scholarly journals Characterization of Clinical Isolates ofEnterococciwith Special Reference to Glycopeptide Susceptibility at a Tertiary Care Center of Eastern Nepal

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Aasish Karna ◽  
Ratna Baral ◽  
Basudha Khanal
Keyword(s):  
Multidrug Resistance ◽  
Minimum Inhibitory Concentration ◽  
Antimicrobial Susceptibility ◽  
Inhibitory Concentration ◽  
Tertiary Care ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disc Diffusion ◽  
Diffusion Technique ◽  
Agar Dilution

Background. Enterococci, once considered as a harmless commensal of intestine, have now emerged as medically important pathogens and are associated with both community-acquired and nosocomial infections. They bear the potential to exhibit resistance against all commonly used antibiotics either by inherent or acquired mechanism, posing a therapeutic challenge.Objectives. This study aimed to characterize enterococci up to the species level and study their antibiogram with special regard to vancomycin.Methods. A descriptive cross-sectional study was conducted in the Department of Microbiology, B.P. Koirala Institute of Health Sciences, Dharan, Nepal, from February to May 2017. A total of 91 enterococcal isolates recovered from clinical specimens were investigated in this study. Their identification and speciation were done according to standard microbiological guidelines. Kirby–Bauer disc diffusion technique was used to study antimicrobial susceptibility pattern, whereas minimum inhibitory concentration of vancomycin was determined by the agar dilution method, with reference to Clinical and Laboratory Standards Institute guidelines.Results. Seven different species of enterococci were isolated,E. faecalisandE. faeciumaccounting about 45% each. The other species encountered wereE.avium,E.cecorum,E.dispar,E.durans, andE.raffinosus. Highest proportion of antimicrobial susceptibility was recorded for linezolid (97.8%), followed by teicoplanin (95.6%) and high-level gentamicin (81.3%). Sensitivity to vancomycin was seen in 79.1% isolates. Likewise, 82.1% of urinary strains were susceptible to nitrofurantoin. A total of 4 disparities were observed between the disc diffusion technique and agar dilution method in determining vancomycin resistance. Multidrug resistance was observed in 31.9% isolates. The overall prevalence of vancomycin-resistant enterococci based on the standard minimum inhibitory concentration method was 25.3%.Conclusions.Enterococcus faecalisandE. faeciumwere the predominant species in causing enterococcal infections. The alarming rise in prevalence of vancomycin and multidrug resistance strains warrants immediate, adequate, and efficient surveillance program to prevent and control its spread.

scholarly journals Antibacterial Activity Tests of Staphylococcus Aureus and Phytochemical Screening in Family Asteraceae, Clusiaceae, Phyllanthaceae

2020 ◽  
Vol 55 (6) ◽  
Author(s):  
Prasetyorini Djarot ◽  
Novi Fajar Utami ◽  
Noerma Veonicha ◽  
Anggita Rahmadini ◽  
Afrizal Nur Iman
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Pathogenic Bacteria ◽  
Inhibitory Concentration ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Skin Infections ◽  
Inhibitory Ability ◽  
Agar Dilution ◽  
Concentration Test ◽  
Material Extraction

Infection is a type of disease that affects many residents of developing countries, including Indonesia. One pathogenic bacteria that is quite dangerous and causes skin infections both sporadically and endemically is S aureus. Several studies intensively report that some of the Asteraceae, Clusiaceae and Phyllanthaceae family plants contain alkaloids, flavonoids, saponins and tannins that have potential as antibacterial S aureus. Therefore, this study aims to identify effective plants to deal with infections caused by S aureus bacteria. To this end, the ingredients used are the leaves of G. procumbens, E. scaber, G. mangostana, G atroviridis, G. xanthochymus, leaves and bark of A. neurocarpum. Plant material extraction was done by maceration using 90% ethanol solvent. Next, an antibacterial test was conducted, which was begun by testing the Minimum Inhibitory Concentration followed by testing the Obstacle Area Width. The Minimum Inhibitory Concentration test was carried out using the agar dilution method, and the Obstacle Area Width test was carried out with paper diffusion discs. The results showed that all the plants have potential as antibacterials, and the mangosteen leaf extract has the largest Obstacle Area Width of 5.1 mm with a concentration of extract of 30% and a fairly strong inhibitory ability.

