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Positive Toxoplasma IgM and IgG test results obtained at NRLs cannot accurately distinguish between acute and chronic infections. To do so, testing at reference laboratories is required, as mandated in 1997 in a letter from the Food and Drug Administration (FDA) to clinicians and laboratories in the United States.The heterogeneity of members of the Streptococcus anginosus group (SAG) has traditionally hampered their correct identification. Recently, the group was subdivided into 6 taxa whose prevalence among human infections is poorly described. We evaluated the accuracy of the Rapid ID32 Strep test, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and a PCR multiplex method to identify 212 SAG isolates recovered from human infections to the species and subspecies level by using multilocus sequence analysis (MLSA) as the gold standard. We also determined the antimicrobial susceptibilities of the isolates. Representatives of all SAG taxa were found among our collection. MALDI-TOF MS and the Rapid ID32 Strep test correctly identified 92% and 68% of the isolates to the species level, respectively, but showed poor performance at the subspecies level, and the latter was responsible for major identification errors. The multiplex PCR method results were in complete agreement with the MLSA identifications but failed to distinguish the subspecies Streptococcus constellatus subsp. pharyngis and S. constellatus subsp. viborgensis. A total of 145 MLSA sequence types were present in our collection, indicating that within each taxon a number of different lineages are capable of causing infection. selleck kinase inhibitor Significant antibiotic resistance was observed only to tetracycline, erythromycin, and clindamycin and was present in most taxa. MALDI-TOF MS is a reliable method for routine SAG species identification, while the need for identification to the subspecies level is not clearly established.Respiratory syncytial virus (RSV) rapid antigen detection tests (RADT) are extensively used in clinical laboratories. We performed a systematic review and meta-analysis to evaluate the accuracy of RADTs for diagnosis of RSV infection and to determine factors associated with accuracy estimates. We searched EMBASE and PubMed for diagnostic-accuracy studies of commercialized RSV RADTs. Studies reporting sensitivity and specificity data compared to a reference standard (reverse transcriptase PCR [RT-PCR], immunofluorescence, or viral culture) were considered. Two reviewers independently extracted data on study characteristics, diagnostic-accuracy estimates, and study quality. Accuracy estimates were pooled using bivariate random-effects regression models. Heterogeneity was investigated with prespecified subgroup analyses. Seventy-one articles met inclusion criteria. Overall, RSV RADT pooled sensitivity and specificity were 80% (95% confidence interval [CI], 76% to 83%) and 97% (95% CI, 96% to 98%), respectively. Positive- and negative-likelihood ratios were 25.5 (95% CI, 18.3 to 35.5) and 0.21 (95% CI, 0.18 to 0.24), respectively. Sensitivity was higher in children (81% [95% CI, 78%, 84%]) than in adults (29% [95% CI, 11% to 48%]). Because of this disparity, further subgroup analyses were restricted to pediatric data (63 studies). Test sensitivity was poorest using RT-PCR as a reference standard and highest using immunofluorescence (74% versus 88%; P less then 0.001). Industry-sponsored studies reported significantly higher sensitivity (87% versus 78%; P = 0.01). Our results suggest that the poor sensitivity of RSV RADTs in adults may preclude their use in this population. Furthermore, industry-sponsored studies and those that did not use RT-PCR as a reference standard likely overestimated test sensitivity.Detailed laboratory characterization of Escherichia coli O157 is essential to inform epidemiological investigations. This study assessed the utility of whole-genome sequencing (WGS) for outbreak detection and epidemiological surveillance of E. coli O157, and the data were used to identify discernible associations between genotypes and clinical outcomes. One hundred five E. coli O157 strains isolated over a 5-year period from human fecal samples in Lothian, Scotland, were sequenced with the Ion Torrent Personal Genome Machine. A total of 8,721 variable sites in the core genome were identified among the 105 isolates; 47% of the single nucleotide polymorphisms (SNPs) were attributable to six "atypical" E. coli O157 strains and included recombinant regions. Phylogenetic analyses showed that WGS correlated well with the epidemiological data. Epidemiological links existed between cases whose isolates differed by three or fewer SNPs. WGS also correlated well with multilocus variable-number tandem repeat analysis (MLsolution of the relationships between E. coli O157 isolates than that provided by MLVA. The method has the potential to streamline the laboratory workflow and provide detailed information for the clinical management of patients and public health interventions.In 54/64 subjects with nosocomial diarrhea, fecal calprotectin levels correlated with the results of stool samples tested for Clostridium difficile toxin gene by PCR. Fecal calprotectin levels can be used as an adjunctive measure to PCR to support the diagnosis of C. difficile infection.Haemophilus influenzae is a major pathogen, and beta-lactams are first-line drugs. Resistance due to altered penicillin-binding protein 3 (rPBP3) is frequent, and susceptibility testing of such strains is challenging. A collection of 154 beta-lactamase-negative isolates with a large proportion of rPBP3 (67.5%) was used to evaluate and compare Etest (Haemophilus test medium [HTM]) and disk diffusion (EUCAST method) for categorization of susceptibility to aminopenicillins and cefuroxime, using MICs generated with broth (HTM) microdilution and clinical breakpoints from CLSI and EUCAST as the