Performance Evaluation of Newly Developed Korean Antimicrobial Susceptibility Testing Panels for MicroScan System Using Clinical Isolates from Teaching Hospitals in Korea / 대한임상미생물학회지

BACKGROUND: Antimicrobial resistant continues to pose a threat to public health. Therefore, rapid and accurate antimicrobial susceptibility testing is very important. The objectives of this study were to evaluate the performance of the MicroScan system (Beckman Coulter, USA) with newly developed Korean Antimicrobial Susceptibility Testing Panels (KSCM panels) for antimicrobial susceptibility testing (AST) against clinical isolates in South Korea. METHODS: Three KSCM panels were designed in this study. For the performance evaluation, a total of 1,325 clinical isolates including 1,027 of Gram-negative bacilli and 298 Gram-positive cocci collected from eight general hospitals in South Korea were used. The results by KSCM panels were compared with those by conventional methods. RESULTS: By KSCM-1 panel for Gram-positive cocci, the rates of categorical agreement (CA) were >90% in all the antimicrobials tested in this study. The rates of major error (ME) were also 90%, ME rates <3%, and VME rates <1.5%. CONCLUSION: The newly developed three KSCM panels for MicroScan system (Beckman Coulter) showed excellent performance in AST against a large number of clinical isolates, and they are applicable to clinical microbiology laboratories.

Evaluation on the performance of MicroScan WalkAway in detecting carbapenem-resistant Enterobacteriaceae / 中国感染与化疗杂志

Objective To investigate the performance of MicroScan WalkAway 96 Plus (MSW) system in detection of carbapenem-resistant Enterobacteriaceae (CRE).Methods A total of 81 stock CRE strains were used in this study. Bacterial identification and antimicrobial susceptibility test were performed by MSW system. Beta-lactamases genes blaKPC,blaIMP,blaVIM, blaOXA-48 and blaNDM were amplified by PCR and subjected to sequencing analysis. Disk diffusion method and PCR were used as gold standard to evaluate the performance and reliability of MSW system in identifying carbapenem-resistant and carbapenemase-producing Enterobacteriaceae.Results Overall, 69.1 % (56/81) of the Enterobacteriaceae strains were identified as CRE by the MSW system. The results of PCR showed that 48 strains were carbapenemase-producing Enterobacteriaceae. When carbapenemase-producing Enterobacteriaceae strains were identified by the instrument using an advanced expert system, the sensitivity was 93.8 % and specificity was 42.4 %. The positive predictive value was 70.3 %, the negative predictive value was 82.4 % and the predictive accuracy value was 72.8 %.Conclusions The MicroScan WalkAway 96 Plus system has shown good performance in detection of CRE.

Evaluación de la microcirculación con sidestream dark field (SDF) Microscan® como método de monitorización en microcirugía en modelo porcino / Microcirculation assessment with sidestream dark field (SDF) Microscan® as flap monitoring method in microsurgery in a porcine model

Objetivo: Determinar la factibilidad de la monitorización en microcirugía por medio de la evaluación no invasiva de la microcirculación con sidestream dark field (SDF) y compararla con otros métodos. Materiales y métodos: Estudio experimental. En 8 cerdos se elevó colgajo pectoral y se disecó pedículo. Se llevó a cabo una instalación sucesiva de dispositivos cutáneos para la evaluación de la microcirculación: SDF para evaluar flujo, y near infrared spectroscopy (NIRS) para evaluar saturación de O2 (SatO2). Posteriormente se evaluó la oclusión venosa, arterial y total con pinzamiento durante 180 s. Resultados: SDF en oclusión venosa: disminución del flujo: 51 s (59-62); SDF en oclusión arterial: disminución del flujo: 3 s (1-5); SDF en oclusión vascular total: disminución del flujo: 3,5 s (2-5). NIRS en oclusión venosa: disminución de la SatO2:15,2 ± 5,3%; NIRS en oclusión arterial: disminución de la SatO2 23,9 ± 13,8%; NIRS en oclusión vascular total: disminución de la SatO2 23,85 ± 13,9%. Doppler en oclusión venosa: no desapareció; Doppler en oclusión arterial y oclusión vascular total: desapareció a los 2 s. En cada una de las mediciones, los cambios clínicos fueron más tardíos que los observados con SDF. Conclusión: Es factible la monitorización en microcirugía por medio de la evaluación de la microcirculación con Microscan®. Este método permite realizar el diagnóstico de oclusión vascular más tempranamente que con NIRS y evaluación clínica.