scholarly journals Antimicrobial Susceptibility of Invasive Streptococcus pneumoniae Isolates in Portugal over an 11-Year Period

2006 ◽  
Vol 50 (6) ◽  
pp. 2098-2105 ◽  
Author(s):  
Ricardo Dias ◽  
Deolinda Louro ◽  
Manuela Caniça
Keyword(s):  
Multidrug Resistance ◽  
Streptococcus Pneumoniae ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Invasive Disease ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
National Surveillance ◽  
Agar Dilution

ABSTRACT This national surveillance study presents the in vitro activities of the main antimicrobial agents against 1,331 S. pneumoniae isolates as tested by an agar dilution method according to the guidelines of the Clinical and Laboratory Standards Institute (formerly NCCLS). The strains were isolated in several regions of Portugal from cases of invasive disease over an 11-year period (1994 to 2004). This study shows that the percentage of penicillin-nonsusceptible strains increased from 12% in 1994 to 28.5% in 2000. Then the rate declined to 17.7% in 2003 but increased again to 23.2% in 2004. Nevertheless, the rate of highly resistant isolates declined consistently, to 0.9% in 2001 to 2004. Ceftriaxone- and cefotaxime-nonsusceptible isolates became less frequent, from 4% and 8%, respectively, in 1994 to ≤1% in 2004. The macrolide-lincosamide-streptogramin B phenotype was the predominant macrolide phenotype found. The increase in the percentage of isolates that were only nonsusceptible to erythromycin (3.7% in 1994 to 1998 to 9.1% in 2002 to 2004) was similar to that for isolates with coresistance to penicillin and erythromycin (3.3% in 1994 to 1998 to 9.1% in 2002 to 2004). The nonsusceptibility to ciprofloxacin increased during recent years, from 0.5% in 2002 to 3.5% in 2004. Multidrug resistance also increased in recent years: from 7.9% in 2002 to 15.6% in 2004. The increasing use of macrolides could be causing the increase in penicillin and multidrug resistance, due to the coresistance to macrolides. The use of penicillin to treat empirical invasive pneumococci infections may need to be reconsidered.

scholarly journals Comparison of the Antimicrobial Susceptibility Results of Bacteroides fragilis Group Isolates Determined by Agar Dilution and the Tentative EUCAST Disk Diffusion Method

2021 ◽  
Author(s):  
Semra Eminoğlu ◽  
Bermal Tekeş ◽  
Elvan Sayın ◽  
Nurver Ülger Toprak
Keyword(s):  
Antimicrobial Susceptibility ◽  
Bacteroides Fragilis ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disc Diffusion ◽  
Disc Diffusion Method ◽  
Bacteroides Fragilis Group ◽  
Agar Dilution

Objective: In this study it was aimed to determine the antimicrobial susceptibility of Bacteroides fragilis group (BFG) bacteria using recently developed European Committee on Antimicrobial Susceptibility Testing (EUCAST) disc diffusion method and agar dilution method recommended by Clinical Laboratory Standart Institude (CLSI) for anaerobes and to investigate the agreement of the results of two tests. Method: The antimicrobial susceptibilities of a total of 56 BFG strains isolated from clinical samples and identified by MALDI-TOF MS analysis between January 2017 and December 2018, were tested to ampicillin, ampicillin/sulbactam, cefoxitin, imipenem, clindamycin, tigecycline, moxifloxacin and metronidazole MICs were determined by agar dilution method using sheep blood supplemented Brucella agar and disk diffusion test using host blood supplemented Fastidius Anaerobic Agar (FAA). Results: Six different BFG species consisting mostly strains of Bacteroides fragilis (n=34, 61%) and Bacteroides thetaiotaomicron (n=11, 20%) isolated from various clinical samples such as intraabdominal abscess (n= 24), blood (n=10) and tissue biopsy samples (n=11).were identified. Imipenem and metronidazole were the most effective antimicrobials with 98.2% susceptibility rates, followed by tigecycline, ampicillin/sulbactam, moxifloxacin and clindamycin with susceptibility rates of 89.3%, 66.1%, 57.1% and 46.4%, respectively. Most concordant results were obtained with metronidazole (100%), imipenem (89.8%) and tigecycline (89.8%). Acceptable compliance rates were not found for other antimicrobials. Conclusion: We can say that disc diffusion method is a fast, easy-to-apply, and reliable method used in clinical microbiology laboratories to determine the susceptibility of BFG bacteria to metronidazole, imipenem and tigecycline. However, to evolve a standard method especially for other antimicrobials, the experimental conditions should be optimized with studies dome with greater number of isolates.

