BD MAX Research Articles

Comparative evaluation of the CerTest VIASURE flu A, B & RSV real time RT-PCR detection kit on the BD MAX system versus a routine in-house assay for detection of influenza A and B virus during the 2016/17 influenza season

BackgroundDiagnosing of influenza rapidly and accurately helps clinicians to initiate appropriate treatment options and isolation protocols. Unnecessary antimicrobial treatment and laboratory testing can also be reduced. Assess commercial alternatives to in-house assays that may not only reduce laboratory technician “hands on” time but also the laboratory turnaround time is of interest. ObjectivesWe evaluated the performance of the VIASURE Flu A, B & RSV Real Time RT-PCR Detection Kit (CerTest Biotec) for detecting Influenza A and B viruses. Study designDuring the 2016/17 influenza season 532 clinical samples were tested with the VIASURE assay on the BD MAX™ system versus an in-house real time RT-PCR assay with discrepant results resolved by a real time RT-PCR assay at a national reference laboratory. ResultsThe VIASURE assay on the BD MAX showed a sensitivity of 99.5% (95% CI: 97.3–100) and a specificity of 99.1% (95% CI: 97.4–99.8) for detection of Influenza A virus. The positive predictive and negative predictive values were 98.5% (95% CI: 95.8–99.7) and 99.7% (95% CI: 98.3–100) respectively. Influenza B virus detection could not be evaluated due to a low positivity rate. The BD MAX platform offered the flexibility of several daily runs, shorter hands-on-time and shorter turnaround time than the in-house assay. ConclusionsThe VIASURE assay on the BD MAX performed well and is now implemented in our clinical laboratory.

Simultaneous detection and characterization of toxigenic Clostridium difficile directly from clinical stool specimens.

We employed a multiplex polymerase chain reaction (PCR) coupled with capillary electrophoresis (mPCR-CE) targeting six Clostridium difficile genes, including tpi, tcdA, tcdB, cdtA, cdtB, and a deletion in tcdC for simultaneous detection and characterization of toxigenic C. difficile directly from fecal specimens. The mPCR-CE had a limit of detection of 10 colony-forming units per reaction with no cross-reactions with other related bacterial genes. Clinical validation was performed on 354 consecutively collected stool specimens from patients with suspected C. difficile infection and 45 isolates. The results were compared with a reference standard combined with BD MAX Cdiff, real-time cell analysis assay (RTCA), and mPCR-CE. The toxigenic C. difficile species were detected in 36 isolates and 45 stool specimens by the mPCR-CE, which provided a positive rate of 20.3% (81/399). The mPCR-CE had a specificity of 97.2% and a sensitivity of 96.0%, which was higher than RTCA (x2 = 5.67, P = 0.017) but lower than BD MAX Cdiff (P = 0.245). Among the 45 strains, 44 (97.8%) were determined as nonribotype 027 by the mPCR-CE, which was fully agreed with PCR ribotyping. Even though ribotypes 017 (n = 8, 17.8%), 001 (n = 6, 13.3%), and 012 (n = 7, 15.6%) were predominant in this region, ribotype 027 was an important genotype monitored routinely. The mPCR-CE provided an alternative diagnosis tool for the simultaneous detection of toxigenic C. difficile in stool and potentially differentiated between RT027 and non-RT027.

A multi-centre prospective evaluation of the Check-Direct ESBL Screen for BD MAX as a rapid molecular screening method for extended-spectrum beta-lactamase-producing Enterobacteriaceae rectal carriage