Aim: Determine the feasibility of using SDF Microscan® as a non-invasive method for monitoring free flap microcirculation, and compare it to other methods. Materials and methods: Experimental study. In 8 pigs a pectoral myocutaneous flap was raised. Microcirculation was evaluated using: SDF Microscan®, near infrared spectroscopy (NIRS), clinical examination and Doppler. Venous, arterial and total occlusion was performed by clamping the vascular pedicle. Mean time to blood flow impairment diagnosis was measured. Results: SDF in venous occlusion: reduced microcirculatory flow index at: 51 s (59-62). SDF in arterial occlusion: reduced microcirculatory flow index at: 3 s (1-5). SDF in total vascular occlusion: reduced microcirculatory flow index at: 3.5 s (2-5). NIRS in venous occlusion: SatO2 decrease was 15.2 ± 5.3%. NIRS in arterial occlusion: SatO2 decrease was 23.9 ± 13.8%. NIRS in total vascular occlusion: SatO2 decrease was 23.85 ± 13.9%. Doppler in venous occlusion: The signal did not disappear. Doppler arterial and total vascular occlusion disappears at 2 s. The clinical changes were later than SDF. Conclusion: Microcirculation monitoring is feasible using SDF Microscan® in a pig model. This method allows to detect blood flow disruption earlier than NIRS and clinical evaluation.

Evaluation of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry-Based VITEK MS System for the Identification of Acinetobacter Species from Blood Cultures: Comparison with VITEK 2 and MicroScan Systems

BACKGROUND: Acinetobacter species are the leading cause of bloodstream infection (BSI), but their correct identification is challenging. We evaluated the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based VITEK MS (bioMerieux, France), and two automated systems, VITEK 2 (bioMerieux) and MicroScan (Siemens, USA) for identification of Acinetobacter BSI isolates. METHODS: A total of 187 BSI isolates recovered at a university hospital in Korea between 2010 and 2012 were analyzed. The identification results obtained using VITEK MS and two automated systems were compared with those of rpoB sequencing. RESULTS: Of 187 isolates analyzed, 176 were identified to the species level by rpoB sequencing: the Acinetobacter baumannii group (ABG; 101 A. baumannii, 43 A. nosocomialis, 10 A. pittii isolates) was most commonly identified (82.4%), followed by Acinetobacter genomic species 13BJ/14TU (5.3%), A. ursingii (2.1%), A. soli (2.1%), A. bereziniae (1.1%), and A. junii (1.1%). Correct identification rates to the species group (ABG) level or the species level was comparable among the three systems (VITEK MS, 90.3%; VITEK 2, 89.2%; MicroScan, 86.9%). However, VITEK MS generated fewer misidentifications (0.6%) than VITEK 2 (10.8%) and MicroScan (13.1%) (P<0.001). In addition, VITEK MS demonstrated higher specificity (100%) for discrimination between ABG and non-ABG isolates than the other systems (both, 31.8%) (P<0.001). CONCLUSIONS: The VITEK MS system is superior to the VITEK 2 and MicroScan systems for identification of Acinetobacter BSI isolates, with fewer misidentifications and better discrimination between the ABG and non-ABG isolates.

Discordance in Colistin Susceptibility Test for Acinetobacter baumannii Showing Resistance: MicroScan versus Etest

BACKGROUND: Acinetobacter baumannii causes various hospital-acquired infections, its multidrug resistance is rapidly increasing worldwide. Although colistin is used in treatments against multidrug-resistant A. baumannii, resistance to colistin has also been reported recently. Few studies have reported colistin susceptibility testing using MicroScan. In this study, we compared colistin susceptibility tests for resistant A. baumannii by MicroScan (Siemens, USA) and Etest (BioMerieux, France). METHODS: We collected 115 A. baumannii clinical isolates, showing colistin resistance (minimum inhibitory concentration [MIC] > or =4 microg/mL) by MicroScan, from July 2014 to March 2015 at Kangdong Sacred Heart Hospital. Species identification and antimicrobial susceptibility tests were performed using the MicroScan Neg Combo Panel Type 72. Additionally, Etest was also performed for comparison. RESULTS: Of the 115 isolates, Etest revealed that 103 (89.6%) were colistin-susceptible (MIC 4 microg/mL by MicroScan were resistant to colistin according to the Etest. CONCLUSIONS: The MicroScan automated system, using the commercial broth microdilution method, exhibited some discrepancies with the Etest for colistin susceptibility in A. baumannii. Therefore, more practical and reliable susceptibility tests for colistin are required in clinical laboratories using MicroScan.

