scholarly journals Vancomycin intermediate and high level vancomycin resistant Staphylococcus aureus clinical isolates in Osogbo, Nigeria

2011 ◽  
Vol 2 (1) ◽  
pp. 6
Author(s):  
Samuel Sunday Taiwo ◽  
Titilope Bosede Bamigboye ◽  
Osatohanmwen Odaro ◽  
Olusegun Adelowo Adefioye ◽  
Solomon Olufemi Fadiora
Keyword(s):  
Staphylococcus Aureus ◽  
Public Health Problem ◽  
Disk Diffusion ◽  
Major Public Health Problem ◽  
Disk Diffusion Test ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
Vancomycin Resistant ◽  
High Level ◽  
Broth Dilution

<p>The decreased vancomycin susceptibility and subsequent emergence of vancomycin resistant <em>Staphylococcus aureus </em>(VRSA) strains already multi-resistant to antibiotics is a major public health problem. In 2009, the Clinical and Laboratory Standards Institute (CLSI) altered its guidelines for vancomycin susceptibility testing in <em>S. aureus</em> and recent data suggests the possibility that VRSA may emerge more frequently than previously expected. Against this background, we conducted a study to ascertain the susceptibility status of clinical <em>S. aureus</em> isolates to vancomycin in our environment using vancomycin agar screen, disk diffusion and broth dilution methods. Of the total 49 <em>S. aureus </em>invasive strains isolated, 25 (51.0%) had vancomycin MIC of ≤2µg/ml by the CLSI standard broth dilution method and are classed as vancomycin susceptible; 18 (36.7%) had MIC of 4-8µg/ml (vancomycin intermediate resistant) and 6 (12.2%) had MIC of &gt;256µg/ml (high level vancomycin resistant). Vancomycin agar screen with Mueller-Hinton agar containing 3µg/ml vancomycin (MHA-V3) correctly identified 20 of 25 (80%) vancomycin susceptible isolates; detected all 6 vancomycin resistant isolates and 16 of 18 (88.9%) vancomycin intermediate strains. Similarly, Mueller-Hinton agar containing 6µg/ml vancomycin (MHA-V6) correctly identified 23 of 25 (92%) vancomycin susceptible isolates and all 6 vancomycin resistant isolates but detected 14 (77.8%) of 18 vancomycin intermediate strains. Vancomycin disk diffusion test correctly identified all the 25 vancomycin susceptible <em>S. aureus</em> isolates giving 100% specificity but detected only 1 of 18 (5.6%) vancomycin intermediate and none (0%) of vancomycin resistant isolates. This result shows the occurrence of VISA and high level VRSA isolates in our environment, which contrary to current belief, may indicate widespread dissemination of VRSA. MHA-V3 agar is a useful alternative screening medium for vancomycin non-susceptibility detection in clinical <em>S. aureus</em> isolates but vancomycin disk diffusion is not useful in this regard.</p>

scholarly journals Synergy of Daptomycin with Oxacillin and Other β-Lactams against Methicillin-Resistant Staphylococcus aureus

2004 ◽  
Vol 48 (8) ◽  
pp. 2871-2875 ◽  
Author(s):  
Kenneth H. Rand ◽  
Herbert J. Houck
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Activity ◽  
Screening Method ◽  
Methicillin Resistant ◽  
Drug Concentrations ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
High Level ◽  
Time Kill

ABSTRACT We previously observed marked synergy between daptomycin and both rifampin and ampicillin against vancomycin-resistant enterococci (VRE). Because the synergy between daptomycin and ampicillin was observed for 100% of VRE strains with high-level ampicillin resistance (ampicillin MIC of ≥128 μg/ml), we looked for synergy between daptomycin and other β-lactams against 18 strains of methicillin-resistant Staphylococcus aureus (MRSA) by employing a time-kill method using Mueller-Hinton broth supplemented to 50 mg of Ca2+/liter. All strains were resistant to oxacillin (16 of 18 strains were resistant at drug concentrations of ≥256 μg/ml), and all strains were susceptible to daptomycin (the MIC at which 90% of the tested isolates were inhibited was 1 μg/ml). Daptomycin was tested at concentrations of 2, 1, 0.5, 0.25, 0.125, and 0.0625 μg/ml alone or in combination with oxacillin at a fixed concentration of 32 μg/ml. Synergy was found for all 18 strains with daptomycin at one-half the MIC in combination with 32 μg of oxacillin/ml, and synergy was found for 11 of 18 strains (61%) with daptomycin at one-fourth the MIC or less in combination with oxacillin. At 24 h, the daptomycin-oxacillin combination with daptomycin at one-half the MIC showed bactericidal activity against all 18 strains, and the combination with one-fourth the daptomycin MIC showed bactericidal activity against 9 of 18 strains. We also used a novel screening method to look for synergy between daptomycin and other β-lactams. In this approach, daptomycin was incorporated into Ca2+-supplemented Mueller-Hinton agar at subinhibitory concentrations, and synergy was screened by comparing test antibiotic Kirby-Bauer disks on agar with and without daptomycin. By this method, daptomycin with ampicillin-sulbactam, ticarcillin-clavulanate, or piperacillin-tazobactam showed synergy comparable to or greater than daptomycin with oxacillin. For seven of the eight strains tested, time-kill studies confirmed synergy between daptomycin and ampicillin-sulbactam with ampicillin in the range of 2 to 8 μg/ml. The combination of daptomycin and β-lactams may be useful for the treatment of MRSA infection, but further studies are needed to elucidate the mechanisms and to determine the in vivo efficacy of the combination.