A multiplex extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) quantitative polymerase chain reaction (qPCR), performed directly on rectal swabs, was compared with a culture-based protocol to study the discrepancies between the two methods, and identify existing challenges to apply this assay in routine clinical practice. The secondary objective was to assess the performance of the qPCR. In two Dutch teaching hospitals, 573 rectal swabs were collected prospectively. Culture with additional testing with the Check-MDR CT103XL (Check-Points) was compared with the Check-Direct ESBL Screen for BD MAX (Check-Points), which detects the presence of the ESBL gene families CTX-M1, CTX-M2, CTX-M9 and SHV2/5-ESBL. The culture-based protocol (with Brilliance agar) was considered as the gold standard to assess the performance of the qPCR. Of the 573 rectal swabs, 74 (12.9%) were culture-positive. Eighty-four (14.7%) were qPCR-positive. There were eight culture-positive/qPCR-negative discrepancies and 18 culture-negative/qPCR-positive discrepancies. Sensitivity and specificity of qPCR vs culture were 87.7% [95% confidence interval (CI) 79.7-95.7] and 96.3% (95% CI 94.6-98.0), respectively. The Check-Direct ESBL Screen for the BD MAX is an easy-to-perform, quick molecular diagnostic test with the potential to significantly speed up screening for rectal ESBL-E carriage. Discrepancies were observed between the culture-based protocol and the qPCR in 4.5% of tested samples. Existing challenges for implementing qPCR are its limited sensitivity, the need for thorough knowledge of the local ESBL-E genes, and interpretation of culture-negative but qPCR-positive samples. It is believed that the limited sensitivity of qPCR could be optimized by including blaTEM as a molecular target, and improving the limit of detection.

Evaluation of a real-time PCR assay for the qualitative detection of Clostridium difficile toxin gene and its clinical application

Objective In comparison of the performances for the detection of Clostridium difficile toxin B genes from stool between BD MAX Cdiff assay and a laboratory-developed (LD) assay.The LD assay was evaluated in clinical application. Methods This study was a clinical application research. A total of 147 stool specimens from patients with diarrhea in Hangzhou First Hospital affiliated with Zhejiang Chinese Medical University were detected by the two assays from 1 July to 30 September 2014. DNA extraction and amplification of the tcdB gene were performed automatically on the BD MAX platform. Meanwhile, the tcdA and tcdB gene were detected by the LD real-time PCR assay after DNA extraction. Then, the results were analyzed by use of SPSS 10.0. Results A total of 147 stool samples were collected. There were 33 C. difficile positive cases and 114 negative cases detected by both of two assays. However, there were four stool samples had incongruent results. In comparison with BD MAX, the LD assay had a sensitivity of 93.94% (31/33), a specificity of 98.25% (112/114), a positive predictive value of 93.94% (31/33), and negative predictive value 98.25% (112/114). Furthermore, the results of the LD assay were statistically coherent with that of the BD assay (Kappa=0.922, P<0.01). Conclusions The LD assay was highly sensitive and accurate as BD MAX Cdiff assay in the detection of toxigenic Clostridium difficile. Furthermore, this LD assay could be also applied to detection of clinical stool samples directly with low cost. The assay will be more promising in diagnosis of toxigenic C. difficile in clinical application in China due to no additional instrument needed.(Chin J Lab Med, 2017, 40: 511-514) Key words: Clostridium difficile; Bacterial toxins; Molecular diagnostic techniques

Clinical sensitivity and specificity of the Check-Points Check-Direct ESBL Screen for BD MAX, a real-time PCR for direct ESBL detection from rectal swabs.

To determine the diagnostic accuracy of the Check-Direct ESBL Screen for BD MAX (ESBL qPCR) and an ESBL culture method to identify ESBLs directly from rectal swabs. Rectal swabs were obtained from clinical patients by performing cross-sectional (point)prevalence measurements in three regional hospitals. Rectal swabs were analysed by direct culture (ChromID ESBL agar) and with the ESBL qPCR. Suspected ESBL-producing isolates were confirmed with the combination disc method and analysed by WGS. Out of 354 rectal swabs and 351 patients, 21 rectal swabs and 20 patients were positive for ESBL-producing isolates, resulting in a regional ESBL colonization prevalence of 5.7%. One rectal swab was false negative with the ESBL qPCR (blaTEM-12) and not covered by the ESBL qPCR. Eight ESBL qPCR-positive rectal swabs could not be confirmed by culture and were classified as false ESBL qPCR positive. The sensitivity and specificity of the ESBL qPCR were 95.2% (n = 20) and 97.6% (n = 323), respectively. When an optimal cycle threshold cut-off value of 37 was used, the ESBL qPCR displayed a sensitivity and specificity of 95.2% (n = 20) and 98.8% (n = 327), respectively (AUC = 0.975, 95% CI = 0.922-1). This ESBL qPCR offers rapid direct detection of the most prevalent ESBL types (blaCTX-M group and blaSHV group) from rectal swabs. The relatively high false-positive rate renders this test the most suitable as a screening test in high-prevalence regions or in an outbreak setting where a fast result is essential.

