Direct Fluorescent Antibodies Research Articles

Brain Infarct and Abscess—A Very Common Disease and a Rare Association

To explore the effectiveness of superficial temporal artery–to–middle cerebral artery (STA-MCA) anastomosis in treating moyamoya disease (MMD).A total of 30 patients with MMD (hemorrhagic type, n = 13; ischemic type, n = 17) who had undergone STA-MCA anastomosis were enrolled in this study (anastomosis group). Cerebral blood flow was evaluated before and after surgery using cerebral angiography and computed tomography (CT) perfusion imaging. In addition, 27 patients with MMD (hemorrhagic type, n = 11; ischemic type, n = 16) who had received only conservative treatment were enrolled as the control group. Patients in both the anastomosis group and the control group were followed up for 5 years, and the incidences of cerebral hemorrhage and cerebral ischemia were analyzed. Blood samples were collected in both groups before and after treatment. Mononuclear cells were separated by density gradient centrifugation. After labeling with 3 direct fluorescent antibodies (CD133, CD34, and vascular endothelial growth factor receptor 2), the number of endothelial progenitor cells (EPCs) was detected using flow cytometry.Cerebral blood flow was remarkably improved after STA-MCA anastomosis. The incidences of cerebral hemorrhage and cerebral ischemia were significantly lower in the anastomosis group than in the control group. The number of EPCs showed no significant change before and after treatment in the control group; in contrast, it was decreased significantly after surgery in the anastomosis group.STA-MCA anastomosis can reduce the number of EPCs in MMD patients, lower the risk of rebreeding, and improve cerebral ischemic attacks.

Effectiveness of Superficial Temporal Artery-to-Middle Cerebral Artery Anastomosis in Treating Moyamoya Disease by Reducing Endothelial Progenitor Cells

To explore the effectiveness of superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis in treating moyamoya disease (MMD). A total of 30 patients with MMD (hemorrhagic type, n= 13; ischemic type, n= 17) who had undergone STA-MCA anastomosis were enrolled in this study (anastomosis group). Cerebral blood flow was evaluated before and after surgery using cerebral angiography and computed tomography (CT) perfusion imaging. In addition, 27 patients with MMD (hemorrhagic type, n= 11; ischemic type, n= 16) who had received only conservative treatment were enrolled as the control group. Patients in both the anastomosis group and the control group were followed up for 5 years, and the incidences of cerebral hemorrhage and cerebral ischemia were analyzed. Blood samples were collected in both groups before and after treatment. Mononuclear cells were separated by density gradient centrifugation. After labeling with 3 direct fluorescent antibodies (CD133, CD34, and vascular endothelial growth factor receptor 2), the number of endothelial progenitor cells (EPCs) was detected using flow cytometry. Cerebral blood flow was remarkably improved after STA-MCA anastomosis. The incidences of cerebral hemorrhage and cerebral ischemia were significantly lower in the anastomosis group than in the control group. The number of EPCs showed no significant change before and after treatment in the control group; in contrast, it was decreased significantly after surgery in the anastomosis group. STA-MCA anastomosis can reduce the number of EPCs in MMD patients, lower the risk of rebreeding, and improve cerebral ischemic attacks.

Incidence of respiratory viruses in Peruvian children with acute respiratory infections.

Acute respiratory infections are responsible for high morbi–mortality in Peruvian children. However, the etiological agents are poorly identified. This study, conducted during the pandemic outbreak of H1N1 influenza in 2009, aims to determine the main etiological agents responsible for acute respiratory infections in children from Lima, Peru. Nasopharyngeal swabs collected from 717 children with acute respiratory infections between January 2009 and December 2010 were analyzed by multiplex RT‐PCR for 13 respiratory viruses: influenza A, B, and C virus; parainfluenza virus (PIV) 1, 2, 3, and 4; and human respiratory syncytial virus (RSV) A and B, among others. Samples were also tested with direct fluorescent‐antibodies (DFA) for six respiratory viruses. RT‐PCR and DFA detected respiratory viruses in 240 (33.5%) and 85 (11.9%) cases, respectively. The most common etiological agents were RSV‐A (15.3%), followed by influenza A (4.6%), PIV‐1 (3.6%), and PIV‐2 (1.8%). The viruses identified by DFA corresponded to RSV (5.9%) and influenza A (1.8%). Therefore, respiratory syncytial viruses (RSV) were found to be the most common etiology of acute respiratory infections. The authors suggest that active surveillance be conducted to identify the causative agents and improve clinical management, especially in the context of possible circulation of pandemic viruses. J. Med. Virol. 87:917–924, 2015. © 2015 Wiley Periodicals, Inc.

