Antimicrobial Stewardship Opportunities in Patients with Bacteremia Not Identified by BioFire FilmArray

A subset of bacteremia cases are caused by organisms not detected by a rapid-diagnostics platform, BioFire blood culture identification (BCID), with unknown clinical characteristics and outcomes. Patients with ≥1 positive blood culture over a 15-month period were grouped by negative (NB-PC) versus positive (PB-PC) BioFire BCID results and compared with respect to demographics, infection characteristics, antibiotic therapy, and outcomes (length of hospital stay [LOS] and in-hospital mortality). Six percent of 1,044 positive blood cultures were NB-PC. The overall mean age was 65 ± 22 years, 54% of the patients were male, and most were admitted from home; fewer NB-PC had diabetes (19% versus 31%, P = 0.0469), although the intensive care unit admission data were similar. Anaerobes were identified in 57% of the bacteremia cases from the NB-PC group by conventional methods: Bacteroides spp. (30%), Clostridium (11%), and Fusobacterium spp. (8%). Final identification of the NB-PC pathogen was delayed by 2 days (P < 0.01) versus the PB-PC group. The sources of bacteremia were more frequently unknown for the NB-PC group (32% versus 11%, P < 0.01) and of pelvic origin (5% versus 0.1%, P < 0.01) compared to urine (31% versus 9%, P < 0.01) for the PB-PC patients. Fewer NB-PC patients received effective treatment before (68% versus 84%, P = 0.017) and after BCID results (82% versus 96%, P = 0.0048). The median LOS was similar (7 days), but more NB-PC patients died from infection (26% versus 8%, P < 0.01). Our findings affirm the need for the inclusion of anaerobes in BioFire BCID or other rapid diagnostic platforms to facilitate the prompt initiation of effective therapy for bacteremia.

Evaluation of the Aries Bordetella Assay for Detection and Identification of Bordetella pertussis in Nasopharyngeal Swab Specimens

The Aries Bordetella assay (Aries BA) (Luminex Corporation) recently received FDA clearance for the detection and differentiation of Bordetella pertussis and Bordetella parapertussis nucleic acids in nasopharyngeal swab (NPS) samples. The objective of this study was to evaluate the performance of the Aries BA in comparison to that of the BioFire FilmArray respiratory panel (RP). The Aries BA was evaluated using retrospective, remnant nasopharyngeal swabs (NPS), previously tested by FilmArray RP. Performance characteristics evaluated included positive percent agreement (PPA) and negative percent agreement (NPA) with the FilmArray RP. Discordant analysis was performed using bidirectional sequencing. A time and motion study was performed to compare the laboratory workflow of the two tests. Three hundred samples were included in the study. There were no samples positive for B. parapertussis The PPA and NPA of the Aries BA were 61.1% (95% confidence interval [CI], 35.8 to 82.7%) and 100% (95% CI, 98.7 to 100%). Discordant results included five Bordetella bronchiseptica results that were incorrectly identified as B. pertussis by the FilmArray RP and one false-negative result for both the Aries BA and the FilmArray RP. The overall agreement between the Aries BA and FilmArray RP for the detection of B. pertussis was considered good at 97.7% with a kappa value of 0.71 (95% CI, 0.51 to 0.9). The Aries BA offers a new diagnostic option for the rapid and targeted approach to the diagnosis of pertussis. Unlike the FilmArray RP, the Aries BA did not cross-react with B. bronchiseptica in our study, although a larger sample set should be tested to confirm this finding.

Recombinant streptavidin fusion proteins as signal reporters in rapid test of human hepatitis C virus infection

BACKGROUND

Early diagnosis of hepatitis C virus (HCV) infection is very important for the treatment of the disease. Development of sensitive and specific rapid detection assays is of great significance for the diagnosis. Here, we describe a promising method of using gold-labeled streptavidin fusion proteins as novel signal reporter in a rapid detection assay for HCV infection.

METHODS

Recombinant genes encoding streptavidin fused with Escherichia coli maltose-binding protein (MBP) or with a portion of bacterial translational initiation factor 2 were cloned in expression vectors pMAL-5CX and pET28 and transformed in proper Escherichia coli host strains. The genes were induced and streptavidin fusion proteins, named M-STV and IF-STV, respectively, were purified by affinity chromatography to over 90% purity. The biotin-binding activity of M-STV and IF-STV was tested by enzyme-linked immunosorbent assay (ELISA). M-STV was labeled with colloidal gold nanoparticles and used as a signal reporter to develop a lateral flow-based rapid test for detecting anti-HCV antibodies in human blood samples.

RESULTS

M-STV showed slightly higher biotin-binding activity and similar binding specificity as compared to commercial streptavidin. The gold-labeled M-STV bound specifically to biotin moieties immobilized on the rapid test strips in a dose-responsive manner and was successfully used in detecting HCV antibodies in serum samples of patients infected with HCV. The rapid test displayed higher detection sensitivity than gold-labeled commercial NeutrAvidin.

CONCLUSION

Our results indicate that gold-labeled M-STV is a promising agent in rapid tests of HCV infection and possibly other viral infections.

Laboratory Evaluation of a Commercially Available Rapid Syphilis Test

Serological diagnosis of syphilis depends on assays that detect treponemal and nontreponemal antibodies. Laboratory certification and trained personnel are needed to perform most of these tests, while high costs and long turnaround time can hinder treatment initiation or linkage to care. A rapid treponemal syphilis test (RST) that is simple to perform, accessible, and inexpensive would be ideal. The Syphilis Health Check (SHC) assay is the only Food and Drug Administration (FDA)-cleared and Clinical Laboratory Improvement Amendments (CLIA)-waived RST in the United States. In this study, 1,406 archived human serum samples were tested using SHC and traditional treponemal and nontreponemal assays. Rapid test results were compared with treponemal data alone and with a laboratory test panel consensus defined as being reactive by both treponemal and nontreponemal assays for a given specimen, or nonreactive by both types of assays. The sensitivity and specificity of the SHC assay compared with treponemal tests alone were 88.7% (95% confidence interval [CI], 86.2 to 90.0%) and 93.1% (95% CI, 90.0 to 94.9%), respectively, while comparison with the laboratory test panel consensus showed 95.7% (95% CI, 93.6 to 97.2%) sensitivity and 93.2% (95% CI, 91.0 to 95.1%) specificity. The data were further stratified based on age, sex, pregnancy, and HIV status. The sensitivity and specificity of the SHC assay ranged from 66.7% (95% CI, 46.0 to 83.5%) to 91.7% (95% CI, 87.7 to 94.7%) and 88% (95% CI, 68.8 to 97.5%) to 100% (95% CI, 47.8 to 100%), respectively, across groups compared to traditional treponemal assays, generally increasing for all groups except the HIV-positive (HIV+) population when factoring in the laboratory test panel consensus. These data contribute to current knowledge of the SHC assay performance for distinct populations and may guide use in various settings.