Rapid detection of Group B streptococcus directly from vaginal–rectal specimens using liquid swabs and the BD Max GBS assay

ObjectiveWe adapted the BD Max GBS assay, an automated platform for the detection of Group B streptococcus (GBS) DNA in vaginal–rectal swab specimens after LIM broth enrichment, to directly detect GBS in specimens collected using cellular foam swabs in Amies liquid medium. We compared the BD Max GBS assay performance to that of enriched culture and the BD GeneOhm StrepB assay. MethodsSeventy-two reference vaginal–rectal specimens were employed to determine the limit of GBS detection and the preferred test volume for direct detection of GBS. A total of 304 clinical specimens were then tested by the optimized BD Max GBS assay, both by direct testing and following broth enrichment. ResultsThe limit of GBS detection was 75 CFU/mL and the preferred test volume was 100 μL. Of 304 clinical specimens tested, GBS was detected in 62 specimens by enriched culture (20.4%); 61 of these yielded GBS by the BD Max GBS assay when performed directly from the liquid swab (sensitivity 98.4%). All 242 culture-negative specimens also yielded negative results by the BD Max GBS assay (specificity 100%). When this assay was performed following broth enrichment, GBS was detected in all 62 culture-positive specimens (100% sensitivity). The sensitivity and specificity of the BD GeneOhm StrepB assay was 90.3% and 99%, respectively. ConclusionsThe BD Max GBS assay is highly sensitive, requires minimal technical skill with <2 min required to set-up, and results are available in under 80 min (versus 24–48 h for culture). It is configured for ‘on demand’ testing and vaginal–rectal specimens can be rapidly screened for GBS without the need for enrichment. The results obtained in this study demonstrate that rapid GBS screening using the BD Max GBS assay at the time of delivery is a viable alternative to the current recommended screening at 35–37 weeks of gestation with pre-enrichment testing methods.

Profile of the triplex assay for detection of chlamydia, gonorrhea and trichomonas using the BD MAX™ System

ABSTRACTIntroduction: Chlamydia, gonorrhea and trichomonas are the most common curable STI. improved access to testing could reduce infection rates and prevent sequelae. nucleic acid amplification tests are the recommend class of diagnostic assay for these infections which are often asymptomatic.Areas covered: A description of the BD MAX™ System (MAX) and the BD MAX CT/GC/TV assay is provided along with data from a large US clinical trial. The capacity of the system for other tests and for lab developed assays is also described.Expert commentary: The CT/GC/TV assay on the MAX is a triplex PCR assay suitable for use with female urine and vaginal or endocervical swab samples. Male urine can be tested by ordering the CT/GC results but has not yet been evaluated for trichomonas. The assay performance characteristics are similar to those of assays run on high-throughput platforms with sensitivity ≥91.5% and specificity ≥98.6% for all analytes. Screening with the CT/GC/TV assay can be combined with testing for vaginitis which would provide a greater depth of coverage for common co-infections. The throughput is moderate (1–48 samples per 8-hour shift) but the menu includes assays beyond STI pathogens making this a suitable platform for moderate volume laboratories.

Rapid Detection of Staphylococcus aureus and Methicillin-Resistant S. aureus in Atopic Dermatitis by Using the BD Max StaphSR Assay.

Eczematous lesions of atopic dermatitis (AD) patients are known to be a source of Staphylococcus aureus (SA) transmission and might be a reservoir for community-associated methicillin-resistant SA (MRSA). The BD Max StaphSR (BD-SR) is a fully automated, multiplex real-time PCR assay for the direct detection and differentiation of SA and MRSA from nasal swab samples. We evaluated the detection rates of SA and MRSA from skin lesions of outpatients with AD using the BD-SR assay, and determined the usefulness of the BD-SR assay. A total of 244 skin swab samples (skin lesions of 213 outpatients with AD and normal skin of 31 healthy controls) were tested directly by using the BD-SR assay. Of the 213 samples from patients with AD, 69 (32.4%) were positive for SA, 6 (8.7%) of which were positive for MRSA. Only 1 (3.2%) of 31 samples from healthy controls was positive for SA. The BD-SR assay is effective for the rapid detection of SA and MRSA from skin swab samples, which can provide important information for managing patients with AD and preventing the spread of MRSA.