PS-371 Respiratory Viruses Might Increase The Risk Of Acquiring Urinary Tract Infections

Background Clinicians often express concerns of serious bacterial infection when facing a child with acute bronchiolitis. Aims The goals of this study were 1) to estimate the prevalence of urinary tract infection (UTI) in infants and children with bronchiolitis, and 2) to evaluate the effect of demographic, clinical characteristics and other related factors on the prevalence rates of UTI. Materials and methods A descriptive and retrospective study was conducted at Hamad Medical Corporation, the only tertiary medical centre in the State of Qatar. Patients ages 0 to 36 months hospitalised with acute bronchiolitis from January 2010 to December 2012 were included in the study. The following data were collected: age at diagnosis, gestational age, nationality, sex, Direct Fluorescent Antibodies (DFA) and urine culture results. For the purpose of data analysis, we divided the patient population into three categories: RSV positive, RSV negative and other than RSV (influenza, Para influenza, parechovirus, etc). Results 836 paediatric patients with acute bronchiolitis were admitted in paediatrics department ward unit. The mean age at diagnosis was 3.61 ± 3.56 months ranged from 0.33 to 34 months. There were 39.2% girls, 68.8% boys; 61.4% Qatari and 38.6% were Non-Qatari nationals. The percentage of UTI was significantly higher among other than RSV (30/224; 13.4%) compared to RSV-positive (11/224; 4.9%) and RSV-negative (8/100; 8%); p = 0.007. Conclusions Infants and young children with might have a higher risk of UTI if presented with bronchiolitis triggered by a respiratory virus other than RSV.

Tracoma em crianças do ensino fundamental no município de Bauru: Estado de São Paulo, Brasil

A survey was carried out with schoolchildren in Bauru, São Paulo State. The purpose of this study was to determine the prevalence of trachoma. One thousand, seven hundred and forty-nine children from 6 to 14 years old were examined during the year of 2005. The schools were randomly chosen, according to the number of schoolchildren and the school region according to the local of the city (downtown, middle and periphery). The diagnosis was performed according to the World Health Organization (WHO) protocol and patients with clinical trachoma detection were submitted to laboratory confirmation by direct smear fluorescent antibodies cytology for Chlamydia trachomatis. Trachoma prevalence was 3.8%. Follicular trachoma was diagnosed in 3.7% of children, and intense trachoma in one child (0.06%). Children with trachoma were living mainly in the middle and peripheral region of the city, places with discontinuous water supply and absence of sewerage system in part of the residences. Trachoma prevalence in Bauru - São Paulo State - is 3.8%. The authors point out the survey results and also treated trachoma carriers. Other positive aspect of the survey was the community mobilization to prevent trachoma blindness.

Index of Suspicion

Index of Suspicion

Evaluation of the ELVIS plate method for the detection and typing of herpes simplex virus in clinical specimens

This study was conducted to assess the reliability of a commercial enzyme-linked viral inducible system (ELVIS) (Diagnostic Hybrids, Inc., Athens, OH) for rapid detection and typing of herpes simplex virus (HSV). Results using ELVIS were compared to those of shell vial culture (SVC) and HSV detection with monoclonal antibodies and an immunoperoxidase stain plus typing with MicroTrak direct fluorescent antibodies (Trinity Biotech PLC, Wicklow, Ireland). Specimens yielding discrepant HSV results were tested by polymerase chain reaction (PCR); those with discrepant typing results were stained with Simulfluor (Chemicon, Temecula, CA). Of the 206 samples tested, 144 were negative and 54 were HSV-positive by both methods (agreement, 96.1%). Five specimens were positive by ELVIS but negative by SVC; 3 of these were positive and 2 were negative by HSV PCR. Both of the latter were the result of mechanical problems early in the study. Three specimens were positive by SVC but negative by ELVIS; all 3 were positive by HSV PCR. After resolution of discrepancies, the sensitivity and specificity for detection of HSV were 95.0% and 100% for SVC, respectively, and 95.0% and 98.6% for ELVIS. Of the 46 HSV-positive samples that were typed, 26 were called type 2 and 18 were type 1 by both methods (agreement, 95.7%). The 2 specimens with discrepant results were called HSV-2 by SVC, staining with MicroTrak, and HSV-1 with ELVIS; both of these were type 2 when stained with the Simulfluor reagent. ELVIS is a reliable alternative to SVC for rapid detection and typing of HSV.

