scholarly journals Antimicrobial Susceptibility of Clinical Oral Isolates of Actinomyces spp.

2022 ◽  
Vol 10 (1) ◽  
pp. 125
Author(s):  
Alexandra Wolff ◽  
Arne C. Rodloff ◽  
Paul Vielkind ◽  
Toralf Borgmann ◽  
Catalina-Suzana Stingu
Keyword(s):  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Oral Diseases ◽  
Low Resistance ◽  
First Choice ◽  
Actinomyces Species ◽  
Resistance Patterns ◽  
Agar Dilution

Actinomyces species play an important role in the pathogenesis of oral diseases and infections. Susceptibility testing is not always routinely performed, and one may oversee a shift in resistance patterns. The aim of the study was to analyze the antimicrobial susceptibility of 100 well-identified clinical oral isolates of Actinomyces spp. against eight selected antimicrobial agents using the agar dilution (AD) and E-Test (ET) methods. We observed no to low resistance against penicillin, ampicillin-sulbactam, meropenem, clindamycin, linezolid and tigecycline (0–2% ET, 0% AD) but high levels of resistance to moxifloxacin (93% ET, 87% AD) and daptomycin (83% ET, 95% AD). The essential agreement of the two methods was very good for benzylpenicillin (EA 95%) and meropenem (EA 92%). The ET method was reliable for correctly categorizing susceptibility, in comparison with the reference method agar dilution, except for daptomycin (categorical agreement 87%). Penicillin is still the first-choice antibiotic for therapy of diseases caused by Actinomyces spp.

scholarly journals A Simplified Method for Testing Bordetella pertussisfor Resistance to Erythromycin and Other Antimicrobial Agents

2000 ◽  
Vol 38 (3) ◽  
pp. 1151-1155 ◽  
Author(s):  
Bertha C. Hill ◽  
Carolyn N. Baker ◽  
Fred C. Tenover
Keyword(s):  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Antimicrobial Susceptibility Testing ◽  
Disk Diffusion ◽  
Mueller Hinton ◽  
Disk Diffusion Testing ◽  
Direct Inoculation ◽  
Agar Dilution

Present methods of antimicrobial susceptibility testing ofBordetella pertussis are time consuming and require specialized media that are not commercially available. We tested 52 isolates of B. pertussis for resistance to erythromycin, trimethoprim-sulfamethoxazole, chloramphenicol, and rifampin by agar dilution with Bordet-Gengou agar (BGA) containing 20% horse blood (reference method), Etest using BGA and Regan-Lowe agar without cephalexin (RL−C), and disk diffusion using BGA and RL−C. The organisms tested included four erythromycin-resistant isolates ofB. pertussis from a single patient, a second erythromycin-resistant strain of B. pertussis from an unrelated patient in another state, and 47 nasopharyngeal surveillance isolates of B. pertussis from children in the western United States. The results of agar dilution testing using direct inoculation of the organisms suspended in Mueller-Hinton broth were within ±1 dilution of those obtained after overnight passage of the inoculum in Stainer-Scholte medium, which is the traditional method of testing B. pertussis. The Etest method produced MICs similar to those of the agar dilution reference method for three of the four antimicrobial agents tested; the trimethoprim-sulfamethoxazole results were lower with Etest, particularly when the direct suspension method was used. Most of the Etest MICs, except for that of erythromycin, were on scale. Disk diffusion testing using RL−C medium was helpful in identifying the erythromycin-resistant strains, which produced no zone of inhibition around the disk; susceptible isolates produced zones of at least 42 mm. Thus, the antimicrobial susceptibility testing of B. pertussis can be simplified by using the Etest or disk diffusion on RL−C to screen for erythromycin-resistant isolates of B. pertussis.

