scholarly journals Comparison of Inhibitory and Bactericidal Activities and Postantibiotic Effects of LY333328 and Ampicillin Used Singly and in Combination against Vancomycin-Resistant Enterococcus faecium

1998 ◽  
Vol 42 (10) ◽  
pp. 2564-2568 ◽  
Author(s):  
Aldona L. Baltch ◽  
Raymond P. Smith ◽  
William J. Ritz ◽  
Lawrence H. Bopp
Keyword(s):  
New York ◽  
Enterococcus Faecium ◽  
Brain Heart Infusion ◽  
Bactericidal Effect ◽  
Considerable Effect ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Pharmacokinetic Studies ◽  
Mueller Hinton ◽  
Vancomycin Resistant

ABSTRACT One hundred ninety-five individual vancomycin-resistantEnterococcus faecium (VRE) isolates from five upstate New York hospitals were studied for antimicrobial susceptibilities to LY333328, quinupristin-dalfopristin, teicoplanin, ampicillin, and gentamicin. LY333328 was the most active antibiotic against VRE. The effect of media and methods on the antibacterial activity of LY333328, its synergy with ampicillin, and the postantibiotic effects (PAE) of LY333328 and ampicillin were evaluated. In microdilution tests, the MIC of LY333328 at which 90% of the isolates were inhibited (MIC90) was 2 μg/ml in Mueller-Hinton II (MH II) broth and 1 μg/ml in brain heart infusion (BHI) broth. In contrast, on MH II agar the MIC90was 4 μg/ml and on BHI agar it was >16 μg/ml. Bactericidal activity was observed for most strains at concentrations from 8 to ≥133 times the MIC of the tube macrodilution in MH II broth. A bactericidal effect of LY333328 plus ampicillin was demonstrated in time-kill studies, but there was great strain-to-strain variability. By the MH II agar dilution method, bacteristatic synergy (defined as a fractional inhibitory concentration of <0.5) with LY333328 and ampicillin was demonstrated for 61% of the strains tested. Under similar conditions, there was synergy with LY333328 and quinupristin-dalfopristin or gentamicin for 27 and 15% of the strains tested, respectively. The PAE of LY333328 was prolonged (23.0 h at 10 times the MIC). However, 50% normal pooled human serum decreased the PAE to 12.2 h at 10 times the MIC. Test conditions and media had a considerable effect on VRE susceptibilities to LY333328. The prolonged PAE of LY333328, a potent new bactericidal glycopeptide, and its synergy with ampicillin in a large proportion of strains suggest that further evaluation of this drug in pharmacokinetic studies and experimental infections, including those with VRE, is 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 Risk factors for intestinal colonization with vancomycin resistant enterococci’ A prospective study in a level III pediatric intensive care unit

2018 ◽  
Vol 10 (01) ◽  
pp. 089-094 ◽  
Author(s):  
Rajesh Amberpet ◽  
Sujatha Sistla ◽  
Subhash Chandra Parija ◽  
Ramachandran Rameshkumar
Keyword(s):  
Risk Factors ◽  
Intensive Care ◽  
Tertiary Care ◽  
Pediatric Intensive Care ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Gut Colonization ◽  
Vancomycin Resistant Enterococci ◽  
Vancomycin Resistant ◽  
A Prospective Study

Abstract PURPOSE: Vancomycin-resistant enterococci (VRE) emerged as one of the major nosocomial pathogens across the globe. Gut colonization rate with VRE is higher in patients admitted to intensive care units (ICUs) due to the higher antibiotic pressure. VRE colonization increases the risk of developing infection up to 5–10 folds. The aim of this study was to determine the rates of VRE colonization among the patients admitted to pediatric ICU (PICU) and risk factors associated with it. MATERIALS AND METHODS: Rectal swabs were collected after 48 h of admission to PICU from 198 patients. The samples were inoculated onto bile esculin sodium azide agar with 6 mg/ml of vancomycin. Growth on this medium was identified by the standard biochemical test, and minimum inhibitory concentration of vancomycin and teicoplanin was detected by agar dilution method. Resistance genes for vancomycin were detected by polymerase chain reaction. Risk factors were assessed by logistic regression analysis. RESULTS: The rates of VRE colonization in patients admitted to PICU was 18.6%. The majority of the isolates were Enterococcus faecium (75.6%) followed by Enterococcus faecalis (24.4%). One patient acquired a VRE bloodstream infection (2.6%) among colonized patients, and none of the noncolonized patients acquired the infection. Consumption of vancomycin was found to be the only risk factor significantly associated with VRE colonization. CONCLUSION: Routine surveillance and isolation of patients found to be VRE colonized may not be possible in tertiary care hospitals; however, educating health-care workers, promoting handwashing with antiseptic soaps or solutions, and antibiotic Stewardship policy may help in the reduction of vancomycin resistance and VRE colonization.

