scholarly journals Antibiotic Resistance among Clinical Ureaplasma Isolates Recovered from Neonates in England and Wales between 2007 and 2013

2015 ◽  
Vol 60 (1) ◽  
pp. 52-56 ◽  
Author(s):  
Michael L. Beeton ◽  
Victoria J. Chalker ◽  
Lucy C. Jones ◽  
Nicola C. Maxwell ◽  
O. Brad Spiller
Keyword(s):  
Antibiotic Resistance ◽  
Molecular Mechanisms ◽  
Treatment Options ◽  
Tetracycline Resistance ◽  
Health Clinic ◽  
Broth Microdilution ◽  
England And Wales ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACTUreaplasmaspp. are associated with numerous clinical sequelae with treatment options being limited due to patient and pathogen factors. This report examines the prevalence and mechanisms of antibiotic resistance among clinical strains isolated from 95 neonates, 32 women attending a sexual health clinic, and 3 patients under investigation for immunological disorders, between 2007 and 2013 in England and Wales. MICs were determined by using broth microdilution assays, and a subset of isolates were compared using the broth microdilution method and the Mycoplasma IST2 assay. The underlying molecular mechanisms for resistance were determined for all resistant isolates. Three isolates carried thetet(M) tetracycline resistance gene (2.3%; confidence interval [CI], 0.49 to 6.86%); two isolates were ciprofloxacin resistant (1.5%; CI, 0.07 to 5.79%) but sensitive to levofloxacin and moxifloxacin, while no resistance was seen to any macrolides tested. The MIC values for chloramphenicol were universally low (2 μg/ml), while inherently high-level MIC values for gentamicin were seen (44 to 66 μg/ml). The Mycoplasma IST2 assay identified a number of false positives for ciprofloxacin resistance, as the method does not conform to international testing guidelines. While antibiotic resistance amongUreaplasmaisolates remains low, continued surveillance is essential to monitor trends and threats from importation of resistant clones.

scholarly journals In VitroActivity of Plazomicin against Gram-Negative and Gram-Positive Isolates Collected from U.S. Hospitals and Comparative Activities of Aminoglycosides against Carbapenem-ResistantEnterobacteriaceaeand Isolates Carrying Carbapenemase Genes

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Mariana Castanheira ◽  
Andrew P. Davis ◽  
Rodrigo E. Mendes ◽  
Alisa W. Serio ◽  
Kevin M. Krause ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Treatment Options ◽  
Broth Microdilution ◽  
Coagulase Negative Staphylococci ◽  
Gram Negative ◽  
Content Type ◽  
Microdilution Method ◽  
Carbapenem Resistant ◽  
Serious Infections ◽  
Broth Microdilution Method

ABSTRACTPlazomicin and comparator agents were tested by using the CLSI reference broth microdilution method against 4,825 clinical isolates collected during 2014 and 2015 in 70 U.S. hospitals as part of the ALERT (Antimicrobial Longitudinal Evaluation and Resistance Trends) program. Plazomicin (MIC50/MIC90, 0.5/2 μg/ml) inhibited 99.2% of 4,362Enterobacteriaceaeat ≤4 μg/ml. Amikacin, gentamicin, and tobramycin inhibited 98.9%, 90.3%, and 90.3% of these isolates, respectively, by applying CLSI breakpoints. The activities of plazomicin were similar amongEnterobacteriaceaespecies, with MIC50values ranging from 0.25 to 1 μg/ml, with the exception ofProteus mirabilisand indole-positiveProteeaethat displayed MIC50values of 2 μg/ml. For 97 carbapenem-resistantEnterobacteriaceae(CRE), which included 87 isolates carryingblaKPC, plazomicin inhibited all but 1 isolate at ≤2 μg/ml (99.0% and 98.9%, respectively). Amikacin and gentamicin inhibited 64.9% and 56.7% of the CRE isolates at the respective CLSI breakpoints. Plazomicin inhibited 96.5 and 95.5% of the gentamicin-resistant isolates, 96.9 and 96.5% of the tobramycin-resistant isolates, and 64.3 and 90.0% of the amikacin-resistant isolates according to CLSI and EUCAST breakpoints, respectively. The activities of plazomicin againstPseudomonas aeruginosa(MIC50/MIC90, 4/16 μg/ml) andAcinetobacterspecies (MIC50/MIC90, 2/16 μg/ml) isolates were similar. Plazomicin was active against coagulase-negative staphylococci (MIC50/MIC90, 0.12/0.5 μg/ml) andStaphylococcus aureus(MIC50/MIC90, 0.5/0.5 μg/ml) but had limited activity againstEnterococcusspp. (MIC50/MIC90, 16/64 μg/ml) andStreptococcus pneumoniae(MIC50/MIC90, 32/64 μg/ml). Plazomicin activity against theEnterobacteriaceaetested, including CRE and isolates carryingblaKPCfrom U.S. hospitals, supports the development plan for plazomicin to treat serious infections caused by resistantEnterobacteriaceaein patients with limited treatment options.