Estudio comparativo entre los sistemas automatizados Vitek YBC® y Microscan Walk Away RYID® con los métodos fenotípicos convencionales para la identificación de levaduras de interés clínico / A comparative study between the Vitek YBC® and Microscan Walk Away RYID® automated systems with conventional phenotypic methods for the identification of yeasts of clinical interest

El objetivo de este trabajo fue comparar la identificación de levaduras de interés clínico por los métodos automatizados Vitek YBC® y Microscan Walk Away RYID® con los métodos fenotípicos convencionales. Se utilizaron 193 aislamientos de levaduras provenientes de muestras clínicas y cinco cepas controles. Todas las levaduras fueron identificadas por los métodos automatizados antes nombrados y los métodos fenotípicos convencionales de asimilación de carbohidratos, visualización de la morfología microscópica con agar harina de maíz y el uso de agar cromogénico. Para evaluar las variables se utilizaron tablas de contingencia de 2×2, Chi cuadrado de Mc Nemar, el índice Kappa, y se calcularon los valores de concordancia, así como los errores mayores y menores de los métodos automatizados. Las levaduras se dividieron en dos grupos: 1) de aislamiento frecuente y 2) de aislamiento poco frecuente. Los sistemas Vitek YBC® y Microscan Walk Away RYID® fueron concordantes en un 88,4 y 85,9% respectivamente, cuando se compararon con los métodos fenotípicos convencionales. Aunque ambos sistemas automatizados se pueden utilizar para la identificación de levaduras, la presencia de errores mayores y menores indica la posibilidad de identificaciones incorrectas, por lo tanto, el operador de estos equipos debe utilizar paralelamente pruebas fenotípicas como la visualización de la morfología microscópica en agar harina de maíz y el agar cromogénico, sobre todo frente a levaduras de aislamiento poco frecuente. Los sistemas automatizados son una herramienta valiosa, sin embargo, la experiencia y el criterio del microbiólogo son una fortaleza importante para asegurar la calidad de los resultados.

The aim of this study was to compare the identification of clinically relevant yeasts by the Vitek YBC® and Microscan Walk Away RYID® automated methods with conventional phenotypic methods. One hundred and ninety three yeast strains isolated from clinical samples and five controls strains were used. All the yeasts were identified by the automated methods previously mentioned and conventional phenotypic methods such as carbohydrate assimilation, visualization of microscopic morphology on corn meal agar and the use of chromogenic agar. Variables were assessed by 2×2 contingency tables, McNemar’s Chi square, the Kappa index, and concordance values were calculated, as well as major and minor errors for the automated methods. Yeasts were divided into two groups: 1) frequent isolation and 2) rare isolation. The Vitek YBC® and Microscan Walk Away RYID® systems were concordant in 88.4 and 85.9% respectively, when compared to conventional phenotypic methods. Although both automated systems can be used for yeasts identification, the presence of major and minor errors indicates the possibility of misidentifications; therefore, the operator of this equipment must use in parallel, phenotypic tests such as visualization of microscopic morphology on corn meal agar and chromogenic agar, especially against infrequently isolated yeasts. Automated systems are a valuable tool; however, the expertise and judgment of the microbiologist are an important strength to ensure the quality of the results.

Comparison of MicroScan and Phoenix Automated Systems for Detection of Extended-Spectrum beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae

The aim of this study was to evaluate the performances of MicroScan (Siemens Healthcare, USA) and Phoenix (Becton Dickinson Diagnostic Systems, USA) automated systems for the detection of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae. ESBL-producers were detected from 18 E. coli strains and 26 K. pneumoniae strains using MicroScan, Phoenix, and double-disk synergy test (DDST). The ESBL types were determined by PCR direct sequencing. ESBL genes were detected in 38 (86.4%) of the 44 test strains. The sensitivities of MicroScan, Phoenix, and DDST were 94.6%, 79%, and 89.5%, respectively. Both MicroScan and Phoenix provided acceptable results for the examination of clinical isolates.

Evaluation of the MicroScan MICroSTREP Plus Antimicrobial Panel for Testing beta-Hemolytic Streptococci and Viridans Group Streptococci / 대한진단검사의학회지

BACKGROUND: In order to determine the clinical usefulness of the MicroScan (Siemens Healthcare Diagnostics, USA) MICroSTREP plus antimicrobial panel (MICroSTREP) for testing antimicrobial susceptibility of beta-hemolytic streptococci (BHS) and viridans group streptococci (VGS), we compared the accuracy of MICroSTREP with that of the CLSI reference method. METHODS: Seventy-five BHS and 59 VGS isolates were tested for antimicrobial susceptibility to ampicillin, penicillin, cefotaxime, meropenem, erythromycin, clindamycin, levofloxacin, and vancomycin by using MICroSTREP and the CLSI agar dilution method. RESULTS: The overall essential agreement with regard to minimum inhibitory concentrations (MICs) (within +/-1 double dilution) between MICroSTREP and the CLSI reference method was 98.2%, and categorical agreement (CA) was 96.9%. For the BHS isolates, the CA for erythromycin was 96.0%, whereas that for cefotaxime, meropenem, levofloxacin, and vancomycin (for ampicillin, penicillin, and clindamycin; 98.7%) was 100%. For the VGS isolates, the CA for penicillin was 84.7% and that for erythromycin, clindamycin, and vancomycin (for meropenem, 86.5%; for ampicillin, 88.1%; and for cefotaxime and levofloxacin, 96.6%) was 100%. All categorical errors of penicillin and ampicillin in the VGS isolates were minor. CONCLUSIONS: The accuracy of MICroSTREP is comparable to that of the CLSI reference method, suggesting that this panel can be effective for testing antimicrobial susceptibility of BHS and VGS.

