Ct value-based real time PCR serotyping of Glaesserella parasuis.

Glaesserella parasuis is the causative agent of Glässer's disease in swine. Serotyping plays an essential role in prevalence investigations and in the development of vaccination strategies for the prevention of this disease. Molecular serotyping based on variation within the capsule loci of the 15 serovars is more accurate and efficient than traditional serological serotyping. To reduce the running time and facilitate ease of data interpretation, we developed a simple and rapid cycle threshold (Ct) value-based real time PCR (qPCR) method for the identification and serotyping of G. parasuis. The qPCR method distinguished between all 15 serovar reference strains of G. parasuis with efficiency values ranging between 85.5 % and 110.4 % and, R2 values > 0.98. The qPCR serotyping was evaluated using 83 clinical isolates with 43 of the isolates having been previously assigned to a serovar by the gel immuno-diffusion (GID) assay and 40 non-typeable isolates. The qPCR results of 41/43 (95.3 %) isolates were concordant with the GID assay except two isolates of serovar 12 were assigned to serovar 5. In addition, the qPCR serotyping assigned a serovar to each of the 40 non-typeable isolates. Of the 83 isolates tested to assign a serovar, a concordance rate of 98.8 % (82/83) was determined between the qPCR and the previously reported multiplex PCR of Howell et al. (2015) (including those that were either serovars 5 or 12). Despite the inability to differentiate between serovars 5 and 12, the Ct value-based qPCR serotyping represents an attractive alternative to current molecular serotyping method for G. parasuis and could be used for both epidemiological monitoring and the guidance of vaccination programs.

A validated method to identify Echinococcus granulosus sensu lato at species level.

The zoonotic tapeworm Echinococcus granulosus sensu lato (s.l.) represents a species complex encompassing multiple causative agents of cystic echinococcosis, a neglected tropical disease affecting more than one million people in the world. At least eight genotypes, grouped in five species, are currently recognized within this species complex, and they differ in terms of relative public health impact. Here we present a molecular method that first identifies the common E. granulosus sensu stricto (s.s.) (genotypes G1 and G3) based on a PCR-RFLP assay, and can further identify the remaining species based on a multiplex PCR assay. We demonstrate the applicability of the method to DNA extracted from parasitic cyst material of human and animal origin, preserved in ethanol or frozen. The method has been developed and validated at the European Union Reference Laboratory for Parasites (EURLP), according to the ISO/IE 17025.

Advantages of a 21-loci short tandem repeat method for detection of cross-contamination in human cell lines.

Cross-contamination of cell lines is a highly relevant and pervasive problem. The analysis of short tandem repeats (STR) is a simple and commercially available technique to authenticate cell lines for more than two decades. At present, STR multiple amplification kits have been developed up to 21 loci while the current STR databases only provide 9-loci STR profiles. Here, we compared the advantages of 21-loci STR methodology using the same algorithm as 9-loci method. The 21-loci method reduced the uncertainty ratio for authentications by 97.5% relative to the 9-loci method and exclude effectively false positive. We show that the additional 12 loci helped to greatly reduce sample-site marker specificity arising from genetic isolation and the occurrence of null alleles, suggesting that inclusion of additional loci in these databases will ultimately improve the efficiency and accuracy of authentication of cell lines. Taken together, we demonstrate the utility of a 21-loci method in human cells, providing a novel marker panel for use as a valuable alternative to 9-loci analyses to minimize cell line authentication errors and reduce costs due to erroneous experiments.

Xpert MTB/RIF and Xpert MTB/RIF Ultra assays for active tuberculosis and rifampicin resistance in children.

