Comparison of the Micronaut Merlin automated broth microtiter system with the standard agar dilution method for antimicrobial susceptibility testing of mucoid and nonmucoid Pseudomonas aeruginosa isolates from cystic fibrosis patients

Balke, B.; Hoy, L.; Weißbrodt, H.; Häußler, Susanne

doi:10.1007/s10096-004-1212-7

Cited by 16 publications

(10 citation statements)

References 14 publications

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“…Therefore, we evaluated the accuracy of the MICRONAUT system for direct AST of positive blood cultures under routine conditions in a clinical microbiology laboratory. The MICRONAUT system is a commercially available, automated, microtiter plate-based broth dilution AST system (2,16). Altogether, 850 positive blood cultures were investigated on a daily basis including weekends during a period of 9 months.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the Merlin MICRONAUT System for Rapid Direct Susceptibility Testing of Gram-Positive Cocci and Gram-Negative Bacilli from Positive Blood Cultures

et al. 2007

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Bloodstream infections are life-threatening conditions which require the timely initiation of antimicrobial therapy. Inappropriate initial antimicrobial therapy of septic patients is associated with adverse outcomes (13,15,20). Automated blood culture systems that monitor blood culture bottles continuously for bacterial growth minimize the time necessary to detect positive blood cultures. Once bacterial growth is detected in blood cultures, rapid identification and susceptibility testing of the isolate are important tasks for the clinical microbiology laboratory. Reducing the turnaround time of microbiological analysis by using automated systems can lead to significant reductions in patient morbidity, mortality, and costs (3, 9, 27).While standard antimicrobial susceptibility testing (AST) of bacteria commonly involves pure overnight subcultures, preparation of the inoculum for automated susceptibility testing directly from the positive blood culture appears extremely attractive with respect to the time to results. Thus, direct antimicrobial susceptibility testing of isolates from positive blood cultures with many automated testing systems, like the Phoenix (BD, Heidelberg, Germany), the VITEK and VITEK 2 (BioMérieux, Nürtingen, Germany), the Sensititre (Trek Diagnostics, West Lake, OH), and the MicroScan (Dade Behring, Eschborn, Germany) systems, has been evaluated previously (4-6, 12, 14, 18, 21, 24, 26, 28). In general, good agreement between direct and standard susceptibility testing results was observed when gram-negative bacilli were tested, including both members of the Enterobacteriaceae and Pseudomonas species (4-6, 12, 14, 18, 21, 24, 26, 28). For direct testing of gram-positive cocci from blood cultures, only limited data from small studies are available for the VITEK, the VITEK 2, the Sensititre, and the MicroScan systems (5,6,8,18,26,29). A significantly higher rate of disagreement between direct and standard testing results for gram-positive cocci than for gramnegative bacilli was found. Reporting of false susceptibility of staphylococci to oxacillin and of enterococci to various antibiotics (18, 26) is a major problem with enormous clinical relevance. Since gram-positive cocci cause the majority of bloodstream infections (23, 29), rapid and reliable automated susceptibility testing of gram-positive bacteria is highly desirable.We evaluated the automated MICRONAUT system (Merlin, Bornheim-Hesel, Germany) for rapid direct microtiter broth susceptibility testing of gram-positive cocci and gram-negative bacilli from BACTEC bottles with positive blood cultures. The study was conducted under routine working conditions in the clinical microbiological laboratory of the University Hospital of Ulm, Ulm, Germany, during a 9-month period and included 850 positive blood cultures.