scholarly journals Antifungal Susceptibility Testing of Malassezia spp. with an Optimized Colorimetric Broth Microdilution Method

2017 ◽  
Vol 55 (6) ◽  
pp. 1883-1893 ◽  
Author(s):  
Cheryl Leong ◽  
Antonino Buttafuoco ◽  
Martin Glatz ◽  
Philipp P. Bosshard
Keyword(s):  
Susceptibility Testing ◽  
Skin Diseases ◽  
Antifungal Susceptibility ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Broth Microdilution ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Colorimetric Indicator

ABSTRACTMalasseziais a genus of lipid-dependent yeasts. It is associated with common skin diseases such as pityriasis versicolor and atopic dermatitis and can cause systemic infections in immunocompromised individuals. Owing to the slow growth and lipid requirements of these fastidious yeasts, convenient and reliable antifungal drug susceptibility testing assays forMalasseziaspp. are not widely available. Therefore, we optimized a broth microdilution assay for the testing ofMalasseziathat is based on the CLSI and EUCAST assays forCandidaand other yeasts. The addition of ingredients such as lipids and esculin provided a broth medium formulation that enabled the growth of allMalasseziaspp. and could be read, with the colorimetric indicator resazurin, by visual and fluorescence readings. We tested the susceptibility of 52 strains of 13Malasseziaspecies to 11 commonly used antifungals. MIC values determined by visual readings were in good agreement with MIC values determined by fluorescence readings. The lowest MICs were found for the azoles itraconazole, posaconazole, and voriconazole, with MIC90values of 0.03 to 1.0 μg/ml, 0.06 to 0.5 μg/ml, and 0.03 to 2.0 μg/ml, respectively. AllMalasseziaspp. were resistant to echinocandins and griseofulvin. SomeMalasseziaspp. also showed high MIC values for ketoconazole, which is the most widely recommended topical antifungal to treatMalasseziaskin infections. In summary, our assay enables the fast and reliable susceptibility testing ofMalasseziaspp. with a large panel of different antifungals.

scholarly journals Antimicrobial Activity of Exebacase (Lysin CF-301) against the Most Common Causes of Infective Endocarditis

2019 ◽  
Vol 63 (10) ◽  
Author(s):  
Aubrey Watson ◽  
Jun Taek Oh ◽  
Karen Sauve ◽  
Patricia A. Bradford ◽  
Cara Cassino ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Cell Wall ◽  
Infective Endocarditis ◽  
Broth Microdilution ◽  
Coagulase Negative Staphylococci ◽  
Content Type ◽  
Microdilution Method ◽  
Cell Wall Hydrolase ◽  
Broth Microdilution Method ◽  
Common Causes

ABSTRACT Exebacase, a recombinantly produced lysin (cell wall hydrolase), and comparator antibiotics were tested by the broth microdilution method against strain sets of Staphylococcus and Streptococcus spp., which are the most common causes of infective endocarditis in humans. Exebacase was active against all Staphylococcus spp. tested, including S. aureus and coagulase-negative staphylococci (MIC50/90, 0.5/1 μg/ml). Activity against Streptococcus spp. was variable, with S. pyogenes, S. agalactiae, and S. dysgalactiae (MIC50/90, 1/2 μg/ml) among the most susceptible.

scholarly journals Multicenter Study of Isavuconazole MIC Distributions and Epidemiological Cutoff Values for the Cryptococcus neoformans-Cryptococcus gattii Species Complex Using the CLSI M27-A3 Broth Microdilution Method