BACKGROUND: Every year, at least one million children become ill with tuberculosis and around 200,000 children die. Xpert MTB/RIF and Xpert Ultra are World Health Organization (WHO)-recommended rapid molecular tests that simultaneously detect tuberculosis and rifampicin resistance in adults and children with signs and symptoms of tuberculosis, at lower health system levels. To inform updated WHO guidelines on molecular assays, we performed a systematic review on the diagnostic accuracy of these tests in children presumed to have active tuberculosis. OBJECTIVES: Primary objectives • To determine the diagnostic accuracy of Xpert MTB/RIF and Xpert Ultra for (a) pulmonary tuberculosis in children presumed to have tuberculosis; (b) tuberculous meningitis in children presumed to have tuberculosis; (c) lymph node tuberculosis in children presumed to have tuberculosis; and (d) rifampicin resistance in children presumed to have tuberculosis - For tuberculosis detection, index tests were used as the initial test, replacing standard practice (i.e. smear microscopy or culture) - For detection of rifampicin resistance, index tests replaced culture-based drug susceptibility testing as the initial test Secondary objectives • To compare the accuracy of Xpert MTB/RIF and Xpert Ultra for each of the four target conditions • To investigate potential sources of heterogeneity in accuracy estimates - For tuberculosis detection, we considered age, disease severity, smear-test status, HIV status, clinical setting, specimen type, high tuberculosis burden, and high tuberculosis/HIV burden - For detection of rifampicin resistance, we considered multi-drug-resistant tuberculosis burden • To compare multiple Xpert MTB/RIF or Xpert Ultra results (repeated testing) with the initial Xpert MTB/RIF or Xpert Ultra result SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Scopus, the WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, and the International Standard Randomized Controlled Trials Number (ISRCTN) Registry up to 29 April 2019, without language restrictions. SELECTION CRITERIA: Randomized trials, cross-sectional trials, and cohort studies evaluating Xpert MTB/RIF or Xpert Ultra in HIV-positive and HIV-negative children younger than 15 years. Reference standards comprised culture or a composite reference standard for tuberculosis and drug susceptibility testing or MTBDRplus (molecular assay for detection of Mycobacterium tuberculosis and drug resistance) for rifampicin resistance. We included studies evaluating sputum, gastric aspirate, stool, nasopharyngeal or bronchial lavage specimens (pulmonary tuberculosis), cerebrospinal fluid (tuberculous meningitis), fine needle aspirates, or surgical biopsy tissue (lymph node tuberculosis). DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed study quality using the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2). For each target condition, we used the bivariate model to estimate pooled sensitivity and specificity with 95% confidence intervals (CIs). We stratified all analyses by type of reference standard. We assessed certainty of evidence using the GRADE approach. MAIN RESULTS: For pulmonary tuberculosis, 299 data sets (68,544 participants) were available for analysis; for tuberculous meningitis, 10 data sets (423 participants) were available; for lymph node tuberculosis, 10 data sets (318 participants) were available; and for rifampicin resistance, 14 data sets (326 participants) were available. Thirty-nine studies (80%) took place in countries with high tuberculosis burden. Risk of bias was low except for the reference standard domain, for which risk of bias was unclear because many studies collected only one specimen for culture. Detection of pulmonary tuberculosis For sputum specimens, Xpert MTB/RIF pooled sensitivity (95% CI) and specificity (95% CI) verified by culture were 64.6% (55.3% to 72.9%) (23 studies, 493 participants; moderate-certainty evidence) and 99.0% (98.1% to 99.5%) (23 studies, 6119 participants; moderate-certainty evidence). For other specimen types (nasopharyngeal aspirate, 4 studies; gastric aspirate, 14 studies; stool, 11 studies), Xpert MTB/RIF pooled sensitivity ranged between 45.7% and 73.0%, and pooled specificity ranged between 98.1% and 99.6%. For sputum specimens, Xpert Ultra pooled sensitivity (95% CI) and specificity (95% CI) verified by culture were 72.8% (64.7% to 79.6%) (3 studies, 136 participants; low-certainty evidence) and 97.5% (95.8% to 98.5%) (3 studies, 551 participants; high-certainty evidence). For nasopharyngeal specimens, Xpert Ultra sensitivity (95% CI) and specificity (95% CI) were 45.7% (28.9% to 63.3%) and 97.5% (93.7% to 99.3%) (1 study, 195 participants). For all specimen types, Xpert MTB/RIF and Xpert Ultra sensitivity were lower against a composite reference standard than against culture. Detection of tuberculous meningitis For cerebrospinal fluid, Xpert MTB/RIF pooled sensitivity and specificity, verified by culture, were 54.0% (95% CI 27.8% to 78.2%) (6 studies, 28 participants; very low-certainty evidence) and 93.8% (95% CI 84.5% to 97.6%) (6 studies, 213 participants; low-certainty evidence). Detection of lymph node tuberculosis For lymph node aspirates or biopsies, Xpert MTB/RIF pooled sensitivity and specificity, verified by culture, were 90.4% (95% CI 55.7% to 98.6%) (6 studies, 68 participants; very low-certainty evidence) and 89.8% (95% CI 71.5% to 96.8%) (6 studies, 142 participants; low-certainty evidence). Detection of rifampicin resistance Xpert MTB/RIF pooled sensitivity and specificity were 90.0% (67.6% to 97.5%) (6 studies, 20 participants; low-certainty evidence) and 98.3% (87.7% to 99.8%) (6 studies, 203 participants; moderate-certainty evidence). AUTHORS' CONCLUSIONS: We found Xpert MTB/RIF sensitivity to vary by specimen type, with gastric aspirate specimens having the highest sensitivity followed by sputum and stool, and nasopharyngeal specimens the lowest; specificity in all specimens was > 98%. Compared with Xpert MTB/RIF, Xpert Ultra sensitivity in sputum was higher and specificity slightly lower. Xpert MTB/RIF was accurate for detection of rifampicin resistance. Xpert MTB/RIF was sensitive for diagnosing lymph node tuberculosis. For children with presumed tuberculous meningitis, treatment decisions should be based on the entirety of clinical information and treatment should not be withheld based solely on an Xpert MTB/RIF result. The small numbers of studies and participants, particularly for Xpert Ultra, limits our confidence in the precision of these estimates.

