Antimicrobial susceptibility of Brucella spp. isolated from Iranian patients during 2016 to 2018

2019 ◽  
Author(s):  
Saeed Alamian ◽  
Maryam Dadar ◽  
Afshar Etemadi ◽  
Davoud Afshar ◽  
Mohammad Mehdi Alamian
Keyword(s):  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
Inhibitory Concentration ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Antibiotic Administration ◽  
Disk Diffusion Method ◽  
Effective Activity ◽  
High Prevalence ◽  
Blood Specimens

Background and Objectives: Brucellosis is a widespread zoonotic disease with a high prevalence in both animals and hu- mans. The present study was aimed to evaluate the susceptibility of Brucella strains isolated from human clinical specimens against commonly used antimicrobial agents. Materials and Methods: A total of 360 blood specimens were collected during 2016-2018 and subjected to culture and Brucella spp. identification. The classical biotyping for Brucella isolates was performed according to Alton and coworker's guidelines. Antimicrobials susceptibility test carried out using disk diffusion and minimal inhibitory concentration (MIC) methods. Results: In this study, sixty B. melitensis strains were isolated from blood samples (16%) and all them belonged to biovar 1. Majority of the tested antibacterial agents, excepting ampicillin-sulbactam had an effective activity against B. melitensis isolates in E-test (MIC) and disk diffusion method. Moreover, probable resistance to rifampin and ampicillin-sulbactam were observed in 60 (100%), 1 (1.7%), 11 (18.4%) and 2 (3.4%) isolates, respectively. Conclusion: Our data suggest that the efficacy of commonly used antibiotics for brucellosis treatment should be regularly monitored. In conclusion, appropriate precaution should be exercised in the context of antibiotic administration to prevent future antibiotic resistance.

scholarly journals SENSITIVITY OF STREPTOCOCCUS VIRIDANS TO ANTIBACTERIAL AGENTS IN HIV-POSITIVE PATIENTS COUPLED TO RESPIRATORY DISEASES

2019 ◽  
Author(s):  
L. Puzyreva ◽  
A. Mordyk ◽  
L. Rodkina ◽  
I. Zhitina ◽  
A. Timofeeva
Keyword(s):  
Minimal Inhibitory Concentration ◽  
Respiratory Diseases ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Clinical Laboratory ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Similar Data ◽  
Disk Diffusion Method ◽  
Facultative Anaerobic Bacteria

The streptococcus group includes numerous types of globular Gram-positive facultative anaerobic bacteria, the classification of which is based on their ability to erythrocyte hemolysis.Streptococci of the viridans group are green streptococci and natural representatives of normal microflora in the oral cavity. However, in case of developing immunodeficiency states, oncology, neutropenia, this pathogen can cause diseases such as bacteremia, sepsis, endocarditis, and pneumonia in some cases.Respiratory diseases are a common cause requiring medical aid for HIV-infected cohort.The role of commensal S.viridans in development of bacterial diseases in HIV-infected patients remains poorly examined. Potential association of S.viridans with other bacterial communities, including pathogenic microorganisms, still unclear. In addition, of might be worthy to evaluate sensitivity of S. viridans to antibacterial agents in area of high HIV infection incidence.The aim of the study was to evaluate sensitivity of sputum viridans streptococci to antibiotics from HIV-infected patients with manifested pneumonia.Materials and Methods. The data from sputum microbiological study in all HIV-infected patients with suspected pneumonia (n = 684) were analyzed in the Infectious Clinical Hospital No. 1 named after D.M. Dalmatov, among which S.viridans was detected in 193 patients (28.2%) within 01.01.2012 – 01.01.2019 timeframe.Bacteriological examination of patient samples was conducted to isolate pure bacterial culture by using standard methods. Next, S.viridans was assessed for sensitivity to antibacterial agents (n=78) according to 2018 clinical recommendations. Initially, antibiotic resistance was determined by disk-diffusion method as a routine and broadly used approach in clinical laboratory. After that, minimal inhibitory concentration was measured by using AutoScan 4 Microscan analyzer (bacteriological semi-automatic analyzer,Beckman Coulter,USA) to identify and determine antibacterial sensitivity.Results. A disk-diffusion method allowed to find in sputum samples penicillin resistance in 28.2% cases, 42.3% – to ampicillin, and 43.6% – to cefazolin. While assessing minimal inhibitory concentration for antibacterial agents, similar data were obtained. Good sensitivity was found for cefotaxime, ceftriaxone, cefepime, fluoroquinolones and vancomycin.

