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 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 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.

Effect on Physician Prescribing Practices of Changing from a Qualitative to a Quantitative Antimicrobial Susceptibility Test Reporting System

1983 ◽  
Vol 17 (7-8) ◽  
pp. 552-555 ◽  
Author(s):  
Thomas T. Ward ◽  
Michael J. Regner ◽  
Karen L. Collell ◽  
Ronald R. Brown ◽  
David L. Sewell
Keyword(s):  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Susceptibility Test ◽  
Disc Diffusion ◽  
Prescribing Practices ◽  
Susceptibility Data ◽  
Before And After ◽  
Physician Prescribing

The use of disc diffusion susceptibility testing has been criticized because it often fails to take into consideration achievable levels of antimicrobial agents at the actual sites of infection. An increasing number of hospitals are converting from disc diffusion antimicrobial susceptibility testing to more quantitative susceptibility testing techniques. Advocates of these latter techniques have suggested that providing information beyond sensitive, intermediate, and resistant reporting will emphasize, more effectively, the importance of considering achievable antibiotic concentrations at the site of infection, when choosing an antimicrobial agent. This study examined whether providing more quantitative susceptibility test reports would affect physicians' antimicrobial prescribing practices. Results obtained on the preeducation and posteducation questionnaires indicate success in improving the collective knowledge of physicians. In retrospective audits of the appropriateness of antimicrobial use, both before and after the educational program, physician usage of antimicrobial agents was categorized as inappropriate in more than ⅔ of the cases. The major reason for the negative outcome in this study is probably due to physicians' indifference to the results of urine culture and susceptibility test data. A change was made in antimicrobial therapy after return of the susceptibility report less than 20 percent of the time. As more laboratories convert to quantitative antimicrobial susceptibility testing, there will be a need for a closer liaison among physicians, clinical pharmacists, microbiologists, and infectious disease specialists, to ensure optimum utilization of the additional susceptibility data provided.

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 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.

Facile syringe filter-enabled bacteria separation, enrichment, and buffer exchange for clinical isolation-free digital detection and characterization of bacterial pathogens in urine

The Analyst ◽  
2021 ◽  
Author(s):  
Pengfei Zhang ◽  
Aniruddha Kaushik ◽  
Kathleen E Mach ◽  
Kuangwen Hsieh ◽  
Joseph C. Liao ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Antibiotic Therapy ◽  
Broad Spectrum ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Evidence Based ◽  
Pathogen Identification ◽  
Accelerated Methods ◽  
Syringe Filter

The development of accelerated methods for pathogen identification (ID) and antimicrobial susceptibility testing (AST) for infectious diseases is necessary to facilitate evidence-based antibiotic therapy and reduce clinical overreliance on broad-spectrum...

Evaluation of standardized automated rapid antimicrobial susceptibility testing of Enterobacterales-containing blood cultures: a proof-of-principle study

2020 ◽  
Vol 75 (11) ◽  
pp. 3218-3229
Author(s):  
Stefano Mancini ◽  
Elias Bodendoerfer ◽  
Natalia Kolensnik-Goldmann ◽  
Sebastian Herren ◽  
Kim Röthlin ◽  
...  
Keyword(s):  
Standard Method ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Bloodstream Infections ◽  
Inhibition Zone ◽  
Blood Cultures ◽  
Antimicrobial Susceptibility Testing ◽  
Disc Diffusion ◽  
Inhibition Zones ◽  
Reading System

Abstract Background Rapid antimicrobial susceptibility testing (RAST) of bacteria causing bloodstream infections is critical for implementation of appropriate antibiotic regimens. Objectives We have established a procedure to prepare standardized bacterial inocula for Enterobacterales-containing clinical blood cultures and assessed antimicrobial susceptibility testing (AST) data generated with the WASPLabTM automated reading system. Methods A total of 258 blood cultures containing Enterobacterales were examined. Bacteria were enumerated by flow cytometry using the UF-4000 system and adjusted to an inoculum of 106 cfu/mL. Disc diffusion plates were automatically streaked, incubated for 6, 8 and 18 h and imaged using the fully automated WASPLabTM system. Growth inhibition zones were compared with those obtained with inocula prepared from primary subcultures following the EUCAST standard method. Due to time-dependent variations of the inhibition zone diameters, early AST readings were interpreted using time-adjusted tentative breakpoints and areas of technical uncertainty. Results and conclusions Inhibition zones obtained after 18 h incubation using an inoculum of 106 cfu/mL prepared directly from blood cultures were highly concordant with those of the EUCAST standard method based on primary subcultures, with categorical agreement (CA) of 95.8%. After 6 and 8 h incubation, 89.5% and 93.0% of the isolates produced interpretable results, respectively, with CA of >98.5% and very low numbers of clinical categorization errors for both the 6 h and 8 h readings. Overall, with the standardized and automated RAST method, consistent AST data from blood cultures containing Enterobacterales can be generated after 6–8 h of incubation and subsequently confirmed by standard reading of the same plate after 18 h.

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