Evaluation of MicroScan Synergies plus Positive Combo 3 Panels for Identification and Antimicrobial Susceptibility Testing of Staphylococcus aureus and Enterococcus Species / 대한진단검사의학회지

BACKGROUND: Few studies have evaluated the performance of the recently introduced MicroScan Synergies plus Positive Combo 3 Panels (SIPC3) (Dade Behring Inc., USA). We evaluated the clinical efficacy of the panels in identification (ID) and antimicrobial susceptibility testing (AST) of Staphylococcusaureus and enterococci. METHODS: To evaluate the panels' accuracy of identification, the results obtained using the test panels were compared with those obtained by using conventional biochemical tests in conjunction with VITEK 2 system (bio-Merieux, USA). In addition, the AST results obtained using the panels were compared with those obtained by performing CLSI broth microdilution. RESULTS: The overall agreement between the approaches for the ID of S. aureus and enterococci was 100% and 96%, respectively. The categorical and essential agreements (CA and EA) for S. aureus were 98%, each. Very major errors (VME), major errors (ME), and minor error (mE) for S. aureus were 0.45%, 0.3%, and 4.2%, respectively. The majority of VMEs were for oxacillin (8.6%), penicillin (2.0%), erythromycin (7.9%), clindamycin (3.8%), and tetracycline (4.1%). For enterococci, the CA, EA, VME, ME, and mE were 88.8%, 93.7%, 4.4%, 0%, and 2.8%, respectively. The 80.5% (29/36) of Enterococcus faecium had concordant ID with the reference. Most of the categorical errors (3 VMEs and 14 mEs) were observed for quinupristin/dalfopristin (Synercid; Catalytica Pharmaceuticals Inc., USA). CONCLUSIONS: The panels compared favorably with conventional methods for the ID and AST of S. aureus. However, we expected a better performance for ID of E. faecium and AST using Synercid.

Evaluation of MicroScan and Phoenix System for Rapid Identification and Susceptibility Testing Using Direct Inoculation from Positive BACTEC Blood Culture Bottles / 대한진단검사의학회지

BACKGROUND: Procedures for rapid identification and susceptibility testing by direct inoculation (DI) from positive blood culture bottles into an automated system have not been standardized. This study was purposed to evaluate DI from BACTEC 9240 blood culture system (BD, USA) into MicroScan (Dade Behring, USA) or Phoenix (BD, USA). METHODS: From May to June 2006, bacterial pellets from positive aerobic bottles showing gram-positive cocci (GPC) or gram-negative rods (GNR) of single morphology were directly inoculated to MicroScan PosCombo1A and NegCombo32 and to Phoenix PMIC/ID-107 and NMIC/ID-53. In addition, the automated instruments were also inoculated from subcultures (standard inoculations, SI). Species identification and susceptibilities were compared between DI and SI and between MicroScan and Phoenix. RESULTS: A total of 108, 104, and 78 specimens were tested with MicroScan, Phoenix, and both, respectively. When DI and SI were matched, 94.8% of GPC were correctly identified with MicroScan, compared to 80.7% with Phoenix, and 93.9% of GNR were correctly identified with MicroScan, compared to 95.7% with Phoenix. DI with MicroScan and Phoenix showed correct susceptibilities in 94.6% of 1,150 and 96.5% of 660 tests (with very major error [VME] of 1.1% and 1.1%), respectively, among GPC and in 94.4% of 942 and 96.3% of 781 tests (with VME of 0.6% and 0%), respectively, of GNR. Correlation of identification/susceptibilities between MicroScan and Phoenix using DI were 81.8%/98.0% for Staphylococcus aureus and 100.0%/95.6% for Escherichia coli. CONCLUSIONS: DI warrants a reliable method for identification and susceptibility testing of both GPC and GNR in MicroScan, and those of only GNR in Phoenix.

