scholarly journals Antimicrobial resistance of Enterococcus faecium and Enterococcus faecalis, isolated from blood culture of patients with hematological malignancies during different study periods

2021 ◽  
Vol 16 (1) ◽  
pp. 54-63
Author(s):  
A. V. Fedorova ◽  
G. A. Klyasova ◽  
I. N. Frolova ◽  
S. A. Khrulnova ◽  
A. V. Vetokhina ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Blood Culture ◽  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
High Susceptibility ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
High Level

Objective: to determine antimicrobial resistance of Enterococcus faecium and Enterococcus faecalis isolated from blood culture of hematological patients during different study periods.Materials and methods. Antimicrobial susceptibility of Enterococcus spp., collected as part of the multicenter study was tested by the broth microdilution method (USA Clinical and Laboratory Standards Institute (CLSI), 2018), to daptomycin by Etest (bioMeriéux, France). High-level gentamicin resistance (HLGR) and high-level streptomycin resistance (HLSR) was performed by the agar dilution method (CLSI (Oxoid, UK), 2018).Results. The susceptibility of 366 E. faecium (157 in 2002-2009 and 209 in 2010-2017) and 86 E. faecalis (44 in 20022009 and 42 in 2010-2017) was studied. In the second study period (2010-2017) the rise of vancomycin-resistant E. faecium (VREF) increased from 8.3 % to 23.4 % (p = 0.0001), and two linezolid-resistant (LREF) were identified. All VREF and LREF remained susceptible to daptomycin and tigecycline. The rate of susceptible to tetracycline E. faecium remained the same (73.9 and 74.6 %), and an increase in susceptibility to chloramphenicol (74.5 and 82.3 %) was observed. Susceptibility of E. faecium to tetracycline was detected with almost the same rate and in a part of isolates, the increase of susceptibility to chloramphenicol was registered during the analyzed periods. The rise of E. faecium susceptible to HLGR and HLSR has increased significantly in 2010-2017 compared to 2002-2009. Erythromycin, levofloxacin, ampicillin and penicillin had the least activity against E. faecium (less than 5 %).All E. faecalis were susceptible to tigecycline, linezolid, and teicoplanin. Only one of E. faecalis had intermediate resistance to vancomycin. High susceptibility to ampicillin in E. faecalis remained unchanged (97.7 and 97.6 %, respectively). In the second period of the study the rise of susceptible E. faecalis decreased significantly to penicillin (from 97.7 % to 76.2 %), to levofloxacin (from 59.1 % to 31 %), to HLSR (from 52.3 % до 31 %), and to HLGR (from 47.7 % to 26.2 %), remained unchanged to chloramphenicol (52.3 % and 50 %) and was minimal to erythromycin and tetracycline.Conclusion. The study demonstrated higher rates of antibiotic resistance among E. faecium, which consisted of an increase in VREF and the appearance of linezolid-resistant strains. High susceptibility to ampicillin remained in E. faecalis, but there was an increase in resistance to penicillin and aminoglycosides.

Multiple-Antibiotic Resistance of Enterococcus faecalis and Enterococcus faecium from Cecal Contents in Broiler Chicken and Turkey Flocks Slaughtered in Canada and Plasmid Colocalization of tetO and ermB Genes

2011 ◽  
Vol 74 (10) ◽  
pp. 1639-1648 ◽  
Author(s):  
CINDY-LOVE TREMBLAY ◽  
ANN LETELLIER ◽  
SYLVAIN QUESSY ◽  
MARTINE BOULIANNE ◽  
DANIELLE DAIGNAULT ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Enterococcus Faecalis ◽  
Resistance Genes ◽  
Enterococcus Faecium ◽  
Broiler Chicken ◽  
Multidrug Resistant ◽  
Poultry Meat ◽  
Antimicrobial Resistance Genes ◽  
High Level ◽  
Level Resistance