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Section: Discussionmentioning

confidence: 99%

Evaluation of the Merlin MICRONAUT System for Rapid Direct Susceptibility Testing of Gram-Positive Cocci and Gram-Negative Bacilli from Positive Blood Cultures

et al. 2007

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“…For automatic measurement and identification, the SARAMIS™ (spectral archived microbial identification system) database application from bioMérieux SA France was applied. Minimal inhibitory concentrations (MICs) of piperacillin/tazobactam (PIP/TAZ), ceftazidime (CAZ), tobramycin (TOB), amikacin (AMK), ciprofloxacin (CIP) and meropenem (MEM) were determined by the broth microdilution method (Micronaut Merlin) as previously described and interpreted using the criteria recommended by the Clinical and Laboratory Standards Institute (CLSI) [5,6]. Multidrug-resistant isolates were defined as isolates intermediate or resistant to at least three drugs in the following classes: β-lactams, carbapenems, aminoglycosides and fluoroquinolones.…”

Section: Patients Materials and Methodsmentioning

confidence: 99%

Molecular epidemiology ofPseudomonas aeruginosa in cystic fibrosis patients from Southeast Austria

Masoud-Landgraf

Badura

Eber

et al. 2012

Wien Klin Wochenschr

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Pseudomonas aeruginosa is the major pathogen in the cystic fibrosis (CF) lung, the predominant source of its acquisition, however, is under discussion. In order to study the molecular epidemiology, we evaluated 86 P. aeruginosa isolates from 43 CF patients from southeast Austria. The DiversiLab system was used to identify genetic relationships among the isolates. Antibiotic susceptibilities were tested with a broth microdilution method (Micronaut Merlin). A total of 39 unrelated P. aeruginosa genotypes were found of which 34 were unique to a single patient and one was unique to a sibling pair. We found low rates of resistance for β-lactams with resistance to piperacillin/tazobactam and ceftazidime ranging from 4 to 6%. Resistance rates for meropenem and ciprofloxacin were 11% and 15%, respectively. The prevalence of multidrug-resistant isolates was 2%. We conclude that the majority of P. aeruginosa isolates from CF patients originate from environmental sources and patient-to-patient spread is very uncommon in our centre.

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“…Inactivation of mucB causes conversion to mucoidy (29), and mucoid clinical isolates have been shown to tend toward more susceptible phenotypes (4).…”

Section: Vol 53 2009mentioning

confidence: 99%

Genomewide Identification of Genetic Determinants of Antimicrobial Drug Resistance inPseudomonas aeruginosa

Dötsch¹,

Becker²,

Pommerenke³

et al. 2009

Antimicrob Agents Chemother

120

112

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The emergence of antimicrobial drug resistance is of enormous public concern due to the increased risk of delayed treatment of infections, the increased length of hospital stays, the substantial increase in the cost of care, and the high risk of fatal outcomes. A prerequisite for the development of effective therapy alternatives is a detailed understanding of the diversity of bacterial mechanisms that underlie drug resistance, especially for problematic gram-negative bacteria such as Pseudomonas aeruginosa. This pathogen has impressive chromosomally encoded mechanisms of intrinsic resistance, as well as the potential to mutate, gaining resistance to current antibiotics. In this study we have screened the comprehensive nonredundant Harvard PA14 library for P. aeruginosa mutants that exhibited either increased or decreased resistance against 19 antibiotics commonly used in the clinic. This approach identified several genes whose inactivation sensitized the bacteria to a broad spectrum of different antimicrobials and uncovered novel genetic determinants of resistance to various classes of antibiotics. Knowledge of the enhancement of bacterial susceptibility to existing antibiotics and of novel resistance markers or modifiers of resistance expression may lay the foundation for effective therapy alternatives and will be the basis for the development of new strategies in the control of problematic multiresistant gram-negative bacteria.

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Comparison of the Micronaut Merlin automated broth microtiter system with the standard agar dilution method for antimicrobial susceptibility testing of mucoid and nonmucoid Pseudomonas aeruginosa isolates from cystic fibrosis patients

Cited by 16 publications

References 14 publications

Evaluation of the Merlin MICRONAUT System for Rapid Direct Susceptibility Testing of Gram-Positive Cocci and Gram-Negative Bacilli from Positive Blood Cultures

Evaluation of the Merlin MICRONAUT System for Rapid Direct Susceptibility Testing of Gram-Positive Cocci and Gram-Negative Bacilli from Positive Blood Cultures

Molecular epidemiology ofPseudomonas aeruginosa in cystic fibrosis patients from Southeast Austria

Genomewide Identification of Genetic Determinants of Antimicrobial Drug Resistance inPseudomonas aeruginosa

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