Hemophagocytic lymphohistiocytosis induced by Toxoplasma gondii infection diagnosed by a bone marrow biopsy and DNA next-generation sequencing in an allogeneic hematopoietic stem cell transplant recipient.

In the United States, toxoplasmosis following allogeneic hematopoietic stem transplant (allo-HCT) is very rare with a rate only between 0.5% and 2%. The reported rates of hemophagocytic lymphohistiocytosis (HLH) following allo-HCT range between 0.3% and 17%. Secondary HLH due to toxoplasmosis infection is extremely rare. Herein, we report a case of secondary HLH due to toxoplasmosis following allo-HCT. The diagnosis was reached by a bone marrow biopsy and confirmed by DNA next generation sequencing and immunohistochemical (IHC) staining. The IHC staining included CD1a, a stain previously known to react with cells infected by Leishmania, here we show CD1a staining of macrophages infected with Toxoplasma gondii. Our report highlights the utility of bone marrow biopsy in diagnosing parasitic infection underlying HLH in post-transplant settings. The pre-transplant evaluation of patients from low endemic countries, is a great opportunity to obtain a travel history to determine the risks and the preventative measures against opportunistic infections including toxoplasmosis.

Prospective Evaluation of Xpert® Xpress Strep A Automated PCR Assay vs. Solana® Group A Streptococcal Nucleic Acid Amplification Testing vs. Conventional Throat Culture.

In our laboratory, the negative rapid group A streptococcal (GAS) antigen assays are backed up by the Solana® GAS Assay by Quidel instead of a Group A streptococcal throat culture. Another FDA cleared RT-PCR assay is the Xpert® Xpress Strep A, which detects Streptococcus pyogenes DNA, and is performed on the Cepheid GeneXpert instrument. Three hundred seventy-five positive and negative specimens were randomly selected from 5489 throat specimens that had been tested by the Solana® GAS Assay during January 2018 and were tested with the Xpress Strep A assay. A throat culture was also set up (sheep blood agar at 35 °C in 5% CO2). All beta-hemolytic streptococci were purified and identified by MALDI-TOF mass spectrometry. Of the 375 samples, 185 were positive by Solana® GAS Assay, and 187 were positive by the Xpress Strep A. The total agreement between the Solana® GAS Assay and the Xpert® Xpress Strep A was 99.5%. The agreement of the Xpert® Xpress Strep A assay with culture was 90.1%. The sensitivity and specificity for Xpress Strep A versus culture were 100% and 83.5%, respectively. The Xpert® Xpress Strep A assay's performance was equivalent to the Solana® GAS Assay, and was highly sensitive. The lower specificity was likely due to the Xpress Strep A assay having higher sensitivity as compared to throat culture.

Multicenter Performance Evaluation of the Simplexa Bordetella Direct Kit in Nasopharyngeal Swab Specimens.

Detection of Bordetella pertussis and Bordetella parapertussis using molecular methods is sensitive and specific with a short turnaround time compared to other diagnostic methods. In this multicenter study, we compared the performance of the Simplexa Bordetella Direct kit to those of other molecular assays in detecting and differentiating B. pertussis and B. parapertussis in nasopharyngeal swab specimens. The limits of detection (LODs) were 150 CFU/ml or 3 fg/µl of DNA for B. pertussis and 1,500 CFU/ml or 10 fg/µl of DNA for B. parapertussis A total of 1,103 fresh and residual frozen specimens from eight clinical sites were tested. Combining the data from individual clinical sites using different comparative assays, the overall positive percent agreement (PPA) and negative percent agreement (NPA) for B. pertussis were 98.7% and 97.3%, respectively. The overall PPA and NPA for B. parapertussis were 96.7% and 100%, respectively. For prospective fresh specimens, the overall PPA and NPA for both targets were 97.7% and 99.3%, respectively. For retrospective frozen specimens, the overall PPA and NPA for both targets were 92.6% and 93.2%, respectively. The percentage of invalid results was 1.0%. A cross-reactivity study using 74 non-Bordetella bacterial species and five yeast species revealed that the Simplexa Bordetella Direct kit was 100% specific. The hands-on time and assay run time of the Simplexa Bordetella Direct kit are favorable compared to those of other commercial and laboratory-developed tests. In summary, the Simplexa Bordetella Direct kit has a performance comparable to those of other molecular assays for the detection of B. pertussis and B. parapertussis.