This study was conducted to characterize the antimicrobial resistance determinants and investigate plasmid colocalization of tetracycline and macrolide genes in Enterococcus faecalis and Enterococcus faecium from broiler chicken and turkey flocks in Canada. A total of 387 E. faecalis and E. faecium isolates were recovered from poultry cecal contents from five processing plants. The percentages of resistant E. faecalis and E. faecium isolates, respectively, were 88.1 and 94% to bacitracin, 0 and 0.9% to chloramphenicol, 0.7 and 14.5% to ciprofloxacin, 72.6 and 80.3% to erythromycin, 3.7 and 41% to flavomycin, 9.6 and 4.3% (high-level resistance) to gentamicin, 25.2 and 17.1% (high-level resistance) to kanamycin, 100 and 94% to lincomycin, 0 and 0% to linezolid, 2.6 and 20.5% to nitrofurantoin, 3 and 27.4% to penicillin, 98.5 and 89.7% to quinupristin-dalfopristin, 7 and 12.8% to salinomycin, 46.7 and 38.5% (high-level resistance) to streptomycin, 95.6 and 89.7% to tetracycline, 73 and 75.2% to tylosin, and 0 and 0% to vancomycin. One predominant multidrug-resistant phenotypic pattern was identified in both E. faecalis and E. faecium (bacitracin, erythromycin, lincomycin, quinupristin-dalfopristin, tetracycline, and tylosin). These isolates were further examined by PCR and sequencing for the genes encoding their antimicrobial resistance. Various combinations of vatD, vatE, bcrR, bcrA, bcrB, bcrD, ermB, msrC, linB, tetM, and tetO genes were detected, and ermB, tetM, and bcrB were the most common antimicrobial resistance genes identified. For the first time, plasmid extraction and hybridization revealed colocalization of tetO and ermB genes on a ca. 11-kb plasmid in E. faecalis isolates, and filter mating experiments demonstrated its transferability. Results indicate that the intestinal enterococci of healthy poultry, which can contaminate poultry meat at slaughter, could be a reservoir for quinupristin-dalfopristin, bacitracin, tetracycline, and macrolide resistance genes.

scholarly journals Comparison of Broth Microdilution Method UsingHaemophilus Test Medium and Agar Dilution Method for Susceptibility Testing of Eikenella corrodens

1998 ◽  
Vol 36 (8) ◽  
pp. 2386-2388 ◽  
Author(s):  
Luis Alcalá ◽  
Fernando García-Garrote ◽  
Emilia Cercenado ◽  
Teresa Peláez ◽  
Gema Ramos ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Broth Microdilution ◽  
Test Medium ◽  
Eikenella Corrodens ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Agar Dilution

Susceptibility testing of Eikenella corrodens is usually performed by a Mueller-Hinton sheep blood agar dilution (AD) method. However, this method is impractical for testing only a few strains. We compared AD with the broth microdilution method usingHaemophilus test medium (HTM) in order to determine the susceptibility of 36 clinical isolates of E. corrodens to eight antimicrobial agents. MICs obtained by the HTM method yielded 95.5 and 84% agreement (within 2 and 1 log2 dilutions, respectively) with those obtained by AD. The HTM method with incubation in CO2 for 48 h was highly reproducible and constitutes an easy alternative for antimicrobial susceptibility testing of E. corrodens.

scholarly journals Validation of a method of broth microdilution for the determination of antibacterial activity of essential oils

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Vanegas David ◽  
Abril-Novillo Andrea ◽  
Khachatryan Aleksandr ◽  
Jerves-Andrade Lourdes ◽  
Peñaherrera Eugenia ◽  
...  
Keyword(s):  
Essential Oils ◽  
Sensitivity And Specificity ◽  
Inhibitory Concentration ◽  
Tween 80 ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Broth Microdilution ◽  
Continuous Contact ◽  
Microdilution Method ◽  
Broth Microdilution Method