Comparison of the MicroScan(R) Combo Panel Synergies plus with the MicroScan(R) Conventional Combo Panel for Diagnostic Performance of Gram-negative and Gram-positive Bacteria / 대한임상미생물학회지

BACKGROUND: To access the clinical usefulness of MicroScan(R) Synergies plus Combo Panels (Siemens, USA) for the identification and antimicrobial susceptibility test (AST) of Gram-negative bacteria (GNB) and Gram-positive cocci (GPC), we compared MicroScan(R) Synergies plus Combo Panels with MicroScan(R) conventional Combo Panels. METHODS: One-hundred four isolates of GNB were simultaneously tested with MicroScan(R) Synergies plus Neg Combo Type 2 Panel (SINC2) and MicroScan(R) Neg Combo Panel Type 44 (NC44). One-hundred isolates of GPC were simultaneously tested with MicroScan(R) Synergies plus Pos Combo 3 Panel (SIPC3) and MicroScan(R) Pos Combo 1A (PC1A). RESULTS: Of the GNB isolates, agreement rate of identification between SINC2 and NC44 were 92.3% to the species level and 93.3% to the genus level. Of the GPC isolates, agreement rate of identification between SIPC3 and PC1A were 85.0% to the species level and 100% to the genus level. Of the GNB isolates, agreement rate of AST according to antimicrobial agents between SINC2 and NC44 ranged from 86.5% to 100%. Among GPC isolates, agreement rate of AST according to antimicrobial agents between SIPC3 and PC1A were higher than 96.0% with the exception of gentamicin and quinupristin-dalfopristin. CONCLUSION: Compared with MicroScan(R) conventional Combo Panels (NC44, PC1A), MicroScan(R) Synergies plus Combo Panels (SINC2, SIPC3) showed high agreement rate of identification and AST, and had the advantage of more rapid reporting.

Identificación de levaduras mediante la técnica convencional y dos técnicas automatizadas / Yeasts identification by the conventional technique and two automated techniques

El objetivo de este trabajo fue evaluar y comparar la identificación de levaduras por los métodos automatizados VitekYBC y MicroScan RYID versus la metodología de referencia (asimilación de carbohidratos). Se diseñó un estudio de corte transversal, aleatorio, a ciegas, comparativo y experimental con 193 cepas de levaduras provenientes de muestras clínicas y 5 cepas derivadas de ATCC, las cuales fueron identificadas por la metodología de referencia, acompañada de la morfología microscópica en agar harina de maíz, y por las metodologías automatizadas. Se usaron la prueba de Mc Nemar y el índice Kappa para evaluar si las variables del estudio se relacionaban entre sí y se calcularon los valores de sensibilidad, intervalos de confianza y porcentajes de concordancia. También se calcularon los errores muy mayores (VM), errores mayores (EM) y errores menores (Em) para las metodologías automatizadas. Los sistemas VitekYBC y MicroScanRYID fueron concordantes en un 88,4% (175/198) y 85,9% (170/198) respectivamente cuando se compararon con el método de referencia, por lo tanto, ambos sistemas automatizados se pueden utilizar como métodos de identificación, ya que mostraron una asociación estadísticamente significativa al compararlos con el método de referencia (p<0,05). El sistema VitekYBC presentó EM= 7,1% y Em= 4,5%, mientras que el sistema MicroScanRYID mostró EM= 11,1% y Em= 3,0%. Los métodos automatizados comparados en este estudio tienen niveles de concordancia aceptables, pero presentan EM y Em que pueden causar que el operador de estos equipos incurra en identificaciones incorrectas. Por lo tanto, es indispensable el uso de pruebas complementarias, como la visualización microscópica de la morfología en agar harina de maíz y los medios cromogénicos, cuando se realice la identificación de levaduras mediante sistemas automatizados. Estos sistemas son una herramienta valiosa para la identificación de levaduras, sin embargo, la experiencia del microbiólogo continúa siendo una fortaleza importante para asegurar la calidad de los resultados.

The objective of this work was to evaluate and to compare yeasts identification by the automated methods Vitek YBC and MicroScan RYID versus the reference methodology (carbohydrates assimilation). A comparative, blindly, random, transverse and experimental study was designed with 193 yeasts isolated from clinical samples and 5 strains derived from the ATCC, which were identified by the reference methodology, accompanied by microscopic morphology in corn meal agar, and by the automated methodologies. Kappa index and Mc Nemar test were used to evaluate the relationship among the variables and sensitivity, confidence intervals and agreement percentages were calculated for the automated methodologies. Very major (VM), major (EM), and minor errors (Em) were also calculated. Vitek® YBC and MicroScan RYID® systems were concordant in 88,4% (175/198) and 85,9% (170/198) respectively, when compared with the reference method, therefore, both automated systems can be used as identification methods since they showed an statistically significant association when were compared with the reference method (p<0,05). The Vitek YBC® system presented EM=7,1% and Em=4,5%, while the MicroScan RYID® system showed EM=11,1% and Em = 3,0%. The automated methods compared in this study have acceptable concordant agreement levels, but the presence of EM and Em can cause that the operator of these equipments incurs in incorrect identifications. Therefore, is indispensable the use of complementary tests as morphology microscopic visualization in corn meal agar and use of chromogenic agar when performing yeasts identification by automated methods. These systems are a valuable tool for the yeasts identification, however, the microbiologist experience continues to be an important strength to assure the quality of the results.