Strongyloides hyperinfection following hematopoietic stem cell transplant in a patient with HTLV-1-associated T-cell leukemia.

Strongyloides stercoralis has the potential to cause accelerated autoinfection in immunocompromised hosts. Screening tests for strongyloidiasis may be falsely negative in the setting of immunosuppression. We report a case of Strongyloides hyperinfection syndrome in a patient with human T-lymphotropic virus type 1-associated T-cell leukemia early after hematopoietic stem cell transplant. The diagnosis was made by stool ova and parasite examination, despite a negative screening enzyme-linked immunosorbent assay. Because of anticipated prolonged neutropenia, an extended course of treatment was utilized.

Comparison of rates of positivity for Bordetella pertussis by real-time PCR between specimens collected with rayon swabs on aluminum wire shaft in Amies gel with charcoal and specimens collected with flocked swabs in universal viral transport medium during an epidemic.

A comparison of real-time PCR positivity rates for Bordetella pertussis between specimens collected with rayon swabs on an aluminum wire shaft in Amies gel with charcoal and those collected with flocked swabs in universal viral transport medium during an epidemic revealed that their performances were comparable.

Evaluation of the Bruker Biotyper and Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of nonfermenting gram-negative bacilli isolated from cultures from cystic fibrosis patients.

The Bruker Biotyper and Vitek MS matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) instruments were evaluated for the identification of nonfermenting gram-negative bacilli (NFGNB) by a blinded comparison to conventional biochemical or molecular methods. Two hundred NFGNB that were recovered from cultures from cystic fibrosis patients in the University of Iowa Health Care (UIHC) Microbiology Laboratory between 1 January 2006 and 31 October 2010 were sent to Mayo Clinic for analysis with the Bruker Biotyper (software version 3.0) and to bioMérieux for testing with Vitek MS (SARAMIS database version 3.62). If two attempts at direct colony testing failed to provide an acceptable MALDI-TOF identification, an extraction procedure was performed. The MS identifications from both of these systems were provided to UIHC for comparison to the biochemical or molecular identification that had been reported in the patient record. Isolates with discordant results were analyzed by 16S rRNA gene sequencing at UIHC. After discrepancy testing, the Bruker Biotyper result agreed with the biochemical or molecular method, with 72.5% of isolates to the species level, 5.5% to the complex level, and 19% to the genus level (3% not identified). The level of agreement for Vitek MS was 80% species, 3.5% complex, 6% genus, and 3.5% family (7% not identified). Both MS systems provided rapid (≤3 min per isolate) and reliable identifications. The agreement of combined species/complex/genus-level identification with the reference method was higher for the Bruker Biotyper (97% versus 89.5%, P = 0.004) but required an extraction step more often. Species-level agreement with the reference method was similar for both MS systems (72.5% and 80%, P = 0.099).

Early-Onset Neonatal Sepsis Caused by Vertical Transmission of Pasteurella multocida.

Early-onset neonatal sepsis contributes substantially to neonatal morbidity and mortality. Presenting signs and symptoms vary, and most causes are due to a limited number of common microbes. However, providers must be cognizant of unusual pathogens when treating early-onset sepsis (EOS). We report a case of a term neonate who presented with respiratory distress, lethargy, and hypoglycemia 5 hours after birth. He was treated for presumed EOS with blood culture, revealing an unusual pathogen, Pasteurella multocida . Sepsis from this pathogen is a rarely reported cause of early onset neonatal sepsis. Our report is one of few that implicate vertical transmission with molecular diagnostic confirmation of P . multocida , subspecies septica. The neonate was treated with antibiotics and supportive care and recovered without ongoing complications. Providers should maintain an index of suspicion for rare causes of neonatal EOS. For these unusual cases, precise microbial identification enables understanding to provide best clinical care and anticipation of complications.

Prevalence and genetic relatedness of methicillin-susceptible Staphylococcus aureus isolates detected by the Xpert MRSA nasal assay.