Abstract Objective The aim of the present study was to adapt and optimize a broth microdilution method and compare it to the agar dilution method for the evaluation of activity of essential oils from medicinal plants against Gram-negative bacteria. Based on bibliographic research, active and not active oils were selected. The sensitivity and specificity were established as parameters for validation. The comparison between both methods was made using contingency analysis tables, based on the observed frequencies. For both methods, the minimum inhibitory concentration was determined against Escherichiacoli strains, in an essential oil concentration range between 0.03 and 0.48% (v/v). Results A stable emulsion formation was achieved with the addition of Tween 80 and constant agitation, guaranteeing the continuous contact of oil with bacteria (critical step in the microdilution method). The statistical analysis of results obtained with both methods presented a good sensitivity and specificity (100% in both cases), which let us correctly discriminate between active and non-active oils. The values obtained for the minimal inhibitory concentration were independent of the technique used. Finally, the obtained results show that the validated microtechnique allows important diminishment of time and resources for investigations dealing with essential oils or lipophilic extracts evaluation.

scholarly journals Antimicrobial Resistance of Campylobacter jejuni, Escherichia coli and Enterococcus faecalis Commensal Isolates from Laying Hen Farms in Spain

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1284
Author(s):  
Jorge Rivera-Gomis ◽  
Pedro Marín ◽  
Cristina Martínez-Conesa ◽  
Julio Otal ◽  
María José Jordán ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Enterococcus Faecalis ◽  
Campylobacter Jejuni ◽  
Laying Hens ◽  
Animal Health ◽  
Laying Hen ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Global Threat

Antimicrobial resistance (AMR) is a global threat for human and animal health. Few studies have been carried out in laying hens. We evaluated the antimicrobial susceptibility of commensal Campylobacter jejuni, Escherichia coli, and Enterococcus faecalis isolates in Spanish laying hens in 2018. The Minimum Inhibitory Concentration (MIC) was used to identify any AMR of the studied isolates by means of a broth microdilution method. C. jejuni was highly resistant to the B category antimicrobials, and 52% of the isolates were susceptible to all the antimicrobials tested. E. coli showed medium and high percentages of resistance to the B and A antibiotic categories, respectively, and 33.33% of the isolates were susceptible to all antimicrobials. The E. faecalis resistance to A category antimicrobials was variable, and 4.62% of the isolates were susceptible to all antimicrobials. In our work, novel data on AMR in laying hen commensal isolates in Spain is provided, and the AMR levels differ from those reported for poultry in the EU. A high resistance to key drugs for human medicine was found, representing a public health risk.

scholarly journals Evolution of the Antimicrobial Resistance of Staphylococcus spp. in Spain: Five Nationwide Prevalence Studies, 1986 to 2002

2004 ◽  
Vol 48 (11) ◽  
pp. 4240-4245 ◽  
Author(s):  
Oscar Cuevas ◽  
Emilia Cercenado ◽  
Ana Vindel ◽  
Jesús Guinea ◽  
Matilde Sánchez-Conde ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Antimicrobial Agents ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Coagulase Negative Staphylococci ◽  
Prevalence Studies ◽  
Treatment Regimens ◽  
Microdilution Method ◽  
Incidence Studies ◽  
Staphylococcus Spp

ABSTRACT Data regarding the evolution of Staphylococcus resistance in a whole country have a definite influence on the design of empirical treatment regimens. Nevertheless, incidence studies over long periods of time are expensive and very difficult to carry out. In order to ascertain the present situation of the antimicrobial resistance of Staphylococcus in Spain and the change of this resistance over time, we performed five point prevalence studies (1986 to 2002) in a large group of Spanish hospitals (from 68 institutions in 1986 to 143 in 2002) collecting all Staphylococcus strains isolated on a single selected day. All microorganisms were identified in the five studies at the same laboratory, and antimicrobial susceptibility testing was performed against 17 antimicrobial agents by the agar dilution method and a microdilution method. During this period, there was an overall increase in resistance to most antimicrobials among Staphylococcus aureus/coagulase-negative staphylococci, mainly to oxacillin (1.5%/32.5% in 1986 versus 31.2%/61.3% in 2002) (P < 0.001), erythromycin (7%/41.1% in 1986 versus 31.7%/63% in 2002) (P < 0.001), gentamicin (5.2%/25.4% in 1986 versus 16.9%/27.8% in 2002) (P < 0.001; P = 0.5), and ciprofloxacin (0.6%/1.1% in 1986 versus 33.9%/44.9% in 2002) (P < 0.001). All of the isolates were uniformly susceptible to glycopeptides, linezolid, and quinupristin/dalfopristin. Resistance of S. aureus to trimethoprim/sulfamethoxazole was very low (from 0.5% to 2.1%) (P = 0.152). Periodic performance of prevalence studies is a useful, inexpensive, and easy tool to know the nationwide situation of a microorganism and its resistance to antimicrobials; it also helps us assess the emergence and spread of antimicrobial resistance.