2014 ◽  
Vol 59 (1) ◽  
pp. 666-668 ◽  
Author(s):  
A. Espinel-Ingroff ◽  
A. Chowdhary ◽  
G. M. Gonzalez ◽  
J. Guinea ◽  
F. Hagen ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Multicenter Study ◽  
Species Complex ◽  
Cryptococcus Gattii ◽  
Broth Microdilution ◽  
Wild Type ◽  
Content Type ◽  
Microdilution Method ◽  
Cutoff Values ◽  
Broth Microdilution Method

ABSTRACTEpidemiological cutoff values (ECVs) of isavuconazole are not available forCryptococcusspp. The isavuconazole ECVs based on wild-type (WT) MIC distributions for 438Cryptococcus neoformansnongenotyped isolates, 870 isolates of genotype VNI, and 406Cryptococcus gattiiisolates from six laboratories and different geographical areas were 0.06, 0.12, and 0.25 μg/ml, respectively. These ECVs may aid in detecting non-WT isolates with reduced susceptibilities to isavuconazole.

scholarly journals In Vitro Activity of Meropenem-Vaborbactam against Clinical Isolates of KPC-Positive Enterobacteriaceae

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Meredith A. Hackel ◽  
Olga Lomovskaya ◽  
Michael N. Dudley ◽  
James A. Karlowsky ◽  
Daniel F. Sahm
Keyword(s):  
Clinical Isolates ◽  
In Vitro Activity ◽  
Broth Microdilution ◽  
Content Type ◽  
Class A ◽  
Microdilution Method ◽  
Fixed Concentration ◽  
Broth Microdilution Method ◽  
The U.S

ABSTRACT Vaborbactam (formerly RPX7009) is a novel inhibitor of serine β-lactamases, including Ambler class A carbapenemases, such as KPCs. The current study evaluated the in vitro activity of the combination agent meropenem-vaborbactam against a global collection of 991 isolates of KPC-positive Enterobacteriaceae collected in 2014 and 2015 using the Clinical and Laboratory Standards Institute (CLSI) standard broth microdilution method. The MIC90 of meropenem (when tested with a fixed concentration of 8 μg/ml of vaborbactam) for isolates of KPC-positive Enterobacteriaceae was 1 μg/ml, and MIC values ranged from ≤0.03 to >32 μg/ml; 99.0% (981/991) of isolates had meropenem-vaborbactam MICs of ≤4 μg/ml, the U.S. FDA-approved MIC breakpoint for susceptibility to meropenem-vaborbactam (Vabomere). Vaborbactam lowered the meropenem MIC50 from 32 to 0.06 μg/ml and the MIC90 from >32 to 1 μg/ml. There were no differences in the activity of meropenem-vaborbactam when the isolates were stratified by KPC variant type. We conclude that meropenem-vaborbactam demonstrates potent in vitro activity against a worldwide collection of clinical isolates of KPC-positive Enterobacteriaceae collected in 2014 and 2015.

scholarly journals In VitroAntibiotic Susceptibilities of Yersinia pestis Determined by Broth Microdilution following CLSI Methods

2015 ◽  
Vol 59 (4) ◽  
pp. 1919-1921 ◽  
Author(s):  
Henry S. Heine ◽  
Jeremy Hershfield ◽  
Charles Marchand ◽  
Lynda Miller ◽  
Stephanie Halasohoris ◽  
...  
Keyword(s):  
Yersinia Pestis ◽  
Broth Microdilution ◽  
Content Type ◽  
Microdilution Method ◽  
Reference Information ◽  
Broth Microdilution Method ◽  
Two Temperatures ◽  
Emergence Of Resistance ◽  
Antibiotic Agents

ABSTRACTIn vitrosusceptibilities to 45 antibiotics were determined for 30 genetically and geographically diverse strains ofYersinia pestisby the broth microdilution method at two temperatures, 28°C and 35°C, following Clinical and Laboratory Standards Institute (CLSI) methods. TheY. pestisstrains demonstrated susceptibility to aminoglycosides, quinolones, tetracyclines, β-lactams, cephalosporins, and carbapenems. Only a 1-well shift was observed for the majority of antibiotics between the two temperatures. Establishing and comparing antibiotic susceptibilities of a diverse but specific set ofY. pestisstrains by standardized methods and establishing population ranges and MIC50and MIC90values provide reference information for assessing new antibiotic agents and also provide a baseline for use in monitoring any future emergence of resistance.