scholarly journals Comparison of methods for the determination of antimicrobial resistance in Campylobacter spp. human and the food chain isolates

2008 ◽  
Vol 52 (No. 4) ◽  
pp. 169-174
Author(s):  
M. Holasova ◽  
R. Karpiskova ◽  
S. Karpiskova ◽  
V. Babak ◽  
J. Schlegelova
Keyword(s):  
Nalidixic Acid ◽  
Antimicrobial Agents ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Study Results ◽  
Agar Dilution

With a microdilution method, using the commercial diagnostic test Sensititre Susceptibility Plates for Campylobacter MIC (Trek Diagnostic Systems, Cleveland, OH, USA), disk diffusion and agar dilution method, resistance to six antimicrobial agents were examined in a reference strain <i>Campylobacter jejuni</i> ATCC 33560 and 73 thermo-tolerant isolates of <i>Campylobacter</i> spp. For the microdilution method and all tested antimicrobial agents, our determined values of microbiological breakpoints of resistant strains were suggested as the minimum inhibitory concentration (MIC<sub>R</sub>) for ciprofloxacin &ge; 0.5, erythromycin &ge; 4, gentamicin &ge; 4, nalidixic acid &ge; 32 and tetracycline &ge; 4 &mu;g/ml. On the basis of our study results, strains resistant to clindamycin were MIC<sub>R</sub> &ge; 2 &mu;g/ml for the dilution methods and a zone diameter R ≤ 16 mm for the disk diffusion method. Comparison of the results of the resistance examination, a microdilution method and disk diffusion method with the reference agar dilution method, showed that all compared methods yielded identical results with the exception of the resistance determination in erythromycin and nalidixic acid. The errors were mostly the result of the interpretation criteria for MIC<sub>R</sub> of agar dilution method and different conditions of cultivation used. However, the compared methods, provide results comparable with the reference method having greater convenience of measurement.

scholarly journals Genetic Characterization of Methicillin-Resistant Staphylococcus aureus Isolates from Human Bloodstream Infections: Detection of MLSB Resistance

Antibiotics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 375
Author(s):  
Vanessa Silva ◽  
Sara Hermenegildo ◽  
Catarina Ferreira ◽  
Célia M. Manaia ◽  
Rosa Capita ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bloodstream Infections ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Accessory Gene ◽  
Spa Typing ◽  
Disk Diffusion Method ◽  
Methicillin Resistant

In this study we aimed to characterize antimicrobial resistance in methicillin-resistant Staphylococcus aureus (MRSA) isolated from bloodstream infections as well as the associated genetic lineages of the isolates. Sixteen MRSA isolates were recovered from bacteremia samples from inpatients between 2016 and 2019. The antimicrobial susceptibility of these isolates was tested by the Kirby–Bauer disk diffusion method against 14 antimicrobial agents. To determine the macrolide–lincosamide–streptogramin B (MLSB) resistance phenotype of the isolates, erythromycin-resistant isolates were assessed by double-disk diffusion (D-test). The resistance and virulence genes were screened by polymerase chain reaction (PCR). All isolates were characterized by multilocus sequence typing (MLST), spa typing, staphylococcal chromosomal cassette mec (SCCmec) typing, and accessory gene regulator (agr) typing. Isolates showed resistance to cefoxitin, penicillin, ciprofloxacin, erythromycin, fusidic acid, clindamycin, and aminoglycosides, confirmed by the presence of the blaZ, ermA, ermC, mphC, msrA/B, aac(6’)-Ie-aph(2’’)-Ia, and ant(4’)-Ia genes. Three isolates were Panton–Valentine-leukocidin-positive. Most strains (n = 12) presented an inducible MLSB phenotype. The isolates were ascribed to eight spa-types (t747, t002, t020, t1084, t008, t10682, t18526, and t1370) and four MLSTs (ST22, ST5, ST105, and ST8). Overall, most (n = 12) MRSA isolates had a multidrug-resistance profile with inducible MLSB phenotypes and belonged to epidemic MRSA clones.

scholarly journals Antibacterial activity of Achillea tenuifolia Lam. extract against standard bacteria and isolated strains