gold standards. In addition, the proficiency of nine disks in screening for the rPBP3 genotype (N526K positive) was evaluated. By Etest, both essential and categorical agreement were generally poor ( less then 70%), with high very major errors (VME) (CLSI, 13.0%; EUCAST, 34.3%) and falsely susceptible rates (FSR) (CLSI, 87.0%; EUCAST, 88.3%) for ampicillin. Ampicillin (2 μg) with adjusted (+2 mm) zone breakpoints was superior to Etest for categorization of susceptibility to ampicillin (agreement, 74.0%; VME, 11.0%; FSR, 28.3%). Conversely, Etest was superior to 30 μg cefuroxime for categorization of susceptibility to cefuroxime (agreement, 57.1% versus 60.4%; VME, 2.6% versus 9.7%; FSR, 7.1% versus 26.8%). Benzylpenicillin (1 unit) (EUCAST screening disk) and cefuroxime (5 μg) identified rPBP3 isolates with highest accuracies (95.5% and 92.2%, respectively). In conclusion, disk screening reliably detects rPBP3 H. influenzae, but false ampicillin susceptibility is frequent with routine methods. We suggest adding a comment recommending high-dose aminopenicillin therapy or the use of other agents for severe infections with screening-positive isolates that are susceptible to aminopenicillins by gradient or disk diffusion.Large clostridial toxin-negative, binary toxin-positive (A(-) B(-) CDT(+)) strains of Clostridium difficile are almost never associated with clinically significant C. difficile infection (CDI), possibly because such strains are not detected by most diagnostic methods. We report the isolation of an A(-) B(-) CDT(+) ribotype 033 (RT033) strain of C. difficile from a young patient with ulcerative colitis and severe diarrhea.Here we report a catalase-negative methicillin-sensitive Staphylococcus aureus isolate collected from a blood culture. Sequencing through the gene encoding catalase, katA, demonstrated a 2-bp insertion. The resulting frameshift mutation generates a protein that has lost 26 amino acids (aa) at its C-terminal domain.Plasmodium nucleic acids have been detected in serum and plasma, but there is little published data describing the diagnostic performance of malaria nucleic acid amplification tests (NAATs) using these specimen types. Previously, our group described a multiplex NAAT for the detection of dengue virus, Leptospira, and Plasmodium species with a callout for P. falciparum (the DLM assay) that demonstrated sensitive detection of P. falciparum from plasma samples during initial evaluation. In this study, we evaluated the sensitivity and specificity of P. falciparum detection in febrile Nigerian patients using the DLM assay, microscopy, and a rapid diagnostic test (BinaxNOW Malaria). Assay performances were compared using a composite reference, which was considered positive if malaria was detected by two or more methods. Serum (n = 182) or plasma (n = 148) from 317 patients was tested; the average sample volume was 70 μl (range, 5 to 300 μl). The sensitivity and specificity of the DLM assay were 97.1% and 93.5%, respectively. The sensitivity of the malaria rapid diagnostic test (98.1%) was similar to that of the DLM assay, and both proved significantly more sensitive than microscopy (79%; P less then 0.0001). When analysis was limited to samples with ≥75 μl of serum or plasma, the sensitivity of the DLM assay improved to 99% and specificity was 97.5%. For P. falciparum cases, cycle threshold values in the DLM assay correlated with the parasite density detected by microscopy (Spearman's rank correlation coefficient, P less then 0.0001). In conclusion, malaria detection using the DLM assay on serum or plasma is more sensitive than and equal in specificity to microscopy in patients with P. falciparum malaria.Streptococcus tigurinus is a newly described member of the Streptococcus mitis group. Due to the difficulty in distinguishing viridans group streptococci (VGS) by phenotype, analysis of 16S rRNA sequences is necessary for the accurate identification of most species. Through a laboratory policy of analyzing all clinically significant isolates from the VGS group by16S rRNA gene sequencing, we identified 14 S. tigurinus isolates from 11 patients. The Vitek 2 system most commonly gave an excellent rating to an incorrect identification (e.g., Streptococcus mitis), as did matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) (e.g., Streptococcus oralis). S. tigurinus strains were recovered from numerous body sites, including the blood, peritoneal fluid, bone, synovial fluid, a perianal abscess, and an arm wound. Retrospective chart review indicated that most isolates were clinically significant, with bacteremia (n = 5), soft tissue infections (n = 3) osteomyelitis (n = 2), infected joint prosthesis (n = 2), and peritonitis (n = 2) being the most common, thus expanding the spectrum of disease associated with S. tigurinus.This study investigates the diversity and taxonomy of Cryptosphaeria species occurring in the western United States on the basis of morphological characters and multilocus phylogenetic analyses of the ribosomal internal transcribed spacer region, parts of a β-tubulin gene, the DNA-dependent RNA polymerase II second-largest subunit gene and the nuclear ribosomal large subunit gene. Cryptosphaeria multicontinentalis sp. nov is described from the Sierra Nevada and central coast of California on Populus tremuloides, P. balsamifera subsp. trichocarpa and P. fremontii. Cryptosphaeria pullmanensis is reported from a wide geographic area in the western United States on the main host, P. fremontii. The pathogen C. lignyota is reported for the first time from the Sierra Nevada of California on P. tremuloides. The phylogenetic analyses showed that C. multicontinentalis is a sister species to C. lignyota. Both species were closely related to C. subcutanea and more distantly related to C. pullmanensis. Characteristics of both teleomorph and anamorph of the newly introduced species C.
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