scholarly journals Baseline Activity of Telavancin against Gram-Positive Clinical Isolates Responsible for Documented Infections in U.S. Hospitals (2011-2012) as Determined by the Revised Susceptibility Testing Method

2014 ◽  
Vol 59 (1) ◽  
pp. 702-706 ◽  
Author(s):  
Rodrigo E. Mendes ◽  
David J. Farrell ◽  
Helio S. Sader ◽  
Robert K. Flamm ◽  
Ronald N. Jones
Keyword(s):  
Staphylococcus Aureus ◽  
Susceptibility Testing ◽  
The United States ◽  
Broth Microdilution ◽  
Content Type ◽  
Testing Method ◽  
Microdilution Method ◽  
Baseline Activity ◽  
Broth Microdilution Method ◽  
Vancomycin Resistant

ABSTRACTTelavancin had MIC50and MIC90values of 0.03 and 0.06 μg/ml (100.0% susceptible), respectively, against methicillin-resistant and -susceptibleStaphylococcus aureus. Telavancin was active against vancomycin-susceptibleEnterococcus faecalis(MIC50/90, 0.12/0.12 μg/ml; 100% susceptible) andEnterococcus faecium(MIC50/90, 0.03/0.06 μg/ml), while higher MIC values were obtained against vancomycin-resistantE. faecium(MIC50/90, 1/2 μg/ml) andE. faecalis(MIC50/90, >2/>2 μg/ml). Streptococci showed telavancin modal MIC results of ≤0.015 μg/ml, except againstStreptococcus agalactiae(i.e., 0.03 μg/ml). This study reestablishes the telavancin spectrum of activity against isolates recovered from the United States (2011-2012) using the revised broth microdilution method.

scholarly journals In Vitro Evaluation of the activity of Ceftazidime-avibactam and Aztreonam-Avibactam against 76 Stenotrophomonas maltophilia isolates from a teaching hospital in Chongqing

2020 ◽  
Author(s):  
Qiuxia Lin ◽  
Hua Zou ◽  
Xian Chen ◽  
Menglu Wu ◽  
Deyu Ma ◽  
...  
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Combined Therapy ◽  
Treatment Options ◽  
Clinical Isolates ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Medical University ◽  
Selection Of

Abstract Background: Treatment options for Stenotrophomonas maltophilia (S. maltophilia) infections were limited. We assessed the efficacy of ceftazidime-avibactam (CAZ-AVI) and aztreonam-avibactam (ATM-AVI) against a selection of 76 S. maltophilia out of the 1179 strains isolated from the First Affiliated Hospital of Chongqing Medical University during 2011-2018. Methods: We investigated the antimicrobial resistance profiles of the 1179 S. maltophilia clinical isolates from the first affiliated hospital of Chongqing Medical University during 2011-2018, a collection of 76 isolates of which were available for further study of microbiological characterization. Minimum inhibitory concentrations (MICs) of ceftazidime (CAZ), ceftazidime-avibactam (CAZ-AVI), aztreonam (ATM) and aztreonam-avibactam (ATM-AVI) were determined via the broth microdilution method. We deemed that CAZ-AVI or ATM-AVI was more effective in vitro than CAZ or ATM alone when CAZ-AVI or ATM-AVI led to a category change from “Resistant” with CAZ or ATM alone to “Susceptible” or “Intermediate” with CAZ-AVI or ATM-AVI, or if the MIC of CAZ-AVI or ATM-AVI was at least 2-fold lower than the MIC of CAZ or ATM alone. Results: For the 76 clinical isolates included in the study, MICs of CAZ, ATM, CAZ-AVI and ATM-AVI ranged from 0.03-64, 1-1024, 0.016-64, and 0.06-64 μg/mL, respectively. In combined therapy, AVI was effective at restoring the susceptibility of 48.48% (16/33) and 89.71% (61/68) of S. maltophilia to CAZ and ATM, respectively. Furthermore, CAZ-AVI showed better results in terms of the proportion of susceptible isolates (77.63% vs.56.58%, P<0.001), MIC50 (2μg/mL vs. 8μg/mL, P<0.05), and MIC distribution (P<0.001) when compared to CAZ. According to our definition, CAZ-AVI was more effective in vitro than CAZ alone for 84.21% of the isolates. Similarly, ATM-AVI also showed better results in terms of the proportion of susceptible isolates (90.79%vs. 10.53%, P<0.001), MIC50 (2μg/mL vs. 64μg/mL, P<0.001), and MIC distribution (P<0.001) when compared to ATM. According to our definition, ATM-AVI was also more effective in vitro than ATM alone for 97.37% of the isolates. Conclusions: AVI potentiated the activity of both CAZ and ATM against S. maltophilia clinical isolates in vitro. We demonstrated that CAZ-AVI and ATM-AVI are both useful therapeutic options to treat infections caused by S. maltophilia.