scholarly journals Examination of the minimum inhibitory concentration of amoxicillin and marbofloxacin against Streptococcus suis using standardised methods

2020 ◽  
Vol 65 (No. 9) ◽  
pp. 377-386
Author(s):  
D Sperling ◽  
H Karembe ◽  
M Zouharova ◽  
K Nedbalcova
Keyword(s):  
Inhibitory Concentration ◽  
Streptococcus Suis ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Microdilution Method ◽  
Linear Relationships ◽  
Broth Microdilution Method ◽  
Significant Difference ◽  
Agar Dilution ◽  
Good Agreement

The results of the antimicrobial susceptibility testing of clinical isolates Streptococcus suis to amoxicillin and marbofloxacin obtained by the agar dilution method and broth microdilution method with the results obtained by the commercially available E-test were compared. Comparisons between the methods based on the determination of the minimal inhibitory concentration (MIC) of the antimicrobials were assessed based on the degree and frequency of the categorical agreement (Agar dilution method as a reference system) and the percentage of the categorical agreement and error rate. A statistical evaluation was determined using the Bland-Atman method. The presented MIC values, determined for the isolates in the E-test, were slightly different from the MIC values determined by the dilution tests, mainly due to the different defined testing concentrations. For the E-test as the test system and agar-dilution method as the reference system, no error of any class was detected (very major, major and minor error) and a complete categorical agreement was obtained between the evaluated methods for amoxicillin. For amoxicillin, the regression and correlation analysis show linear relationships between the E-test and the two dilution methods with significant coefficients of determination (0.62 and 0.75). The slopes of the equality and regression lines were not significantly different. However, the E-test tends to slightly overestimate the MIC values when compared to the microdilution. The reverse is true when compared with the agar dilution. There was good agreement between the E-test and the dilution methods with a low bias (0.001 3 and −0.005 0), all the experimental data were within the computed limits of agreement. For marbofloxacin, the same trends were observed with lower coefficients of determination (0.42 and 0.73) and a less favourable agreement. The E-test constantly underestimated the MIC values when compared to the two dilution methods. No significant difference between the microdilution and agar dilution was obtained.

scholarly journals Problems Related to Determination of MICs of Oximino-Type Expanded-Spectrum Cephems for Proteus vulgaris

2000 ◽  
Vol 38 (2) ◽  
pp. 677-681
Author(s):  
Akira Ohno ◽  
Yoshikazu Ishii ◽  
Ling Ma ◽  
Keizo Yamaguchi
Keyword(s):  
Dilution Method ◽  
Agar Dilution Method ◽  
Proteus Vulgaris ◽  
In Vitro Susceptibility ◽  
Microdilution Method ◽  
Defective Mutant ◽  
Broth Microdilution Method ◽  
Agar Dilution ◽  
Isogenic Mutants

During in vitro susceptibility testing of clinical isolates ofProteus vulgaris, we noted that the MICs of several expanded-spectrum cephems were much higher in the broth microdilution method than in the agar dilution method (termed the MIC gap phenomenon). Here we investigated the mechanism of the MIC gap phenomenon. Cephems with the MIC gap phenomenon were of the oximino type, such as cefotaxime, cefteram, and cefpodoxime, which serve as good substrates for inducible class A β-lactamase (CumA) enzymes produced by P. vulgaris; this finding suggests a relationship between the MIC gap phenomenon and CumA. Since peptidoglycan recycling shares a system common to that inducing CumA, we analyzed the mechanism of the MIC gap phenomenon using P. vulgaris B317 and isogenic mutants with mutations in the peptidoglycan recycling and β-lactamase induction systems. The MIC gap phenomenon was observed in the parent strain B317 but not in B317G (cumG-defective mutant; defective peptidoglycan recycling) and B317R (cumR-defective mutant; defective CumA transcriptional regulator). No β-lactamase activity was detected in B317G and B317R. β-Lactamase activity and the MIC gap phenomenon were restored in B317G/pMD301 (strain transcomplemented by a clonedcumG gene) and B317R/pMD501 (strain transcomplemented by a cloned cumR gene). MICs determined by the agar dilution method increased when lower agar concentrations were used. Our results indicated that the mechanism of the MIC gap phenomenon is related to peptidoglycan recycling and CumA induction systems. However, it remains unclear how β-lactamase induction of P. vulgaris is suppressed on agar plates.