2016 ◽  
Vol 2 (2) ◽  
pp. 49
Author(s):  
Sahar Omidpanah ◽  
Abbas Hadjiakhondi ◽  
Azadeh Manayi
Keyword(s):  
Room Temperature ◽  
Antimicrobial Agents ◽  
Inhibitory Concentration ◽  
Inhibition Zone ◽  
Inhibitory Effect ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Microdilution Method ◽  
Different Sources ◽  
Freeze Dryer

Researchers have been trying to develop new broad-spectrum antibiotics against the infectious diseases caused by bacteria, fungi, viruses, and parasites for many decades. Prolonged usage of the antibiotics has led to the emergence of drug resistance among bacteria; therefore, there is a tremendous need for novel antimicrobial agents from different sources such as plants which are used in traditional medicine. The aim of this study was to evaluate antibacterial effect of <em>Achillea tenuifolia</em>.<em> </em>The plant material was extracted by maceration method using methanol three times at room temperature. The extract was concentrated after removing the solvent by rotary evaporator and then lyophilized using freeze dryer. Inhibitory effect of the extract was examined against four standard bacteria strains and two isolated strains from diseased hen using disk diffusion method and microdilution method to evaluate their inhibition zone diameter (IZD) and minimum inhibitory concentration (MIC), respectively. The results showed that the extract of the plant was active against standard strains including <em>Escherichia coli</em>, <em>Pseudomonas aeruginosa</em>, <em>Staphylococcus aureus </em>and <em>Enterococcus faecalis </em>with IZDs of 10.3±0.5, 14±0.0, 12±0.0 and 11.6±0.5, respectively.<strong> </strong>However, growths of isolated strains were not inhibited in the presence of the extract. Although, the growths of isolated strains were not inhibited by the plant extract, the standard strains were moderately susceptible to the extract; among those <em>P. aeroginosa</em> was more sensible than other tested strains

scholarly journals Antimicrobial susceptibility of flavobacteria as determined by agar dilution and disk diffusion methods.

1997 ◽  
Vol 41 (6) ◽  
pp. 1301-1306 ◽  
Author(s):  
J C Chang ◽  
P R Hsueh ◽  
J J Wu ◽  
S W Ho ◽  
W C Hsieh ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Regression Line ◽  
Error Rates ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Poor Correlation ◽  
Least Squares Regression ◽  
Disk Diffusion Method ◽  
Agar Dilution

A total of 106 clinical isolates of flavobacteria, including 41 isolates of Flavobacterium meningosepticum, 59 of Flavobacterium indologenes, and 6 of Flavobacterium odoratum were collected from January 1992 to December 1995 from patients in Taiwan. The in vitro activities of antimicrobial agents were determined concomitantly by the standard agar dilution and disk diffusion methods. More than 90% of the flavobacterial isolates were resistant to cephalothin, cefotaxime, ceftriaxone, moxalactam, aztreonam, imipenem, aminoglycosides, erythromycin, and glycopeptides. The majority of F. meningosepticum isolates were susceptible to piperacillin and to minocycline but resistant to ceftazidime, with MICs at which 90% of the isolates are inhibited being 8, 4, and > 128 microg/ml, respectively. Approximately half of the F. indologenes isolates were susceptible to piperacillin, cefoperazone, ceftazidime, and minocycline, with MICs at which 50% of the isolates are inhibited being 4, 16, 8, and 4 microg/ml, respectively. The majority of F. odoratum isolates were resistant to all the antimicrobial agents tested except minocycline, to which five of six isolates were susceptible. With least-squares regression analysis and error rate-bounded analysis methods, the following resistant and susceptible zone diameter breakpoints were established: < or = 12 and > or = 17 mm, respectively, for piperacillin against F. meningosepticum and F. indologenes; < or = 13 and > or = 18 mm, respectively, for ceftazidime against F. meningosepticum and F. indologenes, < or = 17 and > or = 21 mm, respectively, for ofloxacin against F. indologenes; < or = 16 and > or = 20 mm, respectively, for ciprofloxacin against F. meningosepticum. Valid breakpoints for the disk diffusion method could not be established for cefoperazone and ofloxacin against F. meningosepticum and for minocycline against F. meningosepticum and F. indologenes due to a poor correlation coefficient for the regression line or for cefoperazone and ciprofloxacin against F. indologenes due to the presence of remarkable error rates.

scholarly journals Resistance to multiple first-line antibiotics among Escherichia coli from poultry in Western Algeria