Diagnóstico laboratorial da infecção pela Chlamydia trachomatis: vantagens e desvantagens das técnicas

O objetivo deste artigo é revisar e comentar as vantagens e desvantagens dos diferentes tipos de testes de detecção de Chlamydia trachomatis na rotina de laboratórios clínicos, com ênfase nas técnicas de amplificação. A Chlamydia trachomatis é considerada a bactéria sexualmente transmissível mais freqüente em países desenvolvidos e de grande impacto no sistema reprodutivo das mulheres. É o agente causador de doenças do trato urogenital, linfogranuloma venéreo (LGV), tracoma, conjuntivite de inclusão e pneumonia no recém-nascido. Um dos fatores de risco para a infecção é a prática sexual entre adolescentes. A recorrência das infecções é comum. Episódios sucessivos de infecção aumentam o risco de desenvolver seqüelas e a chance de contrair a infecção pelo vírus da imunodeficiência humana. O diagnóstico da infecção pela Chlamydia trachomatis ainda é crítico, devido à freqüência de infecções assintomáticas. As técnicas de amplificação de ácidos nucléicos permitem utilizar urina para a detecção da clamídia, simplificando a coleta. Apresentam maior sensibilidade do que a cultura e do que os testes mais utilizados, como a imunofluorescência direta e o enzimaimunoensaio. A cultura celular, utilizada como padrão- ouro, tem especificidade de 100% e sensibilidade de 70% a 85%. De acordo com o Centers for Disease Control (CDC), um diagnóstico é considerado definitivo quando positivo em cultura ou em pelo menos dois testes não-culturais distintos. Os testes de amplificação são mais dispendiosos do que os demais testes não-culturais, mas de menor custo que a cultura.

Direct immunofluorescence and enzyme-linked immunosorbent assays for evaluating organic contaminant degrading bacteria

Immunological procedures were developed to enumerate chlorinated hydrocarbon (CH) degrading bacteria in environmental samples. Polyclonal antibodies (Pabs) were produced by immunizing New Zealand white rabbits against 18 CH-degrading bacteria. These bacteria included methanotrophic and chlorobenzene (CB)-degrading species. An enzyme-linked immunosorbent assay (ELISA) was used to test for cross-reactivity and sensitivity of the Pabs. Direct fluorescent antibodies (DFAs) were developed against selected methanotrophic bacteria isolated from a trichloroethylene (TCE)-contaminated landfill at the Savannah River Site (SRS) and cultures from the American Type Culture Collection (ATCC). Analysis of ELISA results showed some of the Pabs to be group specific while others were species specific. The threshold of sensitivity for the ELISA is 10 5 bacteria cells/ml. Results from the DFA and ELISA techniques for enumeration of methanotrophic bacteria in groundwater were higher but not significantly different ( P<0.05) compared to indirect microbiological techniques such as MPN, although the direct enumerations were accomplished in significantly less time. These methods provide important information on in situ microbial community structure and function for bioremediation applications within 1–4 h of sampling.

Interlaboratory test discordance in screening adolescents for chlamydia with direct immunofluorescence

Chlamydia testing using direct fluorescent antibodies (DFA) is widely employed for screening and in clinical practice. We submitted duplicate DFA specimens to two pairs of laboratories during two study periods separated by a year. We found discordance between reports (one positive, one negative on the same individual) in 75% of chlamydia-positive cases when one pair of laboratories was compared and in 50% of cases when a second pair was compared. Calculations show that with optimum published test performance; a discordance rate of 40% might be anticipated. Our observed discordance of 75% suggests inaccurate test performance by one laboratory with regard to sensitivity and specificity, albeit not to levels differing from those reported by others for in-the-field test performance. The implications of suboptimal test sensitivity and specificity for epidemiologic study and clinical practice are discussed. Because a diagnosis of sexually transmitted disease may be disruptive for adolescent relationships, maximum laboratory accuracy is needed.

Estudo comparativo da sensibilidade das técnicas de imunofluorescência direta, aplicada a decalques de córnea e de inoculação intracerebral em camundongos, a partir da saliva,para diagnóstico precoce da raiva em bovinos

The examination of 57 samples pairs (cornea and saliva ) collected from 18 bovines with experimental rabies by both techniques direct fluorescent antibodies applied to cornea impressions and intracerebral mice inoculation with saliva revealed that the former provided a greater frequency of positive reactions (84,2% ) than the latte r (22,8%). In addition, it was observed that once the cornea test had provided a positive result such condition was maintained until death of the animal, and in no occasion could the virus be detected in saliva without a positive result with the cornea test on the same animal. The false negative values obtained with the cornea test (16,7% ) suggested that a negative result does not exclude the possibility of the disease.