Rapid Antigen Tests for Influenza: Rationale and Significance of the FDA Reclassification

Rapid antigen tests for influenza, here referred to as rapid influenza diagnostic tests (RIDTs), have been widely used for the diagnosis of influenza since their introduction in the 1990s due to their ease of use, rapid results, and suitability for point of care (POC) testing. However, issues related to the diagnostic sensitivity of these assays have been known for decades, and these issues gained greater attention following reports of their poor performance during the 2009 influenza A(H1N1) pandemic. In turn, significant concerns arose about the consequences of false-negative results, which could pose significant risks to both individual patient care and to public health efforts. In response to these concerns, the FDA convened an advisory panel in June 2013 to discuss options to improve the regulation of the performance of RIDTs. A proposed order was published on 22 May 2014, and the final order published on 12 January 2017, reclassifying RIDTs from class I to class II medical devices, with additional requirements to comply with four new special controls. This reclassification is a landmark achievement in the regulation of diagnostic devices for infectious diseases and has important consequences for the future of diagnostic influenza testing with commercial tests, warranting the prompt attention of clinical laboratories, health care systems, and health care providers.

Mismatch Amplification Mutation Assay-Based Real-Time PCR for Rapid Detection of Neisseria gonorrhoeae and Antimicrobial Resistance Determinants in Clinical Specimens

Molecular methods are often used for Neisseria gonorrhoeae detection, but complete definition of antimicrobial resistance (AMR) patterns still requires phenotypic tests. We developed an assay that both identifies N. gonorrhoeae and detects AMR determinants in clinical specimens.

Molecular methods are often used for Neisseria gonorrhoeae detection, but complete definition of antimicrobial resistance (AMR) patterns still requires phenotypic tests. We developed an assay that both identifies N. gonorrhoeae and detects AMR determinants in clinical specimens. We designed a mismatch amplification mutation assay (MAMA)-based SYBR green real-time PCR targeting one N. gonorrhoeae-specific region (opa); mosaic penA alleles (Asp345 deletion [Asp345del], Gly545Ser) associated with decreased susceptibility to cephalosporins; and alterations conferring resistance to ciprofloxacin (GyrA Ser91Phe), azithromycin (23S rRNA A2059G and C2611T), and spectinomycin (16S rRNA C1192T). We applied the real-time PCR to 489 clinical specimens, of which 94 had paired culture isolates, and evaluated its performance by comparison with the performance of commercial diagnostic molecular and phenotypic tests. Our assay exhibited a sensitivity/specificity of 93%/100%, 96%/85%, 90%/91%, 100%/100%, and 100%/90% for the detection of N. gonorrhoeae directly from urethral, rectal, pharyngeal, cervical, and vaginal samples, respectively. The MAMA strategy allowed the detection of AMR mutations by comparing cycle threshold values with the results of the reference opa reaction. The method accurately predicted the phenotype of resistance to four antibiotic classes, as determined by comparison with the MIC values obtained from 94 paired cultures (sensitivity/specificity for cephalosporins, azithromycin, ciprofloxacin, and spectinomycin resistance, 100%/95%, 100%/100%, 100%/100%, and not applicable [NA]/100%, respectively, in genital specimens and NA/72%, NA/98%, 100%/97%, and NA/96%, respectively, in extragenital specimens). False-positive results, particularly for the penA Asp345del reaction, were observed predominantly in pharyngeal specimens. Our real-time PCR assay is a promising rapid method to identify N. gonorrhoeae and predict AMR directly in genital specimens, but further optimization for extragenital specimens is needed.

Operational Performance of a Plasmodium falciparum Ultrasensitive Rapid Diagnostic Test for Detection of Asymptomatic Infections in Eastern Myanmar

In the Greater Mekong Subregion in Southeast Asia, malaria elimination strategies need to target all Plasmodium falciparum parasites, including those carried asymptomatically. More than 70% of asymptomatic carriers are not detected by current rapid diagnostic tests (RDTs) or microscopy.

In the Greater Mekong Subregion in Southeast Asia, malaria elimination strategies need to target all Plasmodium falciparum parasites, including those carried asymptomatically. More than 70% of asymptomatic carriers are not detected by current rapid diagnostic tests (RDTs) or microscopy. An HRP2-based ultrasensitive RDT (uRDT) developed to improve the detection of low-density infections was evaluated during prevalence surveys within a malaria elimination program in a low-transmission area of eastern Myanmar. Surveys were conducted to identify high-prevalence villages. Two-milliliter venous blood samples were collected from asymptomatic adult volunteers and transported to the laboratory. Plasmodium parasites were detected by RDT, uRDT, microscopy, ultrasensitive qPCR (uPCR), and multiplex enzyme-linked immunosorbent assay (ELISA). The sensitivity, specificity, and predictive positive and negative values of RDT and uRDT were calculated compared to uPCR and ELISA. Parasite and antigen concentrations detected by each test were defined using uPCR and ELISA, respectively. A total of 1,509 samples, including 208 P. falciparum-positive samples were analyzed with all tests. The sensitivity of the uRDT was twofold higher than that of RDT, 51.4% versus 25.2%, with minor specificity loss, 99.5% versus 99.9%, against the combined reference (uPCR plus ELISA). The geometric mean parasitemia detected by uRDT in P. falciparum monospecific infections was 3,019 parasites per ml (95% confidence interval [95% CI], 1,790 to 5,094; n = 79) compared to 11,352 parasites per ml (95% CI, 5,643 to 22,837; n = 38) by RDT. The sensitivities of uRDT and RDT dropped to 34.6% and 15.1%, respectively, for the matched tests performed in the field. The uRDT performed consistently better than RDT and microscopy at low parasitemias. It shows promising characteristics for the identification of high-prevalence communities and warrants further evaluation in mass screening and treatment interventions.