2020 ◽  
Vol 13 (2) ◽  
pp. 290-295
Author(s):  
Meki Boutaiba Benklaouz ◽  
Hebib Aggad ◽  
Qada Benameur
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
First Line ◽  
Resistance Level ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Mueller Hinton Agar ◽  
Western Algeria

Background and Aim: Escherichia coli can cause a number of serious infections both in human and veterinary medicine. Their management is increasingly complicated by the emergence and dissemination of multiresistance to various first-line antimicrobial agents. This study aimed to evaluate the resistance level to the commonly used antibiotics, with a focus on the first-line antimicrobial agents, in E. coli strains isolated from poultry in Western Algeria. Materials and Methods: E. coli culture was done on MacConkey agar and their identification was determined by AP20E system. For susceptibility testing, disk diffusion method to 14 antimicrobials, including first-line antibiotics, was used according to Kirby–Bauer disk diffusion method in Mueller-Hinton agar and the results were interpreted according to the Clinical and Laboratory Standards Institute guidelines. E. coli isolates were considered as multidrug resistance (MDR) when found resistant to at least one antimicrobial agent of three different families of antibiotics. Double-disk synergy and combination disk tests were used for initial screening and confirmation for extended-spectrum β-lactamases (ESBLs) production, respectively. Results: A total of 145 E. coli strains were isolated in this study. High resistance levels to various antibiotics, including commonly used first-line antimicrobial agents, were recorded in this study. The highest resistance level was observed against nalidixic acid (90.34%, n=131), followed by tetracycline (86.89%, n=126), ampicillin (82.75%, n=120), enrofloxacin (80.68%, n=117) and neomycin (80.68%, n=117), trimethoprim/sulfamethoxazole (73.79%, n=107), norfloxacin (72.41%, n=105) and cephalothin (72.41%, n=105), amoxicillin/clavulanic acid (51.72%, n=75), chloramphenicol (22.75%, n=33), nitrofurantoin (17.24%, n=25), gentamicin (13.10%, n=19), and ceftiofur (3.44%, n=5). Moreover, resistance to multiple first-line antibiotics was also demonstrated in the present study. Overall, 139 out of 145 isolates (95.86%) demonstrated MDR (resistant to at least three antibiotics). In addition, five E. coli isolates (3.44%) were confirmed to be ESBL producers. Conclusion: The alarming rate of E. coli resistant to multiple first-line antibiotics in poultry demands intensified surveillance. These results call for taking drastic measures to preserve antibiotic effectiveness and reduce the emergence risks of extensively drug-resistant and pandrug-resistant E. coli isolates.

scholarly journals Use of an Oxacillin Disk Screening Test for Detection of Penicillin- and Ceftriaxone-Resistant Pneumococci

1999 ◽  
Vol 37 (4) ◽  
pp. 1178-1181 ◽  
Author(s):  
Louise P. Jetté ◽  
Christian Sinave
Keyword(s):  
Antimicrobial Agents ◽  
Clinical Laboratory ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
National Committee ◽  
Zone Of Inhibition ◽  
Diffusion Test ◽  
Disk Diffusion Method ◽  
Disk Diffusion Test ◽  
Intermediate Resistance

In a context of worldwide emergence of resistance amongStreptococcus pneumoniae strains, early detection of strains with decreased susceptibility to β-lactam antibiotics is important for clinicians. If the 1-μg oxacillin disk diffusion test is used as described by the National Committee for Clinical Laboratory Standards, no interpretation is available for strains showing zone sizes of ≤19 mm, and there is presently no disk diffusion test available for screening cephalosporin resistance. The zones obtained by the diffusion method by using the 1-μg oxacillin disk were compared with penicillin MICs for 1,116 clinical strains and with ceftriaxone MICs for 695 of these strains. Among the 342 strains with growth up to the 1-μg oxacillin disk margin, none were susceptible (MIC, ≤0.06 μg/ml), 62 had intermediate resistance (MIC, 0.12 to 1.0 μg/ml), and 280 were resistant (MIC, ≥2.0 μg/ml) to penicillin. For ceftriaxone, among 98 strains with no zone of inhibition in response to oxacillin, 68 had intermediate resistance (MIC, 1.0 μg/ml), and 22 were resistant (MIC, ≥2.0 μg/ml). To optimize the use of the disk diffusion method, we propose that the absence of a zone of inhibition around the 1-μg oxacillin disk be regarded as an indicator of nonsusceptibility to penicillin and ceftriaxone and recommend that such strains be reported as nonsusceptible to these antimicrobial agents, pending the results of a MIC quantitation method.