scholarly journals Correlation between Mutations inliaFSRof Enterococcus faecium and MIC of Daptomycin: Revisiting Daptomycin Breakpoints

2012 ◽  
Vol 56 (8) ◽  
pp. 4354-4359 ◽  
Author(s):  
Jose M. Munita ◽  
Diana Panesso ◽  
Lorena Diaz ◽  
Truc T. Tran ◽  
Jinnethe Reyes ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Cell Envelope ◽  
Strong Association ◽  
Brain Heart Infusion ◽  
Regulatory System ◽  
Content Type ◽  
Initial Event ◽  
Mueller Hinton ◽  
Envelope Stress ◽  
Mueller Hinton Agar

ABSTRACTMutations inliaFSR, a three-component regulatory system controlling cell-envelope stress response, were recently linked with the emergence of daptomycin (DAP) resistance in enterococci. Our previous work showed that aliaFmutation increased the DAP MIC of a vancomycin-resistantEnterococcus faecalisstrain from 1 to 3 μg/ml (the DAP breakpoint is 4 μg/ml), suggesting that mutations in theliaFSRsystem could be a pivotal initial event in the development of DAP resistance. With the hypothesis that clinical enterococcal isolates with DAP MICs between 3 and 4 μg/ml might harbor mutations inliaFSR, we studied 38Enterococcus faeciumbloodstream isolates, of which 8 had DAP MICs between 3 and 4 μg/ml by Etest in Mueller-Hinton agar. Interestingly, 6 of these 8 isolates had predicted amino acid changes in the LiaFSR system. Moreover, we previously showed that among 6 DAP-resistantE. faeciumisolates (MICs of >4 μg/ml), 5 had mutations inliaFSR. In contrast, none of 16E. faeciumisolates with a DAP MIC of ≤2 μg/ml harbored mutations in this system (P< 0.0001). All but one isolate withliaFSRchanges exhibited DAP MICs of ≥16 μg/ml by Etest using brain heart infusion agar (BHIA), a medium that better supports enterococcal growth. Our findings provide a strong association between DAP MICs within the upper susceptibility range and mutations in theliaFSRsystem. Concomitant susceptibility testing on BHIA may be useful for identifying theseE. faeciumfirst-step mutants. Our results also suggest that the current DAP breakpoint forE. faeciummay need to be reevaluated.

scholarly journals Sensitivity and Efficacy of Boscalid, Fluazinam, and Thiophanate-Methyl for White Mold Control in Snap Bean in New York

Plant Disease ◽  
2017 ◽  
Vol 101 (7) ◽  
pp. 1253-1258 ◽  
Author(s):  
M. S. Lehner ◽  
E. M. Del Ponte ◽  
B. K. Gugino ◽  
J. R. Kikkert ◽  
S. J. Pethybridge
Keyword(s):  
New York ◽  
Growth Inhibition ◽  
Mycelial Growth ◽  
Point Mutations ◽  
Field Trials ◽  
White Mold ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Snap Bean ◽  
Thiophanate Methyl

White mold (Sclerotinia sclerotiorum) of leguminous crops in New York is generally managed with preventive applications of fungicides. However, no research has been conducted during the last decade to assess the sensitivity of the S. sclerotiorum population to fungicides or compare their performance under field conditions. The sensitivity of S. sclerotiorum to boscalid, fluazinam, and thiophanate-methyl was assessed in 151 isolates from 15 fields across New York using an agar dilution method with discriminatory concentrations. In addition, the effective concentration at which mycelial growth is reduced by 50% (EC50) was estimated for one representative isolate from each field. The efficacy of commercial formulations of each fungicide on white mold incidence in plants and pods was also tested in two field trials (2015 and 2016). The EC50 values ranged from 0.068 to 0.219, 0.001 to 0.002, and 1.23 to 2.15 µg/ml for boscalid, fluazinam, and thiophanate-methyl, respectively. Evidence of resistance was not found using the discriminatory concentration tests. The mycelial growth inhibition relative to the control ranged from 56 to 83%, 66 to 84%, and 53 to 83% at discriminatory concentrations of boscalid (5 µg a.i./ml), fluazinam (0.05 µg a.i./ml), and thiophanate-methyl (5 µg a.i./ml), respectively. Fourteen isolates with mycelial growth inhibition lower than 60% at 5 µg/ml of thiophanate-methyl, did not exhibit point mutations within a partial sequence of the β-tubulin gene. In the field trials, fungicides effectively reduced white mold incidence on plants by 75% (2015) and 93% (2016) and on pods by 81% (2015) and 87% (2016), both relative to the nontreated plots. However, fungicide applications led to significant increases in pod yield, relative to the nontreated plots, only in 2015 when the incidence of white mold on plants and pods were higher (85 and 49.2%) than in 2016 (31.3 and 10.3%). Although fungicide resistance was not detected, and thus control failures reported by New York snap bean growers may be due to other factors, further monitoring of sensitivity within the S. sclerotiorum population is encouraged as well as the use of rational systems to base their judicious and economic use.