The Cost-Effectiveness of Rapid Diagnostic Testing for the Diagnosis of Bloodstream Infections with or without Antimicrobial Stewardship

Bloodstream infections are associated with considerable morbidity and health care costs. Molecular rapid diagnostic tests (mRDTs) are a promising complement to conventional laboratory methods for the diagnosis of bloodstream infections and may reduce the time to effective therapy among patients with bloodstream infections. The concurrent implementation of antimicrobial stewardship programs (ASPs) may reinforce these benefits. The aim of this study was to evaluate the cost-effectivenesses of competing strategies for the diagnosis of bloodstream infection alone or combined with an ASP. To this effect, we constructed a decision-analytic model comparing 12 strategies for the diagnosis of bloodstream infection. The main arms compared the use of mRDT and conventional laboratory methods with or without an ASP. The baseline strategy used as the standard was the use of conventional laboratory methods without an ASP, and our decision-analytic model assessed the cost-effectivenesses of 5 principal strategies: mRDT (with and without an ASP), mRDT with an ASP, mRDT without an ASP, conventional laboratory methods with an ASP, and conventional laboratory methods without an ASP. Furthermore, based on the availability of data in the literature, we assessed the cost-effectivenesses of 7 mRDT subcategories, as follows: PCR with an ASP, matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analysis with an ASP, peptide nucleic acid fluorescent in situ hybridization (PNA-FISH) with an ASP, a blood culture nanotechnology microarray system for Gram-negative bacteria (BC-GP) with an ASP, a blood culture nanotechnology microarray system for Gram-positive bacteria (BC-GN) with an ASP, PCR without an ASP, and PNA-FISH without an ASP. Our patient population consisted of adult inpatients in U.S. hospitals with suspected bloodstream infection. The time horizon of the model was the projected life expectancy of the patients. In a base-case analysis, cost-effectiveness was determined by calculating the numbers of bloodstream infection deaths averted, the numbers of quality-adjusted life years gained, and incremental cost-effectiveness ratios (ICERs). In a probabilistic analysis, uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds. In the base-case analysis, MALDI-TOF analysis with an ASP was the most cost-effective strategy, resulting in savings of $29,205 per quality-adjusted life year and preventing 1 death per 14 patients with suspected bloodstream infection tested compared to conventional laboratory methods without an ASP (ICER, -$29,205/quality-adjusted life year). BC-GN with an ASP (ICER, -$23,587/quality-adjusted life year), PCR with an ASP (ICER, -$19,833/quality-adjusted life year), and PCR without an ASP (ICER, -$21,039/quality-adjusted life year) were other cost-effective options. In the probabilistic analysis, mRDT was dominant and cost-effective in 85.1% of simulations. Importantly, mRDT with an ASP had an 80.0% chance of being cost-effective, while mRDT without an ASP had only a 41.1% chance. In conclusion, our findings suggest that mRDTs are cost-effective for the diagnosis of patients with suspected bloodstream infection and can reduce health care expenditures. Notably, the combination of mRDT and an ASP can result in substantial health care savings.

Rapid tests and transfusion safety in Niamey, Niger

To evaluate the virological safety of blood components provided by the Niamey blood transfusion center after undergoing rapid tests. Samples found negative with rapid tests (n = 222) were screened by the Abbott Prism assay. Positive samples were confirmed by appropriate methods. Of 222 samples, nine (4.1%) were reactive for all markers. After confirmation, seven samples were positive (i.e., 3.2% false-negative results) : five (2.3%) for the surface antigen of hepatitis B (HBsAg) and two (0.9%) for the antibody directed against the hepatitis C virus (HCV-Ab). No false negative results were observed for HIV-Ab (antibody directed against the Human Immunodeficiency Virus). The performance of the rapid tests used in Niamey to screen for transfusion-transmissible infections is not satisfactory, especially for hepatitis B and C. The use of more sensitive tests should be considered to minimize the risk of contaminating patients receiving blood components.

A systematic review and meta-analysis of studies evaluating the performance of point-of-care tests for human papillomavirus screening

BACKGROUND

High-risk human papillomavirus (HPV) is a necessary cause of high-grade cervical intraepithelial neoplasia (grade 2 or higher, CIN2+). Simplified and rapid HPV DNA assays designed for use in resource-limited settings have recently become available.

METHODS

We performed a systematic review and meta-analysis by searching Medline, Embase, Global Health and CINAHL databases for studies from 1 January 2004 to 25 February 2017 that reported the performance of careHPV or OncoE6 for the detection of histological CIN2+ in cervical cancer screening. We used bivariate models to estimate pooled sensitivity and specificity for CIN2+ and CIN3+.

RESULTS

A total of 29 657 women were included from seven studies evaluating the performance of careHPV for the detection of CIN2+ and four studies among 27 845 women for the detection of CIN3+. The pooled prevalence for CIN2+ and CIN3+ was 2.3% and 1.1%, respectively. careHPV had sensitivity and specificity of 88.1% (95% CI 81.4 to 92.7) and 83.7% (95% CI 74.9 to 89.8), respectively, for CIN2+ and 90.3% (95% CI 83.4 to 94.5) and 85.3% (95% CI 73.1 to 92.5), respectively, for CIN3+, using clinician-collected cervical specimen. The corresponding pooled estimates using self-collected vaginal swabs were 73.6% (95% CI 64.9 to 80.8) and 88.0% (95% CI 79.1 to 93.5) for CIN2+ and 75.2% (95% CI 66.8 to 82.0) and 90.6% (95% CI 83.4 to 94.9) for CIN3+. Two studies using OncoE6 reported sensitivity and specificity ranging from 31.3% to 42.4% and 99.1%-99.4% for CIN2+, and 53.5% and 98.9% for CIN3+ for one study.

CONCLUSION

CareHPV has good sensitivity and specificity for the detection of CIN2+ and CIN3+, but sensitivity was lower using self-collected vaginal samples. The specificity is lower in high HPV prevalence populations such as women living with HIV. OncoE6 assay warrants further evaluation.