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 Prevalence of erythromycin and clindamycin resistance among clinical isolates of the Streptococcus anginosus group in Germany

2009 ◽  
Vol 58 (2) ◽  
pp. 222-227 ◽  
Author(s):  
Nadine Asmah ◽  
Bettina Eberspächer ◽  
Thomas Regnath ◽  
Mardjan Arvand
Keyword(s):  
Antimicrobial Susceptibility ◽  
Molecular Typing ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Disc Diffusion ◽  
Diffusion Test ◽  
Streptococcus Anginosus ◽  
Intermediate Resistance ◽  
Agar Dilution

Members of the Streptococcus anginosus group (SAG) are frequently involved in pyogenic infections in humans. In the present study, the antimicrobial susceptibility of 141 clinical SAG isolates to six antimicrobial agents was analysed by agar dilution. All isolates were susceptible to penicillin, cefotaxime and vancomycin. However, 12.8 % displayed increased MIC values (0.12 mg l−1) for penicillin. Resistance to erythromycin was detected in eight (5.7 %) isolates. Characterization of the erythromycin-resistant isolates with the double-disc diffusion test revealed Macrolide-Lincosamide-StreptograminB and M-type resistance in six and two isolates, respectively. The erythromycin-resistant isolates were further characterized by PCR for the resistance genes ermA, ermB and mefA. Resistance and intermediate resistance to ciprofloxacin were detected in two and six isolates, respectively. Molecular typing by PFGE revealed a high genetic heterogeneity among the SAG isolates and no evidence for a clonal relationship between the erythromycin-resistant isolates. Our data show that resistance to erythromycin, clindamycin and ciprofloxacin has emerged among SAG isolates in Germany. The implications of these findings for susceptibility testing and antimicrobial therapy of SAG infections are discussed.

scholarly journals Antimicrobial Susceptibility Testing ofMycobacterium bovisIsolates from Michigan White-Tailed Deer during the 2009 Hunting Season

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Scott D. Fitzgerald ◽  
Angie M. Schooley ◽  
Dale E. Berry ◽  
John B. Kaneene
Keyword(s):  
Drug Resistance ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Multidrug Resistant ◽  
Antimicrobial Susceptibility Testing ◽  
Hunting Season ◽  
Extensively Drug Resistant ◽  
Resistance Patterns ◽  
Free Ranging

Michigan has had an ongoing outbreak of endemicMycobacterium boviswhich has been recognized within and sustained by its free-ranging white-tailed deer population since 1994. Worldwide, organisms within theMycobacterium tuberculosiscomplex have exhibited the ability to develop resistance to antimicrobial agents, resulting in both the multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of human tuberculosis. Michigan's Bovine Tuberculosis Working Group has conducted active antimicrobial susceptibility testing on wildlife isolates of the endemicM. bovisorganism at five-year intervals to detect any emerging drug resistance patterns. The results of 33 white-tailed deer origin isolates collected from the 2009 hunting season are reported here. There continues to be no evidence of any drug resistance except for pyrazinamide resistance. These results are likely due to the lack of antibacterial treatment applied to either wildlife or domestic animals which would provide selection pressure for the development of drug resistance.

scholarly journals Antimicrobial susceptible test

2018 ◽  
pp. 084-086
Author(s):  
Tagesu Abdisa
Keyword(s):  
Antimicrobial Susceptibility ◽  
Clinical Condition ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Susceptibility Test ◽  
Disc Diffusion ◽  
Agar Dilution ◽  
Selection Of

Anti-microbial susceptibility test is useful to guide the clinician in the selection of antimicrobial agents to which clinical condition being treated will respond. There are three principal methods of antimicrobial susceptibility testing like disc diffusion, brothy dilution and agar dilution.

scholarly journals In Vitro Activity of OPT-80 Tested against Clinical Isolates of Toxin-Producing Clostridium difficile

2008 ◽  
Vol 52 (11) ◽  
pp. 4163-4165 ◽  
Author(s):  
James A. Karlowsky ◽  
Nancy M. Laing ◽  
George G. Zhanel
Keyword(s):  
Clostridium Difficile ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity ◽  
Agar Dilution

ABSTRACT Agar dilution antimicrobial susceptibility testing (CLSI, M11-A7, 2007) performed for 208 toxin-producing clinical isolates of Clostridium difficile resulted in OPT-80 MICs ranging from 0.06 to 1 μg/ml, with 90% of the isolates inhibited by a concentration of 0.5 μg/ml. The in vitro activity of OPT-80 was independent of the susceptibilities of isolates to nine other antimicrobial agents.

