Adnan Alatoom

Identification of Non-diphtheriae Corynebacterium by Use of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry

ABSTRACT We evaluated the Bruker Biotyper matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry for identification of 92 clinical isolates of Corynebacterium species in comparison to identification using rpoB or 16S rRNA gene sequencing. Eighty isolates (87%) yielded a score of ≥1.700, and all of these were correctly identified to the species level with the exception of Corynebacterium aurimucosum being misidentified as the closely related Corynebacterium minutissimum.

Interpretation of positive molecular tests of common viruses in the cerebrospinal fluid.

Many central nervous system infections are historically difficult to diagnose. Polymerase chain reaction (PCR) has revolutionized the diagnosis of these infections because of their high sensitivity despite the lack of data on clinical usefulness. We conducted a retrospective study that included patients with positive cerebrospinal fluid (CSF) PCR for herpes simplex virus, varicella-zoster virus, JC virus, cytomegalovirus (CMV), and Epstein-Barr virus (EBV) between January 2009 and December 2011. The positive results were grouped into definite, likely, and possible true positives and likely false-positive categories based on pre-specified definitions specific to each virus. Of 1663 CSF viral PCR tests, 88 were positive (5%). The combined positive predictive value (PPV) was 58%. The PPVs were least for CMV and EBV at 29 and 37%, respectively. A positive CSF viral PCR result has to be interpreted with caution due to several false-positive results.

Comparison of 4th-Generation HIV Antigen/Antibody Combination Assay With 3rd-Generation HIV Antibody Assays for the Occurrence of False-Positive and False-Negative Results

OBJECTIVE To assess the false-positive and false-negative rates of a 4th-generation human immunodeficiency virus (HIV) assay, the Abbott ARCHITECT, vs 2 HIV 3rd-generation assays, the Siemens Centaur and the Ortho-Clinical Diagnostics Vitros. METHODS We examined 123 patient specimens. In the first phase of the study, we compared 99 specimens that had a positive screening result via the 3rd-generation Vitros assay (10 positive, 82 negative, and 7 indeterminate via confirmatory immunofluorescent assay [IFA]/Western blot [WB] testing). In the second phase, we assessed 24 HIV-1 RNA-positive (positive result via the nuclear acid amplification test [NAAT] and negative/indeterminate results via the WB test) specimens harboring acute HIV infection. RESULTS The 4th-generation ARCHITECT assay yielded fewer false-positive results (n = 2) than the 3rd-generation Centaur (n = 9; P = .02) and Vitros (n = 82; P <.001) assays. One confirmed positive case had a false-negative result via the Centaur assay. When specimens from the 24 patients with acute HIV-1 infection were tested, the ARCHITECT assay yielded fewer false-negative results (n = 5) than the Centaur (n = 10) (P = .13) and the other 3rd-generation tests (n = 16) (P = .002). CONCLUSIONS This study indicates that the 4th-generation ARCHITECT HIV assay yields fewer false-positive and false-negative results than the 3rd-generation HIV assays we tested.

Fascioliasis in pregnancy

BACKGROUND: Fascioliasis is a common zoonotic infection worldwide, although cases in the United States are uncommon, sporadic, and predominantly found in the immigrant population. The small number of cases identified in the United States may reflect the unfamiliarity of physicians with this infection. CASE: A 28-year-old Hispanic woman who frequently visited northern Central Mexico presented at 36 weeks of gestation with nausea, vomiting, and right upper quadrant pain. She was diagnosed with cholelithiasis. Postpartum endoscopic retrograde cholangiopancreatography and sphincterotomy were performed, with discovery of the trematode Fasciola hepatica. The patient received triclabendazole, which led to clinical improvement. CONCLUSION: Fascioliasis often mimics another common problem in pregnancy, cholelithiasis; clinicians need to be aware of this disease in high-risk populations.

Multiple factors contribute to positive results for hepatitis A virus immunoglobulin M antibody.

CONTEXT In the United States, a successful vaccination program for hepatitis A virus (HAV) infection has decreased both its incidence and the true positive rate for diagnostic immunoglobulin M (IgM) antibody to HAV in acute hepatitis. OBJECTIVE To survey positive results of HAV IgM tests and determine the effect of changing ordering options. DESIGN We reviewed all positive results for IgM antibody to HAV between January 2007 and December 2010. Patient demographics, clinical history, and laboratory data were recorded and the encounter, order, and reason for test reviewed. Each result was categorized as indicating acute, recent, resolved, or indeterminate HAV infection. RESULTS A total of 10,735 tests were performed; 35 patients had 49 positive results. Most positive test results were associated with outpatient visits and were ordered in the assessment of patients with liver disease, but not clinical acute hepatitis. In the final analysis, 4 patients had acute hepatitis A and 20 individual patients had recent and/or resolved hepatitis. All but 1 of the remaining 11 patients had another established cause of liver disease with a positive IgM HAV antibody test result; data to determine causality were insufficient. The total number of tests requested annually decreased more than 35% with the introduction of computerized physician order entry. CONCLUSIONS Current assays for IgM HAV antibodies are overused in the absence of clinical acute hepatitis; future clinical decision support may improve patterns of order entry. Most patients have findings consistent with HAV exposure but not acute hepatitis; dormant viral infection may be a continuing source of antigen.