Rapid Detection of Carbapenemase Production in Enterobacteriaceae by Use of a Modified Paper Strip Carba NP Method

Rapid and accurate detection of carbapenemase-producing Enterobacteriaceae (CPE) is important for preventing their spread in health care settings. We compared the performance of the Carba NP (CNP) test using the CLSI tube method with that using a modified paper strip method for the detection of carbapenemases in 390 Enterobacteriaceae isolates. The isolates were identified by Hong Kong's carbapenem-resistant Enterobacteriaceae surveillance program in 2016 and comprised 213 CPE and 177 carbapenemase-negative Enterobacteriaceae isolates. Molecular genotype was used as the reference. The test results were read at different time points for the CLSI method (1 min, 5 min, 1 h, and 2 h) and strip method (1 min and 5 min). The strip CNP and CLSI CNP tests correctly detect carbapenemase production in 93% and 93% of KPC producers, 100% and 38% of IMI producers, 94% and 85% of IMP producers, 98% and 90% of NDM producers, and 29% and 12% of OXA producers, respectively. Overall, the strip method has superior sensitivity to the CLSI method (86% versus 75%, respectively; P < 0.001, McNemar test). The specificity of both methods was 100%. By the CLSI method, 27%, 14%, 29%, and 6% of the CPE isolates were positive at 1 min, 5 min, 1 h, and 2 h, respectively. In contrast, by the strip method, 76% of the CPE isolates were positive at 1 min, and an additional 10% were positive at 5 min. In conclusion, the Carba NP test by use of the modified strip method has a higher sensitivity and a shorter assay time than that those by use of the CLSI tube method.

Designing HIV Testing Algorithms Based on 2015 WHO Guidelines Using Data from Six Sites in Sub-Saharan Africa

Our objective was to evaluate the performance of HIV testing algorithms based on WHO recommendations, using data from specimens collected at six HIV testing and counseling sites in sub-Saharan Africa (Conakry, Guinea; Kitgum and Arua, Uganda; Homa Bay, Kenya; Douala, Cameroon; Baraka, Democratic Republic of Congo). A total of 2,780 samples, including 1,306 HIV-positive samples, were included in the analysis. HIV testing algorithms were designed using Determine as a first test. Second and third rapid diagnostic tests (RDTs) were selected based on site-specific performance, adhering where possible to the WHO-recommended minimum requirements of ≥99% sensitivity and specificity. The threshold for specificity was reduced to 98% or 96% if necessary. We also simulated algorithms consisting of one RDT followed by a simple confirmatory assay. The positive predictive values (PPV) of the simulated algorithms ranged from 75.8% to 100% using strategies recommended for high-prevalence settings, 98.7% to 100% using strategies recommended for low-prevalence settings, and 98.1% to 100% using a rapid test followed by a simple confirmatory assay. Although we were able to design algorithms that met the recommended PPV of ≥99% in five of six sites using the applicable high-prevalence strategy, options were often very limited due to suboptimal performance of individual RDTs and to shared falsely reactive results. These results underscore the impact of the sequence of HIV tests and of shared false-reactivity data on algorithm performance. Where it is not possible to identify tests that meet WHO-recommended specifications, the low-prevalence strategy may be more suitable.

Point-of-Care Testing for Infectious Diseases: Past, Present, and Future

Point-of-care (POC) diagnostics provide rapid actionable information for patient care at the time and site of an encounter with the health care system. The usual platform has been the lateral flow immunoassay. Recently, emerging molecular diagnostics have met requirements for speed, low cost, and ease of use for POC applications. A major driver for POC development is the ability to diagnose infectious diseases at sites with a limited infrastructure. The potential use in both wealthy and resource-limited settings has fueled an intense effort to build on existing technologies and to generate new technologies for the diagnosis of a broad spectrum of infectious diseases.

Multicenter Clinical Evaluation of the Luminex Aries Flu A/B & RSV Assay for Pediatric and Adult Respiratory Tract Specimens

Influenza A and B viruses and respiratory syncytial virus (RSV) are three common viruses implicated in seasonal respiratory tract infections and are a major cause of morbidity and mortality in adults and children worldwide. In recent years, an increasing number of commercial molecular tests have become available to diagnose respiratory viral infections. The Luminex Aries Flu A/B & RSV assay is a fully automated sample-to-answer molecular diagnostic assay for the detection of influenza A, influenza B, and RSV. The clinical performance of the Aries Flu A/B & RSV assay was prospectively evaluated in comparison to that of the Luminex xTAG respiratory viral panel (RVP) at four North American clinical institutions over a 2-year period. Of the 2,479 eligible nasopharyngeal swab specimens included in the prospective study, 2,371 gave concordant results between the assays. One hundred eight specimens generated results that were discordant with those from the xTAG RVP and were further analyzed by bidirectional sequencing. Final clinical sensitivity values of the Aries Flu A/B & RSV assay were 98.1% for influenza A virus, 98.0% for influenza B virus, and 97.7% for RSV. Final clinical specificities for all three pathogens ranged from 98.6% to 99.8%. Due to the low prevalence of influenza B, an additional 40 banked influenza B-positive specimens were tested at the participating clinical laboratories and were all accurately detected by the Aries Flu A/B & RSV assay. This study demonstrates that the Aries Flu A/B & RSV assay is a suitable method for rapid and accurate identification of these causative pathogens in respiratory infections.

Evaluation of the Accelerate Pheno System for Fast Identification and Antimicrobial Susceptibility Testing from Positive Blood Cultures in Bloodstream Infections Caused by Gram-Negative Pathogens

Bloodstream infections (BSI) are an important cause of morbidity and mortality. Increasing rates of antimicrobial-resistant pathogens limit treatment options, prompting an empirical use of broad-range antibiotics. Fast and reliable diagnostic tools are needed to provide adequate therapy in a timely manner and to enable a de-escalation of treatment. The Accelerate Pheno system (Accelerate Diagnostics, USA) is a fully automated test system that performs both identification and antimicrobial susceptibility testing (AST) directly from positive blood cultures within approximately 7 h. In total, 115 episodes of BSI with Gram-negative bacteria were included in our study and compared to conventional culture-based methods. The Accelerate Pheno system correctly identified 88.7% (102 of 115) of all BSI episodes and 97.1% (102 of 105) of isolates that are covered by the system's identification panel. The Accelerate Pheno system generated an AST result for 91.3% (95 of 104) samples in which the Accelerate Pheno system identified a Gram-negative pathogen. The overall category agreement between the Accelerate Pheno system and culture-based AST was 96.4%, the rates for minor discrepancies 1.4%, major discrepancies 2.3%, and very major discrepancies 1.0%. Of note, ceftriaxone, piperacillin-tazobactam, and carbapenem resistance was correctly detected in blood culture specimens with extended-spectrum beta-lactamase-producing Escherichia coli (n = 7) and multidrug-resistant Pseudomonas aeruginosa (n = 3) strains. The utilization of the Accelerate Pheno system reduced the time to result for identification by 27.49 h (P < 0.0001) and for AST by 40.39 h (P < 0.0001) compared to culture-based methods in our laboratory setting. In conclusion, the Accelerate Pheno system provided fast, reliable results while significantly improving turnaround time in blood culture diagnostics of Gram-negative BSI.