Pre-empting Pandora's Box: Blastocystis Subtypes Revisited.

Blastocystis is a genetically diverse intestinal protist colonizing both human and non-human hosts. By 2013, 17 subtypes had been acknowledged. Since then, nine more subtypes have been proposed. We argue that several recently proposed subtypes are invalid. We also revisit recommendations regarding the requirements for annotating sequences as new subtypes.

Evaluation of the automated BD Phoenix CPO Detect test for detection and classification of carbapenemases in Gram negatives.

We evaluated the performance of the automated BD Phoenix CPO Detect test (BD-CPO test) for detection and Ambler classification of carbapenemases in Enterobacteriaceae, P.aeruginosa and A.baumannii complex. A collection of 287 Gram-negative clinical isolates, with a reduced susceptibility to at least one carbapenem including 184 carbapenemase-producing organisms (CPO) and 103 non-CPO, was tested. The BD-CPO test showed an overall sensitivity of 89.7% and specificity of 83.5% for carbapenemase detection. 1/7 of class A, 82.9% of class B, and 89.8% of class D carbapenemases were correctly classified. Poor detection sensitivity of 68.9% and specificity of 62.1% in P.aeruginosa was observed. However, combination with ceftazidime/avibactam susceptibility, provided by this panel, increased the performances for P.aeruginosa. The integration of an automated carbapenemase detection and classification in routine susceptibility panels would save time and help for therapeutic management. Further developments are needed to improve the accuracy of the BD-CPO test.

Diagnostic Efficacy, Sensitivity, and Specificity of Xpert MTB/RIF Assay for Spinal Tuberculosis and Rifampicin Resistance.

STUDY DESIGN: A cross-sectional observational study. OBJECTIVE: This study aims to determine the diagnostic accuracy, sensitivity, and specificity of the Xpert MTB/RIF assay (Mycobacterium Tuberculosis/Rifampicin resistance) for the detection of spinal Tuberculosis (TB) and rifampicin (RIF) resistance. SUMMARY OF BACKGROUND DATA: The Spinal TB is often a paucibacillary extra pulmonary tuberculosis which gives a major challenge in early diagnosis and initializing the correct anti-tubercular treatment (ATT). Due to its rapidity and sensitivity, the dependence and reliability on the Xpert MTB/RIF assay has increased in the last few years. The studies describing accuracy of the Xpert MTB/RIF assay in spinal TB are scanty. METHODS: This institutional review board-approved study included 360 diagnosed spinal TB patients. To determine the accuracy of the Xpert MTB/RIF assay, it was compared with other diagnostic tests like histopathology, acid fast bacilli (AFB) smear, culture, and drug sensitivity testing (DST). RESULTS: The Xpert MTB/RIF assay showed 86.3% sensitivity and 85.3% specificity when compared with culture for the diagnosis of Spinal TB and showed 75.86% sensitivity, 96.12% specificity for RIF resistance when compared to DST. Four cases were false positive and 11 cases were false negative for RIF resistance on the Xpert MTB/RIF assay. CONCLUSION: The Xpert MTB/RIF assay is an efficient technique for the rapid diagnosis of spinal TB; however, a clinician should not solely rely on it for starting ATT. As there are false results also with this test which should be read cautiously and be well correlated with culture and DST pattern to guide the start of sensitive drug regimen only. The purpose is to prevent exposure of the second line drugs to false cases found on the Xpert MTB/RIF assay and avoid emergence of new acquired drug resistance. LEVEL OF EVIDENCE: 4.