scholarly journals Antimicrobial Activity of Murepavadin Tested against Clinical Isolates of Pseudomonas aeruginosa from the United States, Europe, and China

2018 ◽  
Vol 62 (7) ◽  
Author(s):  
Helio S. Sader ◽  
Glenn E. Dale ◽  
Paul R. Rhomberg ◽  
Robert K. Flamm
Keyword(s):  
United States ◽  
Pseudomonas Aeruginosa ◽  
Cyclic Peptide ◽  
Polymyxin B ◽  
The United States ◽  
Broth Microdilution ◽  
Content Type ◽  
Microdilution Method ◽  
Medical Centers ◽  
Broth Microdilution Method

ABSTRACT Murepavadin (formerly POL7080), a 14-amino-acid cyclic peptide, and comparators were tested by the broth microdilution method against 1,219 Pseudomonas aeruginosa isolates from 112 medical centers. Murepavadin (MIC 50/90 , 0.12/0.12 mg/liter) was 4- to 8-fold more active than colistin (MIC 50/90 , 1/1 mg/liter) and polymyxin B (MIC 50/90 , 0.5/1 mg/liter) and inhibited 99.1% of isolates at ≤0.5 mg/liter. Only 4 isolates (0.3%) exhibited murepavadin MICs of >2 mg/liter. Murepavadin was equally active against isolates from Europe, the United States, and China.

scholarly journals International Evaluation of MIC Distributions and Epidemiological Cutoff Value (ECV) Definitions for Fusarium Species Identified by Molecular Methods for the CLSI Broth Microdilution Method

2015 ◽  
Vol 60 (2) ◽  
pp. 1079-1084 ◽  
Author(s):  
A. Espinel-Ingroff ◽  
A. L. Colombo ◽  
S. Cordoba ◽  
P. J. Dufresne ◽  
J. Fuller ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Fusarium Species ◽  
Gene Mutations ◽  
The United States ◽  
Wild Type ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
The Relationship ◽  
Dna Pcr

ABSTRACTThe CLSI epidemiological cutoff values (ECVs) of antifungal agents are available for variousCandidaspp.,Aspergillusspp., and the Mucorales. However, those categorical endpoints have not been established forFusariumspp., mostly due to the difficulties associated with collecting sufficient CLSI MICs for clinical isolates identified according to the currently recommended molecular DNA-PCR-based identification methodologies. CLSI MIC distributions were established for 53Fusarium dimerumspecies complex (SC), 10F. fujikuroi, 82F. proliferatum, 20F. incarnatum-F. equisetiSC, 226F. oxysporumSC, 608F. solaniSC, and 151F. verticillioidesisolates originating in 17 laboratories (in Argentina, Australia, Brazil, Canada, Europe, Mexico, and the United States). According to the CLSI guidelines for ECV setting, ECVs encompassing ≥97.5% of pooled statistically modeled MIC distributions were as follows: for amphotericin B, 4 μg/ml (F. verticillioides) and 8 μg/ml (F. oxysporumSC andF. solaniSC); for posaconazole, 2 μg/ml (F. verticillioides), 8 μg/ml (F. oxysporumSC), and 32 μg/ml (F. solaniSC); for voriconazole, 4 μg/ml (F. verticillioides), 16 μg/ml (F. oxysporumSC), and 32 μg/ml (F. solaniSC); and for itraconazole, 32 μg/ml (F. oxysporumSC andF. solaniSC). Insufficient data precluded ECV definition for the other species. Although these ECVs could aid in detecting non-wild-type isolates with reduced susceptibility to the agents evaluated, the relationship between molecular mechanisms of resistance (gene mutations) and MICs still needs to be investigated forFusariumspp.

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