Comparison of BACTEC Plus Aerobic/F Media and BacT/Alert FA Media to Detect Bacteria in Blood Culture Bottles Containing Peak Therapeutic Levels of Antimicrobials / 대한임상미생물학회지

BACKGROUND: Blood culture bottles with an antimicrobial removal system have been developed for patients treated with antibiotics. This study compared the ability of BACTEC Plus Aerobic/F bottles (Becton Dickinson, USA, BACTEC Plus) and BacT/Alert FA bottles (bio-Merieux Vitek, France) to effectively remove antimicrobials. METHODS: BACTEC Plus and BacT/Alert FA bottles were spiked with 5 mL human blood, peak therapeutic concentrations of 9 antimicrobials and 7 type strains. Three rounds of duplicate testing were completed per antimicrobial/strain combination and growth control without antimicrobials. The time to detection (TTD) and recovery rates for bacteria were compared for both systems. RESULTS: Overall, the BACTEC Plus and BacT/Alert FA recovered 76% (128/168) and 34% (57/168) of strains from test bottles, respectively. BACTEC Plus detected all of gram-positive bacteria except S. pneumoniae with ampicillin and ceftriaxone, but BacT/Alert FA detected 0~50% of gram-positive bacteria except E. faecalis with vancomycin and methicillin-resistant S. aureus with oxacillin. In presence of cefepime, cefotaxime, cefoxitin and ceftriaxone, BACTEC Plus detected 33~100% of gram-negative bacteria, but BacT/ Alert FA did not detect gram-negative bacteria at all. In presence of ciprofloxacin, BacT/Alert FA detected 100% of E. coli and K. pneumoniae compared with 33% of those for BACTEC Plus. Overall, TTD of BACTEC Plus was shorter than that of BacT/Alert FA except in detecting gram-negative bacteria with ciprofloxacin (P<0.05). CONCLUSION: BACTEC Plus Aerobic/F media containing peak therapeutic levels of antimicrobials are more effective and faster detection of bacteria than BacT/Alert FA media.

Performance of the VITEK2 System for Detection of Inducible Clindamycin Resistance in Staphylococci / 대한임상미생물학회지

BACKGROUND: The Clinical and Laboratory Standards Institute (CLSI) recommends testing for inducible clindamycin resistance in clindamycin non-resistant and erythromycin resistant (CNR-ER) staphylococci by using a D-zone test. Recently, the VITEK2 system was developed to detect inducible clindamycin resistance in staphylococci. We evaluated the performance of the VITEK2 system by comparing it with a D-zone test. METHODS: In detecting inducible clindamycin resistance, a total of 142 clinical isolates of staphylococci were tested by using the VITEK2 Antimicrobial Susceptibility Test (AST)-P601 card (bioMerieux, Marcy l'Etoile, France) and the D-zone test. Of the 142 isolates of staphylococci tested, 114 were CNR-ER staphylococci [40 coagulase-negative staphylococci (CoNS), 74 Staphylococcus aureus] and 28 were staphylococci, either resistant or susceptible to clindamycin and erythromycin (1 CoNS and 27 S. aureus). RESULTS: Of the 114 CNR-ER staphylococci, 98.6% (73/74) of S. aureus and 32.5% (13/40) of CoNS were inducible clindamycin resistant according to the Dzone test. Overall sensitivity and specificity of the VITEK2 system were 98.8% (85/86) and 98.2% (55/56) respectively, and the agreement between the VITEK2 system and the D-zone test was 98.6% (140/142). CONCLUSION: The VITEK2 system shows high concordance with a D-zone test. The inducible clindamycin resistance in staphylococci can be detected easily and conveniently by the VITEK2 system.

Comparisons of Latex Agglutination, Immunochromatography and Enzyme Immunoassay Methods for the Detection of Rotavirus Antigen / 대한진단검사의학회지

BACKGROUND: Rotavirus is the most common cause of childhood gastroenteritis during winter season. Rapid, accurate diagnosis is essential for preventing severe complications of rotaviral gastroenteritis. The sensitivity and specificity of five detection test kits for rotavirus including latex agglutination (LAT), enzyme immunoassay (EIA) and three immunochromatographic methods (ICG) were evaluated in this study. METHODS: A total of 95 stool samples collected from patients with acute gastroenteritis were studied. The test kits were as follows: LAT (Slidex latex, bioMerieux Vitek, France); three kinds of ICG (Dipstick ROTA, Eiken, Japan; SAS Rota Test, SA Scientific, Inc., USA; and ASAN Easy Test Rota strip, ASAN Pharmaceutical., Korea); and EIA (VIDAS Rotavirus, bioMerieux Vitek). The samples showing discordant results were reevaluated by reverse-transcription (RT) PCR and clinical manifestations. RESULTS: Of a total of 95 cases, 56 (58.9%) were positive and 39 (41.1%) were negative. Thirteen cases showed discordant results. Sensitivity and specificity were, respectively, 85.7% and 100% for LAT, 100% and 95% for both of Dipstick ROTA and SAS Rota, 86.7% and 87.5% for ASAN Rota strip and 98.1% and 97.3% for EIA. CONCLUSIONS: LAT was rapid and easy to perform and showed the lowest sensitivity among the five test kits. ICG showed a good agreement with EIA and RT-PCR. EIA was the best in respect of sensitivity and specificity, but difficulty in interpretations of equivocal results and time-consuming procedures were limitations. In conclusion, ICG, which is easy to perform at a low cost, may be an optimal method in place of LAT for the detection of rotavirus.