Improving the Specificity of Plasmodium falciparum Malaria Diagnosis in High-Transmission Settings with a Two-Step Rapid Diagnostic Test and Microscopy Algorithm

Poor specificity may negatively impact rapid diagnostic test (RDT)-based diagnostic strategies for malaria. We performed real-time PCR on a subset of subjects who had undergone diagnostic testing with a multiple-antigen (histidine-rich protein 2 and pan-lactate dehydrogenase pLDH [HRP2/pLDH]) RDT and microscopy. We determined the sensitivity and specificity of the RDT in comparison to results of PCR for the detection of Plasmodium falciparum malaria. We developed and evaluated a two-step algorithm utilizing the multiple-antigen RDT to screen patients, followed by confirmatory microscopy for those individuals with HRP2-positive (HRP2⁺)/pLDH-negative (pLDH^-) results. In total, dried blood spots (DBS) were collected from 276 individuals. There were 124 (44.9%) individuals with an HRP2⁺/pLDH⁺ result, 94 (34.1%) with an HRP2⁺/pLDH^- result, and 58 (21%) with a negative RDT result. The sensitivity and specificity of the RDT compared to results with real-time PCR were 99.4% (95% confidence interval [CI], 95.9 to 100.0%) and 46.7% (95% CI, 37.7 to 55.9%), respectively. Of the 94 HRP2⁺/pLDH^- results, only 32 (34.0%) and 35 (37.2%) were positive by microscopy and PCR, respectively. The sensitivity and specificity of the two-step algorithm compared to results with real-time PCR were 95.5% (95% CI, 90.5 to 98.0%) and 91.0% (95% CI, 84.1 to 95.2), respectively. HRP2 antigen bands demonstrated poor specificity for the diagnosis of malaria compared to that of real-time PCR in a high-transmission setting. The most likely explanation for this finding is the persistence of HRP2 antigenemia following treatment of an acute infection. The two-step diagnostic algorithm utilizing microscopy as a confirmatory test for indeterminate HRP2⁺/pLDH^- results showed significantly improved specificity with little loss of sensitivity in a high-transmission setting.

Detection of Salmonella enterica in Meat in Less than 5 Hours by a Low-Cost and Noncomplex Sample Preparation Method

Salmonella is recognized as one of the most important foodborne bacteria and has wide health and socioeconomic impacts worldwide. Fresh pork meat is one of the main sources of Salmonella, and efficient and fast methods for detection are therefore necessary. Current methods for Salmonella detection in fresh meat usually include >16 h of culture enrichment, in a few cases <12 h, thus requiring at least two working shifts. Here, we report a rapid (<5 h) and high-throughput method for screening of Salmonella in samples from fresh pork meat, consisting of a 3-h enrichment in standard buffered peptone water and a real-time PCR-compatible sample preparation method based on filtration, centrifugation, and enzymatic digestion, followed by fast-cycling real-time PCR detection. The method was validated in an unpaired comparative study against the Nordic Committee on Food Analysis (NMKL) reference culture method 187. Pork meat samples (n = 140) were either artificially contaminated with Salmonella at 0, 1 to 10, or 10 to 100 CFU/25 g of meat or naturally contaminated. Cohen's kappa for the degree of agreement between the rapid method and the reference was 0.64, and the relative accuracy, sensitivity, and specificity for the rapid method were 81.4, 95.1, and 97.9%, respectively. The 50% limit of detections (LOD50s) were 8.8 CFU/25 g for the rapid method and 7.7 CFU/25 g for the reference method. Implementation of this method will enable faster release of Salmonella low-risk meat, providing savings for meat producers, and it will help contribute to improved food safety.IMPORTANCE While the cost of analysis and hands-on time of the presented rapid method were comparable to those of reference culture methods, the fast product release by this method can provide the meat industry with a competitive advantage. Not only will the abattoirs save costs for work hours and cold storage, but consumers and retailers will also benefit from fresher meat with a longer shelf life. Furthermore, the presented sample preparation might be adjusted for application in the detection of other pathogenic bacteria in different sample types.

EU-approved rapid tests might underestimate bovine spongiform encephalopathy infection in goats

We report the diagnostic sensitivity of 3 EU-approved rapid tests (ELISAs; 1 from IDEXX and 2 from Bio-Rad) for the detection of transmissible spongiform encephalopathy diseases in goats. Ninety-eight goat brainstem samples were tested. All the rapid tests had 100% specificity and ≥80% sensitivity, with the IDEXX test significantly more sensitive than the 2 Bio-Rad tests. All tests detected 100% of samples from goats with clinical scrapie, but missed 8% (IDEXX) to 33% (Bio-Rad SG) of samples from preclinical goats. Importantly, only IDEXX picked up all samples from clinical bovine spongiform encephalopathy (BSE)-infected goats, whereas the other 2 rapid tests missed 15% (Bio-Rad SG) to 25% (Bio-Rad SAP). These results show that a fraction of preclinical scrapie infections are likely missed by EU surveillance, with sensitivity of detection strongly dependent on the choice of the rapid test. Moreover, a significant proportion of clinical BSE infections are underestimated by using either Bio-Rad test. Assuming that the same sensitivity on preclinical goats would also occur in BSE-infected goats, our data suggest that IDEXX is likely the most sensitive test for detecting preclinical field cases of BSE infection in goats, although with an 8% failure rate. These results raise some concerns about the reliability of current EU surveillance figures on BSE infection in goats.