scholarly journals Vancomycin-resistant Enterococcus faecium in Algeria: phenotypic and genotypic characterization of clinical isolates

2021 ◽  
Vol 15 (01) ◽  
pp. 95-101
Author(s):  
Nabila Benamrouche ◽  
Badia Guettou ◽  
Fatma Zohra Henniche ◽  
Farida Assaous ◽  
Houcine Laouar ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
Public Health Problem ◽  
Test Method ◽  
Control Measures ◽  
Molecular Characteristics ◽  
Major Public Health Problem ◽  
Vancomycin Resistant Enterococcus ◽  
Infection Control Measures ◽  
Vancomycin Resistant ◽  
High Level

Introduction: vancomycin-resistant Enterococcus faecium (VREfm) is a major public health problem worldwide. The aim of our study was to determine the microbiological, epidemiological and molecular characteristics of VREfm isolated in north-central, eastern and western Algeria. Methodology: a collection of 48 VREfm isolated from September 2010 to April 2017 in several Algerian hospitals were studied. Minimum inhibitory concentrations (MICs) were determined by E-test method according to CLSI guidelines. the detection of van genotype of all strains was performed by PCR. Clonal relationship of five VREfm targeted by region were characterized using multilocus sequence typing (MLST). Results: All isolates have multidrug-resistance (MDR) and were resistant to at least five classes of antibiotics; however, all were susceptible to tigecycline and daptomycin with MIC50 at 0.094 µg/mL and 2 µg/mL respectively. All strains belonged to vanA genotype and have high level of resistance to vancomycin and teicoplanin. MLST revealed two sequence types (STs): ST80 (from the four regions of Algeria) and ST789, both belonging to the former hospital-adapted clonal complex CC17. Conclusions: the alarming dissemination of MDR E. faecium vanA and the ST80 in several regions of Algeria suggest a clonal spread of VREfm strains, which urgently require implementation of adequate infection control measures.

scholarly journals Determination of Colistin Resistance by Simple Disk Diffusion Test Using Modified Mueller-Hinton Agar

2020 ◽  
Vol 40 (4) ◽  
pp. 306-311 ◽  
Author(s):  
Jean Damascene Uwizeyimana ◽  
Daewon Kim ◽  
Hyunsook Lee ◽  
Jung-Hyun Byun ◽  
Dongeun Yong
Keyword(s):  
Disk Diffusion ◽  
Colistin Resistance ◽  
Diffusion Test ◽  
Disk Diffusion Test ◽  
Mueller Hinton ◽  
Mueller Hinton Agar

scholarly journals Antibiotic Susceptibility of Staphylococcus aureus Isolated from Retailed Raw Beef at Choba Market, Rivers State

2021 ◽  
pp. 25-30
Author(s):  
Onoriode C. Eruteya ◽  
Patience O. Osariemen
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Susceptibility ◽  
Multidrug Resistant ◽  
Antibiotic Resistant ◽  
Mannitol Salt Agar ◽  
Randomized Design ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
High Level ◽  
Rivers State

Aims: The aim of the study was to determine the presence of antibiotic resistant Staphylococcus aureus in retail raw beef in Choba market, Nigeria. Study design: The study is based on a completely randomized design with two replicates and the mean being calculated. Place and Duration of Study: Major’s Laboratory, Department of Microbiology, University of Port Harcourt within three months. Methodology: The presence, characterization and antibiotic susceptibility of S. aureus from 30 retail raw beef samples was done using standard microbiological method involving the use of mannitol salt agar (MSA) and Mueller Hinton agar (MHA). Results: All the samples were positive for Staphylococcus species of which 18 (60.00%) were positive for S. aureus. The S. aureus strains were least resistant to gentamycin (22.22%) and cotrimoxazole (38.89%) with varying resistance against erythromycin (83.33%), tetracycline (88.88) and chloramphenicol (61.11%). All the S. aureus isolates in this study were 100% resistant to cloxacillin, amoxicillin and augmentin or amoxicillin-clavulanic acid combination. These results also showed the potential dissemination of multidrug-resistant S. aureus strains in the raw beef samples examined. Conclusion: The results of this study suggested high-level contamination of meat with multi-drug resistant S. aureus and this highlights the public health consequences associated with consuming such unhygienic products if poorly prepared.