scholarly journals In Vitro Activities of Gemifloxacin versus Five Quinolones and Two Macrolides against 271 Spanish Isolates of Legionella pneumophila: Influence of Charcoal on Susceptibility Test Results

2000 ◽  
Vol 44 (8) ◽  
pp. 2176-2178 ◽  
Author(s):  
M. T. García ◽  
C. Pelaz ◽  
M. J. Giménez ◽  
L. Aguilar
Keyword(s):  
Legionella Pneumophila ◽  
Free Drug ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Test Results ◽  
Progressive Decrease ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Agar Dilution

ABSTRACT The MICs at which 90% of isolates are inhibited for gemifloxacin, trovafloxacin, and grepafloxacin were low (≤0.01 μg/ml) for 271Legionella isolates when they were determined by the broth microdilution method but increased (≥6 dilutions) when they were determined by the agar dilution method. This was due to the charcoal in the agar dilution medium, as shown by the progressive decrease in the MICs when the charcoal concentrations decreased. As free drug is the active fraction, charcoal binding should be considered.

scholarly journals Genetic diversity of vancomycinresistant Enterococcus faecium isolated from blood culture in patients with hematological malignancies

2021 ◽  
Vol 23 (3) ◽  
pp. 305-313
Author(s):  
Svetlana A. Khrulnova ◽  
Galina A. Klyasova ◽  
A.V. Fedorova ◽  
I.N. Frolova ◽  
B.V. Biderman
Keyword(s):  
Genetic Diversity ◽  
High Risk ◽  
Blood Culture ◽  
Enterococcus Faecium ◽  
Hematological Malignancies ◽  
Clonal Complex ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Polymerase Chain ◽  
Sequence Types

Objective. To study the genetic diversity of vancomycin-resistant Enterococcus faecium (VR-E. faecium) isolated from the blood culture in patients with hematological malignancies by multilocus sequence typing (MLST). Materials and Methods. VR-E. faecium isolated from the blood culture in hematological patients in 6 hospitals of 4 Russian cities (2003–2019) were evaluated. Susceptibility to vancomycin was tested by the broth microdilution method (CLSI, 2018). Vancomycin-resistance genes (vanA, vanB) were identified by polymerase chain reaction. Genotyping of VR-E. faecium was performed by MLST. Results. A total of 83 VR-E. faecium were examined. The vanA genes were detected in 71.1% (n = 59) VR-E. faecium, vanB genes – in 28.9% (n = 24). A total of 22 sequence types (STs) belonging to epidemic clonal complex CC17 were detected. The dominant sequence types were ST17 (19.3%), ST78 (18.1%), ST80 (16.9%), and comprised 54.3% VR-E. faecium. Other sequence types included 1 to 4 strains. VR-E. faecium carrying vanA, in comparison with VR-E. faecium vanB, significantly more often belonged to ST78 (23.7% vs. 4.2%, p = 0.0559, respectively) and ST80 (23.7% versus 0%, p = 0.0079, respectively) and less frequently to ST17 (6,8% versus 50%, р < 0.0001). Circulation of 9 STs including «high-risk» clones ST17 and ST78 was detected during two study periods (2003–2011 and 2012–2019). Conclusions. This study showed a genetic diversity of VR-E. faecium that was represented by 22 STs. All VR-E. faecium belonged to epidemic clonal complex CC17 and comprised «high-risk» clones ST17, ST78 and less common STs.

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