Multicenter Evaluation of the Portrait Staph ID/R Blood Culture Panel for Rapid Identification of Staphylococci and Detection of the mecA Gene

Bloodstream infections are a leading cause of morbidity and mortality in the United States and are associated with increased health care costs. We evaluated the Portrait Staph ID/R blood culture panel (BCP) multiplex PCR assay (Great Basin Scientific, Salt Lake City, UT) for the rapid and simultaneous identification (ID) of Staphylococcus aureus, Staphylococcus lugdunensis, and Staphylococcus species to the genus level and the detection of the mecA gene directly from a positive blood culture bottle. A total of 765 Bactec bottles demonstrating Gram-positive cocci in singles or clusters were tested during the prospective trial at 3 clinical sites. The Portrait Staph ID/R BCP results were compared with results from conventional biochemical and cefoxitin disk methods performed at an independent laboratory. Discordant ID and mecA results were resolved by rpoB gene sequencing and mecA gene sequencing, respectively. A total of 658 Staphylococcus species isolates (S. aureus, 211 isolates; S. lugdunensis, 3 isolates; and Staphylococcus spp., 444 isolates) were recovered from monomicrobial and 33 polymicrobial blood cultures. After discrepant analysis, the overall ratios of Portrait Staph ID/R BCP positive percent agreement and negative percent agreement were 99.4%/99.9% for Staphylococcus ID and 99.7%/99.2% for mecA detection.

Evaluation of Alere i RSV for Rapid Detection of Respiratory Syncytial Virus in Children Hospitalized with Acute Respiratory Tract Infection

Alere i RSV is a novel rapid test which applies a nicking enzyme amplification reaction to detect respiratory syncytial virus in point-of-care settings. In this study, we evaluated the Alere i RSV assay by using frozen nasopharyngeal swab samples that were collected in viral transport medium from children hospitalized with acute respiratory tract infection during the 2015-2016 winter season. Alere i RSV assay results were compared to those for Altona RealStar RSV real-time reverse transcription-PCR (RT-PCR). We found that the overall sensitivity and specificity of the Alere i RSV test was 100% (95% confidence intervals [CI], 93% to 100%) and 97% (95% CI, 89% to 100%), respectively. Positive samples were identified within 5 to 7 min from sample collection. Overall, the Alere i RSV test performed well compared to the RT-PCR assay and has the potential to facilitate the detection of RSV in point-of-care settings.

Cost Analysis of Implementing Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry Plus Real-Time Antimicrobial Stewardship Intervention for Bloodstream Infections

Studies evaluating rapid diagnostic testing plus stewardship intervention have consistently demonstrated improved clinical outcomes for patients with bloodstream infections. However, the cost of implementing new rapid diagnostic testing can be significant, and such testing usually does not generate additional revenue. There are minimal data evaluating the impact of adding matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for rapid organism identification and dedicating pharmacy stewardship personnel time on the total hospital costs. A cost analysis was performed utilizing patient data generated from the hospital cost accounting system and included additional costs of MALDI-TOF equipment, supplies and personnel, and dedicated pharmacist time for blood culture review and of making interventions to antimicrobial therapy. The cost analysis was performed from a hospital perspective for 3-month blocks before and after implementation of MALDI-TOF plus stewardship intervention. A total of 480 patients with bloodstream infections were included in the analysis: 247 in the preintervention group and 233 in the intervention group. Thirty-day mortality was significantly improved in the intervention group (12% versus 21%, P < 0.01), and the mean length of stay was reduced, although the difference was not statistically significant (13.0 ± 16.5 days versus 14.2 ± 16.7 days, P = 0.44). The total hospital cost per bloodstream infection was lower in the intervention group ($42,580 versus $45,019). Intensive care unit cost per bloodstream infection accounted for the largest share of the total costs in each group and was also lower in the intervention group ($10,833 versus $13,727). Implementing MALDI-TOF plus stewardship review and intervention decreased mortality for patients with bloodstream infections. Despite the additional costs of implementing MALDI-TOF and of dedicating pharmacy stewardship personnel time to interventions, the total hospital costs decreased by $2,439 per bloodstream infection, for an approximate annual cost savings of $2.34 million.

Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS)

Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption-ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems.

Antimicrobial Stewardship: How the Microbiology Laboratory Can Right the Ship

Antimicrobial stewardship is a bundle of integrated interventions employed to optimize the use of antimicrobials in health care settings. While infectious-disease-trained physicians, with clinical pharmacists, are considered the main leaders of antimicrobial stewardship programs, clinical microbiologists can play a key role in these programs. This review is intended to provide a comprehensive discussion of the different components of antimicrobial stewardship in which microbiology laboratories and clinical microbiologists can make significant contributions, including cumulative antimicrobial susceptibility reports, enhanced culture and susceptibility reports, guidance in the preanalytic phase, rapid diagnostic test availability, provider education, and alert and surveillance systems. In reviewing this material, we emphasize how the rapid, and especially the recent, evolution of clinical microbiology has reinforced the importance of clinical microbiologists' collaboration with antimicrobial stewardship programs.

Implementation of rapid HIV and HCV testing within harm reduction programmes for people who inject drugs: a pilot study

Including HCV and HIV rapid tests in harm reduction programmes (HRP) for people who inject drugs (PWID) can increase detection of these infections in high-risk populations who do not seek conventional health care.

AIMS

To assess acceptability and feasibility of rapid HIV and HCV tests in HRP; to identify HIV and HCV prevalence rates in HRP; to identify the percentage of PWID with a reactive test that attend hospital for confirmation and follow-up. Rapid oral tests for HCV and HIV were offered to users of 13 HRP from both mobile units and facility-based centres. A total of 172 HCV and 198 HIV tests were performed, with a refusal rate of 1.7% and 10.4%, respectively. Injectors made up 64.9% of all drug users and 35.1% did not inject drugs. Overall, 20.3% of HCV tests and 2.5% of HIV test were reactive. Only 24 of the 35 reactive HCV could be confirmed (68.6%) and one was false-negative. Of the five HIV reactive cases, only two could be confirmed (40%) with 1 false-positive case. Acceptability of rapid HIV and HCV tests among HRP users was high. The usefulness of oral rapid tests in HRP has been demonstrated, especially in mobile HRP.