scholarly journals Complete ciprofloxacin resistance in gonococcal isolates in an urban Ugandan clinic: findings from a cross-sectional study

2018 ◽  
Vol 30 (3) ◽  
pp. 256-263 ◽  
Author(s):  
Emily Mabonga ◽  
Rosalind Parkes-Ratanshi ◽  
Stefan Riedel ◽  
Sheila Nabweyambo ◽  
Olive Mbabazi ◽  
...  
Keyword(s):  
Sex Workers ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Outpatient Service ◽  
Tetracycline Resistance ◽  
Disk Diffusion ◽  
Reference Laboratory ◽  
Transmitted Infection ◽  
Cross Sectional ◽  
Agar Dilution

Antimicrobial resistance (AMR) to gonorrhoea is a threat to global health security. There have been concerns expressed that countries with high rates of disease have poor surveillance. The objectives of the study were to determine the AMR patterns of Neisseria gonorrhoeae clinical isolates to antimicrobial agents in patients with HIV or high risk of HIV acquisition, to compare the concordance of disk diffusion and agar dilution as methods for determining AMR to N. gonorrhoeae, and to describe methodological challenges to carrying out AMR testing. The study was conducted at an HIV outpatient service for at-risk populations and an outreach clinic for commercial sex workers in Kampala. Patients were offered a sexually transmitted infection screen using a polymerase chain reaction (PCR)-based assay. Samples positive for gonorrhoea were cultured. Antimicrobial susceptibility testing was performed using disk diffusion and isolates were sent to a reference laboratory for agar dilution direct susceptibility testing. Five hundred and seventy-five patients were screened. There were 33 (5.7%) patients with gonorrhoea detected by PCR. Of the 16 viable N. gonorrhoeae isolates, 100% were resistant to ciprofloxacin and tetracycline by disk diffusion and 31% exhibited reduced susceptibility to ceftriaxone and cefixime. By agar dilution, 100% of isolates were resistant to ciprofloxacin and all isolates were susceptible to ceftriaxone and cefixime. There was concordance between disk diffusion and agar dilution for ciprofloxacin and tetracycline resistance and a significant discordance for third-generation cephalosporins. More than half the women with gonorrhoea were asymptomatic and represent a potential reservoir for ongoing transmission. AMR testing of N. gonorrhoeae isolates is needed to ensure optimal treatment and prevention of antibiotic resistance progression.

scholarly journals The Frequency of Methicillin-Resistant Staphylococcus aureus and Coagulase Gene Polymorphism in Egypt

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Hend M. Abdulghany ◽  
Rasha M. Khairy
Keyword(s):  
Staphylococcus Aureus ◽  
Gene Polymorphism ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Methicillin Resistant ◽  
Microbiological Methods ◽  
Rflp Typing

The current study aimed to use Coagulase gene polymorphism to identify methicillin-resistant Staphylococcus aureus (MRSA) subtypes isolated from nasal carriers in Minia governorate, Egypt, evaluate the efficiency of these methods in discriminating variable strains, and compare these subtypes with antibiotypes. A total of 400 specimens were collected from nasal carriers in Minia governorate, Egypt, between March 2012 and April 2013. Fifty-eight strains (14.5%) were isolated and identified by standard microbiological methods as MRSA. The identified isolates were tested by Coagulase gene RFLP typing. Out of 58 MRSA isolates 15 coa types were classified, and the amplification products showed multiple bands (1, 2, 3, 4, 5, and 8 bands). Coagulase gene PCR-RFLPs exhibited 10 patterns that ranged from 1 to 8 fragments with AluI digestion. Antimicrobial susceptibility testing with a panel of 8 antimicrobial agents showed 6 different antibiotypes. Antibiotype 1 was the most common phenotype with 82.7%. The results have demonstrated that many new variants of the coa gene are present in Minia, Egypt, different from those reported in the previous studies. So surveillance of MRSA should be continued.

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