Multicenter Evaluation of the Simplexa VZV Direct Assay for Detection of Varicella-Zoster Virus in Cerebrospinal Fluid and Lesion-Swab Specimens.

Varicella-zoster virus (VZV) is the etiologic agent of varicella (chickenpox) and herpes zoster (shingles) infections commonly involving skin, mucous membranes, and less frequently the central nervous system. Traditional methods for the laboratory diagnosis of these infections are time-consuming, labor-intensive, and often insensitive. As such, these tests are being replaced by more sensitive and rapid molecular methods. This study evaluated the performance of two different molecular assays, the Simplexa VZV Direct and Simplexa VZV Swab Direct, to detect VZV DNA in cerebrospinal fluid (CSF) and lesion-swab specimens, respectively. The Simplexa VZV Direct and Simplexa VZV Swab Direct assays were compared against individual composite reference methods that varied depending on the sample cohort examined. A total of 883 CSF and 452 cutaneous and mucocutaneous prospective, retrospective, and contrived specimens were evaluated in this multicenter study. The results of this study showed that the Simplexa assays demonstrated near perfect agreement (k = 0.98) compared to the composite reference methods for the detection of VZV in CSF and lesion swab specimens. A further comparison between the standard of care molecular assays employed at the site of specimen collection and the Simplexa assays demonstrated excellent agreement (k = 1.0). The Simplexa assays offer rapid and reliable alternatives for the detection of VZV in certain clinical specimens without the need for nucleic acid extraction.

Multicenter Evaluation of NeuMoDx Group B Streptococcus Assay on the NeuMoDx 288 Molecular System.

Group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis in developed countries. Recommendations for antepartum GBS detection include enriched culture with several options for identifying GBS, some of which are time-consuming. To reduce the time for identification and determination of the maternal GBS colonization status, rapid nucleic acid amplification technologies have been developed and commercialized. For rapid detection of GBS, a three-site clinical study was conducted to evaluate the NeuMoDx GBS assay, a real-time PCR test performed for vaginal/rectal swab specimens in Lim broth enrichment culture on the NeuMoDx 288 molecular system (NeuMoDx system); these data were used to a support 510(k) submission. A total of 1,250 eligible remnant samples were prospectively enrolled and tested during the study. The results of the PCR assay were compared to the results of the Centers for Disease Control and Prevention (CDC)-recommended enriched-culture method, which served as the gold standard reference method for the study. The NeuMoDx GBS assay results yielded a sensitivity of 96.9% (95% confidence interval [CI] = 94.1 to 98.4), specificity of 96.0% (95% CI = 94.6 to 97.1), and a total agreement with the reference method of 96.2% (95% CI = 93.8 to 98.3). NeuMoDx GBS assay results were also compared to results obtained using the BD MAX GBS assay on the BD MAX system. The two systems demonstrated a total percent agreement of 98.0% (95% CI = 95.5 to 100.0). The performance of the NeuMoDx GBS assay implemented on the NeuMoDx system compared favorably to the CDC enriched-culture method and to the BD MAX GBS assay.

Legionella indianapolisensis sp. nov., isolated from a patient with pulmonary abscess.

BACKGROUND: To date, at least 50 species of Legionella have been described. These organisms are ubiquitous in nature and have been isolated from diverse ecological environments, including man-made structures such as cooling towers and spas. Legionellae have also been isolated from human and veterinary clinical specimens, and their roles in disease are well-established. This report describes the isolation of a novel Legionella species from a respiratory specimen from a patient with influenza and suspected pulmonary embolus. CASE: A 68-year-old male presented to an Indianapolis-area hospital with pulmonary disease; upon workup, he was found to have influenza A. Bronchoalveolar lavage fluid was also submitted for conventional bacterial culture and Legionella culture. The patient was prescribed a broad-spectrum antibiotic and recovered. RESULTS: A Legionella-like bacterium was isolated on buffered charcoal yeast extract agar, and mass spectrometry and comparative 16S rRNA gene sequencing inconclusively identified the isolate as a Legionella sp. Further analysis of the 16S rRNA gene confirmed the strain to be a new species, related to Legionella hackeliae. Physiochemical and morphological testing were used to confirm the discovery of a novel species, Legionella indianapolisensis sp. nov., type strain SMNF-IS.

Characterization of Pontibacter altruii, sp. nov., isolated from a human blood culture.

The genus Pontibacter is a recent addition to the family Cytophagaceae, phylum Bacteroidetes. Previous reports of its cultivation and molecular detection are from a variety of environmental sources, including marine and desert habitats. We report the first description of a Pontibacter sp., which was initially identified as Elizabethkingia meningoseptica, isolated from a human clinical specimen. On the basis of 16S rRNA gene sequence, unique mass spectral profile and phenotypic characterization, this isolate represents a novel species within the genus Pontibacter that has been named Pontibacter altruii, sp. nov., strain Grand Forks.

Multicenter Evaluation of BD Max Enteric Parasite Real-Time PCR Assay for Detection of Giardia duodenalis, Cryptosporidium hominis, Cryptosporidium parvum, and Entamoeba histolytica.

Common causes of chronic diarrhea among travelers worldwide include protozoan parasites. The majority of parasitic infections are caused by Giardia duodenalis, Entamoeba histolytica, Cryptosporidium parvum, and Cryptosporidium hominis Similarly, these species cause the majority of parasitic diarrhea acquired in the United States. Detection of parasites by gold standard microscopic methods is time-consuming and requires considerable expertise; enzyme immunoassays and direct fluorescent-antibody (DFA) stains have lowered hands-on time for testing, but improvements in sensitivity and technical time may be possible with a PCR assay. We performed a clinical evaluation of a multiplex PCR panel, the enteric parasite panel (EPP), for the detection of these common parasites using the BD Max instrument, which performs automated extraction and amplification. A total of 2,495 compliant specimens were enrolled, including 2,104 (84%) specimens collected prospectively and 391 (16%) specimens collected retrospectively. Approximately equal numbers were received in 10% formalin (1,273 specimens) and unpreserved (1,222 specimens). The results from the EPP were compared to those from alternate PCR and bidirectional sequencing (APCR), as well as DFA (G. duodenalis and C. parvum or C. hominis) or trichrome stain (E. histolytica). The sensitivity and specificity for prospective and retrospective specimens combined were 98.2% and 99.5% for G. duodenalis, 95.5% and 99.6 for C. parvum or C. hominis, and 100% and 100% for E. histolytica, respectively. The performance of the FDA-approved BD Max EPP compared well to the reference methods and may be an appropriate substitute for microscopic examination or immunoassays.