Development and Validation of a Lateral Flow Immunoassay for the Rapid Screening of Okadaic Acid and All Dinophysis Toxins from Shellfish Extracts

A single-step lateral flow immunoassay was developed and validated to detect okadaic acid (OA) and dinophysis toxins (DTXs), which cause diarrhetic shellfish poisoning. The performance characteristics of the test were investigated, in comparison to reference methods (liquid chromatography tandem mass spectrometry and/or bioassay), using both spiked and naturally contaminated shellfish. A portable reader was used to generate a qualitative result, indicating the absence or presence of OA-group toxins, at concentrations relevant to the maximum permitted level (MPL). Sample homogenates could be screened in 20 min (including extraction and assay time) for the presence of free toxins (OA, DTX1, DTX2). DTX3 detection could be included with the addition of a hydrolysis procedure. No matrix effects were observed from the species evaluated (mussels, scallops, oysters, and clams). Results from naturally contaminated samples (n = 72) indicated no false compliant results and no false noncompliant results at <50% MPL. Thus, the development of a new low-cost but highly effective tool for monitoring a range of important phycotoxins has been demonstrated.

Comparison of eleven commercially available rapid tests for detection of Bacillus anthracis, Francisella tularensis and Yersinia pestis

Yersinia pestis, Bacillus anthracis and Francisella tularensis cause serious zoonotic diseases and have the potential to cause high morbidity and mortality in humans. In case of natural outbreaks and deliberate or accidental release of these pathogens rapid detection of the bacteria is crucial for limitation of negative effects of the release. In the present study, we evaluated 11 commercially available rapid test kits for the detection of Y. pestis, B. anthracis and F. tularensis in terms of sensitivity, specificity and simplicity of the procedure. The results revealed that rapid and easy-to-perform lateral flow assays for detection of highly pathogenic bacteria have very limited sensitivity. In contrast, the immunofiltration assays showed high sensitivity but limited specificity and required a too complicated procedure to be applied in the field by nonlaboratory workers (e.g. First Responders like fire, police and emergency medical personnel). Each sample - whether tested negative or positive by the rapid tests - should be retested in a reference laboratory using validated methods.

SIGNIFICANCE AND IMPACT OF THE STUDY

Rapid detection of highly pathogenic bacteria causing anthrax, plague and tularemia is crucial for the limitation of negative effects of a potential release (natural, accidental or deliberate). In the study, commercially available rapid tests for detection of Bacillus anthracis, Yersinia pestis and Francisella tularensis were investigated in terms of sensitivity, specificity and ease-to-perform. The study showed problems which could be faced during testing and results interpretation. Conclusions from this study should be helpful not only in selection of the most appropriate test for particular group of First Responders but also in undertaking decisions in situation of a contamination suspicion which have high social and economical impacts.

Hepatitis B virus surface antigen and anti-hepatitis C virus rapid tests underestimate hepatitis prevalence among HIV-infected patients

OBJECTIVES

In the case of coinfection with HIV and hepatitis B virus (HBV) and/or hepatitis C virus (HCV), hepatic disease progression is often accelerated, with higher rates of liver cirrhosis and liver-related mortality. We aimed to evaluate the performance of the rapid tests used routinely to detect HBV surface antigen (HBsAg) and anti-HCV among HIV-infected patients in Guinea-Bissau.

METHODS

Blood samples from HIV-infected patients in Guinea-Bissau were stored after testing for HBsAg and anti-HCV with rapid tests. Samples were subsequently re-tested for HBsAg and anti-HCV in Denmark.

RESULTS

Two rapid tests were used in Guinea-Bissau: HBsAg Strip Ref 2034 (VEDA.LAB, Alençon, France; sensitivity 62.3%; specificity 99.2%) and HEPA-SCAN (Bhat Bio-Tech, Bangalore, India; sensitivity 57.1%; specificity 99.7%). In the two tests the ability to obtain the correct outcome depended on the antigen and antibody concentrations, respectively. Sex, age, CD4 cell count and antiretroviral therapy status did not differ between false negative and true positive samples in either of the tests. The study is limited by a low number of anti-HCV positive samples.

CONCLUSIONS

New diagnostic rapid tests should always be evaluated in the setting in which they will be used before implementation.

Attitudes to rapid HIV testing among Spanish General Practitioners

OBJECTIVES

The objectives of this study were to investigate the acceptability of rapid HIV testing among general practitioners in Spain and to identify perceived barriers and needs in order to implement rapid testing in primary care settings.

METHODS

An anonymous questionnaire was distributed online to all members of the two largest Spanish scientific medical societies for family and community medicine. The study took place between 15th June and 31st October 2010.

RESULTS

Completed questionnaires were returned by 1308 participants. The majority (90.8%) of respondents were General Practitioners (GP). Among all respondents, 70.4% were aware of the existence of rapid tests for the diagnosis of HIV but they did not know how to use them. Nearly 80% of participants would be willing to offer rapid HIV testing in their practices and 74.7% would be confident of the results obtained by these tests. The barriers most commonly identified by respondents were a lack of time and a need for training, both in the use of rapid tests (44.3% and 56.4%, respectively) and required pre- and post-test counselling (59.2% and 34.5%, respectively).

CONCLUSIONS

This study reveals a high level of acceptance and willingness on the part of GPs to offer rapid HIV testing in their practices. Nevertheless, the implementation of rapid HIV testing in primary care will not be possible without moving from comprehensive pre-test counselling towards brief pre-test information and improving training in the use of rapid tests.

Detection of human immunodeficiency virus using oral mucosal transudate by rapid test

CONTEXT

On the cusp of the fourth decade of the acquired immunodeficiency syndrome epidemic, the world has turned the corner - it has halted and began to reverse the spread of human immunodeficiency virus (HIV). Oral fluid-based Rapid tests have potential advantages over blood-based tests hence the time is ripe for their use to scale up HIV screening and testing programmes.

AIMS AND OBJECTIVES

To detect HIV using oral mucosal transudate (OMT) and to assess the sensitivity and specificity of the HIV Rapid test using OMT.

SETTINGS AND DESIGN

OraQuick Rapid HIV-1/2 Diagnostic test was evaluated in sera and oral fluids from 83 subjects.

MATERIALS AND METHODS

The study group comprised of 50 HIV seropositive subjects and the control group comprised of 33 seronegative subjects. Serum samples were collected using the standard phlebotomy technique and oral samples were collected using OraQuick Rapid HIV 1/2 Antibody test OMT collecting device.

STATISTICAL ANALYSIS USED

The statistical analysis was done using statistical package for social sciences version 16.0, SPSS Inc., 233 South Wacker Drive, 11(th) Floor, Chicago, IL 60606-6412. The Sensitivity, specificity, positive predictive value, negative predictive value were used.