Identification of Brachyspira species by cpn60 universal target sequencing is superior to NADH oxidase gene sequencing.

The pig colon is the habitat of diverse Brachyspira species, of which only a few are of clinical importance. Methods for identification have shifted from phenotypic to molecular testing over the last two decades. Following the emergence of B. hampsonii it became evident that relying on species-specific PCRs carries the risk of overlooking important new species. Consequently, sequencing was proposed as an unbiased alternative for identification of isolates. So far, the main target for identification across species has been the NADH oxidase gene (nox). However, multiple copies of this gene in the genome and potential lateral gene transfer reduce confidence when using this gene. This study compared identification and phylogentic relationship inferred from nox sequencing to that inferred from sequencing of the cpn60 universal target using a collection of 168 isolates from different Brachyspira species. The majority of isolates had an identical identification with both methods. There were a few outliers in the trees with uncertain assignment to a species by BLAST analysis. A few major discrepancies pertained to the pathogenic species B. hampsonii (2), B. pilosicoli (1) and B. suanatina (1). Weakly haemolytic variants of B. hyodysenteriae were assigned to the correct species by both methods. Some of the isolates identified as B. hampsonii also had a weakly haemolytic phenotype.

Alinity m HR HPV Assay Fulfills Criteria for Human Papillomavirus Test Requirements in Cervical Cancer Screening Settings.

The Alinity m HR HPV assay (Alinity) is a novel human papillomavirus (HPV) assay that individually identifies genotypes HPV16, HPV18, and HPV45 while reporting on 11 other high-risk HPV (hrHPV) genotypes in two aggregates: HPV31/33/52/58 and HPV35/39/51/56/59/66/68. The clinical performance of Alinity for screening for cervical cancer was evaluated in population-based settings. For women aged ≥30 years, the clinical sensitivity (n = 68) and specificity (n = 3,077) for the detection of cervical intraepithelial neoplasia grade 2+ (CIN2+) of Alinity were 100.0% and 92.4%, respectively, and were not inferior to those of the Qiagen Digene Hybrid Capture 2 high-risk HPV DNA assay (hc2) (P = 0.0006 and P < 0.0001, respectively). The intralaboratory reproducibility and interlaboratory agreement of Alinity were 96.7% (kappa, 0.92) and 98.7% (kappa, 0.97), respectively. In the group ≥30 years of age, women who were baseline hrHPV negative had a lower risk for CIN2+ at 3 years using Alinity (0.04%) than those with a normal baseline cytology (0.65%) and had a risk comparable to that determined by the Abbott RealTime High Risk HPV assay (0.04%), hc2 (0.08%), or the Roche Cobas 4800 HPV assay (0.04%). High-risk HPV16/18 infection was associated with a significantly higher baseline and 3-year CIN2+ and CIN3+ risk than the absence of HPV16/18 or the presence of hrHPVs at the baseline (all P values were <0.05). The baseline CIN2+ risk was 8.8% for those with HPV31/33/52/58 infection and 2.5% for those with HPV35/39/51/56/59/66/68 infection, while the 3-year CIN2+ risk was 17.0% and 4.9%, respectively (relative risk, 3.4 [P = 0.03] and 3.5 [P = 0.003], respectively), suggesting that extended genotyping by Alinity may be valuable in improving patient risk stratification. Alinity fulfills international consensus guideline criteria for primary cervical cancer screening and can be considered clinically validated, demonstrating safety comparable to that of other clinically validated HPV tests.

Evaluation of High-Resolution Melting for Rapid Differentiation of Phytophthora Hybrids and Their Parental Species.