SEARCH FOR ANTIMICROBIAL AGENTS: QUINOXALINE AS A PROMISING TARGET

INDIAN DRUGS ◽  
2017 ◽  
Vol 54 (07) ◽  
pp. 5-9
Author(s):  
R. G Ingle ◽  
◽  
S. J. Wadher
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Agents ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
Gram Negative ◽  
E Coli ◽  
Promising Target ◽  
Quinoxaline Derivatives

A set of ten new 2,3-diphenyl-6-sulfonamido quinoxaline derivatives was synthesized and screened for antimicrobial activity by disk diffusion method. Test derivatives R3, R5, R’’1 and R’’2 show promising results against bacterial strains S. aureus gram positive and E. coli gram negative organism with the concentration 1000 μg/mL in disk diffusion method. Rest of the derivatives show sensitivity against the same organisms. All the synthesized derivatives were confirmed by their spectral data.

scholarly journals Comparative Evaluation of Antibacterial Effects of Nanoparticle-Incorporated Orthodontic Primer: An In Vitro Study

2021 ◽  
pp. 030157422098818
Author(s):  
Cheepurupalli Meher Vineesha ◽  
D Praveen Kumar Varma ◽  
P Arun Bhupathi ◽  
CV Padma Priya ◽  
M Anoosha ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Antimicrobial Agents ◽  
In Vitro Study ◽  
Diffusion Method ◽  
Zone Of Inhibition ◽  
Antibacterial Effects ◽  
Disk Diffusion Method

Aim and Objectives: To compare and evaluate the antibacterial efficacy of various nanoparticles incorporated in orthodontic primer with that of conventional antimicrobial agents at different concentrations on Streptococcus mutans ( S. mutans) strain. Materials and Methods: Transbond XT Primer was mixed with 2.5% and 5% benzalkonium chloride (BAC), 0.2% and 2.5% chlorhexidine, 1% and 3% titanium dioxide (TiO2) nanoparticles, 0.2% and 0.5% nanohydroxyapatite, and 0.2% and 0.5% silica-doped nanohydroxyapatite powders. Antibacterial activity against S. mutans for all the materials was evaluated by the disk diffusion method for periods of 48 (T1) and 72 (T2) hours. Results: There was a significant increase in the antimicrobial activity of the orthodontic primer modified by the addition of antibacterial agents. The highest zone of inhibition against S. mutans was observed for silica-doped nanohydroxyapatite of 0.5% (11.03 mm) among all the nanoparticles, which was similar to the conventional antibacterial agents used in our study. Conclusions: • Among all the groups, BAC at 5% concentration showed the highest antimicrobial activity, and the least activity was exhibited by 1% TiO2 nanoparticles. • Silica-doped nanohydroxyapatite at 0.5% expressed the greatest antibacterial activity among all the nanoparticles. • All the materials showed sustained antibacterial activity even after 72 hours.

scholarly journals An Efficient Approach to the Synthesis of Novel Oxazolidinones as Potential Antimicrobial Agents

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Kavita Devi ◽  
Yumna Asmat ◽  
Sonika Jain ◽  
Swapnil Sharma ◽  
Jaya Dwivedi
Keyword(s):  
Medicinal Chemistry ◽  
Antimicrobial Agents ◽  
Biological Activities ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Efficient Approach ◽  
Fungal Strains

Oxazolidinone, either mononuclear or condensed with other heterocyclics, has established its importance in medicinal chemistry. A variety of biological activities have been reported by oxazolidinone derivatives. The present work describes the synthesis of several oxazolidinone derivatives, 3-(2-(7-chloroquinoline-4-ylamino)ethyl)-2-imino-5-(4-chloro/nitro/methoxy benzylidene)oxazolidin-4-one 4(a–c) and 4-(2-(7-chloroquinolin-4-ylamino)ethyl)-2(4-chloro/nitro/methoxy-benzylidene)-1,6-diox-4,9-di-azaspiro[4,4]nonane-3,8-dione 5(a–c). Synthesized compounds (1, 3, 4a, 5a, and 5c) were screened against bacterial strains such asS. aureus(MTCC 96) andE. coli(MTCC119) and fungal strainsA. niger(MTCC 1344) andC. albicans(MTCC 871) compared with penicillin for bacteria and fluconazole for fungi as reference drugs by disk diffusion method. All synthesized compounds were identified by the means of IR, NMR, and MS.

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