RESULTS

All the subjects who tested either positive/reactive or negative/non-reactive with Western blot/enzyme-linked immunosorbent assay (ELISA) produced similar results with Rapid test using OMT in study, our study also revealed that the subjects whether on anti-retroviral therapy or not had 100% sensitivity and specificity with the Rapid test using OMT.

CONCLUSIONS

The Rapid test using OMT is highly accurate as the diagnostic efficacy in our study was 100% for HIV antibody detection and produced similar results to that of conventional Western blot/ELISA tests.

Chromatographic immunoassays for Helicobacter pylori detection--are they reliable in Mali, West Africa?

INTRODUCTION

Gastrointestinal diseases are major reasons for morbidity in Mali. As Helicobacter pylori is known to play a major role in gastritis and gastric ulcer we wanted to find a simple method for detection.

METHODS

Twenty-nine volunteers with confirmed gastric ulcer by gastroscopy and 59 randomly selected volunteers were diagnosed by using the rapid serological test Clearview(®) H. Pylori. The ImmunoCard STAT!(®) HpSA(®)test was applied on stool from 65 volunteers seeking help for gastrointestinal related ailments.

RESULTS

A Helicobacter pylori prevalence of 21% was found among the individuals with confirmed gastric ulcer, 44% among the randomly selected volunteers and 14% in individuals with gastrointestinal related ailments.

CONCLUSION

According to what is already known about the aetiology of gastric ailments and the prevalence of Helicobacter pylori in neighboring countries, the infection rates in our study appear strikingly low. This might indicate that Clearview(®) H. Pylori and ImmunoCard STAT!(®) HpSA(®) have low sensitivities in the populations studied. Strain variability of H. pylori may be an explanation. The tests need to be properly evaluated in Mali before they can be relied upon as diagnostic tools.

Detection of human immunodeficiency virus using oral mucosal transudate by rapid test

CONTEXT

On the cusp of the fourth decade of the acquired immunodeficiency syndrome epidemic, the world has turned the corner - it has halted and began to reverse the spread of human immunodeficiency virus (HIV). Oral fluid-based Rapid tests have potential advantages over blood-based tests hence the time is ripe for their use to scale up HIV screening and testing programmes.

AIMS AND OBJECTIVES

To detect HIV using oral mucosal transudate (OMT) and to assess the sensitivity and specificity of the HIV Rapid test using OMT.

SETTINGS AND DESIGN

OraQuick Rapid HIV-1/2 Diagnostic test was evaluated in sera and oral fluids from 83 subjects.

MATERIALS AND METHODS

The study group comprised of 50 HIV seropositive subjects and the control group comprised of 33 seronegative subjects. Serum samples were collected using the standard phlebotomy technique and oral samples were collected using OraQuick Rapid HIV 1/2 Antibody test OMT collecting device.

STATISTICAL ANALYSIS USED

The statistical analysis was done using statistical package for social sciences version 16.0, SPSS Inc., 233 South Wacker Drive, 11(th) Floor, Chicago, IL 60606-6412. The Sensitivity, specificity, positive predictive value, negative predictive value were used.

RESULTS

All the subjects who tested either positive/reactive or negative/non-reactive with Western blot/enzyme-linked immunosorbent assay (ELISA) produced similar results with Rapid test using OMT in study, our study also revealed that the subjects whether on anti-retroviral therapy or not had 100% sensitivity and specificity with the Rapid test using OMT.

CONCLUSIONS

The Rapid test using OMT is highly accurate as the diagnostic efficacy in our study was 100% for HIV antibody detection and produced similar results to that of conventional Western blot/ELISA tests.

Rapid HIV screening: missed opportunities for HIV diagnosis and prevention

BACKGROUND

Although rapid HIV tests increase the number of persons who are aware of their HIV status, they may fail to detect early HIV infection.

OBJECTIVES

To evaluate the sensitivity for early HIV infection of several rapid tests and third- and fourth-generation assays compared with nucleic acid amplification testing (NAAT).

STUDY DESIGN

Sensitivity for early HIV infection was evaluated using 62 NAAT-positive/WB-negative or indeterminate specimens from the CDC Acute HIV Infection study. Specimens underwent third-generation testing with Genetic Systems 1/2+O(®) and rapid testing with Multispot HIV-1/HIV-2. A subset was also tested with four FDA-approved rapid tests and Determine HIV-1 Antigen/Antibody Rapid Test(®) and Architect HIV Antigen/Antibody Combo(®), both fourth-generation tests.

RESULTS

Of 99,111 specimens screened from April 2006 to March 2008, 62 met the definition for early HIV infection (60 NAAT-positive/seronegative and 2 NAAT-positive/Western blot indeterminate). Third-generation testing correctly detected antibody in 34 specimens (55%; 95% confidence interval (CI): 42-67); Multispot detected antibody in 16 (26%; 95% CI: 16-38). Of the 62 specimens, 33 (53%) had sufficient quantity for further testing. Rapid test sensitivities for early HIV infection ranged from 22-33% compared with 55-57% for the third-generation assay and 76-88% for the fourth-generation tests.

CONCLUSIONS

Many rapid HIV tests failed to detect half of the early HIV infection cases in whom antibody was present. Programs that screen high-incidence populations with rapid tests should consider supplemental testing with NAAT or other antigen-based tests. These data support the need for more sensitive antigen-based point-of-care screening tests for early HIV infection.

Rapid tests for sexually transmitted infections (STIs): the way forward

In the developing world, laboratory services for sexually transmitted infections (STIs) are either not available, or where limited services are available, patients may not be able to pay for or physically access those services. Despite the existence of national policy for antenatal screening to prevent congenital syphilis and substantial evidence that antenatal screening is cost-effective, implementation of syphilis screening programmes remains unacceptably low because of lack of screening tools that can be used in primary health care settings. The World Health Organization Sexually Transmitted Diseases Diagnostics Initiative (SDI) has developed the ASSURED criteria as a benchmark to decide if tests address disease control needs: Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free and Deliverable to end-users. Rapid syphilis tests that can be used with whole blood approach the ASSURED criteria and can now be deployed in areas where no previous screening has been possible. Although rapid tests for chlamydia and gonorrhoea lack sensitivity, more tests are in development. The way forward for STI diagnostics requires a continuing quest for ASSURED tests, the development of a road map for test introduction, sustainable programmes for quality assurance, and the creation of a robust infrastructure linked to HIV prevention that ensures sustainability of STI control efforts that includes viral STIs.