Phytophthora species hybrids have been repeatedly reported as causing damaging diseases to cultivated and wild plants. Two known hybrids, P. andina and P. × pelgrandis, are pathogens of Solanaceae and ornamentals, respectively, although the extent of their host ranges are unknown. P. andina emerged from hybridization of P. infestans and an unidentified related species, whereas P. × pelgrandis emerged from P. nicotianae and P. cactorum. Considering that hybrids and parental species can coexist in the same regions and to distinguish them usually requires cloning or whole genome sequencing, we aimed to develop a rapid tool to distinguish them. Specifically, we used high-resolution melting (HRM) assays to differentiate genotypes based on their amplicon melting profiles. We designed primers for P. × pelgrandis and parental species based on available sequences of P. nicotianae and P. cactorum nuclear genes containing polymorphisms between species. For P. andina, heterozygous sites from Illumina short reads were used for the same purpose. We identified multiple amplicons exhibiting differences in melting curves between parental species and hybrids. We propose HRM as a rapid method for differentiation of P. andina and P. × pelgrandis hybrids from parental species that could be employed to advance research on these pathogens.

Profile of the BD HPV OnclarityTM assay.

Introduction: Validated molecular assays for the detection of high risk (hr) Human Papillomavirus (HPV) DNA underpin the screening protocols against cervical cancer. New molecular assays based on real-time PCR also display the genotype of hrHPV. Areas covered: Recently, the BD Onclarity™ HPV assay (Onclarity), extended HPV genotyping test, for use on the BD Viper™ LT Instrument, has been developed. Onclaritys application for the detection and genotyping of hrHPV has been validated for the identification of women at high risk for cervical intraepithelial neoplasia of grade 2 or more in accordance with European Guidelines and FDA specifications. Expert opinion: Onclarity displays good sensitivity and specificity performance for HR-HPV detection and offers the possibility for genotype-specific reporting: the latter could provide risk-stratification for high-grade cervical disease during screening and facilitate surveillance for persistent genotypes in women at follow-up visits.

GroEL gene typing and genetic diversity of Anaplasma bovis in ticks in Shaanxi, China.

Anaplasma bovis, causative agent of bovine anaplasmosis, is usually identified by nested-PCR amplifying the rrs gene. However, it is difficult to determine the genetic relationship among different variants within A. bovis using this gene because of high conservation. In this study, two tick species, identified as Rhipicephalus microplus and Haemaphysalis longicornis based on morphological and molecular methods by analyzing COI gene, were collected from cattle, goat or sheep. Subsequently, A. bovis was initially detected by PCR amplifying the rrs gene in ticks in Shaanxi Province, China. The sequencing and Blast results showed that some false positive samples were found when only based on the amplification of partial rrs gene, presenting these sequences resembled those of other Alphaproteobacteria rather than A. bovis. Although major surface proteins genes were proposed and used successfully to identify members within Anaplasmataceae, these genes were unavailable for A. bovis. Hence, primers targeting the groEL gene were designed and a PCR assay was developed. The PCR products were sequenced and similarity and phylogenetic analysis suggested all these sequences are the groEL gene of A. bovis. In addition, phylogenetic analysis based on the groEL gene also revealed the genetic diversity of A. bovis worldwide, as well as in Shaanxi Province of China, which wasn't reflected by analyzing the rrs gene. In sum, groEL gene is important for molecular detection and phylogenetic analysis of A. bovis.

A Clinical TB Detection Method Based on Molecular Typing Technique with Quality Control.

The gold standard for diagnosing pulmonary Mycobacterium tuberculosis (TB) is the detection of tubercle bacillus in patient sputum samples. However, current methods either require long waiting times to culture the bacteria or have a risk of getting false-positive results due to cross-contamination. In this study, a method to detect tubercle bacillus based on the molecular typing technique is presented. This method can detect genetic units, variable number of tandem repeat (VNTR), which are the characteristic of tuberculosis (TB), and performs quality control using a mathematical model, ensuring the reliability of the results. Compared to other methods, the proposed method was able to process and diagnose a large volume of samples in a run time of six hours, with high sensitivity and specificity. Our method is also in the pipeline for implementation in clinical testing. Reliable and confirmed results are stored into a database, and these data are used to further refine the model. As the volume of data processed from reliable samples increases, the diagnostic power of the model improves. In addition to improving the quality control scheme, the collected data can be also used to support other TB research, such as that regarding the evolution of the tubercle bacillus.

