Internal quality assurance in diagnostic microbiology: A simple approach for insightful data.

Given the importance of microbiology results on patient care, high quality standards are expected. Internal quality assurance (IQA) could mitigate the limitations of internal quality control, competency assessment and external quality assurance, adding a longitudinal insight, including pre- and post-analytical steps. Here, we implemented an IQA program in our clinical microbiology facilities with blind resubmission of routine samples during 22 months.

Early detection of extended-spectrum β-lactamase from blood culture positive for an Enterobacteriaceae using βLACTA test.

Bacterial pellets from Enterobacteriaceae positive blood cultures prepared using ammonium chloride were tested for rapid detection of β-lactamase using the commercial βLACTA test and read after 30 minutes. During 7 months, 137 bacterial pellets were tested prospectively. βLACTA test exhibited a sensitivity of 75% and a specificity of 100% for the detection of third-generation cephalosporin resistance.

Preparation of a blood culture pellet for rapid bacterial identification and antibiotic susceptibility testing.

Bloodstream infections and sepsis are a major cause of morbidity and mortality. The successful outcome of patients suffering from bacteremia depends on a rapid identification of the infectious agent to guide optimal antibiotic treatment. The analysis of Gram stains from positive blood culture can be rapidly conducted and already significantly impact the antibiotic regimen.

A simple blood-culture bacterial pellet preparation for faster accurate direct bacterial identification and antibiotic susceptibility testing with the VITEK 2 system.

An ammonium chloride procedure was used to prepare a bacterial pellet from positive blood cultures, which was used for direct inoculation of VITEK 2 cards. Correct identification reached 99% for Enterobacteriaceae and 74% for staphylococci. For antibiotic susceptibility testing, very major and major errors were 0.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry for direct bacterial identification from positive blood culture pellets.

An ammonium chloride erythrocyte-lysing procedure was used to prepare a bacterial pellet from positive blood cultures for direct matrix-assisted laser desorption-ionization time of flight (MALDI-TOF) mass spectrometry analysis. Identification was obtained for 78.7% of the pellets tested.

Interlaboratory comparison of results of susceptibility testing with caspofungin against Candida and Aspergillus species.

Seventeen laboratories participated in a study of interlaboratory reproducibility with caspofungin microdilution susceptibility testing against panels comprising 30 isolates of Candida spp. and 20 isolates of Aspergillus spp. The laboratories used materials supplied from a single source to determine the influence of growth medium (RPMI 1640 with or without glucose additions and antibiotic medium 3 [AM3]), the same incubation times (24 h and 48 h), and the same end point definition (partial or complete inhibition of growth) for the MIC of caspofungin.

Asymptomatic oral yeast carriage in HIV-infected patients: frequency and fluconazole susceptibility profile.

OBJECTIVES: Fluconazole-resistant oropharyngeal candidiasis (OPC) is a rapidly growing problem in HIV-infected patients. To better understand the pathogenesis of fluconazole resistance in this setting, asymptomatic candidal carriage was determined by means of oral swabs regularly performed in all patients without clinical signs of OPC seen at our HIV outpatient clinic. Controls were 204 asymptomatic healthcare workers without previous exposure to fluconazole.