Cryptococcus spp. en Venezuela y su relación con el biotipo del MicroScan® / Cryptococcus spp. in Venezuela and its relationship with the MicroScan® biotype

El lector del panel microbiológico automatizado autoScan®-4 detecta el crecimiento del hongo en diversos sustratos bioquímicos, presentes en los pozos de los paneles del MicroScan®. El propósito de este estudio fue relacionar el ¨biotipo¨ identificado por el MicroScan® con la especie causante de criptococosis, con el objeto de permitir una identificación en el menor tiempo posible. Se evaluaron 82 cepas de Cryptococcus spp. aisladas a partir de muestras clínicas entre 1995 y 2004. Para garantizar la pureza de las cepas, se realizó la identificación de las mismas por métodos convencionales; para identificar las especies se utilizó el medio L-canavanina-glicina-azul de bromotimol (CGB). Se utilizó también el panel de identificación rápida de levaduras del MicroScan®, con el fin de determinar el ¨biotipo¨. El MicroScan® reveló 27 diferentes ¨biotipos¨. De los 82 aislados tipificados con el uso del medio CGB, el 91,46 % correspondieron a C. neoformans y 8,54 % a C. gattii. No se encontró una diferencia significativa entre los ¨biotipos¨ y las especies (p>0,05). Sin embargo, se encontró significancia estadística entre las especies C. gattii y C. neoformans y la asimilación de p-nitrofenil-N-acetil-ß-D-glucosamina (NAG) (p<0,05). El panel de identificación rápida de levaduras del MicroScan® no fue capaz de diferenciar ambas especies.

The automated reader of the AutoScan® -4 microbiological panels detects fungi growth in various biological substrates present in the MicroScan® panel wells. The purpose of this study was to relate the biotype identified by the MicroScan® with the species causing the criptococcosis, in order to obtain identification in the shortest possible period. The evaluation included 82 Cryptococcus spp. strains isolated from clinical samples between 1995 and 2004. To guarantee the purity of the strains they were also identified by conventional methods; to identify the species we used L-canavanin-glycine-bromthymol blue medium (CGB). We also used the fast yeast identification MicroScan® panel with the purpose of determining the “biotype”. The MicroScan® revealed 27 different “biotypes”. Of the 82 isolates typed with the CGB medium, 91.46% corresponded to C. neoformans and 8.5% to C. gattii. No significant difference was found among the “biotypes” and the species (p<0,05). Nevertheless, there was a statistically significant difference between the assimilation of p-nitrophenil-N-acetyl-ß-D-glucosamine (NAG) (p<0.05) by the C. gattii and the C. neoformans species. The fast yeast identification MicroScan® panel was not able to differentiate between both species.

Evaluation of MicroScan MICroSTREP Plus Antimicrobial Susceptibility Panel for Testing Streptococcus pneumoniae / 대한임상미생물학회지

BACKGROUND: The MicroScan MICroSTREP plus panel for susceptibility testing of various streptococci, including Streptococcus pneumoniae, has recently been introduced in Korea. The current study evaluated the usefulness of MicroScan MICroSTREP plus panel for antimicrobial susceptibility test of S. pneumoniae. METHODS: A total of 75 clinical isolates of S. pneumoniae were tested for antimicrobial susceptibility to penicillin, cefotaxime, ceftriaxone, meropenem, vancomycin, clindamycin, erythromycin, and levofloxacin with the MicroScan MICroSTREP plus panel and clinical and laboratory standard institute (CLSI) reference broth microdilution method. For 46 of 75 isolates, additional susceptibility tests to penicillin and cefotaxime were performed with Etest. RESULTS: The overall essential agreement of MICs (within one dilution of MICs) defined by the MicroScan MICroSTREP plus panel and reference method was 93.0%. Overall there were 11.7% minor, 0.7% major, and 0.7% very major interpretative category errors observed. The results of antibiotic susceptibility testing by Etest were similar to those obtained by the MicroScan MICroSTREP plus panel. CONCLUSION: The MicroScan MICroSTREP plus panel, a commercial broth microdilution method, has a comparable accuracy to CLSI broth microdilution method for the resistance testing of S. pneumonia. This panel can be used for determining susceptibilities of S. pneumoniae to a wide variety of antimicrobial agents in clinical microbiology laboratories.