scholarly journals Emergence of Vancomycin Resistant Staphylococcus aureus during Hospital Admission at a Tertiary Care Hospital in Bangladesh

2017 ◽  
Vol 3 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Shahana Khanam ◽  
Jalaluddin Ashraful Haq ◽  
SM Shamsuzzaman ◽  
Md Motlabur Rahman ◽  
Kazi Zulfiquer Mamun
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Tertiary Care ◽  
Control Measures ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Care Hospital ◽  
Medical College ◽  
Nasal Swab Sample ◽  
Vancomycin Resistant

Background: Glycopeptides such as vancomycin are frequently the choice of antibiotics for the treatment of infections caused by methicillin resistant Staphylococcus aureus (MRSA). For the last 7 years incidence of vancomycin intermediate S. aureus and vancomycin resistant S. aureus (VISA and VRSA respectively) has been increasing in various parts of the world.Objective: The present study was carried out to find out the presence of VISA and VRSA among isolated MRSA strains.Methodology: This cross sectional study was carried out in the Department of Microbiology in Dhaka medical college during period of January 2010 to December 2011. All S. aureus isolates were screened to detect methicillin resistance and then all MRSA isolates were subjected for MIC testing against vancomycin and oxacillin by agar dilution method, disc diffusion testing and PCR for mecA and pvl genes detection.Result: A total 112 S. aureus were isolated from 500 nasal swab sample collected from adult patients who were admitted in various departments and wards in Dhaka Medical College Hospital. Among 38 MRSA strains out of 112 Staph aureus isolates 3(7.89%) strains were resistance to vancomycin of which 2(5.26%) strains had MIC > 256 mg/mL and one strain had MIC 256mg/mL. All vancomycin resistance strains had MIC of oxacillin > 256 mg/mL. All isolates possess mec-A gene.Conclusion: The present study reveals that emergence of VRSA upon admission at a tertiary care of hospital in Bangladesh. Continuous efforts should be made to prevent the spread and the emergence of VRSA by early detection of the resistant strains and using the proper infection control measures in the hospital setting.Bangladesh Journal of Infectious Diseases 2016;3(1):11-16

scholarly journals High Frequency of Vancomycin-Resistant Enterococci in Sewage and Fecal Samples of Healthy Carriers

2019 ◽  
Vol 13 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Fakhri Haghi ◽  
Neda Shirmohammadlou ◽  
Rabab Bagheri ◽  
Sama Jamali ◽  
Habib Zeighami
Keyword(s):  
Antibiotic Resistance ◽  
High Frequency ◽  
Municipal Sewage ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Fecal Samples ◽  
Vancomycin Resistant Enterococci ◽  
Agar Dilution ◽  
Vancomycin Resistant ◽  
Healthy Carriers

Objectives:Enterococci are part of the microbial flora of the gastrointestinal tract of animals and human and can be released into the environment through fecal materials. These microorganisms play an important role in the dissemination of antibiotic resistance genes. Vancomycin-Resistant Enterococci (VRE) have been obtained in municipal sewage, hospital and agricultural wastes and healthy carriers. The aim of this study was to investigate the frequency of VRE in sewage and fecal samples of healthy carriers.Methods:This study was performed on fecal specimens of 100 healthy carriers and 100 samples of sewage in Zanjan Province. Fecal and sewage samples were cultured on Trypticase Soy Agar and biochemical tests were performed for Enterococci identification. Antimicrobial susceptibility testing was performed as CLSI guidelines and vancomycin resistance was determined using the agar dilution method.Result:Of 200 cultured samples, 141 isolates of Enterococci were detected. 64 isolates were detected from fecal and 77 were isolated from the sewage samples. Antibiotic resistance profile of fecal isolates was as follows: tetracycline (57.8%), ciprofloxacin (54.7%), phosphomycin (54.7%), erythromycin (51.5%), chloramphenicol (12.5%), amoxicillin (21.8%) and gatifloxacin (23.5%). Also for the sewage samples, the most antibiotic resistance was detected against ciprofloxacin (76.6%) followed by tetracycline (74%), erythromycin (68.8%), phosphomycin (61%). According to Agar dilution method, among 141 isolates of Enterococci, 15 (10.6%) isolates were vancomycin resistant: 11 of sewage isolates (14.3%) and 4 of the carrier isolates (6.2%).Conclusion:Our study describes the high frequency of VRE in municipal sewage and healthy carriers. Regarding the importance of VRE strains in the clinical and environment, it seems necessary to follow up on the issue.