Utilizing BD MAX\u2122 Enteric Bacterial Panel to Detect Stool Pathogens from Rectal Swabs

BackgroundThe BD MAX™ Enteric Bacterial Panel (BDM-EBP) is designed and FDA-cleared to detect Salmonella, Shigella, Campylobacter, and Shiga toxin genes stx1/2 from stool samples. However, rectal swabs, which are not FDA-cleared for clinical testing with the BDM-EBP, are common specimens received from pediatric patients for enteric pathogen testing. The purpose of this study was to evaluate the ability of the BDM-EBP to detect stool pathogens from rectal swabs.MethodsRoutine cultures, Shiga toxin testing, and molecular testing with BDM-EBP were performed on 272 sequential rectal swabs collected from August 2015 to December 2015. Discrepant test results were resolved using Verigene® Enteric Pathogens Nucleic Acid Test (EP). 36 challenge samples (13 Salmonella spp., 3 Shigella spp., 10 Campylobacter spp., and 10 Shiga toxin positive Escherichia coli) were tested using reference strains (American Type Culture Collection) and previous patient isolates diluted to103-104 cfu/ml in saline then added to Sample Buffer Tube (SBT) with negative stool matrix delivered via a swab. Limit of detection testing was performed by serial 10 fold dilutions in saline then added to SBT with negative stool matrix provided via a swab.ResultsA total of 272 rectal swab specimens were evaluated and 89 were positive by culture and/or MAX EBP. All discrepant results were BDM-EBP positive and culture negative. 21 of 31 (68%) of the apparent false positive BDM-EBP discrepant results resolved as positive with Nanosphere’s Verigene® EP. After resolution of the discordant results, the Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) are as follows for each target: Salmonella (n = 4) 100%, PPA and 100%, NPA; Shigella (n = 79) 100%, PPA and 95.3%, NPA; Campylobacter (n = 4) 100%, PPA and 99.6%, NPA; and Shiga toxin producing organisms (n = 2) 100%, PPA and 100%, NPA. 8.8% of the patient samples did not initially yield a result on the BDM-System. Upon repeat, half of the problematic samples resolved, and 4.4% of the total specimen tested did not yield a result. All organisms in the challenge samples were detected. Limits of detection for BDM-EBP testing of rectal swabs were as follows (in cfu/ml in SBT): Salmonella-1.44 × 102; Shigella-5.10 × 100; Campylobacter-1.51 × 101; and Shiga Toxin-1.13 ×103.ConclusionRectal swabs are acceptable samples for detecting Salmonella, Shigella, Campylobacter, and Shiga toxin using BDM-EBP.

Detection of Mycobacterium chelonae, Mycobacterium abscessus Group, and Mycobacterium fortuitum Complex by a Multiplex Real-Time PCR Directly from Clinical Samples Using the BD MAX System

A new multiplex PCR test was designed to detect Mycobacterium chelonae, Mycobacterium abscessus group, and Mycobacterium fortuitum complex on the BD MAX System. A total of 197 clinical samples previously submitted for mycobacterial culture were tested using the new protocol. Samples were first treated with proteinase K, and then each sample was inoculated into the BD MAX Sample Buffer Tube. Extraction and multiplex PCR were performed by the BD MAX System, using the BD MAX ExK TNA-3 extraction kit and BD TNA Master Mix, along with specific in-house designed primers and probes for each target. The limit of detection of each target, as well as specificity, was evaluated. Of 197 clinical samples included in this study, 133 were positive and 60 were negative for mycobacteria by culture, andanother 4 negative samples were spiked with M. chelonae ATCC 35752. The new multiplex PCR on the BD MAX had 97% concordant results with culture for M. abscessus group detection, 99% for M.chelonae, and 100% for M. fortuitum complex. The new multiplex PCR test performed on the BD MAX System proved to be a sensitive and specific test to detect M. chelonae, M. abscessus group, and M.fortuitum complex by real-time PCR on an automated sample-in results-out platform.