An Overview of Arboviruses and Bunyaviruses

Arboviruses belong to various families of viruses that are transmitted by arthropods, mainly mosquitoes and ticks. Arboviruses that cause human encephalitis in the United States are members of 3 main virus families: Togaviridae, Flaviviridae, and Bunyaviridae; they include St. Louis encephalitis (SLE), Western equine encephalitis (WEE), Eastern equine encephalitis (EEE), La Crosse virus (LAC), and other California serogroup viruses. In the United States, the incidence is usually 150 to 3,000 cases per year. Most infections are asymptomatic or may result in a nonspecific flu-like syndrome, but if clinical cases do occur, the consequences may be serious. Diseases caused by arboviruses include encephalitis, febrile diseases, and hemorrhagic fevers. Rapid serologic assays such as IgM-capture ELISA (MAC-ELISA) and IgG ELISA can be used soon after infection for diagnosis. There is no spe- cific treatment and therapy is mainly support- ive. Prevention includes vector control, educat- ing the public to avoid high-risk areas, wearing protective clothing, and using DEET-containing insect repellents.

Fasciola hepatica Infection in the United States

Fascioliasis is a worldwide infection caused by the liver fluke, Fasciola hepatica. In the United States, fascioliasis is an uncommon infection and is mainly reported among the immigrant population. Fasciola hepatica infection comprises 2 distinct stages (hepatic and biliary) and manifests mainly as abdominal pain, elevated liver enzymes, and eosinophilia. Enzyme-linked immunosorbent assay (ELISA) testing is sensitive for both stages while stool exams for F. hepatica eggs are positive only in the biliary stage. Radiographic findings using computed tomography and ultrasonography are not specific but support the diagnosis. Endoscopic retrograde cholangiopancreatography (ERCP) has been increasingly used to diagnose F. hepatica and to remove the adult fluke from the biliary tree. Triclabendazole is currently the recommended drug for treating F. hepatica infection. The rarity of the disease in the United States can result in a delayed diagnosis and sometimes in mismanagement. Physicians should consider this infection in patients with abnormal liver function and peripheral eosinophilia, especially in the immigrant population.

Implications of false positive serology of Toxoplasma gondii in a pre-transplant patient.

PATIENT A 21-year-old white male with cystic fibrosis. CHIEF COMPLAINT Pre-transplant workup in preparation for bilateral lung transplant. PAST MEDICAL HISTORY Cystic fibrosis diagnosed at age 3, onset of insulin-dependent diabetes around age 20, and multiple hospitalizations for pulmonary and gastrointestinal complications. FAMILY AND SOCIAL HISTORY: The patient lives with his father and stepmother, has a pet bearded dragon, and has multiple tattoos and piercings. His stepmother has a cat, but he does not clean the litter box. PRINCIPAL LABORATORY FINDINGS The pre-transplant workup included several tests for infectious diseases, tests of organ function, radiology studies, and markers of malignancy. The only significant finding was a positive Toxoplasma gondii (T. gondii) IgM titer (> or = 1:40) (reference values for IgM: negative; < 1:40, positive; > or = 1:40) and IgG (1:2048) (reference values for IgG: negative; < 1:16, equivocal; > or = 1:16 - < 1:256, positive; > or = 1:256). Testing was done by indirect immunofluorescence assay (IFA) in April 2012 in our hospital laboratory. The patient was treated with sulfadiazine, leucovorin, and pyrimethamine. Three months later (July), he returned for follow-up testing. Real-time polymerase chain reaction (PCR) for T. gondii DNA performed by a reference laboratory was negative. One month later (August), Toxoplasma serology was performed by enzyme-linked immunosorbent assay (ELISA) by a different reference laboratory and showed an elevated IgM of 0.95 IU/mL (reference values: negative; < 0.55 IU/mL, equivocal; > or = 0.55- < 0.65 IU/mL, positive; > or = 0.65 IU/mL) and a normal level of IgG (< 4 IU/mL). At this time, PCR was repeated and was negative. An additional month later (September), the patients serology studies were performed at a third reference laboratory and showed an elevated IgM of 1.32 IU/mL (reference values: negative; 0.89, equivocal; 0.90 - 1.09, positive; > 1.10) and a normal IgG.

Fast Track to Accreditation: An Implementation Review of College of American Pathologists and International Organization for Standardization 15189 Accreditation

CONTEXT - This review examines challenges and opportunities in preparing laboratories in a startup phase for accreditation by both the College of American Pathologists (CAP) and International Organization for Standardization (ISO) 15189 in an international setting as it relates to our experience at Cleveland Clinic Abu Dhabi Laboratory. It also discusses some of the strategies used in executing those projects and the added advantages in pursuing both types of accreditations. OBJECTIVES - To share our experience with CAP and ISO 15189 accreditations in a startup international operation in relation to the challenges encountered and implementation strategy success factors. DATA SOURCES - MEDLINE (PubMed) database was used to review this topic as well as peer-reviewed articles and World Health Organization publications on the topic. CONCLUSIONS - Accreditation is a perfect means toward building quality medical laboratories in a diverse workforce environment and improving patient safety. Further, it establishes a strong foundation on which any new operation can build a sustainable quality improvement culture. Accreditations by CAP and/or ISO are among the most reputable and well-established accreditation systems that clinical laboratories could aim for. As a result of both accreditations offering synergistic and complementing features, we recommend that any laboratory seeking excellence in quality and performance should consider exploring both. Key elements to success include having dedicated project management and change management support while preparing for accreditation. Laboratories seeking accreditation in early operational stages may face a number of challenges; however, significant opportunities will also be present to optimize various operational components from the beginning.