Human Papillomavirus Genome based Detection and Typing: A Holistic Molecular Approach.

Human Papillomavirus (HPV) is a species specific double-stranded DNA virus infecting human cutaneous or mucosal tissues. The genome structure of HPV is extremely polymorphic hence making it difficult to discriminate between them. HPV exhibits numerous dissimilar types that can be subdivided into high-risk (HR), probably high-risk and low-risk (LR), causing numerous types of cancers and warts around the genital organs in humans. Several screening methods are performed in order to detect cytological abnormalities and presence or absence of HPV genome. Currently available commercial kits and methods are designed to detect only a few HR/LR-HPV types, which are expensive adding to the economic burden of the affected individual and are not freely available. These gaps could be minimized through Polymerase Chain reaction (PCR) method, which is a gold standard and a cost-effective technique for the detection of most HPV (both known and unknown) types by using specific consensus primers in minimal lab setup. In this context, numerous studies have validated the effectiveness of different sets of consensus primers in the screening of HPVs. Numerous consensus primers, such as E6, E6/E7, GP-E6/E7, MY09/11, GP5+/GP6+, SPF10, and PGMY09/11 have been developed to detect the presence of HPV DNA. In addition, HPV detection sensitivity could be achieved through consensus primer sets targeting specific ORF regions like L1 and E6, which may finally assist in better diagnosis of several unknown HR-HPVs. The present review, provides a summary of the available methods, kits and consensus primer sets for HPV genome based detection, their advantages and limitations along with future goals to be set for HPV detection.

Diagnostic accuracy of TB-LAMP for pulmonary tuberculosis: a systematic review and meta-analysis.

BACKGROUND: The need for a rapid, molecular test to diagnose tuberculosis (TB) has prompted exploration of TB-LAMP (Eiken; Tokyo, Japan) for use in resource-limited settings. We conducted a systematic review to assess the accuracy of TB-LAMP as a diagnostic test for pulmonary TB. METHODS: We analyzed individual-level data for eligible patients from all studies of TB-LAMP conducted between Jan 2012 and October 2015 to compare the diagnostic accuracy of TB-LAMP with that of smear microscopy and Xpert MTB/RIF® using 3 reference standards of varying stringency. Pooled sensitivity and specificity and pooled differences in sensitivity and specificity were estimated using random effects meta-analysis. Study quality was evaluated using QUADAS-2. RESULTS: Four thousand seven hundred sixty individuals across 13 studies met eligibility criteria. Methodological quality was judged to be low for all studies. TB-LAMP had higher sensitivity than sputum smear microscopy (pooled sensitivity difference + 13·2, 95% CI 4·5-21·9%) and similar sensitivity to Xpert MTB/RIF (pooled sensitivity difference - 2·5, 95% CI -8·0 to + 2·9) using the most stringent reference standard available. Specificity of TB-LAMP was similar to that of sputum smear microscopy (pooled specificity difference - 1·8, 95% CI -3·8 to + 0·2) and Xpert MTB/RIF (pooled specificity difference 0·5, 95% CI -0·9 to + 1·8). CONCLUSIONS: From the perspective of diagnostic accuracy, TB-LAMP may be considered as an alternative test for sputum smear microscopy. Additional factors such as cost, feasibility, and acceptability in settings that continue to rely on sputum smear microscopy should be considered when deciding to adopt this technology. Xpert MTB/RIF should continue to be preferred in settings where resource and infrastructure requirements are adequate and where HIV co-infection or drug-resistance is of concern.

Genotyping of Pneumocystis jirovecii by Use of a New Simplified Nomenclature System Based on the Internal Transcribed Spacer Regions and 5.8S rRNA Gene of the rRNA Operon.