Evaluation of Xpert MRSA Gen 3 and BD MAX MRSA XT for meticillin-resistant Staphylococcusaureus screening in a routine diagnostic setting in a low-prevalence area.

Screening and pre-emptive isolation of at-risk patients are important aspects of the Danish approach to the prevention of meticillin-resistant Staphylococcusaureus (MRSA) infection, but screening with conventional culture can take up to 3 days for results to become available with attendant costs and disadvantages of prolonged isolation. We sought to evaluate the accuracy, time to availability of results and potential economic benefits of two next-generation MRSA screening assays, Xpert MRSA Gen 3 (GX MRSA) and BD MAX MRSA XT, in a setting of a consolidated laboratory serving a number of hospitals with a low prevalence of MRSA and using enrichment culture as a reference method. Four hundred and forty-seven screening samples together with 49 previously positive MRSA samples were evaluated. Xpert MRSA Gen 3 demonstrated sensitivity, specificity, positive predictive value and negative predictive value of 88.2, 97.9, 62.5 and 99.5 %, respectively, and for BD MAX MRSA XT, they were 88.2, 97.4, 57.7 and 99.5 %, respectively. Hands-on time was 8.8 and 21.6 min, respectively, for the Xpert MRSA Gen 3 and BD MAX MRSA XT PCR assays when five samples were handled simultaneously. The mean laboratory turnaround time was 2.9 (1-6) hours for the Xpert MRSA Gen 3 assay, 6.5 (2-46) hours for BD MAX MRSA XT and 49.6 (42-122) hours for enriched culture. Despite laboratory costs being higher for the rapid PCR assays, when the costs of isolation are taken into account, the assays offer the potential for significant cost savings.

Evaluation of the automated Becton Dickinson MAX real-time PCR platform for detection of Pneumocystis jirovecii.

We evaluated the performance of the automated quantitative BD MAX (Becton Dickinson) real-time PCR platform for detecting Pneumocystis jirovecii. A total of 34 retrospective and 137 prospective samples were included. Retrospectively, all (100%) positive samples were correctly detected by this platform compared with a nested PCR. Among prospective samples, the overall sensitivity, specificity, positive likelihood ratio and negative likelihood ratio were 92.6%, 94.5%, 17.0 and 0.1, respectively. All bronchoalveolar lavage fluid (BALF)/bronchial washing samples were correctly identified by this platform. Samples from patients with colonization had significantly higher median amplification cycle threshold values than patients with P. jirovecii pneumonia. The quantitative BD MAX real-time PCR is a rapid and highly sensitive modality for detecting P. jirovecii, especially in samples from bronchoalveolar lavage fluid/bronchial washing fluid.

Prevalence and molecular epidemiology of Clostridium difficile infection in Thailand.

Little is known about Clostridium difficile infection (CDI) in Asia generally, and specifically in Thailand. Given the high prevalence of inappropriate antibiotic usage in this region, CDI is likely to be common. This study investigated the prevalence and molecular epidemiology of CDI in Thailand. Stool specimens collected from inpatients with diarrhoea at Siriraj hospital in Bangkok (n = 422) were cultured on ChromID Cdiff agar and any presumptive C. difficile colonies were identified, PCR ribotyped and toxin profiled. As part of the routine C. difficile testing at Siriraj Hospital, 370 specimens also underwent testing with the BD MAX Cdiff assay to detect the presence of tcdB. With direct culture, 105 different isolates of C. difficile were recovered from 23.7% (100/422) of the stool specimens. The prevalence of toxigenic and nontoxigenic isolates was 9.2% (39/422) and 15.6% (66/422), respectively. Of the toxigenic isolates, 69.2% (27/39) and 30.8% (12/39) were tcdA and tcdB positive (A+B+), and A−B+, respectively; none contained binary toxin genes. The five most prevalent ribotypes (RTs) were 014/020 group (17/105), 010 (12/105), 017 (12/105), 039 (9/105) and 009 (6/105). Using toxigenic culture as the reference standard, the sensitivity, specificity, positive predictive value and negative predictive value of the BD MAX Cdiff assay were 68.6, 95.1, 63.2 and 96.1%, respectively. The high proportion of A−B+, RT 017 strains emphasises the need for diagnostic tests that detect either both toxins or just tcdB. Continued surveillance that involves stool culturing will allow molecular tracking and assist in elucidating the epidemiology of CDI in Thailand.

