Performance Evaluation of the CLINITEK Novus Automated Urine Chemistry Analyzer

BACKGROUND: We aimed to evaluate the performance of the CLINITEK Novus urine chemistry analyzer (Siemens, UK). METHODS: The precision, correlation, and carryover study were performed using two kinds of commercial quality control materials and 40-55 freshly collected patient specimens. We calculated exact and within-1-block agreement, along with kappa agreement, to compare the semi-quantitative results between urine chemistry analyzers. The urine specific gravity taken by a refractometer was compared with the analyzer results. Moreover, we analyzed additional urine specimens for protein to evaluate the agreement of results between those of the CLINITEK Novus and the AU680 analyzers (Beckman Coulter, Japan). RESULTS: The precision study showed acceptable results; within-1-block agreement was 100% in all tested items. The urine chemistry results from the CLNITEK Novus analyzer demonstrated ≥85.1% within-1-block agreements with those of the Uriscan Super, and the kappa test results were ≥0.81. The comparison of specific gravity with manual refractometer showed a good correlation (r=0.991), and the protein comparison with the AU680 analyzer also showed a good correlation (with exact and within-1-block agreements being 75.9% and 100.0%, respectively). The carryover rates were 0% in all tested items, except specific gravity and heavy blood tests. CONCLUSIONS: The CLINITEK Novus analyzer showed good performance in terms of precision, comparison, and carryover in this study. Therefore, the CLINITEK Novus automated urine analysis is expected to be useful for routine urinalysis in a clinical laboratory.

In Vitro Activities of Ceftriaxone-Sulbactam against Major Aerobic and Anaerobic Bacteria from Clinical Samples

BACKGROUND: beta-lactam antibiotics are one of the most common antimicrobial agents. However, the increasing of beta-lactamase-producing bacteria makes these agents less useful. Therefore, agents stable for beta-lactamase have been developed. This study was conducted to determine the activities of the combination agent ceftriaxone-sulbactam and to compare its activities with other agents. METHODS: A total of 437 clinical isolates of aerobic and anaerobic bacteria were collected in Severance Hospital from 2007 to 2011. Using 23 antimicrobial agents, antimicrobial susceptibility tests were performed using the Clinical and Laboratory Standards Institute (CLSI) agar dilution method. RESULTS: The minimal inhibitory concentrations (MICs) of ceftriaxone and ceftriaxone-sulbactam were similar to or lower than those of other beta-lactam antibiotics for methicillin-susceptible Staphylococcus aureus (MSSA), Streptococcus pneumoniae, S. pyogenes, and viridans group streptococci. For Moraxella catarrhalis, Neisseria gonorrhoeae, Haemophilus influenzae, and H. parainfluenzae, ceftriaxone and the ceftriaxone-sulbactam combination also show low MIC50 and MIC90. For extended-spectrum beta-lactamase (ESBL)-producing E. coli, the MICs of ceftriaxone-sulbactam were lower than those of other cephalosporins. Among the anaerobes, ceftriaxone-sulbactam showed good activity compared to ceftriaxone alone for the Bacteroides fragilis group, B. thetaiotaomicron, other Bacteroides sp., Prevotella sp., and Porphyromonas sp. CONCLUSIONS: Ceftriaxone-sulbactam showed good antimicrobial activity and thus is useful for the treatment of infections by MSSA, S. pneumoniae, S. pyogenes, viridans group streptococci, M. catarrhalis, N. gonorrhoeae, H. influenzae, H. parainfluenzae, E. coli, and K. pneumoniae, B. fragilis group, B. thetaiotaomicron, other Bacteroides sp., Prevotella sp., and Porphyromonas sp.