Methicillin-susceptible Staphylococcus aureus (MSSA) isolates lacking mecA yet testing positive on the Xpert MRSA assay were recovered from culture for 7.7% of 248 Xpert-positive nasal samples. These "false-positive" Xpert results may be attributed to staphylococcal cassette chromosome (SCC) elements without the mecA gene. Pulsed-field gel electrophoresis (PFGE) analysis revealed a diverse population of MSSA strains.

Initial determination of COVID-19 seroprevalence among outpatients and healthcare workers in Minnesota using a novel SARS-CoV-2 total antibody ELISA.

OBJECTIVES: To avoid the significant risks posed by the use of COVID-19 serology tests with supply chain constraints or poor performance characteristics, we developed an in-house SARS-CoV-2 total antibody test. Our test was compared with three commercial methods, and was used to determine COVID-19 seroprevalence among healthcare workers and outpatients in Minnesota. METHODS: Seventy-nine plasma and serum samples from 50 patients 4-69 days after symptom onset who tested positive by a SARS-CoV-2 PCR method using a nasopharyngeal (NP) swab were used to evaluate our test's clinical performance. Seropositive samples were analyzed for IgG titers in a follow-up assay. Thirty plasma and serum from 12 patients who tested negative by a SARS-CoV-2 PCR method using a nasopharyngeal (NP) swab and 210 negative pre-pandemic serum samples were also analyzed. Among samples from patients > 14 days after symptom onset, the assay had 100% clinical sensitivity and 100% clinical specificity, 100% positive predictive value and 100% negative predictive value. Analytical specificity was 99.8%, indicating minimal cross-reactivity. A screening study was conducted to ascertain COVID-19 seroprevalence among healthcare workers and outpatients in Minnesota. RESULTS: Analysis of serum collected between April 13 and May 21, 2020 indicated a COVID-19 seroprevalence of 2.96% among 1,282 healthcare workers and 4.46% among 2,379 outpatients. CONCLUSIONS: Our in-house SARS-CoV-2 total antibody test can be used to conduct reliable epidemiological studies to inform public health decisions during the COVID-19 pandemic.

Comparison of BD Phoenix AP Workflow with Vitek 2.

The BD Phoenix AP instrument reduced the manual setup time for the Phoenix system by 50%. For batches of 14 organisms, the average manual manipulation time per isolate was 89.5 s for BD Phoenix by the use of the AP instrument and 101 s for Vitek 2 (P<0.001).

Evaluation of a Multiplex Fully Automated Treponemal and Nontreponemal (Rapid Plasma Reagin) Assay.

OBJECTIVES: In June 2017, Bio-Rad Laboratories received US Food and Drug Administration clearance for its BioPlex 2200 Syphilis Total & RPR (rapid plasma reagin) assay. It is the first fully automated treponemal/nontreponemal multiplex flow immunoassay, simultaneously detecting Treponema pallidum and reagin antibodies and an RPR titer. We compared the performance of the BioPlex Syphilis Total & RPR assay with the LIAISON Treponema Assay and the manual BD Macro-Vue RPR 18-mm Circle Test. METHODS: In total, 314 serum specimens were tested for treponemal immunoglobulin G/immunoglobulin M and RPR with the LIAISON Treponema Assay, the BioPlex 2200 Syphilis Total & RPR assay, and the manual BD Macro-Vue RPR card test. All discordant results were further tested with the T pallidum particle agglutination assay from Fujirebio Diagnostics. RESULTS: The overall percent agreement for the BioPlex assay for treponemal antibodies with the LIAISON Treponema Assay was 96.1%. Sensitivity and specificity for the BioPlex RPR assay were 90.5% and 97.2%, respectively (the manual RPR assay was considered the gold standard). CONCLUSIONS: The BioPlex 2200 Syphilis Total & RPR assay performance was comparable to the LIAISON Treponema Assay and the manual RPR test. Compared with the manual RPR, the automation of RPR testing offered labor savings, objective result reporting, and improved workflow.

Disseminated Hormographiella aspergillata Infection with Lung and Brain Involvement after Allogenic Hematopoietic Stem-Cell Transplantation in a 54-Year-Old Man.

