., Poitrasia circinans, Syncephalastrum racemosum and Sporothrix schenckii were received from hospitals. Their identification had been confirmed in our lab and susceptibility tests were performed using Sensititre® YeastOne and CLSI M38 broth microdilution method. The significant differences between two methods were calculated using Wilcoxon Sign Rank test.Results: Mean of the minimum inhibitory concentrations (MIC) for Aspergillus spp. and Fusarium were within 0.25 μg/mL-2.00 μg/mL by two methods except A. calidoutus, F. solani and F. keratoplasticum. Moreover, mean of MIC for S. schenkii were around 3.00 μg/mL by two methods. In contrast, mean of MIC for Rhizopus spp., Mucor sp., P. circinans and S. racemosum were ≥6.00 μg/mL by two methods. Generally, the MIC obtained by Sensititre YeastOne was one two-fold increase or decrease compared with the results obtained by CLSI method. The overall agreement between Sensititre YeastOne and CLSI methods to test susceptibility testing of voricaonazole was more than 70% except A. sydowii. The significant differences between two methods were significant when tested on A. niger, A. flavus, A. fumigatus, A. versicolor, A. sydowii, F. solani and S. schenkii. Conclusions: In conclusion, Sensititre YeastOne method appears to be an alternative procedure for antifungal susceptibility testing for some Malaysian moulds.

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Flow Cytometry Antifungal Susceptibility Testing of Pathogenic Yeasts other than Candida albicans and Comparison with the NCCLS Broth Microdilution Test

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.44.10.2752-2758.2000 ◽

2000 ◽

Vol 44 (10) ◽

pp. 2752-2758 ◽

Cited By ~ 44

Author(s):

Rama Ramani ◽

Vishnu Chaturvedi

Keyword(s):

Flow Cytometry ◽

Candida Albicans ◽

Amphotericin B ◽

Susceptibility Testing ◽

Antifungal Susceptibility ◽

Antifungal Susceptibility Testing ◽

Broth Microdilution ◽

Nitrogen Base ◽

Microdilution Method ◽

Broth Microdilution Method

ABSTRACT Candida species other than Candida albicansfrequently cause nosocomial infections in immunocompromised patients. Some of these pathogens have either variable susceptibility patterns or intrinsic resistance against common azoles. The availability of a rapid and reproducible susceptibility-testing method is likely to help in the selection of an appropriate regimen for therapy. A flow cytometry (FC) method was used in the present study for susceptibility testing ofCandida glabrata, Candida guilliermondii,Candida krusei, Candida lusitaniae,Candida parapsilosis, Candida tropicalis, andCryptococcus neoformans based on accumulation of the DNA binding dye propidium iodide (PI). The results were compared with MIC results obtained for amphotericin B and fluconazole using the NCCLS broth microdilution method (M27-A). For FC, the yeast inoculum was prepared spectrophotometrically, the drugs were diluted in either RPMI 1640 or yeast nitrogen base containing 1% dextrose, and yeast samples and drug dilutions were incubated with amphotericin B and fluconazole, respectively, for 4 to 6 h. Sodium deoxycholate and PI were added at the end of incubation, and fluorescence was measured with a FACScan flow cytometer (Becton Dickinson). The lowest drug concentration that showed a 50% increase in mean channel fluorescence compared to that of the growth control was designated the MIC. All tests were repeated once. The MICs obtained by FC for all yeast isolates except C. lusitaniae were in very good agreement (within 1 dilution) of the results of the NCCLS broth microdilution method. Paired ttest values were not statistically significant (P = 0.377 for amphotericin B; P = 0.383 for fluconazole). Exceptionally, C. lusitaniae isolates showed higher MICs (2 dilutions or more) than in the corresponding NCCLS broth microdilution method for amphotericin B. Overall, FC antifungal susceptibility testing provided rapid, reproducible results that were statistically comparable to those obtained with the NCCLS method.

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