Withdrawal of a novel-design duodenoscope ends outbreak of a VIM-2-producing Pseudomonas aeruginosa.

BACKGROUND AND STUDY AIMS: Infections are a recognized risk of endoscopic retrograde cholangiopancreatography (ERCP). This paper reports on a large outbreak of VIM-2-producing Pseudomonas aeruginosa that was linked to the use of a recently introduced duodenoscope with a specific modified design (Olympus TJF-Q180V). METHODS: Epidemiological investigations and molecular typing were executed in order to identify the source of the outbreak. Audits on implementation of infection control measures were performed. Additional infection control strategies were implemented to prevent further transmission. The design and the ability to clean and disinfect the duodenoscope were evaluated, and the distal tip was dismantled. RESULTS: From January to April 2012, 30 patients with a VIM-2-positive P. aeruginosa were identified, of whom 22 had undergone an ERCP using a specific duodenoscope, the TJF-Q180V. This was a significant increase compared with the hospital-wide baseline level of 2 - 3 cases per month. Clonal relatedness of the VIM-2 P. aeruginosa was confirmed for all 22 cases and for the VIM-2 strain isolated from the recess under the forceps elevator of the duodenoscope. An investigational study of the new modified design, including the dismantling of the duodenoscope tip, revealed that the fixed distal cap hampered cleaning and disinfection, and that the O-ring might not seal the forceps elevator axis sufficiently. The high monthly number of cases decreased below the pre-existing baseline level following withdrawal of the TJF-Q180V device from clinical use. CONCLUSIONS: Duodenoscope design modifications may compromise microbiological safety as illustrated by this outbreak. Extensive pre-marketing validation of the reprocessability of any new endoscope design and stringent post-marketing surveillance are therefore mandatory.

Automated indirect immunofluorescence microscopy enables the implementation of a quantitative internal quality control system for anti-nuclear antibody (ANA) analysis.

BACKGROUND: Screening for anti-nuclear antibodies by indirect immunofluorescence (ANA-IIF) remains mandatory in the serological work-up of connective tissue diseases. Recently, automated approaches were introduced that may improve harmonization. Here, we investigated whether the introduction of automated ANA-IIF and more specifically the use of its quantitative measure, could improve ANA-IIF internal quality control (IQC) management. METHODS: We retrospectively reviewed results of two cohorts of routine samples and parallel IQC data collected from January 2010 to February 2013 and from February to mid October 2013. For the first cohort, data were collected using conventional microscopy. The second cohort was analyzed by an automated ANA-IIF microscope (Zenit G sight, A. Menarini). Retrospectively, we evaluated the applicability of the probability index (PI) of control material measurements and patient results for IQC management based on Westgard multirules. This approach was also compared with monthly monitoring of the %ANA-IIF positive samples. RESULTS: In our historical data set, we showed that monitoring of %ANA positives identified systematic errors that were not detected by monitoring control material results. Data resulting from automated microscopy showed that PI measurements on control material remained stable within the observed period and that Westgard multirules can be used for IQC follow-up. Parallel monitoring of the daily median patient PI and the monthly %ANA positives, showed that the daily median was a sensitive and fast tool for detecting systematic errors. CONCLUSIONS: The introduction of the automated ANA-IIF microscope could enable objective IQC procedures and should be considered an important step forward in ANA-IIF harmonization.

Automated indirect immunofluorescence antinuclear antibody analysis is a standardized alternative for visual microscope interpretation.

