ABSTRACT
We evaluated the DxU 850m Iris Urine Microscopy analyzer as a screening tool for excluding negative urine samples (n = 1337). At a cutoff of 103 colony counts·mL-1, sensitivity was 55.1 %, specificity 68.6 %. The DxU 850m Iris does not offer acceptable prediction of culture-negative urine samples at the tested cutoff.
Subject(s)
Microscopy , Sensitivity and Specificity , Urinalysis , Urine , Humans , Microscopy/methods , Urinalysis/methods , Urinalysis/instrumentation , Urine/microbiology , Urinary Tract Infections/diagnosis , Urinary Tract Infections/microbiology , Automation, Laboratory/methodsABSTRACT
This study evaluated the MBT-ASTRA for antimicrobial susceptibility testing of Bacteroides fragilis with different classes of antibiotics. MALDI-TOF MS peak AUCs from suspensions with B. fragilis with and without an antibiotic were used to calculate the relative growth (AUC "with antibiotic" divided by "without antibiotic"). Antimicrobial susceptibility testing of B. fragilis ATCC 25285 (susceptible) and B. fragilis O18 (resistant) was demonstrated with a clear difference of the relative growth between susceptible and resistant. The MBT-ASTRA needs further development and assessment but could be a relatively easy and inexpensive method for rapid antimicrobial susceptibility testing in specific cases of infection with B. fragilis.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteroides fragilis/drug effects , Microbial Sensitivity Tests/methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Bacteroides Infections/microbiology , Bacteroides fragilis/chemistry , Bacteroides fragilis/growth & development , Bacteroides fragilis/isolation & purification , HumansABSTRACT
OBJECTIVES: To investigate the performance of the meropenem and imipenem double-ended Etestâ±âEDTA and the tablet-based (meropenem and meropenemâ+âdipicolinic acid) KPC/MBL Confirm Kit to detect cfiA metallo-ß-lactamase (MBL) in Bacteroides fragilis. METHODS: Well-characterized B. fragilis isolates, most from previously published studies, harbouring the cfiA gene and covering a wide range of meropenem MICs were included (nâ=â21). RESULTS: The imipenem double-ended Etest showed an indeterminate result in 95% of the included isolates with the cfiA gene (20 of 21), whereas the meropenem double-ended Etest gave an MIC ratio ≥8 (positive test) with all the isolates. All isolates that were meropenem intermediate or resistant had a zone diameter difference ≥6 mm with the KPC/MBL Confirm Kit. CONCLUSIONS: The meropenem double-ended Etest and not imipenem should be preferred for phenotypic detection of MBLs in B. fragilis. The KPC/MBL Confirm Kit could be an alternative with isolates that are meropenem intermediate or resistant (MIC >2 mg/L).