Medically Important Vector Borne Disease Control-Botanical Plant Extract Trials

2018 ◽  
Vol 4 (4) ◽  
pp. 513
Author(s):  
Rakhshan .
Keyword(s):  
Disease Control ◽  
Public Health Problem ◽  
Major Public Health Problem ◽  
Vector Borne Disease ◽  
Development Of Resistance ◽  
Vector Borne ◽  
Synthetic Pesticides ◽  
High Level ◽  
Continuous Use ◽  
Chemical Pesticides

Mosquitoes are vectors of many pathogens which causes serious human diseases like Malaria, Filariasis, Japanese encephalitis, Dengue fever, Chikungunya, Yellow fever and Zika virus which constitute a major public health problem globally. Mosquito borne diseases cause high level of economic impact all over the world and result in millions of death every year. They infect around 700,000,000 people annually worldwide and 40,000,000 only in India. The continuous use of synthetic pesticides to control vector mosquitoes has caused physiological resistance, toxic effect on human health, environmental pollution and addition to these, its adverse effects can be observed on non-target organisms. Synthetic chemical pesticides have been proved to be effective, but overall in last 5 decades indiscriminate use of synthetic pesticides against vector borne disease control have originated several ecological issues due to their residual accumulation and development of resistance in target vectors and their chronic effects.

Biological Evaluation of Selected 1,2,3-triazole Derivatives as Antibacterial and Antibiofilm Agents

2020 ◽  
Vol 20 (24) ◽  
pp. 2186-2191
Author(s):  
Lialyz Soares Pereira André ◽  
Renata Freire Alves Pereira ◽  
Felipe Ramos Pinheiro ◽  
Aislan Cristina Rheder Fagundes Pascoal ◽  
Vitor Francisco Ferreira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Public Health Problem ◽  
Biological Evaluation ◽  
Major Public Health Problem ◽  
Community Environments ◽  
Scanning Electron

Background: Resistance to antimicrobial agents is a major public health problem, being Staphylococcus aureus prevalent in infections in hospital and community environments and, admittedly, related to biofilm formation in biotic and abiotic surfaces. Biofilms form a complex and structured community of microorganisms surrounded by an extracellular matrix adhering to each other and to a surface that gives them even more protection from and resistance against the action of antimicrobial agents, as well as against host defenses. Methods: Aiming to control and solve these problems, our study sought to evaluate the action of 1,2,3- triazoles against a Staphylococcus aureus isolate in planktonic and in the biofilm form, evaluating the activity of this triazole through Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) tests. We have also performed cytotoxic evaluation and Scanning Electron Microscopy (SEM) of the biofilms under the treatment of the compound. The 1,2,3-triazole DAN 49 showed bacteriostatic and bactericidal activity (MIC and MBC 128 μg/mL). In addition, its presence interfered with the biofilm formation stage (1/2 MIC, p <0.000001) and demonstrated an effect on young preformed biofilm (2 MICs, p <0.05). Results: Scanning Electron Microscopy images showed a reduction in the cell population and the appearance of deformations on the surface of some bacteria in the biofilm under treatment with the compound. Conclusion: Therefore, it was possible to conclude the promising anti-biofilm potential of 1,2,3-triazole, demonstrating the importance of the synthesis of new compounds with biological activity.

scholarly journals Evaluation of Mannitol Salt Agar for Detection of Oxacillin Resistance in Staphylococcus aureus by Disk Diffusion and Agar Screening

1998 ◽  
Vol 36 (8) ◽  
pp. 2254-2257 ◽  
Author(s):  
Günter Kampf ◽  
Christoph Lecke ◽  
Ann-Katrin Cimbal ◽  
Klaus Weist ◽  
Henning Rüden
Keyword(s):  
Staphylococcus Aureus ◽  
Disk Diffusion ◽  
Diffusion Test ◽  
Mannitol Salt Agar ◽  
Disk Diffusion Test ◽  
Zone Diameter ◽  
Oxacillin Resistance

Mannitol salt agar was evaluated for detection of oxacillin resistance in 136 Staphylococcus aureus isolates. AllmecA-positive isolates (n = 54) were correctly categorized as oxacillin resistant by the disk diffusion test (1-μg disk; zone diameter, <16 mm); the specificity was 97.6%. Agar screening (2 μg of oxacillin per ml) revealed a sensitivity of 98.1% and a specificity of 95.1%.

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