Identification of Vibrio vulnificus by the Microscan and the Vitek II Systems / 대한진단검사의학회지

BACKGROUND: Vibrio vulnificus sepsis requires a rapid and accurate bacteriological diagnosis for optimal management of the patient because of its high mortality. We evaluated two automated bacteriological identification systems, Microscan (WalkAway 96, Dade Behring, West Sacramento, CA, USA) and Vitek II (bioMerieux, Durham, NC, USA), for their ability to identify V. vulnificus strains isolated from clinical specimens. METHODS: A total of 60 V. vulnificus strains isolated from clinical specimens in Chonnam University Hospital during 1993-2003 were tested. For the identification of the isolates by the Microscan, Neg Combo type 32 was used and four different panel inoculation methods were evaluated for accuracy. Identification by the Vitek II system was carried out using Vitek ID-GNB cards in accordance with the manufacturers, instruction using 0.45% saline media. RESULTS: With the Microscan, the most accurate identification result was obtained after a modified inoculation method of the panel with a bacterial suspension prepared in 0.85% saline; the identification rate was 100%. The identification rate of Vitek II system was 96.7%; two strains of V. vulnificus were misidentified as V. harveyi and V. alginolyticus. CONCLUSIONS: These results indicate that both Microscan and Vitek II are adequate for the identification of clinical isolates of V. vulnificus, but for the identification by the Microscan a modified inoculation method should be used by suspending the organisms in 0.85% saline.

Database Conversion and Analysis of Antimicrobial Resistance Profile for Microscan using BacLink 2 Software / 임상검사와정도관리

BACKGROUND: In hospital laboratory using Microscan, the search for an isolate or the analysis for antimicrobial susceptibility rates were obtained by the Data Management System (DMS) software. However, it is hard to convert DMS database to other file formats in addition to some limitation in using the database. We applied BacLink 2 and WHONET 5.1 softwares to convert and analyse DMS database for the utilization of the isolate profiles and the antimicrobial resistance rates. METHODS: Specimen and microbial data were printed as 'Short report form', an ASCII text file, from Microscan DMS. BacLink 2 software was used to convert the printed file to dBASE format file. Statistical analyses were performed using WHONET 5.1 software. RESULTS: Data of isolates were obtained as 'Short report form' in one month intervals. This file could be converted to other database file using BacLink 2 software. The antimicrobial resistant profiles were obtained, and the susceptibility, intermediate resistant, and resistant rates for each isolates could be analyzed. CONCLUSIONS: In this study, BacLink 2 and WHONET 5.1 software were successfully applied for the conversion of the database. Analysis of isolate profiles and antimicrobial resistant rates could be performed in other personal computer systems. The database management by BacLink 2 and WHONET 5.1 software could be applicable for the convenient statistical analysis in microbiology laboratories using Microscan.

Comparison of MicroScan and Vitek ESBL test with NCCLS ESBL Confirmatory Test / 대한임상미생물학회지

BACKGROUND: This study was designed to evaluate the ability of the Vitek and MicroScan ESBL test by comparing with NCCLS ESBL phenotypic confirmatory test by disk diffusion and to know the frequency of ESBL producers in the Seoul Veterans Hospital. METHODS: A total of 1,261 isolates(Escherichia coli 705, Klebsiella pneumoniae 502, K. oxytoca 54) from 883 patients were included in ESBL screening test by Vitek (494 strains) and MicroScan (767 strains). After excluding repetitive isolates from same patients, NCCLS ESBL confirmatory test was performed for 197 ESBL screening positives and 184 ESBL screening negatives. RESULTS: The overall frequency of ESBL screening positives was 22.3% (by MicroScan 26.2%, by Vitek 15.6%), and that of NCCLS ESBL positives was 18.9%(18.3% in E. coli, 21% in K. pneumoniae). MicroScan and Vitek ESBL test showed 100% and 92.3% sensitivity, 77.1% and 95.5% specificity, respectively. Among the 158 NCCLS ESBL positives, 17.7% showed clavulanic acid effect in cefotaxime only, 10.1% in ceftazidime only, and 72.2% in both. MicroScan Neg ComboPanel Type 21 test revealed that 91.4% of suspicious ESBL producers flagged by one or two antimicrobials were erroneous. In contrast, 96.2% of strains flagged by all five antimicrobials were correct. CONCLUSION: Suspicious ESBL producers by MicroScan showing three or four antimicrobial flags should be retested by NCCLS ESBLconfirmatory test. But strains with two or less flags and strains with all 5 flags can be reported as Non-ESBL producers and ESBL producers, respectively.