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.

scholarly journals Correlation of Oxacillin MIC with mecAGene Carriage in Coagulase-Negative Staphylococci

2000 ◽  
Vol 38 (2) ◽  
pp. 752-754 ◽  
Author(s):  
Zafar Hussain ◽  
Luba Stoakes ◽  
Viki Massey ◽  
Deb Diagre ◽  
Viivi Fitzgerald ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Clinical Laboratory ◽  
National Committee ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Agar Dilution

The National Committee for Clinical Laboratory Standards has recently changed the oxacillin breakpoint from ≥4 mg/liter to ≥0.5 mg/liter to detect methicillin-resistant coagulase-negative staphylococci (CoNS) because the previous breakpoint lacked sensitivity. To determine the correlation between the new oxacillin breakpoint and the presence of themecA gene, 493 CoNS of 11 species were tested. The presence of the mecA gene was determined by PCR, and oxacillin susceptibility was determined by the agar dilution method with Mueller-Hinton agar containing 2% NaCl and oxacillin (0.125 to 4.0 mg/liter). The new breakpoint correctly classified all CoNS strains with mecA as methicillin resistant and strains ofStaphylococcus epidermidis, S. haemolyticus, and S. hominiswithout mecA as methicillin susceptible. The breakpoint of ≥0.5 mg/liter was not specific for S. cohnii, S. lugdunensis, S. saprophyticus, S. warneri, and S. xylosus, in that it categorized 70 of 74 strains of these species withoutmecA (94.6%) as methicillin resistant. The results of this study indicate that the new oxacillin breakpoint accurately identifies strains of CoNS with mecAbut is not specific for strains of certain species of CoNS withoutmecA.

scholarly journals Time-Kill and Synergism Studies of Ceftobiprole against Enterococcus faecalis, Including β-Lactamase-Producing and Vancomycin-Resistant Isolates

2007 ◽  
Vol 51 (6) ◽  
pp. 2043-2047 ◽  
Author(s):  
Cesar A. Arias ◽  
Kavindra V. Singh ◽  
Diana Panesso ◽  
Barbara E. Murray
Keyword(s):  
Enterococcus Faecalis ◽  
Vitro Activity ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
In Vitro Activity ◽  
Inoculum Concentration ◽  
High Inoculum ◽  
Vancomycin Resistant ◽  
Time Kill

ABSTRACT Ceftobiprole (BAL9141) is an investigational cephalosporin with broad in vitro activity against gram-positive cocci, including enterococci. Ceftobiprole MICs were determined for 93 isolates of Enterococcus faecalis (including 16 β-lactamase [Bla] producers and 17 vancomycin-resistant isolates) by an agar dilution method following the Clinical and Laboratory Standards Institute recommendations. Ceftobiprole MICs were also determined with a high inoculum concentration (107 CFU/ml) for a subset of five Bla producers belonging to different previously characterized clones by a broth dilution method. Time-kill and synergism studies (with either streptomycin or gentamicin) were performed with two β-lactamase-producing isolates (TX0630 and TX5070) and two vancomycin-resistant isolates (TX2484 [VanB] and TX2784 [VanA]). The MICs of ceftobiprole for 50 and 90% of the isolates tested were 0.25 and 1 μg/ml, respectively. All Bla producers and vancomycin-resistant isolates were inhibited by concentrations of ≤1 and ≤4 μg/ml, respectively, at the standard inoculum concentration. Ceftobiprole MICs at a high inoculum concentration for a subset of five Bla+ E. faecalis isolates were ≤1 μg/ml. Bactericidal activity was observed against four isolates tested at concentrations as low as 1 μg/ml regardless of the production of β-lactamase or vancomycin resistance. A combination of ceftobiprole (0.5 μg/ml) and streptomycin (25 μg/ml) was synergistic against Bla+ TX0630 and TX5070. Ceftobiprole (0.5 μg/ml) plus gentamicin (10 μg/ml) was synergistic against VanB isolate TX2484 and showed enhanced killing, but not synergism, against TX2784 (VanA), despite the absence of high-level resistance to gentamicin. In conclusion, ceftobiprole exhibited good in vitro activity against E. faecalis, including Bla+ and vancomycin-resistant strains, and exhibited synergism with aminoglycosides against selected isolates.

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