scholarly journals Antimicrobial susceptibility of Campylobacter cuniculorum isolated from rabbits reared in intensive and rural farms

2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Silvia Piva ◽  
Daniela Florio ◽  
Domenico Mion ◽  
Renato Giulio Zanoni
Keyword(s):  
Nalidixic Acid ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Inhibitory Concentration ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Pathogenic Role ◽  
Agar Dilution ◽  
Human Campylobacteriosis

The present study aimed to investigate the antimicrobial susceptibility in <em>Campylobacter cuniculorum</em> of 29 isolates on non-selective media from rabbits reared in 18 intensive and 11 rural farms not epidemiologically correlated. Minimum inhibitory concentration (MIC) of 8 antimicrobial agents was determined using the agar dilution method recommended by Clinical and Laboratory Standards Institute (CLSI), modified, for what concern the supplements in the base medium and incubation conditions, for <em>C. cuniculorum</em> isolates. The isolates obtained from rural farming resulted susceptible to all the antimicrobial agents tested, with the exception of one isolate resistant to nalidixic acid. All the isolates obtained from intensively farmed rabbits were sensitive to chloramphenicol and ampicillin; 16 isolates were resistant to tetracycline; 15 to nalidixic acid and erythromycin, 13 and 10 isolates to, ciprofloxacin and enrofloxacin respectively and only 1 to gentamicin. The resistance of several isolates to macrolides and fluoroquinolones, which represent the drugs of choice in treatment of human campylobacteriosis, could pose a risk to human health if a pathogenic role of <em>C. cuniculorum</em> was demonstrated.

scholarly journals Antimicrobial Susceptibility Pattern of Enterococcus Species Isolated from Various Clinical Specimens in a Tertiary Care Hospital, Kathmandu, Nepal

2018 ◽  
Vol 20 (4) ◽  
pp. 173-177
Author(s):  
Ram Prasad Adhikari ◽  
S. Shrestha ◽  
A. Barakoti ◽  
J.R. Rai ◽  
R. Amatya
Keyword(s):  
Antimicrobial Susceptibility ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Disc Diffusion ◽  
Clinical Specimens ◽  
Enterococcus Spp ◽  
Gentamicin Resistance ◽  
Agar Dilution ◽  
High Level

Resistance to vancomycin and high level aminoglycosides are common among Enterococcus spp. and are being increasingly reported from different parts of the world. These resistance phenomena in enterococci have limited the therapeutic options to treat the infections caused by them. The objective of our study was to determine the antimicrobial resistance patterns of Enterococcus spp. (n=60) isolated over a year from clinical specimens received from patients visiting Nepal Medical College Teaching Hospital, Kathmandu, Nepal. All enterococci were subjected to antimicrobial susceptibility testing, high level gentamicin resistance testing by disc diffusion method and minimum inhibitory concentration of vancomycin by agar dilution method. Prevalence of high level gentamicin resistance among enterococci was 55%. None of the isolates were resistant to vancomycin by both disc diffusion and agar dilution method. However 8.3% of them were intermediate to vancomycin. All of these vancomycin intermediate isolates were from samples from hospital admitted patients and resistant to ampicillin, ciprofloxacin, erythromycin and high level gentamicin. Present findings were suggestive of possible emergence of vancomycin resistant enterococci in the hospital if immediate and adequate control measures are not implemented.

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 Drug resistance of yeasts isolated from oropharyngeal candidiasis in aids patients

1998 ◽  
Vol 29 (4) ◽  
pp. 271-275
Author(s):  
Maria do Rosário Rodrigues Silva ◽  
Claudete Rodrigues de Paula ◽  
Soraya Cristina Silva ◽  
Théo Rodrigues Costa ◽  
Márcio Rodrigues Costa
Keyword(s):  
Amphotericin B ◽  
High Frequency ◽  
Inhibitory Concentration ◽  
Serum Levels ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Oropharyngeal Candidiasis ◽  
Candida Spp ◽  
Aids Patients ◽  
Agar Dilution