Detection of Methicillin-Resistance of Coagulase-negative Staphylococci / 대한임상미생물학회지

BACKGROUND: Coagulase-negative staphylococci (CNS) has been considered as a major causative agent of nosocomial infections. A prompt and accurate detection of methicillin resistance (MR) in staphylococci is a current issue of clinical microbiology laboratories. This study was purposed to evaluate various methods for detecting MR from CNS. METHODS: We selected 78 CNS strains obtained from blood cultures from April 1999 through July 2001 including 20 strains of Staphylococcus epidermidis, 20 S. hominis (SHO), 19 S. capitis, 9 S. haemolyticus, 3 S. saccharolyticus, 1 S. saprophyticus (SAP), 2 S. warneri (SWA), 2 S. xylosus, 1 S. lugdunensis, and 1 S. auricularis. In addition, one SAP strain received from World Health Organization for proficiency tests was also studied. The following methods were compared to the mecA gene PCR: MicroScan PosCombo 12, oxacillin salt agar containing 6 microgram/mL (OSA-6) or 0.6 microgram/mL (OSA- 0.6) of oxacillin, oxacillin disk diffusion (ODD), and MRSA-Screen latex agglutination (LA) for detecting penicillin binding protein 2a. RESULTS: One SWA was failed in mecA-PCR and fifty-nine of 78 (75.6%) CNS were positive for mecA gene. The agreement rates, sensitivities, and specificities for each test were as follows: for MicroScan, 97.3%, 98.2%, 88.9%; for OSA-6 and OSA-0.6 at 24-h incubation, 79.5%, 74.6%, 94.7% and 79.5%, 72.9%, 100%, respectively, and at 48-h incubation, 91.0%, 91.5%, 89.5% and 91.0%, 96.6%, 73.7%, respectively; ODD, 84.6%, 84.7%, 84.2%; LA, 80.8%, 76.3%, 94.7%. One SHO and one SAP that were mecA-negative showed resistance in the MicroScan, ODD, and OSA. CONCLUSIONS: MicroScan appears a reliable method to detect MR in all species of CNS except SHO and SAP. ODD and LA were not appropriate in detecting MRCNS due to a low sensitivity. Although OSA-0.6 at 48-h incubation showed a high sensitivity, the low specificity may limit a routine use in clinical laboratory.

Evaluation of MicroScan Neg Combo Panel type 21 to Detect ESBL / 대한임상미생물학회지

BACKGROUND: Escherichia coli and Klebsiella pneumoniae resistant to 3rd generation cephalosporin have been reported with increasing frequency in tertiary-care hospital in Korea. MicroScan Neg Combo Panel Type 21 (Type 21) contains a 1 microgram/mL cepfodoxime (POD) in addition to other screen wells containing ceftazidime, cefotaxime, ceftriaxone, and aztreonam, which are designed for detecting extended-spectrum beta-lactamase (ESBL)-producing E. coli and Klebsiella species. We evaluated the Type 21 panel for its ability to detect ESBL. METHODS: From November to December in 1998, 496 E. coli and 326 K. pneumoniae strains isolated from clinical specimens were tested with Type 21 panel The isolates flagged as ESBL producers by the panel were confirmed by the double disk synergy test (DDS). To evaluate the specificity of POD, n-lactamases of 54 E, coli and 20 K. pneumoniae strains that were flagged by, POD only from January to May 1999 were analyzed by isoelectric focusing(IEF). RESULTS: 75/496(15%) E. coli and 68/326(21%) K. pneumoniae were flagged as ESBL producers by Type 21 panel. Of those, 94 isolates including 38/75 (51%) of E. coli and 56/68 (82%) of K. pneumoniae were positive for DDS. Among the 94 ESBL producers, all were detected by POD, 84% by cefotaxime, 85% by ceftazidime, 84% by ceftriaxone, and 86% by aztreonam. The 74 strains that were flagged as ESBL producers by POD screen well only were mostly DDS-negative, cefoxitin- resistant and showed beta-lactamases with pls of 5.4 and 7.6 or no band, which could be interpreted as the presence of TEM-1 or SHV-1 type beta-lactamases and/or basal AmpC beta-lactamases, not ESBL. CONCLUSION: MicroScan Neg Combo Panel Type 21 was able to detect a greater number of ESBL producers by inclusion of POD in its screening well. However, the specificity of POD was compromised by flagging a significant number of DDS negative strains. We conclude that the isolates with reduced susceptibility to 3rd generation cephalosporins as well as POD can be reported as ESBL-producers and those resistant to POD only should be confirmed by DDS.