Hormographiella is a rare fungal pathogen in humans; however, case reports have described disseminated infection in immunocompromised hosts. This pathogen has been described to yield poor prognosis in patients who harbor it. Herein, we present a case report of autopsy-proven disseminated Hormographiella aspergillata infection, confirmed by DNA sequencing, in a patient experiencing a relapse of leukemia. This 54-year-old Caucasian man with chronic myelogenous leukemia (CML) that had been diagnosed in 1989, after having received a hematopoietic cell allotransplant from a compatible sibling donor, had B-cell lymphoid-blast phase of CML in April of 2013, with multiple relapses. His most recent relapse was in September of 2016, when bone marrow biopsy showed 90% blasts. The results of bronchoalveolar lavage (BAL) cultures were positive for filamentous fungus infection. The patient developed encephalopathy and worsening respiratory statusand tachycardia with flutter and hypotension, which resulted in his death. At autopsy, bilateral pleural effusions, multiple right pleural nodules, and subarachnoid hemorrhage were noted. Angioinvasive hyphal fungi were found in the right frontal lobe of the brain and the right upper lobe of the lung. Morphologically, the fungi had multiseptate, branching hyphae. The bronchoalveolar lavage specimen grew a fungus for which the colony morphologic characteristics and microscopic features were compatible with a Hormographiella species. H. aspergillata from the bronchoalveolar lavage was further identified by sequencing the D2 hypervariable region of the large-subunit (LSU) ribosomal DNA gene and the full internal transcribed spacer (ITS) regions.

Prospective Postimplementation Study of Solana Group A Streptococcal Nucleic Acid Amplification Test vs Conventional Throat Culture.

OBJECTIVES: We evaluated the Solana Group A Streptococcus Assay (Quidel, San Diego, CA), a nucleic acid amplification test (NAAT), as a substitute for backup culture on throat specimens with a negative rapid group A Streptococcus (GAS) antigen assay. METHODS: During October 2016, all throat swabs from patients with a negative GAS antigen assay from local urgent care centers were processed by NAAT and conventional culture in real time. RESULTS: The overall agreement of the 2,090 tested throat swab specimens of the NAAT with the culture was 2,050 (98%) of 2,090. Sensitivity, specificity, positive predictive value, and negative predictive value were 91.4%, 98.5%, 78.0%, and 99.5%, respectively. CONCLUSIONS: In summary, this postimplementation study supported high sensitivity and specificity of the GAS NAAT as a backup test for negative rapid GAS antigen tests.

Urinary tract blastomycosis diagnosed by urine cytology.

Urinary tract blastomycosis is an uncommon manifestation of disseminated Blastomyces infection. Here, we report a 50-year-old male with common variable immunodeficiency who presented with urinary symptoms and a renal mass concerning for a kidney neoplasm. Urine cytology revealed typical broad-based budding yeasts with thick-walled refractile capsules, leading to diagnosis of urinary tract blastomycosis. In this case, urine cultures were negative, and urine cytology was the main method of diagnosis of blastomycosis. Thus, urine cytology represents a rapid and reliable method of diagnosing blastomycosis, which in the current case led to prompt treatment of this potentially life threatening infection.

Lymph Node With Extensive Involvement by Cryptococcus Shortly Following Liver Transplantation.

Herein, we present a case of extensive lymph node involvement by disseminated Cryptococcus infection developing in the immediate period after liver transplantation and initiation of immunosuppressive therapy. The patient, a 56 year old ethnicity unknown man, received a liver transplant for acute decompensated liver. Beginning 24 days after transplantation, he was found to have Cryptococcus neoformans infection, involving the pleural fluid, blood, cerebrospinal fluid (CSF), liver, and lymph nodes. He received treatment with amphotericin B and flucytosine; he was transitioned to fluconazole, and his response was good. This relatively rapid development of disease raises the possibility of donor-derived Cryptococcus infection.

Epidemiologic Analysis of Respiratory Viral Infections Mainly in Hospitalized Children and Adults in a Midwest University Medical Center After the Implementation of a 14-Virus Multiplex Nucleic Acid Amplification Test.