Development and evaluation of a multiplex real-time PCR for the detection of IMP, VIM, and OXA-23 carbapenemase gene families on the BD MAX open system

A multiplex real-time polymerase chain reaction (PCR) assay was developed for the detection of clinically prevalent IMP, VIM, and OXA-23 gene families. The assay was designed to work on the BD MAX open platform which is a fully automated system for all PCR processes including sample extraction to PCR resulting. A total of 107 well-characterized carbapenem resistant Enterobacteriaceae were evaluated and the results were 100% concordant with the reference test isolates. This assay will serve to complement PCR screens that detect the major carbapenemase families of NDM, KPC, and OXA-48-like.

Low frequency of asymptomatic carriage of toxigenic Clostridium difficile in an acute care geriatric hospital: prospective cohort study in Switzerland.

BackgroundThe role of asymptomatic carriers of toxigenic Clostridium difficile (TCD) in nosocomial cross-transmission remains debatable. Moreover, its relevance in the elderly has been sparsely studied.ObjectivesTo assess asymptomatic TCD carriage in an acute care geriatric population.MethodsWe performed a prospective cohort study at the 296-bed geriatric hospital of the Geneva University Hospitals. We consecutively recruited all patients admitted to two 15-bed acute-care wards. Patients with C. difficile infection (CDI) or diarrhoea at admission were excluded. First bowel movement after admission and every two weeks thereafter were sampled. C. difficile toxin B gene was identified using real-time polymerase chain-reaction (BD MAXTMCdiff). Asymptomatic TCD carriage was defined by the presence of the C. difficile toxin B gene without diarrhoea.ResultsA total of 102 patients were admitted between March and June 2015. Two patients were excluded. Among the 100 patients included in the study, 63 were hospitalized and 1 had CDI in the previous year, and 36 were exposed to systemic antibiotics within 90 days prior to admission. Overall, 199 stool samples were collected (median 2 per patient, IQR 1-3). Asymptomatic TCD carriage was identified in two patients (2 %).ConclusionsWe found a low prevalence of asymptomatic TCD carriage in a geriatric population frequently exposed to antibiotics and healthcare. Our findings suggest that asymptomatic TCD carriage might contribute only marginally to nosocomial TCD cross-transmission in our and similar healthcare settings.

Performance of the BD MAX™ instrument with Check-Direct CPE real-time PCR for the detection of carbapenemase genes from rectal swabs, in a setting with endemic dissemination of carbapenemase-producing Enterobacteriaceae

Carbapenemase-producing Enterobacteriaceae (CPE) represent an increasing public health issue and the early detection of colonization by CPE can help the implementation of infection control measures among inpatients. In this study, BD MAX Check-Direct CPE screen, with two different Master Mixes (BDMix and CPMix), using the automatic BD MAX™ instrument, was evaluated for the detection of blaKPC, blaOXA-48, blaVIM and blaNDM genes, in comparison to selective broth enrichment and direct culture from rectal swabs. Among a total of 557 rectal swabs samples, 29 (5.2%) tested positive for CPE (23 for blaKPC, 5 for blaVIM and one for blaOXA-48). The sensitivity, specificity, positive and negative likelihood ratios values were 93.1%, 97.3%, 34.5 and 0.07, for BMix, and 100%, 97.1 %, 34.5 and 0 for CPMix, respectively. Five samples were positive with molecular methods only. The turn-around time was reduced from 18-24 hours (direct culture), or 48 h (broth enrichment) to only 3 h.