Candida spp was isolated from 59 (68.60%) out of eighty six samples of oral mucosa of AIDS patients. The identification, based or the production of a germ tube and chlamydospores, and on the assimilation and fermentation of carbohydrates, revealed 52 strains (88.13%) of C. albicans, 4 (6.77%) of C. tropicalis and 3 (5.08%) of C. krusei. The susceptibility of these strains to amphotericin B, flucytosine, itraconazole, fluconazole and ketoconazole was determined using the agar dilution method. Comparing the minimum inhibitory concentration values found in the susceptibility test with the serum levels achieved by these drugs, only 8.47% and 5.08% of the yeasts strains proved to be resistant to amphotericin B and flucitosyne, respectively. A high frequency of strains resistant to azole derivatives (25.42%, to itraconazole, 45.76%, to ketoconazole and 66.10% to fluconazole) was observed.

scholarly journals Broth Microdilution and Gradient Diffusion Strips vs. Reference Agar Dilution Method: First Evaluation for Clostridiales Species Antimicrobial Susceptibility Testing

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 975
Author(s):  
Florian Baquer ◽  
Asma Ali Sawan ◽  
Michel Auzou ◽  
Antoine Grillon ◽  
Benoît Jaulhac ◽  
...  
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Antimicrobial Susceptibility Testing ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Broth Microdilution ◽  
Multicenter Studies ◽  
Gradient Diffusion ◽  
Agar Dilution

Antimicrobial susceptibility testing of anaerobes is challenging. Because MIC determination is recommended by both CLSI and EUCAST, commercial broth microdilution and diffusion strip tests have been developed. The reliability of broth microdilution methods has not been assessed yet using the agar dilution reference method. In this work, we evaluated two broth microdilution kits (MICRONAUT-S Anaerobes® MIC and Sensititre Anaerobe MIC®) and one gradient diffusion strip method (Liofilchem®) for antimicrobial susceptibility testing of 47 Clostridiales isolates (Clostridium, Clostridioides and Hungatella species) using the agar dilution method as a reference. The evaluation focused on comparing six antimicrobial molecules available in both microdilution kits. Analytical performances were evaluated according to the Food and Drug Administration (FDA) recommendations. Essential agreements (EA) and categorical agreements (CA) varied greatly according to the molecule and the evaluated method. Vancomycin had values of essential and categorical agreements above 90% for the three methods. The CA fulfilled the FDA criteria for three major molecules in the treatment of Gram-positive anaerobic infections (metronidazole, piperacillin/tazobactam and vancomycin). The highest rate of error was observed for clindamycin. Multicenter studies are needed to further validate these results.

scholarly journals Real-time monitoring of bacterial growth and fast antimicrobial susceptibility tests exploiting multiple light scattering

2018 ◽  
Author(s):  
SeungYun Han ◽  
HyunJung Kim ◽  
Jongchan Park ◽  
SangYun Lee ◽  
KyeoReh Lee ◽  
...  
Keyword(s):  
Real Time ◽  
Bacterial Growth ◽  
Antimicrobial Susceptibility ◽  
Low Cost ◽  
Laser Speckle ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Antimicrobial Susceptibility Tests ◽  
Agar Dilution ◽  
Susceptibility Tests

Abstract:Antimicrobial susceptibility test (AST) is widely used to provide the minimum inhibitory concentration of bacteria, and crucial to provide appropriate uses of antibiotics and to address the issue of drug-resistance bacteria. However, ASTs require the time-consuming incubation about 16-20 h for the visual determination of the growth of bacterial colonies, which has been a major obstacle to on-site applications of ASTs. In this study, we propose a rapid and non-invasive method based on laser speckles to evaluate the bacterial growth movements in real time, thus reducing the time for the agar dilution method. With a simple configuration compatible with conventional agar plates, the analysis of laser speckle from samples enables the early detection of the presence of growth as well as its detailed history of the colony-forming movement on agar plates. Using the samples prepared through the same procedure as the agar dilution method, we obtained the AST results at least 4-8 hours earlier than the conventional method without compromising the accuracy. This technique does not require for the use of exogenous agents, but works for most bacteria regardless of their species. Furthermore, the distinctive responses of several species to microbial agents were revealed through the present technique supporting a comprehensive analysis of the effect of the antibiotics. The findings suggest that this new method could be a useful tool for rapid, simple, and low-cost ASTs in addition to providing the historical information of the bacterial growth on agar plates.

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