OBJECTIVES: To investigate the etiology of viral respiratory tract infections mainly in hospitalized children and adults over a 12-month consecutive period after implementation of a 14-virus multiplex nucleic acid amplification test. METHODS: From January 2014 to January 2015, a total of 2,237 respiratory samples were analyzed with the US Food and Drug Administration-cleared eSensor Respiratory Viral Panel (GenMark Diagnostics, Carlsbad, CA). RESULTS: Of the 2,237 specimens tested, 788 specimens were positive for at least one virus, giving a positivity rate of 35.2%, and because of viral codetection, a total of 862 viral targets were identified. The age groups with the highest positivity rates were the 0- to 1-year (73.5%) and 2- to 6-year (78.4%) age groups. The overall viral codetection rate was 9.1%. Human rhinovirus (HRV) was the most prevalent respiratory virus found in children and adults. The peak of HRV seen in September 2014 represented a combination of HRV and enterovirus D68, 2014 epidemic respiratory infections. CONCLUSION: The ability to detect a wider range of respiratory viruses gave us a better understanding of the etiology of respiratory infections in our population, particularly for HRV and enhanced our ability to detect viral coinfection.

Prospective and Retrospective Evaluation of the Performance of the FDA-Approved Cepheid Xpert Flu/RSV XC Assay.

Rapid and accurate detection of respiratory viruses is important in patient care and in guiding therapy and infection prevention policy. Rapid viral antigen assays are simple to perform and provide results within 15 to 30 minutes but are limited by their modest-to-moderate sensitivity. Molecular assays are more sensitive and specific but require more technical time and expertise and are more expensive. We verified the performance of the Xpert Flu/RSV XC assay prospectively, using patient respiratory samples from the 2014-2015 respiratory season, and, retrospectively, with frozen patient samples from the previous respiratory season. A total of 60 specimens were assayed on the Xpert Flu/RSV XC assay and by the GenMark Diagnostics eSensor Respiratory Viral Panel. The sensitivity of the Xpert Flu/RSV XC for Flu A was 100% (23/23), for Flu B, 80% (8/10), and for respiratory syncytial virus (RSV), 94.1% (16/17), compared to the reference assay (GenMark). The specificity was 100%. Eight specimens were positive for viruses other than Flu A/B or RSV, and this did not interfere with detection of targets in the Xpert assay. We demonstrated that the performance of the Xpert Flu/RSV XC was comparable to the more comprehensive molecular respiratory assay.

A Noninvasive Rhizopus Infection With a Bladder Fungal Ball in a Patient With Poorly Controlled Diabetes Mellitus.

Here we present the first reported case of a noninvasive Rhizopus fungal ball confined to the bladder of a patient with poorly controlled diabetes and right flank pain. The patient developed bilateral hydronephrosis after several hospital admissions for urinary tract infections with multiple failed courses of antibiotics. During cystoscopy to replace a ureteral stent, he was found to harbor a fungal ball in the bladder that was removed and grew Rhizopus in culture. Patient received treatment with amphotericin B and transitioned to long-term posaconazole therapy. This case highlights the importance of considering fungal agents in urinary tract infections, especially in persistent or refractory cases, and the role of the clinical microbiology laboratory in correct identification of the infectious source.

Trichosporon loubieri Fungemia in a 39-Year-Old Caucasian Woman With B-Cell Lymphoblastic Leukemia.

We report a case of Trichosporon loubieri (T. loubieri) fungemia with likely liver involvement in a 39-year-old Caucasian patient with relapsed B-cell acute lymphoblastic leukemia after an allogeneic hematopoietic cell transplant. This is the fifth published case of T. loubieri infection and only the third case of T. loubieri fungemia, to our knowledge. All 3 cases of T. loubieri infection with fungemia had liver involvement.

Pasteurella multocida Bacteremia With Associated Knee Arthroplasty Infection in an 80-Year-Old Caucasian Man.

OBJECTIVES: To identify the gram-negative rods grown from blood cultures and a right-knee fluid aspirate from an 80-year-old caucasian man who had undergone a total right knee arthroplastic procedure 6 years ago, and to assess the genetic similarity between the 2 isolates. METHODS: We used 3 different approaches: biochemical testing, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, and 16S ribosomal RNA (rRNA) gene sequencing. RESULTS: The 3 methods identified the gram-negative rods as Pasteurella multocida; 16S rRNA gene sequencing further identified the organisms as P. multocida subsp. septica. CONCLUSION: A concordant identification of P. multocida was observed using biochemical testing, mass spectrometry, and 16S rRNA gene sequencing. Only 16S rRNA sequencing was able to determine the subspecies of P. multocida and to determine the genetic relatedness of the 2 isolates.