BACKGROUND: Screening for antinuclear antibodies (ANA) is a basic tool in the serological work-up of systemic rheumatic disorders. Despite the emergence of alternative screening methods and the difficulties in standardization, indirect immunofluorescence (IIF) remains the recommended method for ANA detection. This study aimed to assess the reliability of automated ANA IIF analysis as a standardized alternative for the conventional manual approach. METHODS: ANA testing on HEp-2000 cells was performed on 304 consecutive routine sera, 28 serumbank samples displaying rare staining patterns, 219 samples of well-defined disease cohorts [141 systemic sclerosis (SSc), 13 polymyalgia rheumatica, 22 osteoarthritis, 5 ANCA-associated vasculitis and 38 spondyloarthritis] and 100 healthy donors. All samples were analyzed by automated IIF (Zenit G-sight), by conventional visual IIF microscopy and two ANA screening enzyme immunoassays (EIA). RESULTS: Automated and conventional ANA IIF analysis were comparable for negative/positive interpretation as well as intensity assessment (>90% agreement). In contrast, the accuracy of pattern recognition (26%) was limited. Likelihood ratios (LR) for SSc on results intervals of both Zenit G-sight and EIA increased with increasing level of positivity. Sensitivity within the SSc-associated antibody subsets was higher for Zenit G-sight (97%-100%) than EIA (10%-96%). A significant correlation between the quantitative result obtained by Zenit G-sight and the conventional end-point titer was found. CONCLUSIONS: The use of Zenit G-sight for automated ANA IIF analysis offers opportunities to improve standardization. However, a complementary role of the expert technicians remains, especially for pattern recognition and classification of uncertain/negative samples.

Evaluation of the Seegene Allplex™ Respiratory Panel for diagnosis of acute respiratory tract infections.

Objectives: The Seegene AllplexTM Respiratory panel was retrospectively challenged using a collection of quality control samples (QCMD) and clinical samples previously analysed with validated routine methods. Methods: A collection of 111 samples [43 QCMD samples, 13 bronchoalveolar lavage fluids and 55 nasopharyngeal aspirates/swabs] was tested with Seegene AllplexTM. The clinical samples were tested previously using either FTD® Respiratory Pathogens 21 qPCR assay (Fast Track Diagnostics), an in-house multiplex PCR for Bordetella, or BioGX Sample-ReadyTM Atypical pneumo panel (Becton Dickinson). Samples were stored at -80°C prior to analysis with Seegene Allplex™, nucleic acids were automatically extracted with NucliSENS Easymag (bioMérieux). Samples returning discordant results were subjected to repeat testing and/or additional testing by reference laboratories. Results: Seegene correctly identified 41/43 QCMD samples (95.4%); two samples positive for respiratory syncytial virus (RSV) and human metapneumovirus, respectively, were only correctly identified following repeat testing. In the 56 clinical samples, overall, 97 pathogens were identified: 65 pathogens (67.0%) were detected both by routine methods and Seegene, 24 pathogens (24.7%) only by routine methods, and 8 pathogens (8.2%) only by Seegene. The majority of discordant results was detected in samples with low pathogen load (22/32, 68.8%) and in samples containing multiple pathogens (25/32, 78.1%). Full agreement between methods was observed for influenza, RSV, adenovirus, Bordetella (para)pertussis and Chlamydia pneumoniae. Discordance was observed for human metapneumovirus, coronavirus OC43, bocavirus and parainfluenza virus, mainly type 4. Conclusion: Overall, the Seegene AllplexTM assay performed well for routine detection of important respiratory targets. Acceptable agreement was observed between Seegene and other routine assays.

Severe sensitivity loss in an influenza A molecular assay due to antigenic drift variants during the 2014/15 influenza season.

The 2014-2015 influenza season in Belgium was dominated by the circulation of 2 influenza A(H3N2) subgroups: 3C.2a and 3C.3b. Analysis of 166 nasopharyngeal aspirates, collected in patients with respiratory illness at the start of the epidemic season, showed a decreased sensitivity for the detection of influenza A(H3N2)/3C.2a using a commercially available multiplex assay. Gene sequencing of the matrix protein showed a point mutation (C163T) leading to a mismatch with the assay probes.

Multicenter evaluation of BD Veritor System and RSV K-SeT for rapid detection of respiratory syncytial virus in a diagnostic laboratory setting.

The recently introduced BD Veritor System RSV laboratory kit (Becton Dickinson, Sparks, MD, USA) with automatic reading was evaluated and compared with the RSV K-SeT (Coris BioConcept, Gembloux, Belgium) for the detection of respiratory syncytial virus (RSV) using 248 nasopharyngeal aspirates of children younger than 6 years old with respiratory tract infection. Compared to reverse transcriptase polymerase chain reaction as gold standard, both tests had an identical sensitivity of 78.1% and a specificity of 96.8% and 95.8% for the BD Veritor System and RSV K-SeT, respectively. Both antigen tests can be used to reliably confirm RSV in young children. However, a negative result does not definitively exclude the presence of RSV.