Implementation and Evaluation of a Fully Automated Multiplex Real-Time PCR Assay on the BD Max Platform to Detect and Differentiate Herpesviridae from Cerebrospinal Fluids.

A fully automated multiplex real-time PCR assay—including a sample process control and a plasmid based positive control—for the detection and differentiation of herpes simplex virus 1 (HSV1), herpes simplex virus 2 (HSV2) and varicella-zoster virus (VZV) from cerebrospinal fluids (CSF) was developed on the BD Max platform. Performance was compared to an established accredited multiplex real time PCR protocol utilizing the easyMAG and the LightCycler 480/II, both very common devices in viral molecular diagnostics. For clinical validation, 123 CSF specimens and 40 reference samples from national interlaboratory comparisons were examined with both methods, resulting in 97.6% and 100% concordance for CSF and reference samples, respectively. Utilizing the BD Max platform revealed sensitivities of 173 (CI 95%, 88–258) copies/ml for HSV1, 171 (CI 95%, 148–194) copies/ml for HSV2 and 84 (CI 95%, 5–163) copies/ml for VZV. Cross reactivity could be excluded by checking 25 common viral, bacterial and fungal human pathogens. Workflow analyses displayed shorter test duration as well as remarkable fewer and easier preparation steps with the potential to reduce error rates occurring when manually assessing patient samples. This protocol allows for a fully automated PCR assay on the BD Max platform for the simultaneously detection of herpesviridae from CSF specimens. Singular or multiple infections due to HSV1, HSV2 and VZV can reliably be differentiated with good sensitivities. Control parameters are included within the assay, thereby rendering its suitability for current quality management requirements.

Validation of a Multiplex Real-Time PCR Assay for Detection of Mycobacterium spp., Mycobacterium tuberculosis Complex, and Mycobacterium avium Complex Directly from Clinical Samples by Use of the BD Max Open System.

A multiplex real-time PCR was validated on the BD Max open system to detect different Mycobacterium tuberculosis complex, Mycobacterium avium complex, and Mycobacterium spp. directly from clinical samples. The PCR results were compared to those with traditional cultures. The multiplex PCR assay was found to be a specific and sensitive method for the rapid detection of mycobacteria directly from clinical specimens.

Evaluation of the BD max multiplex enteric pathogen PCR system versus routine culture – rapid and accurate diagnosis of common bacterial diarrhoeal disease

Evaluation of the BD max multiplex enteric pathogen PCR system versus routine culture – rapid and accurate diagnosis of common bacterial diarrhoeal disease

Routine detection of Clostridium difficile in Western Australia

Despite increasing infection rates, Clostridium difficile is not currently routinely tested for in all diarrhoeal faecal specimens in Australia. In July 2014, all diarrhoeal specimens submitted to a diagnostic laboratory in Western Australia were surveyed to determine the true prevalence of C. difficile. In total, 1010 diarrhoeal non-duplicate faecal specimens were received during the month. Testing for C. difficile was requested, or the criteria for a C. difficile investigation were met, for 678 specimens which were investigated by PCR for the tcdB gene using the BD MAX platform, followed by toxigenic culture on PCR-positive samples. The remaining 332 specimens, with either no C. difficile test request or the criteria for a C. difficile investigation were not met, were examined by toxigenic culture. All isolates were PCR ribotyped. C. difficile was the most commonly detected diarrhoeal pathogen among all specimens. The overall prevalence of C. difficile in all 1010 specimens was 6.4%; 7.2% in the routinely tested group, and 4.8% in the non-requested group. The proportion of non-requested positive detections among all cases was 24.6%. Community-onset infection was present in 50.8% of all cases. The median age of all CDI cases was 60.0 years and the age range in CDI patients in the routine group was 0.6–96.6 years (median 72.7 years), compared to 0.2–2.3 years (median 0.8 years) in the non-requested group. The most common ribotype (RT) found was RT 014/020 (34.1% in the routine group, 43.8% in the non-requested group), followed by RTs 002, 056, 005 and 018. While the routine testing group and the non-requested group differed markedly in age and patient classification, C. difficile was the most common cause of diarrhoea in hospitals and the community in Western Australia. The significance of finding C. difficile in the community paediatric population requires further study.