Genotyping based on internal transcribed spacer 1 (ITS1) and ITS2 of the rRNA operon has played an important role in understanding the transmission and epidemiology of Pneumocystis jirovecii, one of the major opportunistic pathogens in individuals with AIDS and other immunocompromised individuals. The widespread use of this typing system has resulted in several problems, including inconsistent genotype nomenclatures, difficult data transferability, and complicated interpretation of the length variation in multiple homopolymeric tracts. The aim of this study was to establish a new, simplified genotype nomenclature system for P. jirovecii based on the ITS1 and ITS2 sequences. We first analyzed the complete ITS1, 5.8S rRNA gene, and ITS2 sequences (termed ITS1-5.8S-ITS2) in 27 recent P. jirovecii isolates from China and identified 18 unique genotypes. Subsequently, we performed a comprehensive classification of more than 400 ITS1- and ITS2-related sequences from GenBank and an in-depth evaluation of the length variation of multiple homopolymeric tracts within ITS1-5.8S-ITS2. Integration of the results from these analyses led to a new, simplified genotype nomenclature system including 62 unique ITS1-5.8S-ITS2 genotypes, simply designated types 1 through 62. This new system offers several advantages over traditional ITS1- and ITS2-based typing systems, including a simpler analysis and interpretation process, a higher discriminative power, and no limitation in assigning potential new genotypes. This new system is expected to facilitate the standardization of P. jirovecii genotyping and easy data exchanges across different laboratories.

Comparison between Vitek MS, Bruker Biotyper, Vitek2, and API20E for differentiation of species of the genus Raoultella.

Rapid and reliable identification of microorganisms in the clinical laboratory is essential for an early and accurate diagnosis guiding timely therapy. However, conventional methods are sometimes unreliable and show controversial outcomes. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a rapid and reliable method for identification of bacteria and fungi isolated from clinical samples. Members of the genus Raoultella are increasingly recognized as clinically relevant. There are difficulties in their identification at the species level since sequencing the 16S rRNA or the rpoB genes does not show conclusive results. The aim of this study has been to compare two MALDI-TOF MS systems (Vitek MS and Bruker Biotyper) with Vitek2 and API20E systems for differentiation of Raoultella species. A collection of 97 clinical isolates of Raoultella species was identified with Vitek MS, in parallel with Vitek2 and API, and finally with Bruker Biotyper. Among the two most widely used MALDI-TOF MS platforms, results obtained with Vitek MS were slightly superior to those obtained with the Bruker Biotyper system, with sensitivities and specificities of 98.9/57.9% and 98.8/37.0%, respectively. The current commercial phenotypic identification systems are not optimized for the identification of Raoultella species. Our results indicate that MALDI-TOF-based identification is more accurate and sensitive than that provided by phenotypic methods.

Poor Performance of Rapid Molecular Tests to Define Eligibility for the Shortcourse Multidrug-resistant Tuberculosis Regimen.

The World Health Organization recommends shortcourse regimen (SCR) to treat multidrug resistant tuberculosis for patients with strains susceptible by line-probe assays (LPAs) to second-line drugs. Our retrospective study shows LPAs have suboptimal specificity in predicting eligibility for SCR; a quarter of eligible patients would receive inadequate therapy with SCR.

McSpoligotyping, a One-Step Melting Curve Analysis-Based Protocol for Spoligotyping of Mycobacterium tuberculosis.

The direct repeat (DR) region in the Mycobacterium tuberculosis (MTB) genome is composed of highly polymorphic direct variant repeats, which are the basis of spacer oligonucleotide typing (spoligotyping) to study the population structure and epidemiology of M. tuberculosis However, the membrane hybridization-based detection format requires various post-PCR manipulations and is prone to carryover contamination, restricting its wide use in high-TB-burden and resource-limited countries. We developed a one-step spoligotyping protocol, termed McSpoligotyping, based on real-time PCR. The typing results can be generated within 3 h by a single step of DNA addition. When evaluated with a collection of 1,968 isolates of MTB, McSpoligotyping agreed 97.71% (1,923/1,968) by sample and 99.93% (84,568/84,624) by spacer with traditional spoligotyping. Sequencing results showed that McSpoligotyping was even more accurate than spoligotyping (99.34% versus 98.37%). Further exploration of the false results of McSpoligotyping revealed the presence of single-nucleotide polymorphisms in the DR region. We concluded that McSpoligotyping could be used in epidemiology studies of tuberculosis by taking advantage of the shortened procedure, ease of use, and compatibility of results with standard spoligotyping.